IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network42.28.0.0/16

Usable hosts65,534

Subnet mask255.255.0.0

Addresses65,536

Network address: 42.28.0.0
Broadcast address: 42.28.255.255
First usable: 42.28.0.1
Last usable: 42.28.255.254
Usable hosts: 65,534 (65,536 less the network and broadcast addresses)
Subnet mask: 255.255.0.0
Wildcard mask: 0.0.255.255 (Cisco ACLs, OSPF)
Prefix length: /16
Type: Public public
Old class: A (default /8)
As numbers: Hex 2A1C0000 · Integer 706478080 to 706543615
Reverse DNS zone: 28.42.in-addr.arpa

Binary

Binary view
	Binary (network bits bold, host bits grey)	Dotted
Address	`00101010.00011100..00000000.00000000`	`42.28.0.0`
Subnet mask	`11111111.11111111..00000000.00000000`	`255.255.0.0`
Network	`00101010.00011100..00000000.00000000`	`42.28.0.0`
Broadcast	`00101010.00011100..11111111.11111111`	`42.28.255.255`

Split into smaller subnets/24

/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

42.28.0.0/16 makes 256 subnets of /24.

Subnets
#	Subnet	Usable hosts range	Broadcast	Hosts
1	`42.28.0.0/24`	`42.28.0.1` to `42.28.0.254`	42.28.0.255	254
2	`42.28.1.0/24`	`42.28.1.1` to `42.28.1.254`	42.28.1.255	254
3	`42.28.2.0/24`	`42.28.2.1` to `42.28.2.254`	42.28.2.255	254
4	`42.28.3.0/24`	`42.28.3.1` to `42.28.3.254`	42.28.3.255	254
5	`42.28.4.0/24`	`42.28.4.1` to `42.28.4.254`	42.28.4.255	254
6	`42.28.5.0/24`	`42.28.5.1` to `42.28.5.254`	42.28.5.255	254
7	`42.28.6.0/24`	`42.28.6.1` to `42.28.6.254`	42.28.6.255	254
8	`42.28.7.0/24`	`42.28.7.1` to `42.28.7.254`	42.28.7.255	254
9	`42.28.8.0/24`	`42.28.8.1` to `42.28.8.254`	42.28.8.255	254
10	`42.28.9.0/24`	`42.28.9.1` to `42.28.9.254`	42.28.9.255	254
11	`42.28.10.0/24`	`42.28.10.1` to `42.28.10.254`	42.28.10.255	254
12	`42.28.11.0/24`	`42.28.11.1` to `42.28.11.254`	42.28.11.255	254
13	`42.28.12.0/24`	`42.28.12.1` to `42.28.12.254`	42.28.12.255	254
14	`42.28.13.0/24`	`42.28.13.1` to `42.28.13.254`	42.28.13.255	254
15	`42.28.14.0/24`	`42.28.14.1` to `42.28.14.254`	42.28.14.255	254
16	`42.28.15.0/24`	`42.28.15.1` to `42.28.15.254`	42.28.15.255	254
17	`42.28.16.0/24`	`42.28.16.1` to `42.28.16.254`	42.28.16.255	254
18	`42.28.17.0/24`	`42.28.17.1` to `42.28.17.254`	42.28.17.255	254
19	`42.28.18.0/24`	`42.28.18.1` to `42.28.18.254`	42.28.18.255	254
20	`42.28.19.0/24`	`42.28.19.1` to `42.28.19.254`	42.28.19.255	254
21	`42.28.20.0/24`	`42.28.20.1` to `42.28.20.254`	42.28.20.255	254
22	`42.28.21.0/24`	`42.28.21.1` to `42.28.21.254`	42.28.21.255	254
23	`42.28.22.0/24`	`42.28.22.1` to `42.28.22.254`	42.28.22.255	254
24	`42.28.23.0/24`	`42.28.23.1` to `42.28.23.254`	42.28.23.255	254
25	`42.28.24.0/24`	`42.28.24.1` to `42.28.24.254`	42.28.24.255	254
26	`42.28.25.0/24`	`42.28.25.1` to `42.28.25.254`	42.28.25.255	254
27	`42.28.26.0/24`	`42.28.26.1` to `42.28.26.254`	42.28.26.255	254
28	`42.28.27.0/24`	`42.28.27.1` to `42.28.27.254`	42.28.27.255	254
29	`42.28.28.0/24`	`42.28.28.1` to `42.28.28.254`	42.28.28.255	254
30	`42.28.29.0/24`	`42.28.29.1` to `42.28.29.254`	42.28.29.255	254
31	`42.28.30.0/24`	`42.28.30.1` to `42.28.30.254`	42.28.30.255	254
32	`42.28.31.0/24`	`42.28.31.1` to `42.28.31.254`	42.28.31.255	254
