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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.

Network156.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
156.0.0.0
Broadcast address
159.255.255.255
First usable
156.0.0.1
Last usable
159.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
B (default /16)
As numbers
Hex 9C000000 · Integer 2617245696 to 2684354559
Reverse DNS zones
156.in-addr.arpa
157.in-addr.arpa
158.in-addr.arpa
159.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10011100.00000000.00000000.00000000156.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10011100.00000000.00000000.00000000156.0.0.0
Broadcast10011111.11111111.11111111.11111111159.255.255.255
Split into smaller subnets/15
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

156.0.0.0/6 makes 512 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1156.0.0.0/15156.0.0.1 to 156.1.255.254156.1.255.255131,070
2156.2.0.0/15156.2.0.1 to 156.3.255.254156.3.255.255131,070
3156.4.0.0/15156.4.0.1 to 156.5.255.254156.5.255.255131,070
4156.6.0.0/15156.6.0.1 to 156.7.255.254156.7.255.255131,070
5156.8.0.0/15156.8.0.1 to 156.9.255.254156.9.255.255131,070
6156.10.0.0/15156.10.0.1 to 156.11.255.254156.11.255.255131,070
7156.12.0.0/15156.12.0.1 to 156.13.255.254156.13.255.255131,070
8156.14.0.0/15156.14.0.1 to 156.15.255.254156.15.255.255131,070
9156.16.0.0/15156.16.0.1 to 156.17.255.254156.17.255.255131,070
10156.18.0.0/15156.18.0.1 to 156.19.255.254156.19.255.255131,070
11156.20.0.0/15156.20.0.1 to 156.21.255.254156.21.255.255131,070
12156.22.0.0/15156.22.0.1 to 156.23.255.254156.23.255.255131,070
13156.24.0.0/15156.24.0.1 to 156.25.255.254156.25.255.255131,070
14156.26.0.0/15156.26.0.1 to 156.27.255.254156.27.255.255131,070
15156.28.0.0/15156.28.0.1 to 156.29.255.254156.29.255.255131,070
16156.30.0.0/15156.30.0.1 to 156.31.255.254156.31.255.255131,070
17156.32.0.0/15156.32.0.1 to 156.33.255.254156.33.255.255131,070
18156.34.0.0/15156.34.0.1 to 156.35.255.254156.35.255.255131,070
19156.36.0.0/15156.36.0.1 to 156.37.255.254156.37.255.255131,070
20156.38.0.0/15156.38.0.1 to 156.39.255.254156.39.255.255131,070
21156.40.0.0/15156.40.0.1 to 156.41.255.254156.41.255.255131,070
22156.42.0.0/15156.42.0.1 to 156.43.255.254156.43.255.255131,070
23156.44.0.0/15156.44.0.1 to 156.45.255.254156.45.255.255131,070
24156.46.0.0/15156.46.0.1 to 156.47.255.254156.47.255.255131,070
25156.48.0.0/15156.48.0.1 to 156.49.255.254156.49.255.255131,070
26156.50.0.0/15156.50.0.1 to 156.51.255.254156.51.255.255131,070
27156.52.0.0/15156.52.0.1 to 156.53.255.254156.53.255.255131,070
28156.54.0.0/15156.54.0.1 to 156.55.255.254156.55.255.255131,070
29156.56.0.0/15156.56.0.1 to 156.57.255.254156.57.255.255131,070
30156.58.0.0/15156.58.0.1 to 156.59.255.254156.59.255.255131,070
31156.60.0.0/15156.60.0.1 to 156.61.255.254156.61.255.255131,070
32156.62.0.0/15156.62.0.1 to 156.63.255.254156.63.255.255131,070
33156.64.0.0/15156.64.0.1 to 156.65.255.254156.65.255.255131,070
34156.66.0.0/15156.66.0.1 to 156.67.255.254156.67.255.255131,070
