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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.

Network252.0.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
252.0.0.0
Broadcast address
252.15.255.255
First usable
252.0.0.1
Last usable
252.15.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FC000000 · Integer 4227858432 to 4228907007
Reverse DNS zones
0.252.in-addr.arpa
1.252.in-addr.arpa
2.252.in-addr.arpa
3.252.in-addr.arpa
4.252.in-addr.arpa
5.252.in-addr.arpa
6.252.in-addr.arpa
7.252.in-addr.arpa
8.252.in-addr.arpa
9.252.in-addr.arpa
10.252.in-addr.arpa
11.252.in-addr.arpa
12.252.in-addr.arpa
13.252.in-addr.arpa
14.252.in-addr.arpa
15.252.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111100.00000000.00000000.00000000252.0.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network11111100.00000000.00000000.00000000252.0.0.0
Broadcast11111100.00001111.11111111.11111111252.15.255.255
Split into smaller subnets/24
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

252.0.0.0/12 makes 4,096 subnets of /24; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1252.0.0.0/24252.0.0.1 to 252.0.0.254252.0.0.255254
2252.0.1.0/24252.0.1.1 to 252.0.1.254252.0.1.255254
3252.0.2.0/24252.0.2.1 to 252.0.2.254252.0.2.255254
4252.0.3.0/24252.0.3.1 to 252.0.3.254252.0.3.255254
5252.0.4.0/24252.0.4.1 to 252.0.4.254252.0.4.255254
6252.0.5.0/24252.0.5.1 to 252.0.5.254252.0.5.255254
7252.0.6.0/24252.0.6.1 to 252.0.6.254252.0.6.255254
8252.0.7.0/24252.0.7.1 to 252.0.7.254252.0.7.255254
9252.0.8.0/24252.0.8.1 to 252.0.8.254252.0.8.255254
10252.0.9.0/24252.0.9.1 to 252.0.9.254252.0.9.255254
11252.0.10.0/24252.0.10.1 to 252.0.10.254252.0.10.255254
12252.0.11.0/24252.0.11.1 to 252.0.11.254252.0.11.255254
13252.0.12.0/24252.0.12.1 to 252.0.12.254252.0.12.255254
14252.0.13.0/24252.0.13.1 to 252.0.13.254252.0.13.255254
15252.0.14.0/24252.0.14.1 to 252.0.14.254252.0.14.255254
16252.0.15.0/24252.0.15.1 to 252.0.15.254252.0.15.255254
17252.0.16.0/24252.0.16.1 to 252.0.16.254252.0.16.255254
18252.0.17.0/24252.0.17.1 to 252.0.17.254252.0.17.255254
19252.0.18.0/24252.0.18.1 to 252.0.18.254252.0.18.255254
20252.0.19.0/24252.0.19.1 to 252.0.19.254252.0.19.255254
21252.0.20.0/24252.0.20.1 to 252.0.20.254252.0.20.255254
22252.0.21.0/24252.0.21.1 to 252.0.21.254252.0.21.255254
23252.0.22.0/24252.0.22.1 to 252.0.22.254252.0.22.255254
24252.0.23.0/24252.0.23.1 to 252.0.23.254252.0.23.255254
25252.0.24.0/24252.0.24.1 to 252.0.24.254252.0.24.255254
26252.0.25.0/24252.0.25.1 to 252.0.25.254252.0.25.255254
27252.0.26.0/24252.0.26.1 to 252.0.26.254252.0.26.255254
28252.0.27.0/24252.0.27.1 to 252.0.27.254252.0.27.255254
29252.0.28.0/24252.0.28.1 to 252.0.28.254252.0.28.255254
30252.0.29.0/24252.0.29.1 to 252.0.29.254252.0.29.255254