33	`42.28.32.0/24`	`42.28.32.1` to `42.28.32.254`	42.28.32.255	254
34	`42.28.33.0/24`	`42.28.33.1` to `42.28.33.254`	42.28.33.255	254
35	`42.28.34.0/24`	`42.28.34.1` to `42.28.34.254`	42.28.34.255	254
36	`42.28.35.0/24`	`42.28.35.1` to `42.28.35.254`	42.28.35.255	254
37	`42.28.36.0/24`	`42.28.36.1` to `42.28.36.254`	42.28.36.255	254
38	`42.28.37.0/24`	`42.28.37.1` to `42.28.37.254`	42.28.37.255	254
39	`42.28.38.0/24`	`42.28.38.1` to `42.28.38.254`	42.28.38.255	254
40	`42.28.39.0/24`	`42.28.39.1` to `42.28.39.254`	42.28.39.255	254
41	`42.28.40.0/24`	`42.28.40.1` to `42.28.40.254`	42.28.40.255	254
42	`42.28.41.0/24`	`42.28.41.1` to `42.28.41.254`	42.28.41.255	254
43	`42.28.42.0/24`	`42.28.42.1` to `42.28.42.254`	42.28.42.255	254
44	`42.28.43.0/24`	`42.28.43.1` to `42.28.43.254`	42.28.43.255	254
45	`42.28.44.0/24`	`42.28.44.1` to `42.28.44.254`	42.28.44.255	254
46	`42.28.45.0/24`	`42.28.45.1` to `42.28.45.254`	42.28.45.255	254
47	`42.28.46.0/24`	`42.28.46.1` to `42.28.46.254`	42.28.46.255	254
48	`42.28.47.0/24`	`42.28.47.1` to `42.28.47.254`	42.28.47.255	254
49	`42.28.48.0/24`	`42.28.48.1` to `42.28.48.254`	42.28.48.255	254
50	`42.28.49.0/24`	`42.28.49.1` to `42.28.49.254`	42.28.49.255	254
51	`42.28.50.0/24`	`42.28.50.1` to `42.28.50.254`	42.28.50.255	254
52	`42.28.51.0/24`	`42.28.51.1` to `42.28.51.254`	42.28.51.255	254
53	`42.28.52.0/24`	`42.28.52.1` to `42.28.52.254`	42.28.52.255	254
54	`42.28.53.0/24`	`42.28.53.1` to `42.28.53.254`	42.28.53.255	254
55	`42.28.54.0/24`	`42.28.54.1` to `42.28.54.254`	42.28.54.255	254
56	`42.28.55.0/24`	`42.28.55.1` to `42.28.55.254`	42.28.55.255	254
57	`42.28.56.0/24`	`42.28.56.1` to `42.28.56.254`	42.28.56.255	254
58	`42.28.57.0/24`	`42.28.57.1` to `42.28.57.254`	42.28.57.255	254
59	`42.28.58.0/24`	`42.28.58.1` to `42.28.58.254`	42.28.58.255	254
60	`42.28.59.0/24`	`42.28.59.1` to `42.28.59.254`	42.28.59.255	254
61	`42.28.60.0/24`	`42.28.60.1` to `42.28.60.254`	42.28.60.255	254
62	`42.28.61.0/24`	`42.28.61.1` to `42.28.61.254`	42.28.61.255	254
63	`42.28.62.0/24`	`42.28.62.1` to `42.28.62.254`	42.28.62.255	254
64	`42.28.63.0/24`	`42.28.63.1` to `42.28.63.254`	42.28.63.255	254
65	`42.28.64.0/24`	`42.28.64.1` to `42.28.64.254`	42.28.64.255	254
66	`42.28.65.0/24`	`42.28.65.1` to `42.28.65.254`	42.28.65.255	254
67	`42.28.66.0/24`	`42.28.66.1` to `42.28.66.254`	42.28.66.255	254
68	`42.28.67.0/24`	`42.28.67.1` to `42.28.67.254`	42.28.67.255	254
69	`42.28.68.0/24`	`42.28.68.1` to `42.28.68.254`	42.28.68.255	254
70	`42.28.69.0/24`	`42.28.69.1` to `42.28.69.254`	42.28.69.255	254
71	`42.28.70.0/24`	`42.28.70.1` to `42.28.70.254`	42.28.70.255	254
72	`42.28.71.0/24`	`42.28.71.1` to `42.28.71.254`	42.28.71.255	254
73	`42.28.72.0/24`	`42.28.72.1` to `42.28.72.254`	42.28.72.255	254
74	`42.28.73.0/24`	`42.28.73.1` to `42.28.73.254`	42.28.73.255	254
75	`42.28.74.0/24`	`42.28.74.1` to `42.28.74.254`	42.28.74.255	254
76	`42.28.75.0/24`	`42.28.75.1` to `42.28.75.254`	42.28.75.255	254
77	`42.28.76.0/24`	`42.28.76.1` to `42.28.76.254`	42.28.76.255	254
78	`42.28.77.0/24`	`42.28.77.1` to `42.28.77.254`	42.28.77.255	254
79	`42.28.78.0/24`	`42.28.78.1` to `42.28.78.254`	42.28.78.255	254
