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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.

Network136.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
136.0.0.0
Broadcast address
139.255.255.255
First usable
136.0.0.1
Last usable
139.255.255.254
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 88000000 · Integer 2281701376 to 2348810239
Reverse DNS zones
136.in-addr.arpa
137.in-addr.arpa
138.in-addr.arpa
139.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
Address10001000.00000000.00000000.00000000136.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10001000.00000000.00000000.00000000136.0.0.0
Broadcast10001011.11111111.11111111.11111111139.255.255.255
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)

136.0.0.0/6 makes 512 subnets of /15; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1136.0.0.0/15136.0.0.1 to 136.1.255.254136.1.255.255131,070
2136.2.0.0/15136.2.0.1 to 136.3.255.254136.3.255.255131,070
3136.4.0.0/15136.4.0.1 to 136.5.255.254136.5.255.255131,070
4136.6.0.0/15136.6.0.1 to 136.7.255.254136.7.255.255131,070
5136.8.0.0/15136.8.0.1 to 136.9.255.254136.9.255.255131,070
6136.10.0.0/15136.10.0.1 to 136.11.255.254136.11.255.255131,070
7136.12.0.0/15136.12.0.1 to 136.13.255.254136.13.255.255131,070
8136.14.0.0/15136.14.0.1 to 136.15.255.254136.15.255.255131,070
9136.16.0.0/15136.16.0.1 to 136.17.255.254136.17.255.255131,070
10136.18.0.0/15136.18.0.1 to 136.19.255.254136.19.255.255131,070
11136.20.0.0/15136.20.0.1 to 136.21.255.254136.21.255.255131,070
12136.22.0.0/15136.22.0.1 to 136.23.255.254136.23.255.255131,070
13136.24.0.0/15136.24.0.1 to 136.25.255.254136.25.255.255131,070
14136.26.0.0/15136.26.0.1 to 136.27.255.254136.27.255.255131,070
15136.28.0.0/15136.28.0.1 to 136.29.255.254136.29.255.255131,070
16136.30.0.0/15136.30.0.1 to 136.31.255.254136.31.255.255131,070
17136.32.0.0/15136.32.0.1 to 136.33.255.254136.33.255.255131,070
18136.34.0.0/15136.34.0.1 to 136.35.255.254136.35.255.255131,070
19136.36.0.0/15136.36.0.1 to 136.37.255.254136.37.255.255131,070
20136.38.0.0/15136.38.0.1 to 136.39.255.254136.39.255.255131,070
21136.40.0.0/15136.40.0.1 to 136.41.255.254136.41.255.255131,070
22136.42.0.0/15136.42.0.1 to 136.43.255.254136.43.255.255131,070
23136.44.0.0/15136.44.0.1 to 136.45.255.254136.45.255.255131,070
24136.46.0.0/15136.46.0.1 to 136.47.255.254136.47.255.255131,070
25136.48.0.0/15136.48.0.1 to 136.49.255.254136.49.255.255131,070
26136.50.0.0/15136.50.0.1 to 136.51.255.254136.51.255.255131,070
27136.52.0.0/15136.52.0.1 to 136.53.255.254136.53.255.255131,070
28136.54.0.0/15136.54.0.1 to 136.55.255.254136.55.255.255131,070
29136.56.0.0/15136.56.0.1 to 136.57.255.254136.57.255.255131,070
30136.58.0.0/15136.58.0.1 to 136.59.255.254136.59.255.255131,070
31136.60.0.0/15136.60.0.1 to 136.61.255.254136.61.255.255131,070
32136.62.0.0/15136.62.0.1 to 136.63.255.254136.63.255.255131,070
33136.64.0.0/15136.64.0.1 to 136.65.255.254136.65.255.255131,070
34136.66.0.0/15136.66.0.1 to 136.67.255.254136.67.255.255131,070