31252.0.30.0/24252.0.30.1 to 252.0.30.254252.0.30.255254
32252.0.31.0/24252.0.31.1 to 252.0.31.254252.0.31.255254
33252.0.32.0/24252.0.32.1 to 252.0.32.254252.0.32.255254
34252.0.33.0/24252.0.33.1 to 252.0.33.254252.0.33.255254
35252.0.34.0/24252.0.34.1 to 252.0.34.254252.0.34.255254
36252.0.35.0/24252.0.35.1 to 252.0.35.254252.0.35.255254
37252.0.36.0/24252.0.36.1 to 252.0.36.254252.0.36.255254
38252.0.37.0/24252.0.37.1 to 252.0.37.254252.0.37.255254
39252.0.38.0/24252.0.38.1 to 252.0.38.254252.0.38.255254
40252.0.39.0/24252.0.39.1 to 252.0.39.254252.0.39.255254
41252.0.40.0/24252.0.40.1 to 252.0.40.254252.0.40.255254
42252.0.41.0/24252.0.41.1 to 252.0.41.254252.0.41.255254
43252.0.42.0/24252.0.42.1 to 252.0.42.254252.0.42.255254
44252.0.43.0/24252.0.43.1 to 252.0.43.254252.0.43.255254
45252.0.44.0/24252.0.44.1 to 252.0.44.254252.0.44.255254
46252.0.45.0/24252.0.45.1 to 252.0.45.254252.0.45.255254
47252.0.46.0/24252.0.46.1 to 252.0.46.254252.0.46.255254
48252.0.47.0/24252.0.47.1 to 252.0.47.254252.0.47.255254
49252.0.48.0/24252.0.48.1 to 252.0.48.254252.0.48.255254
50252.0.49.0/24252.0.49.1 to 252.0.49.254252.0.49.255254
51252.0.50.0/24252.0.50.1 to 252.0.50.254252.0.50.255254
52252.0.51.0/24252.0.51.1 to 252.0.51.254252.0.51.255254
53252.0.52.0/24252.0.52.1 to 252.0.52.254252.0.52.255254
54252.0.53.0/24252.0.53.1 to 252.0.53.254252.0.53.255254
55252.0.54.0/24252.0.54.1 to 252.0.54.254252.0.54.255254
56252.0.55.0/24252.0.55.1 to 252.0.55.254252.0.55.255254
57252.0.56.0/24252.0.56.1 to 252.0.56.254252.0.56.255254
58252.0.57.0/24252.0.57.1 to 252.0.57.254252.0.57.255254
59252.0.58.0/24252.0.58.1 to 252.0.58.254252.0.58.255254
60252.0.59.0/24252.0.59.1 to 252.0.59.254252.0.59.255254
61252.0.60.0/24252.0.60.1 to 252.0.60.254252.0.60.255254
62252.0.61.0/24252.0.61.1 to 252.0.61.254252.0.61.255254
63252.0.62.0/24252.0.62.1 to 252.0.62.254252.0.62.255254
64252.0.63.0/24252.0.63.1 to 252.0.63.254252.0.63.255254
65252.0.64.0/24252.0.64.1 to 252.0.64.254252.0.64.255254
66252.0.65.0/24252.0.65.1 to 252.0.65.254252.0.65.255254
67252.0.66.0/24252.0.66.1 to 252.0.66.254252.0.66.255254
68252.0.67.0/24252.0.67.1 to 252.0.67.254252.0.67.255254
69252.0.68.0/24252.0.68.1 to 252.0.68.254252.0.68.255254
70252.0.69.0/24252.0.69.1 to 252.0.69.254252.0.69.255254
71252.0.70.0/24252.0.70.1 to 252.0.70.254252.0.70.255254
72252.0.71.0/24252.0.71.1 to 252.0.71.254252.0.71.255254
73252.0.72.0/24252.0.72.1 to 252.0.72.254252.0.72.255254
74252.0.73.0/24252.0.73.1 to 252.0.73.254252.0.73.255254
75252.0.74.0/24252.0.74.1 to 252.0.74.254252.0.74.255254
76252.0.75.0/24252.0.75.1 to 252.0.75.254252.0.75.255254
77252.0.76.0/24252.0.76.1 to 252.0.76.254252.0.76.255254
78252.0.77.0/24252.0.77.1 to 252.0.77.254252.0.77.255254