80	`42.28.79.0/24`	`42.28.79.1` to `42.28.79.254`	42.28.79.255	254
81	`42.28.80.0/24`	`42.28.80.1` to `42.28.80.254`	42.28.80.255	254
82	`42.28.81.0/24`	`42.28.81.1` to `42.28.81.254`	42.28.81.255	254
83	`42.28.82.0/24`	`42.28.82.1` to `42.28.82.254`	42.28.82.255	254
84	`42.28.83.0/24`	`42.28.83.1` to `42.28.83.254`	42.28.83.255	254
85	`42.28.84.0/24`	`42.28.84.1` to `42.28.84.254`	42.28.84.255	254
86	`42.28.85.0/24`	`42.28.85.1` to `42.28.85.254`	42.28.85.255	254
87	`42.28.86.0/24`	`42.28.86.1` to `42.28.86.254`	42.28.86.255	254
88	`42.28.87.0/24`	`42.28.87.1` to `42.28.87.254`	42.28.87.255	254
89	`42.28.88.0/24`	`42.28.88.1` to `42.28.88.254`	42.28.88.255	254
90	`42.28.89.0/24`	`42.28.89.1` to `42.28.89.254`	42.28.89.255	254
91	`42.28.90.0/24`	`42.28.90.1` to `42.28.90.254`	42.28.90.255	254
92	`42.28.91.0/24`	`42.28.91.1` to `42.28.91.254`	42.28.91.255	254
93	`42.28.92.0/24`	`42.28.92.1` to `42.28.92.254`	42.28.92.255	254
94	`42.28.93.0/24`	`42.28.93.1` to `42.28.93.254`	42.28.93.255	254
95	`42.28.94.0/24`	`42.28.94.1` to `42.28.94.254`	42.28.94.255	254
96	`42.28.95.0/24`	`42.28.95.1` to `42.28.95.254`	42.28.95.255	254
97	`42.28.96.0/24`	`42.28.96.1` to `42.28.96.254`	42.28.96.255	254
98	`42.28.97.0/24`	`42.28.97.1` to `42.28.97.254`	42.28.97.255	254
99	`42.28.98.0/24`	`42.28.98.1` to `42.28.98.254`	42.28.98.255	254
100	`42.28.99.0/24`	`42.28.99.1` to `42.28.99.254`	42.28.99.255	254
101	`42.28.100.0/24`	`42.28.100.1` to `42.28.100.254`	42.28.100.255	254
102	`42.28.101.0/24`	`42.28.101.1` to `42.28.101.254`	42.28.101.255	254
103	`42.28.102.0/24`	`42.28.102.1` to `42.28.102.254`	42.28.102.255	254
104	`42.28.103.0/24`	`42.28.103.1` to `42.28.103.254`	42.28.103.255	254
105	`42.28.104.0/24`	`42.28.104.1` to `42.28.104.254`	42.28.104.255	254
106	`42.28.105.0/24`	`42.28.105.1` to `42.28.105.254`	42.28.105.255	254
107	`42.28.106.0/24`	`42.28.106.1` to `42.28.106.254`	42.28.106.255	254
108	`42.28.107.0/24`	`42.28.107.1` to `42.28.107.254`	42.28.107.255	254
109	`42.28.108.0/24`	`42.28.108.1` to `42.28.108.254`	42.28.108.255	254
110	`42.28.109.0/24`	`42.28.109.1` to `42.28.109.254`	42.28.109.255	254
111	`42.28.110.0/24`	`42.28.110.1` to `42.28.110.254`	42.28.110.255	254
112	`42.28.111.0/24`	`42.28.111.1` to `42.28.111.254`	42.28.111.255	254
113	`42.28.112.0/24`	`42.28.112.1` to `42.28.112.254`	42.28.112.255	254
114	`42.28.113.0/24`	`42.28.113.1` to `42.28.113.254`	42.28.113.255	254
115	`42.28.114.0/24`	`42.28.114.1` to `42.28.114.254`	42.28.114.255	254
116	`42.28.115.0/24`	`42.28.115.1` to `42.28.115.254`	42.28.115.255	254
117	`42.28.116.0/24`	`42.28.116.1` to `42.28.116.254`	42.28.116.255	254
118	`42.28.117.0/24`	`42.28.117.1` to `42.28.117.254`	42.28.117.255	254
119	`42.28.118.0/24`	`42.28.118.1` to `42.28.118.254`	42.28.118.255	254
120	`42.28.119.0/24`	`42.28.119.1` to `42.28.119.254`	42.28.119.255	254
121	`42.28.120.0/24`	`42.28.120.1` to `42.28.120.254`	42.28.120.255	254
122	`42.28.121.0/24`	`42.28.121.1` to `42.28.121.254`	42.28.121.255	254
123	`42.28.122.0/24`	`42.28.122.1` to `42.28.122.254`	42.28.122.255	254
124	`42.28.123.0/24`	`42.28.123.1` to `42.28.123.254`	42.28.123.255	254
125	`42.28.124.0/24`	`42.28.124.1` to `42.28.124.254`	42.28.124.255	254