35136.68.0.0/15136.68.0.1 to 136.69.255.254136.69.255.255131,070
36136.70.0.0/15136.70.0.1 to 136.71.255.254136.71.255.255131,070
37136.72.0.0/15136.72.0.1 to 136.73.255.254136.73.255.255131,070
38136.74.0.0/15136.74.0.1 to 136.75.255.254136.75.255.255131,070
39136.76.0.0/15136.76.0.1 to 136.77.255.254136.77.255.255131,070
40136.78.0.0/15136.78.0.1 to 136.79.255.254136.79.255.255131,070
41136.80.0.0/15136.80.0.1 to 136.81.255.254136.81.255.255131,070
42136.82.0.0/15136.82.0.1 to 136.83.255.254136.83.255.255131,070
43136.84.0.0/15136.84.0.1 to 136.85.255.254136.85.255.255131,070
44136.86.0.0/15136.86.0.1 to 136.87.255.254136.87.255.255131,070
45136.88.0.0/15136.88.0.1 to 136.89.255.254136.89.255.255131,070
46136.90.0.0/15136.90.0.1 to 136.91.255.254136.91.255.255131,070
47136.92.0.0/15136.92.0.1 to 136.93.255.254136.93.255.255131,070
48136.94.0.0/15136.94.0.1 to 136.95.255.254136.95.255.255131,070
49136.96.0.0/15136.96.0.1 to 136.97.255.254136.97.255.255131,070
50136.98.0.0/15136.98.0.1 to 136.99.255.254136.99.255.255131,070
51136.100.0.0/15136.100.0.1 to 136.101.255.254136.101.255.255131,070
52136.102.0.0/15136.102.0.1 to 136.103.255.254136.103.255.255131,070
53136.104.0.0/15136.104.0.1 to 136.105.255.254136.105.255.255131,070
54136.106.0.0/15136.106.0.1 to 136.107.255.254136.107.255.255131,070
55136.108.0.0/15136.108.0.1 to 136.109.255.254136.109.255.255131,070
56136.110.0.0/15136.110.0.1 to 136.111.255.254136.111.255.255131,070
57136.112.0.0/15136.112.0.1 to 136.113.255.254136.113.255.255131,070
58136.114.0.0/15136.114.0.1 to 136.115.255.254136.115.255.255131,070
59136.116.0.0/15136.116.0.1 to 136.117.255.254136.117.255.255131,070
60136.118.0.0/15136.118.0.1 to 136.119.255.254136.119.255.255131,070
61136.120.0.0/15136.120.0.1 to 136.121.255.254136.121.255.255131,070
62136.122.0.0/15136.122.0.1 to 136.123.255.254136.123.255.255131,070
63136.124.0.0/15136.124.0.1 to 136.125.255.254136.125.255.255131,070
64136.126.0.0/15136.126.0.1 to 136.127.255.254136.127.255.255131,070
65136.128.0.0/15136.128.0.1 to 136.129.255.254136.129.255.255131,070
66136.130.0.0/15136.130.0.1 to 136.131.255.254136.131.255.255131,070
67136.132.0.0/15136.132.0.1 to 136.133.255.254136.133.255.255131,070
68136.134.0.0/15136.134.0.1 to 136.135.255.254136.135.255.255131,070
69136.136.0.0/15136.136.0.1 to 136.137.255.254136.137.255.255131,070
70136.138.0.0/15136.138.0.1 to 136.139.255.254136.139.255.255131,070
71136.140.0.0/15136.140.0.1 to 136.141.255.254136.141.255.255131,070
72136.142.0.0/15136.142.0.1 to 136.143.255.254136.143.255.255131,070
73136.144.0.0/15136.144.0.1 to 136.145.255.254136.145.255.255131,070
74136.146.0.0/15136.146.0.1 to 136.147.255.254136.147.255.255131,070
75136.148.0.0/15136.148.0.1 to 136.149.255.254136.149.255.255131,070
76136.150.0.0/15136.150.0.1 to 136.151.255.254136.151.255.255131,070
77136.152.0.0/15136.152.0.1 to 136.153.255.254136.153.255.255131,070
78136.154.0.0/15136.154.0.1 to 136.155.255.254136.155.255.255131,070
79136.156.0.0/15136.156.0.1 to 136.157.255.254136.157.255.255131,070