35156.68.0.0/15156.68.0.1 to 156.69.255.254156.69.255.255131,070
36156.70.0.0/15156.70.0.1 to 156.71.255.254156.71.255.255131,070
37156.72.0.0/15156.72.0.1 to 156.73.255.254156.73.255.255131,070
38156.74.0.0/15156.74.0.1 to 156.75.255.254156.75.255.255131,070
39156.76.0.0/15156.76.0.1 to 156.77.255.254156.77.255.255131,070
40156.78.0.0/15156.78.0.1 to 156.79.255.254156.79.255.255131,070
41156.80.0.0/15156.80.0.1 to 156.81.255.254156.81.255.255131,070
42156.82.0.0/15156.82.0.1 to 156.83.255.254156.83.255.255131,070
43156.84.0.0/15156.84.0.1 to 156.85.255.254156.85.255.255131,070
44156.86.0.0/15156.86.0.1 to 156.87.255.254156.87.255.255131,070
45156.88.0.0/15156.88.0.1 to 156.89.255.254156.89.255.255131,070
46156.90.0.0/15156.90.0.1 to 156.91.255.254156.91.255.255131,070
47156.92.0.0/15156.92.0.1 to 156.93.255.254156.93.255.255131,070
48156.94.0.0/15156.94.0.1 to 156.95.255.254156.95.255.255131,070
49156.96.0.0/15156.96.0.1 to 156.97.255.254156.97.255.255131,070
50156.98.0.0/15156.98.0.1 to 156.99.255.254156.99.255.255131,070
51156.100.0.0/15156.100.0.1 to 156.101.255.254156.101.255.255131,070
52156.102.0.0/15156.102.0.1 to 156.103.255.254156.103.255.255131,070
53156.104.0.0/15156.104.0.1 to 156.105.255.254156.105.255.255131,070
54156.106.0.0/15156.106.0.1 to 156.107.255.254156.107.255.255131,070
55156.108.0.0/15156.108.0.1 to 156.109.255.254156.109.255.255131,070
56156.110.0.0/15156.110.0.1 to 156.111.255.254156.111.255.255131,070
57156.112.0.0/15156.112.0.1 to 156.113.255.254156.113.255.255131,070
58156.114.0.0/15156.114.0.1 to 156.115.255.254156.115.255.255131,070
59156.116.0.0/15156.116.0.1 to 156.117.255.254156.117.255.255131,070
60156.118.0.0/15156.118.0.1 to 156.119.255.254156.119.255.255131,070
61156.120.0.0/15156.120.0.1 to 156.121.255.254156.121.255.255131,070
62156.122.0.0/15156.122.0.1 to 156.123.255.254156.123.255.255131,070
63156.124.0.0/15156.124.0.1 to 156.125.255.254156.125.255.255131,070
64156.126.0.0/15156.126.0.1 to 156.127.255.254156.127.255.255131,070
65156.128.0.0/15156.128.0.1 to 156.129.255.254156.129.255.255131,070
66156.130.0.0/15156.130.0.1 to 156.131.255.254156.131.255.255131,070
67156.132.0.0/15156.132.0.1 to 156.133.255.254156.133.255.255131,070
68156.134.0.0/15156.134.0.1 to 156.135.255.254156.135.255.255131,070
69156.136.0.0/15156.136.0.1 to 156.137.255.254156.137.255.255131,070
70156.138.0.0/15156.138.0.1 to 156.139.255.254156.139.255.255131,070
71156.140.0.0/15156.140.0.1 to 156.141.255.254156.141.255.255131,070
72156.142.0.0/15156.142.0.1 to 156.143.255.254156.143.255.255131,070
73156.144.0.0/15156.144.0.1 to 156.145.255.254156.145.255.255131,070
74156.146.0.0/15156.146.0.1 to 156.147.255.254156.147.255.255131,070
75156.148.0.0/15156.148.0.1 to 156.149.255.254156.149.255.255131,070
76156.150.0.0/15156.150.0.1 to 156.151.255.254156.151.255.255131,070
77156.152.0.0/15156.152.0.1 to 156.153.255.254156.153.255.255131,070
78156.154.0.0/15156.154.0.1 to 156.155.255.254156.155.255.255131,070
79156.156.0.0/15156.156.0.1 to 156.157.255.254156.157.255.255131,070
