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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.

Network156.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
156.0.0.0
Broadcast address
156.255.255.255
First usable
156.0.0.1
Last usable
156.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex 9C000000 · Integer 2617245696 to 2634022911
Reverse DNS zone
156.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011100..00000000.00000000.00000000156.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10011100..00000000.00000000.00000000156.0.0.0
Broadcast10011100..11111111.11111111.11111111156.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

156.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1156.0.0.0/16156.0.0.1 to 156.0.255.254156.0.255.25565,534
2156.1.0.0/16156.1.0.1 to 156.1.255.254156.1.255.25565,534
3156.2.0.0/16156.2.0.1 to 156.2.255.254156.2.255.25565,534
4156.3.0.0/16156.3.0.1 to 156.3.255.254156.3.255.25565,534
5156.4.0.0/16156.4.0.1 to 156.4.255.254156.4.255.25565,534
6156.5.0.0/16156.5.0.1 to 156.5.255.254156.5.255.25565,534
7156.6.0.0/16156.6.0.1 to 156.6.255.254156.6.255.25565,534
8156.7.0.0/16156.7.0.1 to 156.7.255.254156.7.255.25565,534
9156.8.0.0/16156.8.0.1 to 156.8.255.254156.8.255.25565,534
10156.9.0.0/16156.9.0.1 to 156.9.255.254156.9.255.25565,534
11156.10.0.0/16156.10.0.1 to 156.10.255.254156.10.255.25565,534
12156.11.0.0/16156.11.0.1 to 156.11.255.254156.11.255.25565,534
13156.12.0.0/16156.12.0.1 to 156.12.255.254156.12.255.25565,534
14156.13.0.0/16156.13.0.1 to 156.13.255.254156.13.255.25565,534
15156.14.0.0/16156.14.0.1 to 156.14.255.254156.14.255.25565,534
16156.15.0.0/16156.15.0.1 to 156.15.255.254156.15.255.25565,534
17156.16.0.0/16156.16.0.1 to 156.16.255.254156.16.255.25565,534
18156.17.0.0/16156.17.0.1 to 156.17.255.254156.17.255.25565,534
19156.18.0.0/16156.18.0.1 to 156.18.255.254156.18.255.25565,534
20156.19.0.0/16156.19.0.1 to 156.19.255.254156.19.255.25565,534
21156.20.0.0/16156.20.0.1 to 156.20.255.254156.20.255.25565,534
22156.21.0.0/16156.21.0.1 to 156.21.255.254156.21.255.25565,534
23156.22.0.0/16156.22.0.1 to 156.22.255.254156.22.255.25565,534
24156.23.0.0/16156.23.0.1 to 156.23.255.254156.23.255.25565,534
25156.24.0.0/16156.24.0.1 to 156.24.255.254156.24.255.25565,534
26156.25.0.0/16156.25.0.1 to 156.25.255.254156.25.255.25565,534
27156.26.0.0/16156.26.0.1 to 156.26.255.254156.26.255.25565,534
28156.27.0.0/16156.27.0.1 to 156.27.255.254156.27.255.25565,534
29156.28.0.0/16156.28.0.1 to 156.28.255.254156.28.255.25565,534
30156.29.0.0/16156.29.0.1 to 156.29.255.254156.29.255.25565,534
31156.30.0.0/16156.30.0.1 to 156.30.255.254156.30.255.25565,534
32156.31.0.0/16156.31.0.1 to 156.31.255.254156.31.255.25565,534
33156.32.0.0/16156.32.0.1 to 156.32.255.254156.32.255.25565,534
34156.33.0.0/16156.33.0.1 to 156.33.255.254156.33.255.25565,534
35156.34.0.0/16156.34.0.1 to 156.34.255.254156.34.255.25565,534
36156.35.0.0/16156.35.0.1 to 156.35.255.254156.35.255.25565,534