126	`42.28.125.0/24`	`42.28.125.1` to `42.28.125.254`	42.28.125.255	254
127	`42.28.126.0/24`	`42.28.126.1` to `42.28.126.254`	42.28.126.255	254
128	`42.28.127.0/24`	`42.28.127.1` to `42.28.127.254`	42.28.127.255	254
129	`42.28.128.0/24`	`42.28.128.1` to `42.28.128.254`	42.28.128.255	254
130	`42.28.129.0/24`	`42.28.129.1` to `42.28.129.254`	42.28.129.255	254
131	`42.28.130.0/24`	`42.28.130.1` to `42.28.130.254`	42.28.130.255	254
132	`42.28.131.0/24`	`42.28.131.1` to `42.28.131.254`	42.28.131.255	254
133	`42.28.132.0/24`	`42.28.132.1` to `42.28.132.254`	42.28.132.255	254
134	`42.28.133.0/24`	`42.28.133.1` to `42.28.133.254`	42.28.133.255	254
135	`42.28.134.0/24`	`42.28.134.1` to `42.28.134.254`	42.28.134.255	254
136	`42.28.135.0/24`	`42.28.135.1` to `42.28.135.254`	42.28.135.255	254
137	`42.28.136.0/24`	`42.28.136.1` to `42.28.136.254`	42.28.136.255	254
138	`42.28.137.0/24`	`42.28.137.1` to `42.28.137.254`	42.28.137.255	254
139	`42.28.138.0/24`	`42.28.138.1` to `42.28.138.254`	42.28.138.255	254
140	`42.28.139.0/24`	`42.28.139.1` to `42.28.139.254`	42.28.139.255	254
141	`42.28.140.0/24`	`42.28.140.1` to `42.28.140.254`	42.28.140.255	254
142	`42.28.141.0/24`	`42.28.141.1` to `42.28.141.254`	42.28.141.255	254
143	`42.28.142.0/24`	`42.28.142.1` to `42.28.142.254`	42.28.142.255	254
144	`42.28.143.0/24`	`42.28.143.1` to `42.28.143.254`	42.28.143.255	254
145	`42.28.144.0/24`	`42.28.144.1` to `42.28.144.254`	42.28.144.255	254
146	`42.28.145.0/24`	`42.28.145.1` to `42.28.145.254`	42.28.145.255	254
147	`42.28.146.0/24`	`42.28.146.1` to `42.28.146.254`	42.28.146.255	254
148	`42.28.147.0/24`	`42.28.147.1` to `42.28.147.254`	42.28.147.255	254
149	`42.28.148.0/24`	`42.28.148.1` to `42.28.148.254`	42.28.148.255	254
150	`42.28.149.0/24`	`42.28.149.1` to `42.28.149.254`	42.28.149.255	254
151	`42.28.150.0/24`	`42.28.150.1` to `42.28.150.254`	42.28.150.255	254
152	`42.28.151.0/24`	`42.28.151.1` to `42.28.151.254`	42.28.151.255	254
153	`42.28.152.0/24`	`42.28.152.1` to `42.28.152.254`	42.28.152.255	254
154	`42.28.153.0/24`	`42.28.153.1` to `42.28.153.254`	42.28.153.255	254
155	`42.28.154.0/24`	`42.28.154.1` to `42.28.154.254`	42.28.154.255	254
156	`42.28.155.0/24`	`42.28.155.1` to `42.28.155.254`	42.28.155.255	254
157	`42.28.156.0/24`	`42.28.156.1` to `42.28.156.254`	42.28.156.255	254
158	`42.28.157.0/24`	`42.28.157.1` to `42.28.157.254`	42.28.157.255	254
159	`42.28.158.0/24`	`42.28.158.1` to `42.28.158.254`	42.28.158.255	254
160	`42.28.159.0/24`	`42.28.159.1` to `42.28.159.254`	42.28.159.255	254
161	`42.28.160.0/24`	`42.28.160.1` to `42.28.160.254`	42.28.160.255	254
162	`42.28.161.0/24`	`42.28.161.1` to `42.28.161.254`	42.28.161.255	254
163	`42.28.162.0/24`	`42.28.162.1` to `42.28.162.254`	42.28.162.255	254
164	`42.28.163.0/24`	`42.28.163.1` to `42.28.163.254`	42.28.163.255	254
165	`42.28.164.0/24`	`42.28.164.1` to `42.28.164.254`	42.28.164.255	254
166	`42.28.165.0/24`	`42.28.165.1` to `42.28.165.254`	42.28.165.255	254
167	`42.28.166.0/24`	`42.28.166.1` to `42.28.166.254`	42.28.166.255	254
168	`42.28.167.0/24`	`42.28.167.1` to `42.28.167.254`	42.28.167.255	254