80156.158.0.0/15156.158.0.1 to 156.159.255.254156.159.255.255131,070
81156.160.0.0/15156.160.0.1 to 156.161.255.254156.161.255.255131,070
82156.162.0.0/15156.162.0.1 to 156.163.255.254156.163.255.255131,070
83156.164.0.0/15156.164.0.1 to 156.165.255.254156.165.255.255131,070
84156.166.0.0/15156.166.0.1 to 156.167.255.254156.167.255.255131,070
85156.168.0.0/15156.168.0.1 to 156.169.255.254156.169.255.255131,070
86156.170.0.0/15156.170.0.1 to 156.171.255.254156.171.255.255131,070
87156.172.0.0/15156.172.0.1 to 156.173.255.254156.173.255.255131,070
88156.174.0.0/15156.174.0.1 to 156.175.255.254156.175.255.255131,070
89156.176.0.0/15156.176.0.1 to 156.177.255.254156.177.255.255131,070
90156.178.0.0/15156.178.0.1 to 156.179.255.254156.179.255.255131,070
91156.180.0.0/15156.180.0.1 to 156.181.255.254156.181.255.255131,070
92156.182.0.0/15156.182.0.1 to 156.183.255.254156.183.255.255131,070
93156.184.0.0/15156.184.0.1 to 156.185.255.254156.185.255.255131,070
94156.186.0.0/15156.186.0.1 to 156.187.255.254156.187.255.255131,070
95156.188.0.0/15156.188.0.1 to 156.189.255.254156.189.255.255131,070
96156.190.0.0/15156.190.0.1 to 156.191.255.254156.191.255.255131,070
97156.192.0.0/15156.192.0.1 to 156.193.255.254156.193.255.255131,070
98156.194.0.0/15156.194.0.1 to 156.195.255.254156.195.255.255131,070
99156.196.0.0/15156.196.0.1 to 156.197.255.254156.197.255.255131,070
100156.198.0.0/15156.198.0.1 to 156.199.255.254156.199.255.255131,070
101156.200.0.0/15156.200.0.1 to 156.201.255.254156.201.255.255131,070
102156.202.0.0/15156.202.0.1 to 156.203.255.254156.203.255.255131,070
103156.204.0.0/15156.204.0.1 to 156.205.255.254156.205.255.255131,070
104156.206.0.0/15156.206.0.1 to 156.207.255.254156.207.255.255131,070
105156.208.0.0/15156.208.0.1 to 156.209.255.254156.209.255.255131,070
106156.210.0.0/15156.210.0.1 to 156.211.255.254156.211.255.255131,070
107156.212.0.0/15156.212.0.1 to 156.213.255.254156.213.255.255131,070
108156.214.0.0/15156.214.0.1 to 156.215.255.254156.215.255.255131,070
109156.216.0.0/15156.216.0.1 to 156.217.255.254156.217.255.255131,070
110156.218.0.0/15156.218.0.1 to 156.219.255.254156.219.255.255131,070
111156.220.0.0/15156.220.0.1 to 156.221.255.254156.221.255.255131,070
112156.222.0.0/15156.222.0.1 to 156.223.255.254156.223.255.255131,070
113156.224.0.0/15156.224.0.1 to 156.225.255.254156.225.255.255131,070
114156.226.0.0/15156.226.0.1 to 156.227.255.254156.227.255.255131,070
115156.228.0.0/15156.228.0.1 to 156.229.255.254156.229.255.255131,070
116156.230.0.0/15156.230.0.1 to 156.231.255.254156.231.255.255131,070
117156.232.0.0/15156.232.0.1 to 156.233.255.254156.233.255.255131,070
118156.234.0.0/15156.234.0.1 to 156.235.255.254156.235.255.255131,070
119156.236.0.0/15156.236.0.1 to 156.237.255.254156.237.255.255131,070
120156.238.0.0/15156.238.0.1 to 156.239.255.254156.239.255.255131,070
121156.240.0.0/15156.240.0.1 to 156.241.255.254156.241.255.255131,070
122156.242.0.0/15156.242.0.1 to 156.243.255.254156.243.255.255131,070
123156.244.0.0/15156.244.0.1 to 156.245.255.254156.245.255.255131,070