79252.0.78.0/24252.0.78.1 to 252.0.78.254252.0.78.255254
80252.0.79.0/24252.0.79.1 to 252.0.79.254252.0.79.255254
81252.0.80.0/24252.0.80.1 to 252.0.80.254252.0.80.255254
82252.0.81.0/24252.0.81.1 to 252.0.81.254252.0.81.255254
83252.0.82.0/24252.0.82.1 to 252.0.82.254252.0.82.255254
84252.0.83.0/24252.0.83.1 to 252.0.83.254252.0.83.255254
85252.0.84.0/24252.0.84.1 to 252.0.84.254252.0.84.255254
86252.0.85.0/24252.0.85.1 to 252.0.85.254252.0.85.255254
87252.0.86.0/24252.0.86.1 to 252.0.86.254252.0.86.255254
88252.0.87.0/24252.0.87.1 to 252.0.87.254252.0.87.255254
89252.0.88.0/24252.0.88.1 to 252.0.88.254252.0.88.255254
90252.0.89.0/24252.0.89.1 to 252.0.89.254252.0.89.255254
91252.0.90.0/24252.0.90.1 to 252.0.90.254252.0.90.255254
92252.0.91.0/24252.0.91.1 to 252.0.91.254252.0.91.255254
93252.0.92.0/24252.0.92.1 to 252.0.92.254252.0.92.255254
94252.0.93.0/24252.0.93.1 to 252.0.93.254252.0.93.255254
95252.0.94.0/24252.0.94.1 to 252.0.94.254252.0.94.255254
96252.0.95.0/24252.0.95.1 to 252.0.95.254252.0.95.255254
97252.0.96.0/24252.0.96.1 to 252.0.96.254252.0.96.255254
98252.0.97.0/24252.0.97.1 to 252.0.97.254252.0.97.255254
99252.0.98.0/24252.0.98.1 to 252.0.98.254252.0.98.255254
100252.0.99.0/24252.0.99.1 to 252.0.99.254252.0.99.255254
101252.0.100.0/24252.0.100.1 to 252.0.100.254252.0.100.255254
102252.0.101.0/24252.0.101.1 to 252.0.101.254252.0.101.255254
103252.0.102.0/24252.0.102.1 to 252.0.102.254252.0.102.255254
104252.0.103.0/24252.0.103.1 to 252.0.103.254252.0.103.255254
105252.0.104.0/24252.0.104.1 to 252.0.104.254252.0.104.255254
106252.0.105.0/24252.0.105.1 to 252.0.105.254252.0.105.255254
107252.0.106.0/24252.0.106.1 to 252.0.106.254252.0.106.255254
108252.0.107.0/24252.0.107.1 to 252.0.107.254252.0.107.255254
109252.0.108.0/24252.0.108.1 to 252.0.108.254252.0.108.255254
110252.0.109.0/24252.0.109.1 to 252.0.109.254252.0.109.255254
111252.0.110.0/24252.0.110.1 to 252.0.110.254252.0.110.255254
112252.0.111.0/24252.0.111.1 to 252.0.111.254252.0.111.255254
113252.0.112.0/24252.0.112.1 to 252.0.112.254252.0.112.255254
114252.0.113.0/24252.0.113.1 to 252.0.113.254252.0.113.255254
115252.0.114.0/24252.0.114.1 to 252.0.114.254252.0.114.255254
116252.0.115.0/24252.0.115.1 to 252.0.115.254252.0.115.255254
117252.0.116.0/24252.0.116.1 to 252.0.116.254252.0.116.255254
118252.0.117.0/24252.0.117.1 to 252.0.117.254252.0.117.255254
119252.0.118.0/24252.0.118.1 to 252.0.118.254252.0.118.255254
120252.0.119.0/24252.0.119.1 to 252.0.119.254252.0.119.255254
121252.0.120.0/24252.0.120.1 to 252.0.120.254252.0.120.255254
122252.0.121.0/24252.0.121.1 to 252.0.121.254252.0.121.255254
123252.0.122.0/24252.0.122.1 to 252.0.122.254252.0.122.255254
124252.0.123.0/24252.0.123.1 to 252.0.123.254252.0.123.255254