80136.158.0.0/15136.158.0.1 to 136.159.255.254136.159.255.255131,070
81136.160.0.0/15136.160.0.1 to 136.161.255.254136.161.255.255131,070
82136.162.0.0/15136.162.0.1 to 136.163.255.254136.163.255.255131,070
83136.164.0.0/15136.164.0.1 to 136.165.255.254136.165.255.255131,070
84136.166.0.0/15136.166.0.1 to 136.167.255.254136.167.255.255131,070
85136.168.0.0/15136.168.0.1 to 136.169.255.254136.169.255.255131,070
86136.170.0.0/15136.170.0.1 to 136.171.255.254136.171.255.255131,070
87136.172.0.0/15136.172.0.1 to 136.173.255.254136.173.255.255131,070
88136.174.0.0/15136.174.0.1 to 136.175.255.254136.175.255.255131,070
89136.176.0.0/15136.176.0.1 to 136.177.255.254136.177.255.255131,070
90136.178.0.0/15136.178.0.1 to 136.179.255.254136.179.255.255131,070
91136.180.0.0/15136.180.0.1 to 136.181.255.254136.181.255.255131,070
92136.182.0.0/15136.182.0.1 to 136.183.255.254136.183.255.255131,070
93136.184.0.0/15136.184.0.1 to 136.185.255.254136.185.255.255131,070
94136.186.0.0/15136.186.0.1 to 136.187.255.254136.187.255.255131,070
95136.188.0.0/15136.188.0.1 to 136.189.255.254136.189.255.255131,070
96136.190.0.0/15136.190.0.1 to 136.191.255.254136.191.255.255131,070
97136.192.0.0/15136.192.0.1 to 136.193.255.254136.193.255.255131,070
98136.194.0.0/15136.194.0.1 to 136.195.255.254136.195.255.255131,070
99136.196.0.0/15136.196.0.1 to 136.197.255.254136.197.255.255131,070
100136.198.0.0/15136.198.0.1 to 136.199.255.254136.199.255.255131,070
101136.200.0.0/15136.200.0.1 to 136.201.255.254136.201.255.255131,070
102136.202.0.0/15136.202.0.1 to 136.203.255.254136.203.255.255131,070
103136.204.0.0/15136.204.0.1 to 136.205.255.254136.205.255.255131,070
104136.206.0.0/15136.206.0.1 to 136.207.255.254136.207.255.255131,070
105136.208.0.0/15136.208.0.1 to 136.209.255.254136.209.255.255131,070
106136.210.0.0/15136.210.0.1 to 136.211.255.254136.211.255.255131,070
107136.212.0.0/15136.212.0.1 to 136.213.255.254136.213.255.255131,070
108136.214.0.0/15136.214.0.1 to 136.215.255.254136.215.255.255131,070
109136.216.0.0/15136.216.0.1 to 136.217.255.254136.217.255.255131,070
110136.218.0.0/15136.218.0.1 to 136.219.255.254136.219.255.255131,070
111136.220.0.0/15136.220.0.1 to 136.221.255.254136.221.255.255131,070
112136.222.0.0/15136.222.0.1 to 136.223.255.254136.223.255.255131,070
113136.224.0.0/15136.224.0.1 to 136.225.255.254136.225.255.255131,070
114136.226.0.0/15136.226.0.1 to 136.227.255.254136.227.255.255131,070
115136.228.0.0/15136.228.0.1 to 136.229.255.254136.229.255.255131,070
116136.230.0.0/15136.230.0.1 to 136.231.255.254136.231.255.255131,070
117136.232.0.0/15136.232.0.1 to 136.233.255.254136.233.255.255131,070
118136.234.0.0/15136.234.0.1 to 136.235.255.254136.235.255.255131,070
119136.236.0.0/15136.236.0.1 to 136.237.255.254136.237.255.255131,070
120136.238.0.0/15136.238.0.1 to 136.239.255.254136.239.255.255131,070
121136.240.0.0/15136.240.0.1 to 136.241.255.254136.241.255.255131,070
122136.242.0.0/15136.242.0.1 to 136.243.255.254136.243.255.255131,070
123136.244.0.0/15136.244.0.1 to 136.245.255.254136.245.255.255131,070
