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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.

Network180.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
180.0.0.0
Broadcast address
181.255.255.255
First usable
180.0.0.1
Last usable
181.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex B4000000 · Integer 3019898880 to 3053453311
Reverse DNS zones
180.in-addr.arpa
181.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110100.00000000.00000000.00000000180.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10110100.00000000.00000000.00000000180.0.0.0
Broadcast10110101.11111111.11111111.11111111181.255.255.255
Split into smaller subnets/15
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

180.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1180.0.0.0/15180.0.0.1 to 180.1.255.254180.1.255.255131,070
2180.2.0.0/15180.2.0.1 to 180.3.255.254180.3.255.255131,070
3180.4.0.0/15180.4.0.1 to 180.5.255.254180.5.255.255131,070
4180.6.0.0/15180.6.0.1 to 180.7.255.254180.7.255.255131,070
5180.8.0.0/15180.8.0.1 to 180.9.255.254180.9.255.255131,070
6180.10.0.0/15180.10.0.1 to 180.11.255.254180.11.255.255131,070
7180.12.0.0/15180.12.0.1 to 180.13.255.254180.13.255.255131,070
8180.14.0.0/15180.14.0.1 to 180.15.255.254180.15.255.255131,070
9180.16.0.0/15180.16.0.1 to 180.17.255.254180.17.255.255131,070
10180.18.0.0/15180.18.0.1 to 180.19.255.254180.19.255.255131,070
11180.20.0.0/15180.20.0.1 to 180.21.255.254180.21.255.255131,070
12180.22.0.0/15180.22.0.1 to 180.23.255.254180.23.255.255131,070
13180.24.0.0/15180.24.0.1 to 180.25.255.254180.25.255.255131,070
14180.26.0.0/15180.26.0.1 to 180.27.255.254180.27.255.255131,070
15180.28.0.0/15180.28.0.1 to 180.29.255.254180.29.255.255131,070
16180.30.0.0/15180.30.0.1 to 180.31.255.254180.31.255.255131,070
17180.32.0.0/15180.32.0.1 to 180.33.255.254180.33.255.255131,070
18180.34.0.0/15180.34.0.1 to 180.35.255.254180.35.255.255131,070
19180.36.0.0/15180.36.0.1 to 180.37.255.254180.37.255.255131,070
20180.38.0.0/15180.38.0.1 to 180.39.255.254180.39.255.255131,070
21180.40.0.0/15180.40.0.1 to 180.41.255.254180.41.255.255131,070
22180.42.0.0/15180.42.0.1 to 180.43.255.254180.43.255.255131,070
23180.44.0.0/15180.44.0.1 to 180.45.255.254180.45.255.255131,070
24180.46.0.0/15180.46.0.1 to 180.47.255.254180.47.255.255131,070
25180.48.0.0/15180.48.0.1 to 180.49.255.254180.49.255.255131,070
26180.50.0.0/15180.50.0.1 to 180.51.255.254180.51.255.255131,070
27180.52.0.0/15180.52.0.1 to 180.53.255.254180.53.255.255131,070
28180.54.0.0/15180.54.0.1 to 180.55.255.254180.55.255.255131,070
29180.56.0.0/15180.56.0.1 to 180.57.255.254180.57.255.255131,070
30180.58.0.0/15180.58.0.1 to 180.59.255.254180.59.255.255131,070
31180.60.0.0/15180.60.0.1 to 180.61.255.254180.61.255.255131,070
32180.62.0.0/15180.62.0.1 to 180.63.255.254180.63.255.255131,070
33180.64.0.0/15180.64.0.1 to 180.65.255.254180.65.255.255131,070
34180.66.0.0/15180.66.0.1 to 180.67.255.254180.67.255.255131,070
35180.68.0.0/15180.68.0.1 to 180.69.255.254180.69.255.255131,070