169	`42.28.168.0/24`	`42.28.168.1` to `42.28.168.254`	42.28.168.255	254
170	`42.28.169.0/24`	`42.28.169.1` to `42.28.169.254`	42.28.169.255	254
171	`42.28.170.0/24`	`42.28.170.1` to `42.28.170.254`	42.28.170.255	254
172	`42.28.171.0/24`	`42.28.171.1` to `42.28.171.254`	42.28.171.255	254
173	`42.28.172.0/24`	`42.28.172.1` to `42.28.172.254`	42.28.172.255	254
174	`42.28.173.0/24`	`42.28.173.1` to `42.28.173.254`	42.28.173.255	254
175	`42.28.174.0/24`	`42.28.174.1` to `42.28.174.254`	42.28.174.255	254
176	`42.28.175.0/24`	`42.28.175.1` to `42.28.175.254`	42.28.175.255	254
177	`42.28.176.0/24`	`42.28.176.1` to `42.28.176.254`	42.28.176.255	254
178	`42.28.177.0/24`	`42.28.177.1` to `42.28.177.254`	42.28.177.255	254
179	`42.28.178.0/24`	`42.28.178.1` to `42.28.178.254`	42.28.178.255	254
180	`42.28.179.0/24`	`42.28.179.1` to `42.28.179.254`	42.28.179.255	254
181	`42.28.180.0/24`	`42.28.180.1` to `42.28.180.254`	42.28.180.255	254
182	`42.28.181.0/24`	`42.28.181.1` to `42.28.181.254`	42.28.181.255	254
183	`42.28.182.0/24`	`42.28.182.1` to `42.28.182.254`	42.28.182.255	254
184	`42.28.183.0/24`	`42.28.183.1` to `42.28.183.254`	42.28.183.255	254
185	`42.28.184.0/24`	`42.28.184.1` to `42.28.184.254`	42.28.184.255	254
186	`42.28.185.0/24`	`42.28.185.1` to `42.28.185.254`	42.28.185.255	254
187	`42.28.186.0/24`	`42.28.186.1` to `42.28.186.254`	42.28.186.255	254
188	`42.28.187.0/24`	`42.28.187.1` to `42.28.187.254`	42.28.187.255	254
189	`42.28.188.0/24`	`42.28.188.1` to `42.28.188.254`	42.28.188.255	254
190	`42.28.189.0/24`	`42.28.189.1` to `42.28.189.254`	42.28.189.255	254
191	`42.28.190.0/24`	`42.28.190.1` to `42.28.190.254`	42.28.190.255	254
192	`42.28.191.0/24`	`42.28.191.1` to `42.28.191.254`	42.28.191.255	254
193	`42.28.192.0/24`	`42.28.192.1` to `42.28.192.254`	42.28.192.255	254
194	`42.28.193.0/24`	`42.28.193.1` to `42.28.193.254`	42.28.193.255	254
195	`42.28.194.0/24`	`42.28.194.1` to `42.28.194.254`	42.28.194.255	254
196	`42.28.195.0/24`	`42.28.195.1` to `42.28.195.254`	42.28.195.255	254
197	`42.28.196.0/24`	`42.28.196.1` to `42.28.196.254`	42.28.196.255	254
198	`42.28.197.0/24`	`42.28.197.1` to `42.28.197.254`	42.28.197.255	254
199	`42.28.198.0/24`	`42.28.198.1` to `42.28.198.254`	42.28.198.255	254
200	`42.28.199.0/24`	`42.28.199.1` to `42.28.199.254`	42.28.199.255	254
201	`42.28.200.0/24`	`42.28.200.1` to `42.28.200.254`	42.28.200.255	254
202	`42.28.201.0/24`	`42.28.201.1` to `42.28.201.254`	42.28.201.255	254
203	`42.28.202.0/24`	`42.28.202.1` to `42.28.202.254`	42.28.202.255	254
204	`42.28.203.0/24`	`42.28.203.1` to `42.28.203.254`	42.28.203.255	254
205	`42.28.204.0/24`	`42.28.204.1` to `42.28.204.254`	42.28.204.255	254
206	`42.28.205.0/24`	`42.28.205.1` to `42.28.205.254`	42.28.205.255	254
207	`42.28.206.0/24`	`42.28.206.1` to `42.28.206.254`	42.28.206.255	254
208	`42.28.207.0/24`	`42.28.207.1` to `42.28.207.254`	42.28.207.255	254
209	`42.28.208.0/24`	`42.28.208.1` to `42.28.208.254`	42.28.208.255	254
210	`42.28.209.0/24`	`42.28.209.1` to `42.28.209.254`	42.28.209.255	254
211	`42.28.210.0/24`	`42.28.210.1` to `42.28.210.254`	42.28.210.255	254
212	`42.28.211.0/24`	`42.28.211.1` to `42.28.211.254`	42.28.211.255	254