124156.246.0.0/15156.246.0.1 to 156.247.255.254156.247.255.255131,070
125156.248.0.0/15156.248.0.1 to 156.249.255.254156.249.255.255131,070
126156.250.0.0/15156.250.0.1 to 156.251.255.254156.251.255.255131,070
127156.252.0.0/15156.252.0.1 to 156.253.255.254156.253.255.255131,070
128156.254.0.0/15156.254.0.1 to 156.255.255.254156.255.255.255131,070
129157.0.0.0/15157.0.0.1 to 157.1.255.254157.1.255.255131,070
130157.2.0.0/15157.2.0.1 to 157.3.255.254157.3.255.255131,070
131157.4.0.0/15157.4.0.1 to 157.5.255.254157.5.255.255131,070
132157.6.0.0/15157.6.0.1 to 157.7.255.254157.7.255.255131,070
133157.8.0.0/15157.8.0.1 to 157.9.255.254157.9.255.255131,070
134157.10.0.0/15157.10.0.1 to 157.11.255.254157.11.255.255131,070
135157.12.0.0/15157.12.0.1 to 157.13.255.254157.13.255.255131,070
136157.14.0.0/15157.14.0.1 to 157.15.255.254157.15.255.255131,070
137157.16.0.0/15157.16.0.1 to 157.17.255.254157.17.255.255131,070
138157.18.0.0/15157.18.0.1 to 157.19.255.254157.19.255.255131,070
139157.20.0.0/15157.20.0.1 to 157.21.255.254157.21.255.255131,070
140157.22.0.0/15157.22.0.1 to 157.23.255.254157.23.255.255131,070
141157.24.0.0/15157.24.0.1 to 157.25.255.254157.25.255.255131,070
142157.26.0.0/15157.26.0.1 to 157.27.255.254157.27.255.255131,070
143157.28.0.0/15157.28.0.1 to 157.29.255.254157.29.255.255131,070
144157.30.0.0/15157.30.0.1 to 157.31.255.254157.31.255.255131,070
145157.32.0.0/15157.32.0.1 to 157.33.255.254157.33.255.255131,070
146157.34.0.0/15157.34.0.1 to 157.35.255.254157.35.255.255131,070
147157.36.0.0/15157.36.0.1 to 157.37.255.254157.37.255.255131,070
148157.38.0.0/15157.38.0.1 to 157.39.255.254157.39.255.255131,070
149157.40.0.0/15157.40.0.1 to 157.41.255.254157.41.255.255131,070
150157.42.0.0/15157.42.0.1 to 157.43.255.254157.43.255.255131,070
151157.44.0.0/15157.44.0.1 to 157.45.255.254157.45.255.255131,070
152157.46.0.0/15157.46.0.1 to 157.47.255.254157.47.255.255131,070
153157.48.0.0/15157.48.0.1 to 157.49.255.254157.49.255.255131,070
154157.50.0.0/15157.50.0.1 to 157.51.255.254157.51.255.255131,070
155157.52.0.0/15157.52.0.1 to 157.53.255.254157.53.255.255131,070
156157.54.0.0/15157.54.0.1 to 157.55.255.254157.55.255.255131,070
157157.56.0.0/15157.56.0.1 to 157.57.255.254157.57.255.255131,070
158157.58.0.0/15157.58.0.1 to 157.59.255.254157.59.255.255131,070
159157.60.0.0/15157.60.0.1 to 157.61.255.254157.61.255.255131,070
160157.62.0.0/15157.62.0.1 to 157.63.255.254157.63.255.255131,070
161157.64.0.0/15157.64.0.1 to 157.65.255.254157.65.255.255131,070
162157.66.0.0/15157.66.0.1 to 157.67.255.254157.67.255.255131,070
163157.68.0.0/15157.68.0.1 to 157.69.255.254157.69.255.255131,070
164157.70.0.0/15157.70.0.1 to 157.71.255.254157.71.255.255131,070
165157.72.0.0/15157.72.0.1 to 157.73.255.254157.73.255.255131,070
166157.74.0.0/15157.74.0.1 to 157.75.255.254157.75.255.255131,070
167157.76.0.0/15157.76.0.1 to 157.77.255.254157.77.255.255131,070
168157.78.0.0/15157.78.0.1 to 157.79.255.254157.79.255.255131,070
169157.80.0.0/15157.80.0.1 to 157.81.255.254157.81.255.255131,070