36180.70.0.0/15180.70.0.1 to 180.71.255.254180.71.255.255131,070
37180.72.0.0/15180.72.0.1 to 180.73.255.254180.73.255.255131,070
38180.74.0.0/15180.74.0.1 to 180.75.255.254180.75.255.255131,070
39180.76.0.0/15180.76.0.1 to 180.77.255.254180.77.255.255131,070
40180.78.0.0/15180.78.0.1 to 180.79.255.254180.79.255.255131,070
41180.80.0.0/15180.80.0.1 to 180.81.255.254180.81.255.255131,070
42180.82.0.0/15180.82.0.1 to 180.83.255.254180.83.255.255131,070
43180.84.0.0/15180.84.0.1 to 180.85.255.254180.85.255.255131,070
44180.86.0.0/15180.86.0.1 to 180.87.255.254180.87.255.255131,070
45180.88.0.0/15180.88.0.1 to 180.89.255.254180.89.255.255131,070
46180.90.0.0/15180.90.0.1 to 180.91.255.254180.91.255.255131,070
47180.92.0.0/15180.92.0.1 to 180.93.255.254180.93.255.255131,070
48180.94.0.0/15180.94.0.1 to 180.95.255.254180.95.255.255131,070
49180.96.0.0/15180.96.0.1 to 180.97.255.254180.97.255.255131,070
50180.98.0.0/15180.98.0.1 to 180.99.255.254180.99.255.255131,070
51180.100.0.0/15180.100.0.1 to 180.101.255.254180.101.255.255131,070
52180.102.0.0/15180.102.0.1 to 180.103.255.254180.103.255.255131,070
53180.104.0.0/15180.104.0.1 to 180.105.255.254180.105.255.255131,070
54180.106.0.0/15180.106.0.1 to 180.107.255.254180.107.255.255131,070
55180.108.0.0/15180.108.0.1 to 180.109.255.254180.109.255.255131,070
56180.110.0.0/15180.110.0.1 to 180.111.255.254180.111.255.255131,070
57180.112.0.0/15180.112.0.1 to 180.113.255.254180.113.255.255131,070
58180.114.0.0/15180.114.0.1 to 180.115.255.254180.115.255.255131,070
59180.116.0.0/15180.116.0.1 to 180.117.255.254180.117.255.255131,070
60180.118.0.0/15180.118.0.1 to 180.119.255.254180.119.255.255131,070
61180.120.0.0/15180.120.0.1 to 180.121.255.254180.121.255.255131,070
62180.122.0.0/15180.122.0.1 to 180.123.255.254180.123.255.255131,070
63180.124.0.0/15180.124.0.1 to 180.125.255.254180.125.255.255131,070
64180.126.0.0/15180.126.0.1 to 180.127.255.254180.127.255.255131,070
65180.128.0.0/15180.128.0.1 to 180.129.255.254180.129.255.255131,070
66180.130.0.0/15180.130.0.1 to 180.131.255.254180.131.255.255131,070
67180.132.0.0/15180.132.0.1 to 180.133.255.254180.133.255.255131,070
68180.134.0.0/15180.134.0.1 to 180.135.255.254180.135.255.255131,070
69180.136.0.0/15180.136.0.1 to 180.137.255.254180.137.255.255131,070
70180.138.0.0/15180.138.0.1 to 180.139.255.254180.139.255.255131,070
71180.140.0.0/15180.140.0.1 to 180.141.255.254180.141.255.255131,070
72180.142.0.0/15180.142.0.1 to 180.143.255.254180.143.255.255131,070
73180.144.0.0/15180.144.0.1 to 180.145.255.254180.145.255.255131,070
74180.146.0.0/15180.146.0.1 to 180.147.255.254180.147.255.255131,070
75180.148.0.0/15180.148.0.1 to 180.149.255.254180.149.255.255131,070
76180.150.0.0/15180.150.0.1 to 180.151.255.254180.151.255.255131,070
77180.152.0.0/15180.152.0.1 to 180.153.255.254180.153.255.255131,070
78180.154.0.0/15180.154.0.1 to 180.155.255.254180.155.255.255131,070
79180.156.0.0/15180.156.0.1 to 180.157.255.254180.157.255.255131,070
80180.158.0.0/15180.158.0.1 to 180.159.255.254180.159.255.255131,070