213	`42.28.212.0/24`	`42.28.212.1` to `42.28.212.254`	42.28.212.255	254
214	`42.28.213.0/24`	`42.28.213.1` to `42.28.213.254`	42.28.213.255	254
215	`42.28.214.0/24`	`42.28.214.1` to `42.28.214.254`	42.28.214.255	254
216	`42.28.215.0/24`	`42.28.215.1` to `42.28.215.254`	42.28.215.255	254
217	`42.28.216.0/24`	`42.28.216.1` to `42.28.216.254`	42.28.216.255	254
218	`42.28.217.0/24`	`42.28.217.1` to `42.28.217.254`	42.28.217.255	254
219	`42.28.218.0/24`	`42.28.218.1` to `42.28.218.254`	42.28.218.255	254
220	`42.28.219.0/24`	`42.28.219.1` to `42.28.219.254`	42.28.219.255	254
221	`42.28.220.0/24`	`42.28.220.1` to `42.28.220.254`	42.28.220.255	254
222	`42.28.221.0/24`	`42.28.221.1` to `42.28.221.254`	42.28.221.255	254
223	`42.28.222.0/24`	`42.28.222.1` to `42.28.222.254`	42.28.222.255	254
224	`42.28.223.0/24`	`42.28.223.1` to `42.28.223.254`	42.28.223.255	254
225	`42.28.224.0/24`	`42.28.224.1` to `42.28.224.254`	42.28.224.255	254
226	`42.28.225.0/24`	`42.28.225.1` to `42.28.225.254`	42.28.225.255	254
227	`42.28.226.0/24`	`42.28.226.1` to `42.28.226.254`	42.28.226.255	254
228	`42.28.227.0/24`	`42.28.227.1` to `42.28.227.254`	42.28.227.255	254
229	`42.28.228.0/24`	`42.28.228.1` to `42.28.228.254`	42.28.228.255	254
230	`42.28.229.0/24`	`42.28.229.1` to `42.28.229.254`	42.28.229.255	254
231	`42.28.230.0/24`	`42.28.230.1` to `42.28.230.254`	42.28.230.255	254
232	`42.28.231.0/24`	`42.28.231.1` to `42.28.231.254`	42.28.231.255	254
233	`42.28.232.0/24`	`42.28.232.1` to `42.28.232.254`	42.28.232.255	254
234	`42.28.233.0/24`	`42.28.233.1` to `42.28.233.254`	42.28.233.255	254
235	`42.28.234.0/24`	`42.28.234.1` to `42.28.234.254`	42.28.234.255	254
236	`42.28.235.0/24`	`42.28.235.1` to `42.28.235.254`	42.28.235.255	254
237	`42.28.236.0/24`	`42.28.236.1` to `42.28.236.254`	42.28.236.255	254
238	`42.28.237.0/24`	`42.28.237.1` to `42.28.237.254`	42.28.237.255	254
239	`42.28.238.0/24`	`42.28.238.1` to `42.28.238.254`	42.28.238.255	254
240	`42.28.239.0/24`	`42.28.239.1` to `42.28.239.254`	42.28.239.255	254
241	`42.28.240.0/24`	`42.28.240.1` to `42.28.240.254`	42.28.240.255	254
242	`42.28.241.0/24`	`42.28.241.1` to `42.28.241.254`	42.28.241.255	254
243	`42.28.242.0/24`	`42.28.242.1` to `42.28.242.254`	42.28.242.255	254
244	`42.28.243.0/24`	`42.28.243.1` to `42.28.243.254`	42.28.243.255	254
245	`42.28.244.0/24`	`42.28.244.1` to `42.28.244.254`	42.28.244.255	254
246	`42.28.245.0/24`	`42.28.245.1` to `42.28.245.254`	42.28.245.255	254
247	`42.28.246.0/24`	`42.28.246.1` to `42.28.246.254`	42.28.246.255	254
248	`42.28.247.0/24`	`42.28.247.1` to `42.28.247.254`	42.28.247.255	254
249	`42.28.248.0/24`	`42.28.248.1` to `42.28.248.254`	42.28.248.255	254
250	`42.28.249.0/24`	`42.28.249.1` to `42.28.249.254`	42.28.249.255	254
251	`42.28.250.0/24`	`42.28.250.1` to `42.28.250.254`	42.28.250.255	254
252	`42.28.251.0/24`	`42.28.251.1` to `42.28.251.254`	42.28.251.255	254
253	`42.28.252.0/24`	`42.28.252.1` to `42.28.252.254`	42.28.252.255	254
254	`42.28.253.0/24`	`42.28.253.1` to `42.28.253.254`	42.28.253.255	254
255	`42.28.254.0/24`	`42.28.254.1` to `42.28.254.254`	42.28.254.255	254
256	`42.28.255.0/24`	`42.28.255.1` to `42.28.255.254`	42.28.255.255	254