37156.36.0.0/16156.36.0.1 to 156.36.255.254156.36.255.25565,534
38156.37.0.0/16156.37.0.1 to 156.37.255.254156.37.255.25565,534
39156.38.0.0/16156.38.0.1 to 156.38.255.254156.38.255.25565,534
40156.39.0.0/16156.39.0.1 to 156.39.255.254156.39.255.25565,534
41156.40.0.0/16156.40.0.1 to 156.40.255.254156.40.255.25565,534
42156.41.0.0/16156.41.0.1 to 156.41.255.254156.41.255.25565,534
43156.42.0.0/16156.42.0.1 to 156.42.255.254156.42.255.25565,534
44156.43.0.0/16156.43.0.1 to 156.43.255.254156.43.255.25565,534
45156.44.0.0/16156.44.0.1 to 156.44.255.254156.44.255.25565,534
46156.45.0.0/16156.45.0.1 to 156.45.255.254156.45.255.25565,534
47156.46.0.0/16156.46.0.1 to 156.46.255.254156.46.255.25565,534
48156.47.0.0/16156.47.0.1 to 156.47.255.254156.47.255.25565,534
49156.48.0.0/16156.48.0.1 to 156.48.255.254156.48.255.25565,534
50156.49.0.0/16156.49.0.1 to 156.49.255.254156.49.255.25565,534
51156.50.0.0/16156.50.0.1 to 156.50.255.254156.50.255.25565,534
52156.51.0.0/16156.51.0.1 to 156.51.255.254156.51.255.25565,534
53156.52.0.0/16156.52.0.1 to 156.52.255.254156.52.255.25565,534
54156.53.0.0/16156.53.0.1 to 156.53.255.254156.53.255.25565,534
55156.54.0.0/16156.54.0.1 to 156.54.255.254156.54.255.25565,534
56156.55.0.0/16156.55.0.1 to 156.55.255.254156.55.255.25565,534
57156.56.0.0/16156.56.0.1 to 156.56.255.254156.56.255.25565,534
58156.57.0.0/16156.57.0.1 to 156.57.255.254156.57.255.25565,534
59156.58.0.0/16156.58.0.1 to 156.58.255.254156.58.255.25565,534
60156.59.0.0/16156.59.0.1 to 156.59.255.254156.59.255.25565,534
61156.60.0.0/16156.60.0.1 to 156.60.255.254156.60.255.25565,534
62156.61.0.0/16156.61.0.1 to 156.61.255.254156.61.255.25565,534
63156.62.0.0/16156.62.0.1 to 156.62.255.254156.62.255.25565,534
64156.63.0.0/16156.63.0.1 to 156.63.255.254156.63.255.25565,534
65156.64.0.0/16156.64.0.1 to 156.64.255.254156.64.255.25565,534
66156.65.0.0/16156.65.0.1 to 156.65.255.254156.65.255.25565,534
67156.66.0.0/16156.66.0.1 to 156.66.255.254156.66.255.25565,534
68156.67.0.0/16156.67.0.1 to 156.67.255.254156.67.255.25565,534
69156.68.0.0/16156.68.0.1 to 156.68.255.254156.68.255.25565,534
70156.69.0.0/16156.69.0.1 to 156.69.255.254156.69.255.25565,534
71156.70.0.0/16156.70.0.1 to 156.70.255.254156.70.255.25565,534
72156.71.0.0/16156.71.0.1 to 156.71.255.254156.71.255.25565,534
73156.72.0.0/16156.72.0.1 to 156.72.255.254156.72.255.25565,534
74156.73.0.0/16156.73.0.1 to 156.73.255.254156.73.255.25565,534
75156.74.0.0/16156.74.0.1 to 156.74.255.254156.74.255.25565,534
76156.75.0.0/16156.75.0.1 to 156.75.255.254156.75.255.25565,534
77156.76.0.0/16156.76.0.1 to 156.76.255.254156.76.255.25565,534
78156.77.0.0/16156.77.0.1 to 156.77.255.254156.77.255.25565,534
79156.78.0.0/16156.78.0.1 to 156.78.255.254156.78.255.25565,534
80156.79.0.0/16156.79.0.1 to 156.79.255.254156.79.255.25565,534
81156.80.0.0/16156.80.0.1 to 156.80.255.254156.80.255.25565,534
82156.81.0.0/16156.81.0.1 to 156.81.255.254156.81.255.25565,534
83156.82.0.0/16156.82.0.1 to 156.82.255.254156.82.255.25565,534