124136.246.0.0/15136.246.0.1 to 136.247.255.254136.247.255.255131,070
125136.248.0.0/15136.248.0.1 to 136.249.255.254136.249.255.255131,070
126136.250.0.0/15136.250.0.1 to 136.251.255.254136.251.255.255131,070
127136.252.0.0/15136.252.0.1 to 136.253.255.254136.253.255.255131,070
128136.254.0.0/15136.254.0.1 to 136.255.255.254136.255.255.255131,070
129137.0.0.0/15137.0.0.1 to 137.1.255.254137.1.255.255131,070
130137.2.0.0/15137.2.0.1 to 137.3.255.254137.3.255.255131,070
131137.4.0.0/15137.4.0.1 to 137.5.255.254137.5.255.255131,070
132137.6.0.0/15137.6.0.1 to 137.7.255.254137.7.255.255131,070
133137.8.0.0/15137.8.0.1 to 137.9.255.254137.9.255.255131,070
134137.10.0.0/15137.10.0.1 to 137.11.255.254137.11.255.255131,070
135137.12.0.0/15137.12.0.1 to 137.13.255.254137.13.255.255131,070
136137.14.0.0/15137.14.0.1 to 137.15.255.254137.15.255.255131,070
137137.16.0.0/15137.16.0.1 to 137.17.255.254137.17.255.255131,070
138137.18.0.0/15137.18.0.1 to 137.19.255.254137.19.255.255131,070
139137.20.0.0/15137.20.0.1 to 137.21.255.254137.21.255.255131,070
140137.22.0.0/15137.22.0.1 to 137.23.255.254137.23.255.255131,070
141137.24.0.0/15137.24.0.1 to 137.25.255.254137.25.255.255131,070
142137.26.0.0/15137.26.0.1 to 137.27.255.254137.27.255.255131,070
143137.28.0.0/15137.28.0.1 to 137.29.255.254137.29.255.255131,070
144137.30.0.0/15137.30.0.1 to 137.31.255.254137.31.255.255131,070
145137.32.0.0/15137.32.0.1 to 137.33.255.254137.33.255.255131,070
146137.34.0.0/15137.34.0.1 to 137.35.255.254137.35.255.255131,070
147137.36.0.0/15137.36.0.1 to 137.37.255.254137.37.255.255131,070
148137.38.0.0/15137.38.0.1 to 137.39.255.254137.39.255.255131,070
149137.40.0.0/15137.40.0.1 to 137.41.255.254137.41.255.255131,070
150137.42.0.0/15137.42.0.1 to 137.43.255.254137.43.255.255131,070
151137.44.0.0/15137.44.0.1 to 137.45.255.254137.45.255.255131,070
152137.46.0.0/15137.46.0.1 to 137.47.255.254137.47.255.255131,070
153137.48.0.0/15137.48.0.1 to 137.49.255.254137.49.255.255131,070
154137.50.0.0/15137.50.0.1 to 137.51.255.254137.51.255.255131,070
155137.52.0.0/15137.52.0.1 to 137.53.255.254137.53.255.255131,070
156137.54.0.0/15137.54.0.1 to 137.55.255.254137.55.255.255131,070
157137.56.0.0/15137.56.0.1 to 137.57.255.254137.57.255.255131,070
158137.58.0.0/15137.58.0.1 to 137.59.255.254137.59.255.255131,070
159137.60.0.0/15137.60.0.1 to 137.61.255.254137.61.255.255131,070
160137.62.0.0/15137.62.0.1 to 137.63.255.254137.63.255.255131,070
161137.64.0.0/15137.64.0.1 to 137.65.255.254137.65.255.255131,070
162137.66.0.0/15137.66.0.1 to 137.67.255.254137.67.255.255131,070
163137.68.0.0/15137.68.0.1 to 137.69.255.254137.69.255.255131,070
164137.70.0.0/15137.70.0.1 to 137.71.255.254137.71.255.255131,070
165137.72.0.0/15137.72.0.1 to 137.73.255.254137.73.255.255131,070
166137.74.0.0/15137.74.0.1 to 137.75.255.254137.75.255.255131,070
167137.76.0.0/15137.76.0.1 to 137.77.255.254137.77.255.255131,070
168137.78.0.0/15137.78.0.1 to 137.79.255.254137.79.255.255131,070
169137.80.0.0/15137.80.0.1 to 137.81.255.254137.81.255.255131,070