81180.160.0.0/15180.160.0.1 to 180.161.255.254180.161.255.255131,070
82180.162.0.0/15180.162.0.1 to 180.163.255.254180.163.255.255131,070
83180.164.0.0/15180.164.0.1 to 180.165.255.254180.165.255.255131,070
84180.166.0.0/15180.166.0.1 to 180.167.255.254180.167.255.255131,070
85180.168.0.0/15180.168.0.1 to 180.169.255.254180.169.255.255131,070
86180.170.0.0/15180.170.0.1 to 180.171.255.254180.171.255.255131,070
87180.172.0.0/15180.172.0.1 to 180.173.255.254180.173.255.255131,070
88180.174.0.0/15180.174.0.1 to 180.175.255.254180.175.255.255131,070
89180.176.0.0/15180.176.0.1 to 180.177.255.254180.177.255.255131,070
90180.178.0.0/15180.178.0.1 to 180.179.255.254180.179.255.255131,070
91180.180.0.0/15180.180.0.1 to 180.181.255.254180.181.255.255131,070
92180.182.0.0/15180.182.0.1 to 180.183.255.254180.183.255.255131,070
93180.184.0.0/15180.184.0.1 to 180.185.255.254180.185.255.255131,070
94180.186.0.0/15180.186.0.1 to 180.187.255.254180.187.255.255131,070
95180.188.0.0/15180.188.0.1 to 180.189.255.254180.189.255.255131,070
96180.190.0.0/15180.190.0.1 to 180.191.255.254180.191.255.255131,070
97180.192.0.0/15180.192.0.1 to 180.193.255.254180.193.255.255131,070
98180.194.0.0/15180.194.0.1 to 180.195.255.254180.195.255.255131,070
99180.196.0.0/15180.196.0.1 to 180.197.255.254180.197.255.255131,070
100180.198.0.0/15180.198.0.1 to 180.199.255.254180.199.255.255131,070
101180.200.0.0/15180.200.0.1 to 180.201.255.254180.201.255.255131,070
102180.202.0.0/15180.202.0.1 to 180.203.255.254180.203.255.255131,070
103180.204.0.0/15180.204.0.1 to 180.205.255.254180.205.255.255131,070
104180.206.0.0/15180.206.0.1 to 180.207.255.254180.207.255.255131,070
105180.208.0.0/15180.208.0.1 to 180.209.255.254180.209.255.255131,070
106180.210.0.0/15180.210.0.1 to 180.211.255.254180.211.255.255131,070
107180.212.0.0/15180.212.0.1 to 180.213.255.254180.213.255.255131,070
108180.214.0.0/15180.214.0.1 to 180.215.255.254180.215.255.255131,070
109180.216.0.0/15180.216.0.1 to 180.217.255.254180.217.255.255131,070
110180.218.0.0/15180.218.0.1 to 180.219.255.254180.219.255.255131,070
111180.220.0.0/15180.220.0.1 to 180.221.255.254180.221.255.255131,070
112180.222.0.0/15180.222.0.1 to 180.223.255.254180.223.255.255131,070
113180.224.0.0/15180.224.0.1 to 180.225.255.254180.225.255.255131,070
114180.226.0.0/15180.226.0.1 to 180.227.255.254180.227.255.255131,070
115180.228.0.0/15180.228.0.1 to 180.229.255.254180.229.255.255131,070
116180.230.0.0/15180.230.0.1 to 180.231.255.254180.231.255.255131,070
117180.232.0.0/15180.232.0.1 to 180.233.255.254180.233.255.255131,070
118180.234.0.0/15180.234.0.1 to 180.235.255.254180.235.255.255131,070
119180.236.0.0/15180.236.0.1 to 180.237.255.254180.237.255.255131,070
120180.238.0.0/15180.238.0.1 to 180.239.255.254180.239.255.255131,070
121180.240.0.0/15180.240.0.1 to 180.241.255.254180.241.255.255131,070
122180.242.0.0/15180.242.0.1 to 180.243.255.254180.243.255.255131,070
123180.244.0.0/15180.244.0.1 to 180.245.255.254180.245.255.255131,070
124180.246.0.0/15180.246.0.1 to 180.247.255.254180.247.255.255131,070