84156.83.0.0/16156.83.0.1 to 156.83.255.254156.83.255.25565,534
85156.84.0.0/16156.84.0.1 to 156.84.255.254156.84.255.25565,534
86156.85.0.0/16156.85.0.1 to 156.85.255.254156.85.255.25565,534
87156.86.0.0/16156.86.0.1 to 156.86.255.254156.86.255.25565,534
88156.87.0.0/16156.87.0.1 to 156.87.255.254156.87.255.25565,534
89156.88.0.0/16156.88.0.1 to 156.88.255.254156.88.255.25565,534
90156.89.0.0/16156.89.0.1 to 156.89.255.254156.89.255.25565,534
91156.90.0.0/16156.90.0.1 to 156.90.255.254156.90.255.25565,534
92156.91.0.0/16156.91.0.1 to 156.91.255.254156.91.255.25565,534
93156.92.0.0/16156.92.0.1 to 156.92.255.254156.92.255.25565,534
94156.93.0.0/16156.93.0.1 to 156.93.255.254156.93.255.25565,534
95156.94.0.0/16156.94.0.1 to 156.94.255.254156.94.255.25565,534
96156.95.0.0/16156.95.0.1 to 156.95.255.254156.95.255.25565,534
97156.96.0.0/16156.96.0.1 to 156.96.255.254156.96.255.25565,534
98156.97.0.0/16156.97.0.1 to 156.97.255.254156.97.255.25565,534
99156.98.0.0/16156.98.0.1 to 156.98.255.254156.98.255.25565,534
100156.99.0.0/16156.99.0.1 to 156.99.255.254156.99.255.25565,534
101156.100.0.0/16156.100.0.1 to 156.100.255.254156.100.255.25565,534
102156.101.0.0/16156.101.0.1 to 156.101.255.254156.101.255.25565,534
103156.102.0.0/16156.102.0.1 to 156.102.255.254156.102.255.25565,534
104156.103.0.0/16156.103.0.1 to 156.103.255.254156.103.255.25565,534
105156.104.0.0/16156.104.0.1 to 156.104.255.254156.104.255.25565,534
106156.105.0.0/16156.105.0.1 to 156.105.255.254156.105.255.25565,534
107156.106.0.0/16156.106.0.1 to 156.106.255.254156.106.255.25565,534
108156.107.0.0/16156.107.0.1 to 156.107.255.254156.107.255.25565,534
109156.108.0.0/16156.108.0.1 to 156.108.255.254156.108.255.25565,534
110156.109.0.0/16156.109.0.1 to 156.109.255.254156.109.255.25565,534
111156.110.0.0/16156.110.0.1 to 156.110.255.254156.110.255.25565,534
112156.111.0.0/16156.111.0.1 to 156.111.255.254156.111.255.25565,534
113156.112.0.0/16156.112.0.1 to 156.112.255.254156.112.255.25565,534
114156.113.0.0/16156.113.0.1 to 156.113.255.254156.113.255.25565,534
115156.114.0.0/16156.114.0.1 to 156.114.255.254156.114.255.25565,534
116156.115.0.0/16156.115.0.1 to 156.115.255.254156.115.255.25565,534
117156.116.0.0/16156.116.0.1 to 156.116.255.254156.116.255.25565,534
118156.117.0.0/16156.117.0.1 to 156.117.255.254156.117.255.25565,534
119156.118.0.0/16156.118.0.1 to 156.118.255.254156.118.255.25565,534
120156.119.0.0/16156.119.0.1 to 156.119.255.254156.119.255.25565,534
121156.120.0.0/16156.120.0.1 to 156.120.255.254156.120.255.25565,534
122156.121.0.0/16156.121.0.1 to 156.121.255.254156.121.255.25565,534
123156.122.0.0/16156.122.0.1 to 156.122.255.254156.122.255.25565,534
124156.123.0.0/16156.123.0.1 to 156.123.255.254156.123.255.25565,534
125156.124.0.0/16156.124.0.1 to 156.124.255.254156.124.255.25565,534
126156.125.0.0/16156.125.0.1 to 156.125.255.254156.125.255.25565,534
127156.126.0.0/16156.126.0.1 to 156.126.255.254156.126.255.25565,534