170137.82.0.0/15137.82.0.1 to 137.83.255.254137.83.255.255131,070
171137.84.0.0/15137.84.0.1 to 137.85.255.254137.85.255.255131,070
172137.86.0.0/15137.86.0.1 to 137.87.255.254137.87.255.255131,070
173137.88.0.0/15137.88.0.1 to 137.89.255.254137.89.255.255131,070
174137.90.0.0/15137.90.0.1 to 137.91.255.254137.91.255.255131,070
175137.92.0.0/15137.92.0.1 to 137.93.255.254137.93.255.255131,070
176137.94.0.0/15137.94.0.1 to 137.95.255.254137.95.255.255131,070
177137.96.0.0/15137.96.0.1 to 137.97.255.254137.97.255.255131,070
178137.98.0.0/15137.98.0.1 to 137.99.255.254137.99.255.255131,070
179137.100.0.0/15137.100.0.1 to 137.101.255.254137.101.255.255131,070
180137.102.0.0/15137.102.0.1 to 137.103.255.254137.103.255.255131,070
181137.104.0.0/15137.104.0.1 to 137.105.255.254137.105.255.255131,070
182137.106.0.0/15137.106.0.1 to 137.107.255.254137.107.255.255131,070
183137.108.0.0/15137.108.0.1 to 137.109.255.254137.109.255.255131,070
184137.110.0.0/15137.110.0.1 to 137.111.255.254137.111.255.255131,070
185137.112.0.0/15137.112.0.1 to 137.113.255.254137.113.255.255131,070
186137.114.0.0/15137.114.0.1 to 137.115.255.254137.115.255.255131,070
187137.116.0.0/15137.116.0.1 to 137.117.255.254137.117.255.255131,070
188137.118.0.0/15137.118.0.1 to 137.119.255.254137.119.255.255131,070
189137.120.0.0/15137.120.0.1 to 137.121.255.254137.121.255.255131,070
190137.122.0.0/15137.122.0.1 to 137.123.255.254137.123.255.255131,070
191137.124.0.0/15137.124.0.1 to 137.125.255.254137.125.255.255131,070
192137.126.0.0/15137.126.0.1 to 137.127.255.254137.127.255.255131,070
193137.128.0.0/15137.128.0.1 to 137.129.255.254137.129.255.255131,070
194137.130.0.0/15137.130.0.1 to 137.131.255.254137.131.255.255131,070
195137.132.0.0/15137.132.0.1 to 137.133.255.254137.133.255.255131,070
196137.134.0.0/15137.134.0.1 to 137.135.255.254137.135.255.255131,070
197137.136.0.0/15137.136.0.1 to 137.137.255.254137.137.255.255131,070
198137.138.0.0/15137.138.0.1 to 137.139.255.254137.139.255.255131,070
199137.140.0.0/15137.140.0.1 to 137.141.255.254137.141.255.255131,070
200137.142.0.0/15137.142.0.1 to 137.143.255.254137.143.255.255131,070
201137.144.0.0/15137.144.0.1 to 137.145.255.254137.145.255.255131,070
202137.146.0.0/15137.146.0.1 to 137.147.255.254137.147.255.255131,070
203137.148.0.0/15137.148.0.1 to 137.149.255.254137.149.255.255131,070
204137.150.0.0/15137.150.0.1 to 137.151.255.254137.151.255.255131,070
205137.152.0.0/15137.152.0.1 to 137.153.255.254137.153.255.255131,070
206137.154.0.0/15137.154.0.1 to 137.155.255.254137.155.255.255131,070
207137.156.0.0/15137.156.0.1 to 137.157.255.254137.157.255.255131,070
208137.158.0.0/15137.158.0.1 to 137.159.255.254137.159.255.255131,070
209137.160.0.0/15137.160.0.1 to 137.161.255.254137.161.255.255131,070
210137.162.0.0/15137.162.0.1 to 137.163.255.254137.163.255.255131,070
211137.164.0.0/15137.164.0.1 to 137.165.255.254137.165.255.255131,070
212137.166.0.0/15137.166.0.1 to 137.167.255.254137.167.255.255131,070
213137.168.0.0/15137.168.0.1 to 137.169.255.254137.169.255.255131,070