170157.82.0.0/15157.82.0.1 to 157.83.255.254157.83.255.255131,070
171157.84.0.0/15157.84.0.1 to 157.85.255.254157.85.255.255131,070
172157.86.0.0/15157.86.0.1 to 157.87.255.254157.87.255.255131,070
173157.88.0.0/15157.88.0.1 to 157.89.255.254157.89.255.255131,070
174157.90.0.0/15157.90.0.1 to 157.91.255.254157.91.255.255131,070
175157.92.0.0/15157.92.0.1 to 157.93.255.254157.93.255.255131,070
176157.94.0.0/15157.94.0.1 to 157.95.255.254157.95.255.255131,070
177157.96.0.0/15157.96.0.1 to 157.97.255.254157.97.255.255131,070
178157.98.0.0/15157.98.0.1 to 157.99.255.254157.99.255.255131,070
179157.100.0.0/15157.100.0.1 to 157.101.255.254157.101.255.255131,070
180157.102.0.0/15157.102.0.1 to 157.103.255.254157.103.255.255131,070
181157.104.0.0/15157.104.0.1 to 157.105.255.254157.105.255.255131,070
182157.106.0.0/15157.106.0.1 to 157.107.255.254157.107.255.255131,070
183157.108.0.0/15157.108.0.1 to 157.109.255.254157.109.255.255131,070
184157.110.0.0/15157.110.0.1 to 157.111.255.254157.111.255.255131,070
185157.112.0.0/15157.112.0.1 to 157.113.255.254157.113.255.255131,070
186157.114.0.0/15157.114.0.1 to 157.115.255.254157.115.255.255131,070
187157.116.0.0/15157.116.0.1 to 157.117.255.254157.117.255.255131,070
188157.118.0.0/15157.118.0.1 to 157.119.255.254157.119.255.255131,070
189157.120.0.0/15157.120.0.1 to 157.121.255.254157.121.255.255131,070
190157.122.0.0/15157.122.0.1 to 157.123.255.254157.123.255.255131,070
191157.124.0.0/15157.124.0.1 to 157.125.255.254157.125.255.255131,070
192157.126.0.0/15157.126.0.1 to 157.127.255.254157.127.255.255131,070
193157.128.0.0/15157.128.0.1 to 157.129.255.254157.129.255.255131,070
194157.130.0.0/15157.130.0.1 to 157.131.255.254157.131.255.255131,070
195157.132.0.0/15157.132.0.1 to 157.133.255.254157.133.255.255131,070
196157.134.0.0/15157.134.0.1 to 157.135.255.254157.135.255.255131,070
197157.136.0.0/15157.136.0.1 to 157.137.255.254157.137.255.255131,070
198157.138.0.0/15157.138.0.1 to 157.139.255.254157.139.255.255131,070
199157.140.0.0/15157.140.0.1 to 157.141.255.254157.141.255.255131,070
200157.142.0.0/15157.142.0.1 to 157.143.255.254157.143.255.255131,070
201157.144.0.0/15157.144.0.1 to 157.145.255.254157.145.255.255131,070
202157.146.0.0/15157.146.0.1 to 157.147.255.254157.147.255.255131,070
203157.148.0.0/15157.148.0.1 to 157.149.255.254157.149.255.255131,070
204157.150.0.0/15157.150.0.1 to 157.151.255.254157.151.255.255131,070
205157.152.0.0/15157.152.0.1 to 157.153.255.254157.153.255.255131,070
206157.154.0.0/15157.154.0.1 to 157.155.255.254157.155.255.255131,070
207157.156.0.0/15157.156.0.1 to 157.157.255.254157.157.255.255131,070
208157.158.0.0/15157.158.0.1 to 157.159.255.254157.159.255.255131,070
209157.160.0.0/15157.160.0.1 to 157.161.255.254157.161.255.255131,070
210157.162.0.0/15157.162.0.1 to 157.163.255.254157.163.255.255131,070
211157.164.0.0/15157.164.0.1 to 157.165.255.254157.165.255.255131,070
212157.166.0.0/15157.166.0.1 to 157.167.255.254157.167.255.255131,070
213157.168.0.0/15157.168.0.1 to 157.169.255.254157.169.255.255131,070