128156.127.0.0/16156.127.0.1 to 156.127.255.254156.127.255.25565,534
129156.128.0.0/16156.128.0.1 to 156.128.255.254156.128.255.25565,534
130156.129.0.0/16156.129.0.1 to 156.129.255.254156.129.255.25565,534
131156.130.0.0/16156.130.0.1 to 156.130.255.254156.130.255.25565,534
132156.131.0.0/16156.131.0.1 to 156.131.255.254156.131.255.25565,534
133156.132.0.0/16156.132.0.1 to 156.132.255.254156.132.255.25565,534
134156.133.0.0/16156.133.0.1 to 156.133.255.254156.133.255.25565,534
135156.134.0.0/16156.134.0.1 to 156.134.255.254156.134.255.25565,534
136156.135.0.0/16156.135.0.1 to 156.135.255.254156.135.255.25565,534
137156.136.0.0/16156.136.0.1 to 156.136.255.254156.136.255.25565,534
138156.137.0.0/16156.137.0.1 to 156.137.255.254156.137.255.25565,534
139156.138.0.0/16156.138.0.1 to 156.138.255.254156.138.255.25565,534
140156.139.0.0/16156.139.0.1 to 156.139.255.254156.139.255.25565,534
141156.140.0.0/16156.140.0.1 to 156.140.255.254156.140.255.25565,534
142156.141.0.0/16156.141.0.1 to 156.141.255.254156.141.255.25565,534
143156.142.0.0/16156.142.0.1 to 156.142.255.254156.142.255.25565,534
144156.143.0.0/16156.143.0.1 to 156.143.255.254156.143.255.25565,534
145156.144.0.0/16156.144.0.1 to 156.144.255.254156.144.255.25565,534
146156.145.0.0/16156.145.0.1 to 156.145.255.254156.145.255.25565,534
147156.146.0.0/16156.146.0.1 to 156.146.255.254156.146.255.25565,534
148156.147.0.0/16156.147.0.1 to 156.147.255.254156.147.255.25565,534
149156.148.0.0/16156.148.0.1 to 156.148.255.254156.148.255.25565,534
150156.149.0.0/16156.149.0.1 to 156.149.255.254156.149.255.25565,534
151156.150.0.0/16156.150.0.1 to 156.150.255.254156.150.255.25565,534
152156.151.0.0/16156.151.0.1 to 156.151.255.254156.151.255.25565,534
153156.152.0.0/16156.152.0.1 to 156.152.255.254156.152.255.25565,534
154156.153.0.0/16156.153.0.1 to 156.153.255.254156.153.255.25565,534
155156.154.0.0/16156.154.0.1 to 156.154.255.254156.154.255.25565,534
156156.155.0.0/16156.155.0.1 to 156.155.255.254156.155.255.25565,534
157156.156.0.0/16156.156.0.1 to 156.156.255.254156.156.255.25565,534
158156.157.0.0/16156.157.0.1 to 156.157.255.254156.157.255.25565,534
159156.158.0.0/16156.158.0.1 to 156.158.255.254156.158.255.25565,534
160156.159.0.0/16156.159.0.1 to 156.159.255.254156.159.255.25565,534
161156.160.0.0/16156.160.0.1 to 156.160.255.254156.160.255.25565,534
162156.161.0.0/16156.161.0.1 to 156.161.255.254156.161.255.25565,534
163156.162.0.0/16156.162.0.1 to 156.162.255.254156.162.255.25565,534
164156.163.0.0/16156.163.0.1 to 156.163.255.254156.163.255.25565,534
165156.164.0.0/16156.164.0.1 to 156.164.255.254156.164.255.25565,534
166156.165.0.0/16156.165.0.1 to 156.165.255.254156.165.255.25565,534
167156.166.0.0/16156.166.0.1 to 156.166.255.254156.166.255.25565,534
168156.167.0.0/16156.167.0.1 to 156.167.255.254156.167.255.25565,534
169156.168.0.0/16156.168.0.1 to 156.168.255.254156.168.255.25565,534
170156.169.0.0/16156.169.0.1 to 156.169.255.254156.169.255.25565,534