214137.170.0.0/15137.170.0.1 to 137.171.255.254137.171.255.255131,070
215137.172.0.0/15137.172.0.1 to 137.173.255.254137.173.255.255131,070
216137.174.0.0/15137.174.0.1 to 137.175.255.254137.175.255.255131,070
217137.176.0.0/15137.176.0.1 to 137.177.255.254137.177.255.255131,070
218137.178.0.0/15137.178.0.1 to 137.179.255.254137.179.255.255131,070
219137.180.0.0/15137.180.0.1 to 137.181.255.254137.181.255.255131,070
220137.182.0.0/15137.182.0.1 to 137.183.255.254137.183.255.255131,070
221137.184.0.0/15137.184.0.1 to 137.185.255.254137.185.255.255131,070
222137.186.0.0/15137.186.0.1 to 137.187.255.254137.187.255.255131,070
223137.188.0.0/15137.188.0.1 to 137.189.255.254137.189.255.255131,070
224137.190.0.0/15137.190.0.1 to 137.191.255.254137.191.255.255131,070
225137.192.0.0/15137.192.0.1 to 137.193.255.254137.193.255.255131,070
226137.194.0.0/15137.194.0.1 to 137.195.255.254137.195.255.255131,070
227137.196.0.0/15137.196.0.1 to 137.197.255.254137.197.255.255131,070
228137.198.0.0/15137.198.0.1 to 137.199.255.254137.199.255.255131,070
229137.200.0.0/15137.200.0.1 to 137.201.255.254137.201.255.255131,070
230137.202.0.0/15137.202.0.1 to 137.203.255.254137.203.255.255131,070
231137.204.0.0/15137.204.0.1 to 137.205.255.254137.205.255.255131,070
232137.206.0.0/15137.206.0.1 to 137.207.255.254137.207.255.255131,070
233137.208.0.0/15137.208.0.1 to 137.209.255.254137.209.255.255131,070
234137.210.0.0/15137.210.0.1 to 137.211.255.254137.211.255.255131,070
235137.212.0.0/15137.212.0.1 to 137.213.255.254137.213.255.255131,070
236137.214.0.0/15137.214.0.1 to 137.215.255.254137.215.255.255131,070
237137.216.0.0/15137.216.0.1 to 137.217.255.254137.217.255.255131,070
238137.218.0.0/15137.218.0.1 to 137.219.255.254137.219.255.255131,070
239137.220.0.0/15137.220.0.1 to 137.221.255.254137.221.255.255131,070
240137.222.0.0/15137.222.0.1 to 137.223.255.254137.223.255.255131,070
241137.224.0.0/15137.224.0.1 to 137.225.255.254137.225.255.255131,070
242137.226.0.0/15137.226.0.1 to 137.227.255.254137.227.255.255131,070
243137.228.0.0/15137.228.0.1 to 137.229.255.254137.229.255.255131,070
244137.230.0.0/15137.230.0.1 to 137.231.255.254137.231.255.255131,070
245137.232.0.0/15137.232.0.1 to 137.233.255.254137.233.255.255131,070
246137.234.0.0/15137.234.0.1 to 137.235.255.254137.235.255.255131,070
247137.236.0.0/15137.236.0.1 to 137.237.255.254137.237.255.255131,070
248137.238.0.0/15137.238.0.1 to 137.239.255.254137.239.255.255131,070
249137.240.0.0/15137.240.0.1 to 137.241.255.254137.241.255.255131,070
250137.242.0.0/15137.242.0.1 to 137.243.255.254137.243.255.255131,070
251137.244.0.0/15137.244.0.1 to 137.245.255.254137.245.255.255131,070
252137.246.0.0/15137.246.0.1 to 137.247.255.254137.247.255.255131,070
253137.248.0.0/15137.248.0.1 to 137.249.255.254137.249.255.255131,070
254137.250.0.0/15137.250.0.1 to 137.251.255.254137.251.255.255131,070
255137.252.0.0/15137.252.0.1 to 137.253.255.254137.253.255.255131,070
256137.254.0.0/15137.254.0.1 to 137.255.255.254137.255.255.255131,070

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.