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
Prefix	Subnet mask	Wildcard	Addresses	Usable hosts	Size	Typical use
/0	0.0.0.0	255.255.255.255	4,294,967,296	4,294,967,294	16,777,216 × /24
/1	128.0.0.0	127.255.255.255	2,147,483,648	2,147,483,646	8,388,608 × /24
/2	192.0.0.0	63.255.255.255	1,073,741,824	1,073,741,822	4,194,304 × /24
/3	224.0.0.0	31.255.255.255	536,870,912	536,870,910	2,097,152 × /24
/4	240.0.0.0	15.255.255.255	268,435,456	268,435,454	1,048,576 × /24
/5	248.0.0.0	7.255.255.255	134,217,728	134,217,726	524,288 × /24
/6	252.0.0.0	3.255.255.255	67,108,864	67,108,862	262,144 × /24
/7	254.0.0.0	1.255.255.255	33,554,432	33,554,430	131,072 × /24
/8	255.0.0.0	0.255.255.255	16,777,216	16,777,214	65,536 × /24	Old class A; 10.0.0.0/8
/9	255.128.0.0	0.127.255.255	8,388,608	8,388,606	32,768 × /24
/10	255.192.0.0	0.63.255.255	4,194,304	4,194,302	16,384 × /24
/11	255.224.0.0	0.31.255.255	2,097,152	2,097,150	8,192 × /24
/12	255.240.0.0	0.15.255.255	1,048,576	1,048,574	4,096 × /24	172.16.0.0/12
/13	255.248.0.0	0.7.255.255	524,288	524,286	2,048 × /24
/14	255.252.0.0	0.3.255.255	262,144	262,142	1,024 × /24
/15	255.254.0.0	0.1.255.255	131,072	131,070	512 × /24
/16	255.255.0.0	0.0.255.255	65,536	65,534	256 × /24	Old class B; 192.168.0.0/16
/17	255.255.128.0	0.0.127.255	32,768	32,766	128 × /24
/18	255.255.192.0	0.0.63.255	16,384	16,382	64 × /24
/19	255.255.224.0	0.0.31.255	8,192	8,190	32 × /24
/20	255.255.240.0	0.0.15.255	4,096	4,094	16 × /24
/21	255.255.248.0	0.0.7.255	2,048	2,046	8 × /24
/22	255.255.252.0	0.0.3.255	1,024	1,022	4 × /24	Large office or guest Wi-Fi (1,022 hosts)
/23	255.255.254.0	0.0.1.255	512	510	2 × /24	Larger office LAN (510 hosts)
/24	255.255.255.0	0.0.0.255	256	254	1 × /24	Typical office LAN (old class C)
/25	255.255.255.128	0.0.0.127	128	126	1/2 of a /24	Smaller LAN or VLAN
/26	255.255.255.192	0.0.0.63	64	62	1/4 of a /24	Smaller LAN or VLAN
/27	255.255.255.224	0.0.0.31	32	30	1/8 of a /24	Small VLAN, phones, cameras
/28	255.255.255.240	0.0.0.15	16	14	1/16 of a /24	Small VLAN, phones, cameras
/29	255.255.255.248	0.0.0.7	8	6	1/32 of a /24	Small fixed public block (5 usable)
/30	255.255.255.252	0.0.0.3	4	2	1/64 of a /24	Point-to-point (old style)
/31	255.255.255.254	0.0.0.1	2	2	1/128 of a /24	Point-to-point link (RFC 3021)
/32	255.255.255.255	0.0.0.0	1	1	1/256 of a /24	One host