171156.170.0.0/16156.170.0.1 to 156.170.255.254156.170.255.25565,534
172156.171.0.0/16156.171.0.1 to 156.171.255.254156.171.255.25565,534
173156.172.0.0/16156.172.0.1 to 156.172.255.254156.172.255.25565,534
174156.173.0.0/16156.173.0.1 to 156.173.255.254156.173.255.25565,534
175156.174.0.0/16156.174.0.1 to 156.174.255.254156.174.255.25565,534
176156.175.0.0/16156.175.0.1 to 156.175.255.254156.175.255.25565,534
177156.176.0.0/16156.176.0.1 to 156.176.255.254156.176.255.25565,534
178156.177.0.0/16156.177.0.1 to 156.177.255.254156.177.255.25565,534
179156.178.0.0/16156.178.0.1 to 156.178.255.254156.178.255.25565,534
180156.179.0.0/16156.179.0.1 to 156.179.255.254156.179.255.25565,534
181156.180.0.0/16156.180.0.1 to 156.180.255.254156.180.255.25565,534
182156.181.0.0/16156.181.0.1 to 156.181.255.254156.181.255.25565,534
183156.182.0.0/16156.182.0.1 to 156.182.255.254156.182.255.25565,534
184156.183.0.0/16156.183.0.1 to 156.183.255.254156.183.255.25565,534
185156.184.0.0/16156.184.0.1 to 156.184.255.254156.184.255.25565,534
186156.185.0.0/16156.185.0.1 to 156.185.255.254156.185.255.25565,534
187156.186.0.0/16156.186.0.1 to 156.186.255.254156.186.255.25565,534
188156.187.0.0/16156.187.0.1 to 156.187.255.254156.187.255.25565,534
189156.188.0.0/16156.188.0.1 to 156.188.255.254156.188.255.25565,534
190156.189.0.0/16156.189.0.1 to 156.189.255.254156.189.255.25565,534
191156.190.0.0/16156.190.0.1 to 156.190.255.254156.190.255.25565,534
192156.191.0.0/16156.191.0.1 to 156.191.255.254156.191.255.25565,534
193156.192.0.0/16156.192.0.1 to 156.192.255.254156.192.255.25565,534
194156.193.0.0/16156.193.0.1 to 156.193.255.254156.193.255.25565,534
195156.194.0.0/16156.194.0.1 to 156.194.255.254156.194.255.25565,534
196156.195.0.0/16156.195.0.1 to 156.195.255.254156.195.255.25565,534
197156.196.0.0/16156.196.0.1 to 156.196.255.254156.196.255.25565,534
198156.197.0.0/16156.197.0.1 to 156.197.255.254156.197.255.25565,534
199156.198.0.0/16156.198.0.1 to 156.198.255.254156.198.255.25565,534
200156.199.0.0/16156.199.0.1 to 156.199.255.254156.199.255.25565,534
201156.200.0.0/16156.200.0.1 to 156.200.255.254156.200.255.25565,534
202156.201.0.0/16156.201.0.1 to 156.201.255.254156.201.255.25565,534
203156.202.0.0/16156.202.0.1 to 156.202.255.254156.202.255.25565,534
204156.203.0.0/16156.203.0.1 to 156.203.255.254156.203.255.25565,534
205156.204.0.0/16156.204.0.1 to 156.204.255.254156.204.255.25565,534
206156.205.0.0/16156.205.0.1 to 156.205.255.254156.205.255.25565,534
207156.206.0.0/16156.206.0.1 to 156.206.255.254156.206.255.25565,534
208156.207.0.0/16156.207.0.1 to 156.207.255.254156.207.255.25565,534
209156.208.0.0/16156.208.0.1 to 156.208.255.254156.208.255.25565,534
210156.209.0.0/16156.209.0.1 to 156.209.255.254156.209.255.25565,534
211156.210.0.0/16156.210.0.1 to 156.210.255.254156.210.255.25565,534
212156.211.0.0/16156.211.0.1 to 156.211.255.254156.211.255.25565,534
213156.212.0.0/16156.212.0.1 to 156.212.255.254156.212.255.25565,534
214156.213.0.0/16156.213.0.1 to 156.213.255.254156.213.255.25565,534