214157.170.0.0/15157.170.0.1 to 157.171.255.254157.171.255.255131,070
215157.172.0.0/15157.172.0.1 to 157.173.255.254157.173.255.255131,070
216157.174.0.0/15157.174.0.1 to 157.175.255.254157.175.255.255131,070
217157.176.0.0/15157.176.0.1 to 157.177.255.254157.177.255.255131,070
218157.178.0.0/15157.178.0.1 to 157.179.255.254157.179.255.255131,070
219157.180.0.0/15157.180.0.1 to 157.181.255.254157.181.255.255131,070
220157.182.0.0/15157.182.0.1 to 157.183.255.254157.183.255.255131,070
221157.184.0.0/15157.184.0.1 to 157.185.255.254157.185.255.255131,070
222157.186.0.0/15157.186.0.1 to 157.187.255.254157.187.255.255131,070
223157.188.0.0/15157.188.0.1 to 157.189.255.254157.189.255.255131,070
224157.190.0.0/15157.190.0.1 to 157.191.255.254157.191.255.255131,070
225157.192.0.0/15157.192.0.1 to 157.193.255.254157.193.255.255131,070
226157.194.0.0/15157.194.0.1 to 157.195.255.254157.195.255.255131,070
227157.196.0.0/15157.196.0.1 to 157.197.255.254157.197.255.255131,070
228157.198.0.0/15157.198.0.1 to 157.199.255.254157.199.255.255131,070
229157.200.0.0/15157.200.0.1 to 157.201.255.254157.201.255.255131,070
230157.202.0.0/15157.202.0.1 to 157.203.255.254157.203.255.255131,070
231157.204.0.0/15157.204.0.1 to 157.205.255.254157.205.255.255131,070
232157.206.0.0/15157.206.0.1 to 157.207.255.254157.207.255.255131,070
233157.208.0.0/15157.208.0.1 to 157.209.255.254157.209.255.255131,070
234157.210.0.0/15157.210.0.1 to 157.211.255.254157.211.255.255131,070
235157.212.0.0/15157.212.0.1 to 157.213.255.254157.213.255.255131,070
236157.214.0.0/15157.214.0.1 to 157.215.255.254157.215.255.255131,070
237157.216.0.0/15157.216.0.1 to 157.217.255.254157.217.255.255131,070
238157.218.0.0/15157.218.0.1 to 157.219.255.254157.219.255.255131,070
239157.220.0.0/15157.220.0.1 to 157.221.255.254157.221.255.255131,070
240157.222.0.0/15157.222.0.1 to 157.223.255.254157.223.255.255131,070
241157.224.0.0/15157.224.0.1 to 157.225.255.254157.225.255.255131,070
242157.226.0.0/15157.226.0.1 to 157.227.255.254157.227.255.255131,070
243157.228.0.0/15157.228.0.1 to 157.229.255.254157.229.255.255131,070
244157.230.0.0/15157.230.0.1 to 157.231.255.254157.231.255.255131,070
245157.232.0.0/15157.232.0.1 to 157.233.255.254157.233.255.255131,070
246157.234.0.0/15157.234.0.1 to 157.235.255.254157.235.255.255131,070
247157.236.0.0/15157.236.0.1 to 157.237.255.254157.237.255.255131,070
248157.238.0.0/15157.238.0.1 to 157.239.255.254157.239.255.255131,070
249157.240.0.0/15157.240.0.1 to 157.241.255.254157.241.255.255131,070
250157.242.0.0/15157.242.0.1 to 157.243.255.254157.243.255.255131,070
251157.244.0.0/15157.244.0.1 to 157.245.255.254157.245.255.255131,070
252157.246.0.0/15157.246.0.1 to 157.247.255.254157.247.255.255131,070
253157.248.0.0/15157.248.0.1 to 157.249.255.254157.249.255.255131,070
254157.250.0.0/15157.250.0.1 to 157.251.255.254157.251.255.255131,070
255157.252.0.0/15157.252.0.1 to 157.253.255.254157.253.255.255131,070
256157.254.0.0/15157.254.0.1 to 157.255.255.254157.255.255.255131,070

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.