IPv6 prefix reference

IPv6 prefix lengths
Prefix	Addresses	/64 LANs	/48 sites	Nibble	Typical use
/3	42,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)	2,305,843,009,213,693,952	35,184,372,088,832	No	All global unicast (2000::/3)
/16	5,192,296,858,534,827,628,530,496,329,220,096 (2^112)	281,474,976,710,656	4,294,967,296	Yes
/20	324,518,553,658,426,726,783,156,020,576,256 (2^108)	17,592,186,044,416	268,435,456	Yes	Large provider allocation (RIPE minimum for some)
/29	633,825,300,114,114,700,748,351,602,688 (2^99)	34,359,738,368	524,288	No	RIPE allocation to a provider (often)
/32	79,228,162,514,264,337,593,543,950,336 (2^96)	4,294,967,296	65,536	Yes	Provider allocation (RIPE default)
/36	4,951,760,157,141,521,099,596,496,896 (2^92)	268,435,456	4,096	Yes
/40	309,485,009,821,345,068,724,781,056 (2^88)	16,777,216	256	Yes
/44	19,342,813,113,834,066,795,298,816 (2^84)	1,048,576	16	Yes
/48	1,208,925,819,614,629,174,706,176 (2^80)	65,536	1	Yes	One site or organisation (RIPE PI / assignment)
/52	75,557,863,725,914,323,419,136 (2^76)	4,096		Yes
/56	4,722,366,482,869,645,213,696 (2^72)	256		Yes	Small site or home (common provider assignment)
/60	295,147,905,179,352,825,856 (2^68)	16		Yes	Some home broadband (16 LANs)
/64	18,446,744,073,709,551,616 (2^64)	1		Yes	One LAN or VLAN (needed for SLAAC)
/72	72,057,594,037,927,936 (2^56)	1/256 of a /64		Yes
/80	281,474,976,710,656 (2^48)	1/65,536 of a /64		Yes
/96	4,294,967,296	1/4,294,967,296 of a /64		Yes	Embeds an IPv4 address (NAT64)
/112	65,536	1/281,474,976,710,656 of a /64		Yes
/120	256	1/72,057,594,037,927,936 of a /64		Yes
/124	16	1/1,152,921,504,606,846,976 of a /64		Yes
/126	4	1/4,611,686,018,427,387,904 of a /64		No
/127	2	1/9,223,372,036,854,775,808 of a /64		No	Point-to-point link (RFC 6164)
/128	1	1/18,446,744,073,709,551,616 of a /64		Yes	One host or loopback

Private and special ranges

IPv4

Special-purpose ranges
Range	Name	What it is
`255.255.255.255/32`	Limited broadcast	Every host on the local network
`0.0.0.0/8`	This network	Not routed; 0.0.0.0 means "any address" in settings
`10.0.0.0/8`	Private (RFC 1918)	Office and home networks; not routed on the internet
`100.64.0.0/10`	Shared address space (CGNAT)	Used by providers behind carrier-grade NAT (RFC 6598)
`127.0.0.0/8`	Loopback	This computer
`169.254.0.0/16`	Link-local (APIPA)	Self-assigned when no DHCP server answers
`172.16.0.0/12`	Private (RFC 1918)	Office and home networks; not routed on the internet
`192.0.0.0/24`	IETF protocol assignments	Special uses such as DS-Lite
`192.0.2.0/24`	Documentation (TEST-NET-1)	For examples; never used on a network
`192.88.99.0/24`	6to4 relay (deprecated)	Formerly anycast for 6to4
`192.168.0.0/16`	Private (RFC 1918)	Office and home networks; not routed on the internet
`198.18.0.0/15`	Benchmarking	Network equipment testing (RFC 2544)
`198.51.100.0/24`	Documentation (TEST-NET-2)	For examples; never used on a network
`203.0.113.0/24`	Documentation (TEST-NET-3)	For examples; never used on a network
`224.0.0.0/4`	Multicast	One-to-many traffic, such as IPTV and routing protocols
`240.0.0.0/4`	Reserved	Future use; not usable on most systems

IPv6

Special-purpose ranges
Range	Name	What it is
`::/128`	Unspecified	No address; :: means "any address" in settings
`::1/128`	Loopback	This computer
`::ffff:0:0/96`	IPv4-mapped	An IPv4 address written as IPv6
`64:ff9b::/96`	NAT64	IPv4 addresses reached through a NAT64 gateway
`100::/64`	Discard only	Traffic sent here is dropped (RFC 6666)
`2001:db8::/32`	Documentation	For examples; never used on a network
`2001::/32`	Teredo	IPv6 tunnelled over IPv4 UDP
`2002::/16`	6to4	IPv6 tunnelled over IPv4 (largely retired)
`3fff::/20`	Documentation	For examples (RFC 9637)
`fc00::/7`	Unique local (ULA)	Private IPv6, like RFC 1918; usually fd00::/8
`fe80::/10`	Link-local	Every IPv6 interface has one; not routed
`ff00::/8`	Multicast	One-to-many traffic; replaces broadcast
`2000::/3`	Global unicast	Public internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.

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Surftec

IP subnet calculator

IPv4 CIDR reference (/0 to /32)

IPv6 prefix reference

Private and special ranges

IPv4

IPv6

About this tool

Common questions

IPv4 CIDR reference (/0 to /32)

IPv6 prefix reference

Private and special ranges

IPv4

IPv6

Common questions

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