125180.248.0.0/15180.248.0.1 to 180.249.255.254180.249.255.255131,070
126180.250.0.0/15180.250.0.1 to 180.251.255.254180.251.255.255131,070
127180.252.0.0/15180.252.0.1 to 180.253.255.254180.253.255.255131,070
128180.254.0.0/15180.254.0.1 to 180.255.255.254180.255.255.255131,070
129181.0.0.0/15181.0.0.1 to 181.1.255.254181.1.255.255131,070
130181.2.0.0/15181.2.0.1 to 181.3.255.254181.3.255.255131,070
131181.4.0.0/15181.4.0.1 to 181.5.255.254181.5.255.255131,070
132181.6.0.0/15181.6.0.1 to 181.7.255.254181.7.255.255131,070
133181.8.0.0/15181.8.0.1 to 181.9.255.254181.9.255.255131,070
134181.10.0.0/15181.10.0.1 to 181.11.255.254181.11.255.255131,070
135181.12.0.0/15181.12.0.1 to 181.13.255.254181.13.255.255131,070
136181.14.0.0/15181.14.0.1 to 181.15.255.254181.15.255.255131,070
137181.16.0.0/15181.16.0.1 to 181.17.255.254181.17.255.255131,070
138181.18.0.0/15181.18.0.1 to 181.19.255.254181.19.255.255131,070
139181.20.0.0/15181.20.0.1 to 181.21.255.254181.21.255.255131,070
140181.22.0.0/15181.22.0.1 to 181.23.255.254181.23.255.255131,070
141181.24.0.0/15181.24.0.1 to 181.25.255.254181.25.255.255131,070
142181.26.0.0/15181.26.0.1 to 181.27.255.254181.27.255.255131,070
143181.28.0.0/15181.28.0.1 to 181.29.255.254181.29.255.255131,070
144181.30.0.0/15181.30.0.1 to 181.31.255.254181.31.255.255131,070
145181.32.0.0/15181.32.0.1 to 181.33.255.254181.33.255.255131,070
146181.34.0.0/15181.34.0.1 to 181.35.255.254181.35.255.255131,070
147181.36.0.0/15181.36.0.1 to 181.37.255.254181.37.255.255131,070
148181.38.0.0/15181.38.0.1 to 181.39.255.254181.39.255.255131,070
149181.40.0.0/15181.40.0.1 to 181.41.255.254181.41.255.255131,070
150181.42.0.0/15181.42.0.1 to 181.43.255.254181.43.255.255131,070
151181.44.0.0/15181.44.0.1 to 181.45.255.254181.45.255.255131,070
152181.46.0.0/15181.46.0.1 to 181.47.255.254181.47.255.255131,070
153181.48.0.0/15181.48.0.1 to 181.49.255.254181.49.255.255131,070
154181.50.0.0/15181.50.0.1 to 181.51.255.254181.51.255.255131,070
155181.52.0.0/15181.52.0.1 to 181.53.255.254181.53.255.255131,070
156181.54.0.0/15181.54.0.1 to 181.55.255.254181.55.255.255131,070
157181.56.0.0/15181.56.0.1 to 181.57.255.254181.57.255.255131,070
158181.58.0.0/15181.58.0.1 to 181.59.255.254181.59.255.255131,070
159181.60.0.0/15181.60.0.1 to 181.61.255.254181.61.255.255131,070
160181.62.0.0/15181.62.0.1 to 181.63.255.254181.63.255.255131,070
161181.64.0.0/15181.64.0.1 to 181.65.255.254181.65.255.255131,070
162181.66.0.0/15181.66.0.1 to 181.67.255.254181.67.255.255131,070
163181.68.0.0/15181.68.0.1 to 181.69.255.254181.69.255.255131,070
164181.70.0.0/15181.70.0.1 to 181.71.255.254181.71.255.255131,070
165181.72.0.0/15181.72.0.1 to 181.73.255.254181.73.255.255131,070
166181.74.0.0/15181.74.0.1 to 181.75.255.254181.75.255.255131,070
167181.76.0.0/15181.76.0.1 to 181.77.255.254181.77.255.255131,070
168181.78.0.0/15181.78.0.1 to 181.79.255.254181.79.255.255131,070
169181.80.0.0/15181.80.0.1 to 181.81.255.254181.81.255.255131,070
170181.82.0.0/15181.82.0.1 to 181.83.255.254181.83.255.255131,070