125252.0.124.0/24252.0.124.1 to 252.0.124.254252.0.124.255254
126252.0.125.0/24252.0.125.1 to 252.0.125.254252.0.125.255254
127252.0.126.0/24252.0.126.1 to 252.0.126.254252.0.126.255254
128252.0.127.0/24252.0.127.1 to 252.0.127.254252.0.127.255254
129252.0.128.0/24252.0.128.1 to 252.0.128.254252.0.128.255254
130252.0.129.0/24252.0.129.1 to 252.0.129.254252.0.129.255254
131252.0.130.0/24252.0.130.1 to 252.0.130.254252.0.130.255254
132252.0.131.0/24252.0.131.1 to 252.0.131.254252.0.131.255254
133252.0.132.0/24252.0.132.1 to 252.0.132.254252.0.132.255254
134252.0.133.0/24252.0.133.1 to 252.0.133.254252.0.133.255254
135252.0.134.0/24252.0.134.1 to 252.0.134.254252.0.134.255254
136252.0.135.0/24252.0.135.1 to 252.0.135.254252.0.135.255254
137252.0.136.0/24252.0.136.1 to 252.0.136.254252.0.136.255254
138252.0.137.0/24252.0.137.1 to 252.0.137.254252.0.137.255254
139252.0.138.0/24252.0.138.1 to 252.0.138.254252.0.138.255254
140252.0.139.0/24252.0.139.1 to 252.0.139.254252.0.139.255254
141252.0.140.0/24252.0.140.1 to 252.0.140.254252.0.140.255254
142252.0.141.0/24252.0.141.1 to 252.0.141.254252.0.141.255254
143252.0.142.0/24252.0.142.1 to 252.0.142.254252.0.142.255254
144252.0.143.0/24252.0.143.1 to 252.0.143.254252.0.143.255254
145252.0.144.0/24252.0.144.1 to 252.0.144.254252.0.144.255254
146252.0.145.0/24252.0.145.1 to 252.0.145.254252.0.145.255254
147252.0.146.0/24252.0.146.1 to 252.0.146.254252.0.146.255254
148252.0.147.0/24252.0.147.1 to 252.0.147.254252.0.147.255254
149252.0.148.0/24252.0.148.1 to 252.0.148.254252.0.148.255254
150252.0.149.0/24252.0.149.1 to 252.0.149.254252.0.149.255254
151252.0.150.0/24252.0.150.1 to 252.0.150.254252.0.150.255254
152252.0.151.0/24252.0.151.1 to 252.0.151.254252.0.151.255254
153252.0.152.0/24252.0.152.1 to 252.0.152.254252.0.152.255254
154252.0.153.0/24252.0.153.1 to 252.0.153.254252.0.153.255254
155252.0.154.0/24252.0.154.1 to 252.0.154.254252.0.154.255254
156252.0.155.0/24252.0.155.1 to 252.0.155.254252.0.155.255254
157252.0.156.0/24252.0.156.1 to 252.0.156.254252.0.156.255254
158252.0.157.0/24252.0.157.1 to 252.0.157.254252.0.157.255254
159252.0.158.0/24252.0.158.1 to 252.0.158.254252.0.158.255254
160252.0.159.0/24252.0.159.1 to 252.0.159.254252.0.159.255254
161252.0.160.0/24252.0.160.1 to 252.0.160.254252.0.160.255254
162252.0.161.0/24252.0.161.1 to 252.0.161.254252.0.161.255254
163252.0.162.0/24252.0.162.1 to 252.0.162.254252.0.162.255254
164252.0.163.0/24252.0.163.1 to 252.0.163.254252.0.163.255254
165252.0.164.0/24252.0.164.1 to 252.0.164.254252.0.164.255254
166252.0.165.0/24252.0.165.1 to 252.0.165.254252.0.165.255254
167252.0.166.0/24252.0.166.1 to 252.0.166.254252.0.166.255254
168252.0.167.0/24252.0.167.1 to 252.0.167.254252.0.167.255254
169252.0.168.0/24252.0.168.1 to 252.0.168.254252.0.168.255254