215156.214.0.0/16156.214.0.1 to 156.214.255.254156.214.255.25565,534
216156.215.0.0/16156.215.0.1 to 156.215.255.254156.215.255.25565,534
217156.216.0.0/16156.216.0.1 to 156.216.255.254156.216.255.25565,534
218156.217.0.0/16156.217.0.1 to 156.217.255.254156.217.255.25565,534
219156.218.0.0/16156.218.0.1 to 156.218.255.254156.218.255.25565,534
220156.219.0.0/16156.219.0.1 to 156.219.255.254156.219.255.25565,534
221156.220.0.0/16156.220.0.1 to 156.220.255.254156.220.255.25565,534
222156.221.0.0/16156.221.0.1 to 156.221.255.254156.221.255.25565,534
223156.222.0.0/16156.222.0.1 to 156.222.255.254156.222.255.25565,534
224156.223.0.0/16156.223.0.1 to 156.223.255.254156.223.255.25565,534
225156.224.0.0/16156.224.0.1 to 156.224.255.254156.224.255.25565,534
226156.225.0.0/16156.225.0.1 to 156.225.255.254156.225.255.25565,534
227156.226.0.0/16156.226.0.1 to 156.226.255.254156.226.255.25565,534
228156.227.0.0/16156.227.0.1 to 156.227.255.254156.227.255.25565,534
229156.228.0.0/16156.228.0.1 to 156.228.255.254156.228.255.25565,534
230156.229.0.0/16156.229.0.1 to 156.229.255.254156.229.255.25565,534
231156.230.0.0/16156.230.0.1 to 156.230.255.254156.230.255.25565,534
232156.231.0.0/16156.231.0.1 to 156.231.255.254156.231.255.25565,534
233156.232.0.0/16156.232.0.1 to 156.232.255.254156.232.255.25565,534
234156.233.0.0/16156.233.0.1 to 156.233.255.254156.233.255.25565,534
235156.234.0.0/16156.234.0.1 to 156.234.255.254156.234.255.25565,534
236156.235.0.0/16156.235.0.1 to 156.235.255.254156.235.255.25565,534
237156.236.0.0/16156.236.0.1 to 156.236.255.254156.236.255.25565,534
238156.237.0.0/16156.237.0.1 to 156.237.255.254156.237.255.25565,534
239156.238.0.0/16156.238.0.1 to 156.238.255.254156.238.255.25565,534
240156.239.0.0/16156.239.0.1 to 156.239.255.254156.239.255.25565,534
241156.240.0.0/16156.240.0.1 to 156.240.255.254156.240.255.25565,534
242156.241.0.0/16156.241.0.1 to 156.241.255.254156.241.255.25565,534
243156.242.0.0/16156.242.0.1 to 156.242.255.254156.242.255.25565,534
244156.243.0.0/16156.243.0.1 to 156.243.255.254156.243.255.25565,534
245156.244.0.0/16156.244.0.1 to 156.244.255.254156.244.255.25565,534
246156.245.0.0/16156.245.0.1 to 156.245.255.254156.245.255.25565,534
247156.246.0.0/16156.246.0.1 to 156.246.255.254156.246.255.25565,534
248156.247.0.0/16156.247.0.1 to 156.247.255.254156.247.255.25565,534
249156.248.0.0/16156.248.0.1 to 156.248.255.254156.248.255.25565,534
250156.249.0.0/16156.249.0.1 to 156.249.255.254156.249.255.25565,534
251156.250.0.0/16156.250.0.1 to 156.250.255.254156.250.255.25565,534
252156.251.0.0/16156.251.0.1 to 156.251.255.254156.251.255.25565,534
253156.252.0.0/16156.252.0.1 to 156.252.255.254156.252.255.25565,534
254156.253.0.0/16156.253.0.1 to 156.253.255.254156.253.255.25565,534
255156.254.0.0/16156.254.0.1 to 156.254.255.254156.254.255.25565,534
256156.255.0.0/16156.255.0.1 to 156.255.255.254156.255.255.25565,534

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.