171181.84.0.0/15181.84.0.1 to 181.85.255.254181.85.255.255131,070
172181.86.0.0/15181.86.0.1 to 181.87.255.254181.87.255.255131,070
173181.88.0.0/15181.88.0.1 to 181.89.255.254181.89.255.255131,070
174181.90.0.0/15181.90.0.1 to 181.91.255.254181.91.255.255131,070
175181.92.0.0/15181.92.0.1 to 181.93.255.254181.93.255.255131,070
176181.94.0.0/15181.94.0.1 to 181.95.255.254181.95.255.255131,070
177181.96.0.0/15181.96.0.1 to 181.97.255.254181.97.255.255131,070
178181.98.0.0/15181.98.0.1 to 181.99.255.254181.99.255.255131,070
179181.100.0.0/15181.100.0.1 to 181.101.255.254181.101.255.255131,070
180181.102.0.0/15181.102.0.1 to 181.103.255.254181.103.255.255131,070
181181.104.0.0/15181.104.0.1 to 181.105.255.254181.105.255.255131,070
182181.106.0.0/15181.106.0.1 to 181.107.255.254181.107.255.255131,070
183181.108.0.0/15181.108.0.1 to 181.109.255.254181.109.255.255131,070
184181.110.0.0/15181.110.0.1 to 181.111.255.254181.111.255.255131,070
185181.112.0.0/15181.112.0.1 to 181.113.255.254181.113.255.255131,070
186181.114.0.0/15181.114.0.1 to 181.115.255.254181.115.255.255131,070
187181.116.0.0/15181.116.0.1 to 181.117.255.254181.117.255.255131,070
188181.118.0.0/15181.118.0.1 to 181.119.255.254181.119.255.255131,070
189181.120.0.0/15181.120.0.1 to 181.121.255.254181.121.255.255131,070
190181.122.0.0/15181.122.0.1 to 181.123.255.254181.123.255.255131,070
191181.124.0.0/15181.124.0.1 to 181.125.255.254181.125.255.255131,070
192181.126.0.0/15181.126.0.1 to 181.127.255.254181.127.255.255131,070
193181.128.0.0/15181.128.0.1 to 181.129.255.254181.129.255.255131,070
194181.130.0.0/15181.130.0.1 to 181.131.255.254181.131.255.255131,070
195181.132.0.0/15181.132.0.1 to 181.133.255.254181.133.255.255131,070
196181.134.0.0/15181.134.0.1 to 181.135.255.254181.135.255.255131,070
197181.136.0.0/15181.136.0.1 to 181.137.255.254181.137.255.255131,070
198181.138.0.0/15181.138.0.1 to 181.139.255.254181.139.255.255131,070
199181.140.0.0/15181.140.0.1 to 181.141.255.254181.141.255.255131,070
200181.142.0.0/15181.142.0.1 to 181.143.255.254181.143.255.255131,070
201181.144.0.0/15181.144.0.1 to 181.145.255.254181.145.255.255131,070
202181.146.0.0/15181.146.0.1 to 181.147.255.254181.147.255.255131,070
203181.148.0.0/15181.148.0.1 to 181.149.255.254181.149.255.255131,070
204181.150.0.0/15181.150.0.1 to 181.151.255.254181.151.255.255131,070
205181.152.0.0/15181.152.0.1 to 181.153.255.254181.153.255.255131,070
206181.154.0.0/15181.154.0.1 to 181.155.255.254181.155.255.255131,070
207181.156.0.0/15181.156.0.1 to 181.157.255.254181.157.255.255131,070
208181.158.0.0/15181.158.0.1 to 181.159.255.254181.159.255.255131,070
209181.160.0.0/15181.160.0.1 to 181.161.255.254181.161.255.255131,070
210181.162.0.0/15181.162.0.1 to 181.163.255.254181.163.255.255131,070
211181.164.0.0/15181.164.0.1 to 181.165.255.254181.165.255.255131,070
212181.166.0.0/15181.166.0.1 to 181.167.255.254181.167.255.255131,070
213181.168.0.0/15181.168.0.1 to 181.169.255.254181.169.255.255131,070