170252.0.169.0/24252.0.169.1 to 252.0.169.254252.0.169.255254
171252.0.170.0/24252.0.170.1 to 252.0.170.254252.0.170.255254
172252.0.171.0/24252.0.171.1 to 252.0.171.254252.0.171.255254
173252.0.172.0/24252.0.172.1 to 252.0.172.254252.0.172.255254
174252.0.173.0/24252.0.173.1 to 252.0.173.254252.0.173.255254
175252.0.174.0/24252.0.174.1 to 252.0.174.254252.0.174.255254
176252.0.175.0/24252.0.175.1 to 252.0.175.254252.0.175.255254
177252.0.176.0/24252.0.176.1 to 252.0.176.254252.0.176.255254
178252.0.177.0/24252.0.177.1 to 252.0.177.254252.0.177.255254
179252.0.178.0/24252.0.178.1 to 252.0.178.254252.0.178.255254
180252.0.179.0/24252.0.179.1 to 252.0.179.254252.0.179.255254
181252.0.180.0/24252.0.180.1 to 252.0.180.254252.0.180.255254
182252.0.181.0/24252.0.181.1 to 252.0.181.254252.0.181.255254
183252.0.182.0/24252.0.182.1 to 252.0.182.254252.0.182.255254
184252.0.183.0/24252.0.183.1 to 252.0.183.254252.0.183.255254
185252.0.184.0/24252.0.184.1 to 252.0.184.254252.0.184.255254
186252.0.185.0/24252.0.185.1 to 252.0.185.254252.0.185.255254
187252.0.186.0/24252.0.186.1 to 252.0.186.254252.0.186.255254
188252.0.187.0/24252.0.187.1 to 252.0.187.254252.0.187.255254
189252.0.188.0/24252.0.188.1 to 252.0.188.254252.0.188.255254
190252.0.189.0/24252.0.189.1 to 252.0.189.254252.0.189.255254
191252.0.190.0/24252.0.190.1 to 252.0.190.254252.0.190.255254
192252.0.191.0/24252.0.191.1 to 252.0.191.254252.0.191.255254
193252.0.192.0/24252.0.192.1 to 252.0.192.254252.0.192.255254
194252.0.193.0/24252.0.193.1 to 252.0.193.254252.0.193.255254
195252.0.194.0/24252.0.194.1 to 252.0.194.254252.0.194.255254
196252.0.195.0/24252.0.195.1 to 252.0.195.254252.0.195.255254
197252.0.196.0/24252.0.196.1 to 252.0.196.254252.0.196.255254
198252.0.197.0/24252.0.197.1 to 252.0.197.254252.0.197.255254
199252.0.198.0/24252.0.198.1 to 252.0.198.254252.0.198.255254
200252.0.199.0/24252.0.199.1 to 252.0.199.254252.0.199.255254
201252.0.200.0/24252.0.200.1 to 252.0.200.254252.0.200.255254
202252.0.201.0/24252.0.201.1 to 252.0.201.254252.0.201.255254
203252.0.202.0/24252.0.202.1 to 252.0.202.254252.0.202.255254
204252.0.203.0/24252.0.203.1 to 252.0.203.254252.0.203.255254
205252.0.204.0/24252.0.204.1 to 252.0.204.254252.0.204.255254
206252.0.205.0/24252.0.205.1 to 252.0.205.254252.0.205.255254
207252.0.206.0/24252.0.206.1 to 252.0.206.254252.0.206.255254
208252.0.207.0/24252.0.207.1 to 252.0.207.254252.0.207.255254
209252.0.208.0/24252.0.208.1 to 252.0.208.254252.0.208.255254
210252.0.209.0/24252.0.209.1 to 252.0.209.254252.0.209.255254
211252.0.210.0/24252.0.210.1 to 252.0.210.254252.0.210.255254
212252.0.211.0/24252.0.211.1 to 252.0.211.254252.0.211.255254
213252.0.212.0/24252.0.212.1 to 252.0.212.254252.0.212.255254