214181.170.0.0/15181.170.0.1 to 181.171.255.254181.171.255.255131,070
215181.172.0.0/15181.172.0.1 to 181.173.255.254181.173.255.255131,070
216181.174.0.0/15181.174.0.1 to 181.175.255.254181.175.255.255131,070
217181.176.0.0/15181.176.0.1 to 181.177.255.254181.177.255.255131,070
218181.178.0.0/15181.178.0.1 to 181.179.255.254181.179.255.255131,070
219181.180.0.0/15181.180.0.1 to 181.181.255.254181.181.255.255131,070
220181.182.0.0/15181.182.0.1 to 181.183.255.254181.183.255.255131,070
221181.184.0.0/15181.184.0.1 to 181.185.255.254181.185.255.255131,070
222181.186.0.0/15181.186.0.1 to 181.187.255.254181.187.255.255131,070
223181.188.0.0/15181.188.0.1 to 181.189.255.254181.189.255.255131,070
224181.190.0.0/15181.190.0.1 to 181.191.255.254181.191.255.255131,070
225181.192.0.0/15181.192.0.1 to 181.193.255.254181.193.255.255131,070
226181.194.0.0/15181.194.0.1 to 181.195.255.254181.195.255.255131,070
227181.196.0.0/15181.196.0.1 to 181.197.255.254181.197.255.255131,070
228181.198.0.0/15181.198.0.1 to 181.199.255.254181.199.255.255131,070
229181.200.0.0/15181.200.0.1 to 181.201.255.254181.201.255.255131,070
230181.202.0.0/15181.202.0.1 to 181.203.255.254181.203.255.255131,070
231181.204.0.0/15181.204.0.1 to 181.205.255.254181.205.255.255131,070
232181.206.0.0/15181.206.0.1 to 181.207.255.254181.207.255.255131,070
233181.208.0.0/15181.208.0.1 to 181.209.255.254181.209.255.255131,070
234181.210.0.0/15181.210.0.1 to 181.211.255.254181.211.255.255131,070
235181.212.0.0/15181.212.0.1 to 181.213.255.254181.213.255.255131,070
236181.214.0.0/15181.214.0.1 to 181.215.255.254181.215.255.255131,070
237181.216.0.0/15181.216.0.1 to 181.217.255.254181.217.255.255131,070
238181.218.0.0/15181.218.0.1 to 181.219.255.254181.219.255.255131,070
239181.220.0.0/15181.220.0.1 to 181.221.255.254181.221.255.255131,070
240181.222.0.0/15181.222.0.1 to 181.223.255.254181.223.255.255131,070
241181.224.0.0/15181.224.0.1 to 181.225.255.254181.225.255.255131,070
242181.226.0.0/15181.226.0.1 to 181.227.255.254181.227.255.255131,070
243181.228.0.0/15181.228.0.1 to 181.229.255.254181.229.255.255131,070
244181.230.0.0/15181.230.0.1 to 181.231.255.254181.231.255.255131,070
245181.232.0.0/15181.232.0.1 to 181.233.255.254181.233.255.255131,070
246181.234.0.0/15181.234.0.1 to 181.235.255.254181.235.255.255131,070
247181.236.0.0/15181.236.0.1 to 181.237.255.254181.237.255.255131,070
248181.238.0.0/15181.238.0.1 to 181.239.255.254181.239.255.255131,070
249181.240.0.0/15181.240.0.1 to 181.241.255.254181.241.255.255131,070
250181.242.0.0/15181.242.0.1 to 181.243.255.254181.243.255.255131,070
251181.244.0.0/15181.244.0.1 to 181.245.255.254181.245.255.255131,070
252181.246.0.0/15181.246.0.1 to 181.247.255.254181.247.255.255131,070
253181.248.0.0/15181.248.0.1 to 181.249.255.254181.249.255.255131,070
254181.250.0.0/15181.250.0.1 to 181.251.255.254181.251.255.255131,070
255181.252.0.0/15181.252.0.1 to 181.253.255.254181.253.255.255131,070
256181.254.0.0/15181.254.0.1 to 181.255.255.254181.255.255.255131,070

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.