214252.0.213.0/24252.0.213.1 to 252.0.213.254252.0.213.255254
215252.0.214.0/24252.0.214.1 to 252.0.214.254252.0.214.255254
216252.0.215.0/24252.0.215.1 to 252.0.215.254252.0.215.255254
217252.0.216.0/24252.0.216.1 to 252.0.216.254252.0.216.255254
218252.0.217.0/24252.0.217.1 to 252.0.217.254252.0.217.255254
219252.0.218.0/24252.0.218.1 to 252.0.218.254252.0.218.255254
220252.0.219.0/24252.0.219.1 to 252.0.219.254252.0.219.255254
221252.0.220.0/24252.0.220.1 to 252.0.220.254252.0.220.255254
222252.0.221.0/24252.0.221.1 to 252.0.221.254252.0.221.255254
223252.0.222.0/24252.0.222.1 to 252.0.222.254252.0.222.255254
224252.0.223.0/24252.0.223.1 to 252.0.223.254252.0.223.255254
225252.0.224.0/24252.0.224.1 to 252.0.224.254252.0.224.255254
226252.0.225.0/24252.0.225.1 to 252.0.225.254252.0.225.255254
227252.0.226.0/24252.0.226.1 to 252.0.226.254252.0.226.255254
228252.0.227.0/24252.0.227.1 to 252.0.227.254252.0.227.255254
229252.0.228.0/24252.0.228.1 to 252.0.228.254252.0.228.255254
230252.0.229.0/24252.0.229.1 to 252.0.229.254252.0.229.255254
231252.0.230.0/24252.0.230.1 to 252.0.230.254252.0.230.255254
232252.0.231.0/24252.0.231.1 to 252.0.231.254252.0.231.255254
233252.0.232.0/24252.0.232.1 to 252.0.232.254252.0.232.255254
234252.0.233.0/24252.0.233.1 to 252.0.233.254252.0.233.255254
235252.0.234.0/24252.0.234.1 to 252.0.234.254252.0.234.255254
236252.0.235.0/24252.0.235.1 to 252.0.235.254252.0.235.255254
237252.0.236.0/24252.0.236.1 to 252.0.236.254252.0.236.255254
238252.0.237.0/24252.0.237.1 to 252.0.237.254252.0.237.255254
239252.0.238.0/24252.0.238.1 to 252.0.238.254252.0.238.255254
240252.0.239.0/24252.0.239.1 to 252.0.239.254252.0.239.255254
241252.0.240.0/24252.0.240.1 to 252.0.240.254252.0.240.255254
242252.0.241.0/24252.0.241.1 to 252.0.241.254252.0.241.255254
243252.0.242.0/24252.0.242.1 to 252.0.242.254252.0.242.255254
244252.0.243.0/24252.0.243.1 to 252.0.243.254252.0.243.255254
245252.0.244.0/24252.0.244.1 to 252.0.244.254252.0.244.255254
246252.0.245.0/24252.0.245.1 to 252.0.245.254252.0.245.255254
247252.0.246.0/24252.0.246.1 to 252.0.246.254252.0.246.255254
248252.0.247.0/24252.0.247.1 to 252.0.247.254252.0.247.255254
249252.0.248.0/24252.0.248.1 to 252.0.248.254252.0.248.255254
250252.0.249.0/24252.0.249.1 to 252.0.249.254252.0.249.255254
251252.0.250.0/24252.0.250.1 to 252.0.250.254252.0.250.255254
252252.0.251.0/24252.0.251.1 to 252.0.251.254252.0.251.255254
253252.0.252.0/24252.0.252.1 to 252.0.252.254252.0.252.255254
254252.0.253.0/24252.0.253.1 to 252.0.253.254252.0.253.255254
255252.0.254.0/24252.0.254.1 to 252.0.254.254252.0.254.255254
256252.0.255.0/24252.0.255.1 to 252.0.255.254252.0.255.255254

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic 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.