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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.

Network191.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
191.0.0.0
Broadcast address
191.7.255.255
First usable
191.0.0.1
Last usable
191.7.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
B (default /16)
As numbers
Hex BF000000 · Integer 3204448256 to 3204972543
Reverse DNS zones
0.191.in-addr.arpa
1.191.in-addr.arpa
2.191.in-addr.arpa
3.191.in-addr.arpa
4.191.in-addr.arpa
5.191.in-addr.arpa
6.191.in-addr.arpa
7.191.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111111.00000000.00000000.00000000191.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network10111111.00000000.00000000.00000000191.0.0.0
Broadcast10111111.00000111.11111111.11111111191.7.255.255
Split into smaller subnets/23
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

191.0.0.0/13 makes 1,024 subnets of /23; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1191.0.0.0/23191.0.0.1 to 191.0.1.254191.0.1.255510
2191.0.2.0/23191.0.2.1 to 191.0.3.254191.0.3.255510
3191.0.4.0/23191.0.4.1 to 191.0.5.254191.0.5.255510
4191.0.6.0/23191.0.6.1 to 191.0.7.254191.0.7.255510
5191.0.8.0/23191.0.8.1 to 191.0.9.254191.0.9.255510
6191.0.10.0/23191.0.10.1 to 191.0.11.254191.0.11.255510
7191.0.12.0/23191.0.12.1 to 191.0.13.254191.0.13.255510
8191.0.14.0/23191.0.14.1 to 191.0.15.254191.0.15.255510
9191.0.16.0/23191.0.16.1 to 191.0.17.254191.0.17.255510
10191.0.18.0/23191.0.18.1 to 191.0.19.254191.0.19.255510
11191.0.20.0/23191.0.20.1 to 191.0.21.254191.0.21.255510
12191.0.22.0/23191.0.22.1 to 191.0.23.254191.0.23.255510
13191.0.24.0/23191.0.24.1 to 191.0.25.254191.0.25.255510
14191.0.26.0/23191.0.26.1 to 191.0.27.254191.0.27.255510
15191.0.28.0/23191.0.28.1 to 191.0.29.254191.0.29.255510
16191.0.30.0/23191.0.30.1 to 191.0.31.254191.0.31.255510
17191.0.32.0/23191.0.32.1 to 191.0.33.254191.0.33.255510
18191.0.34.0/23191.0.34.1 to 191.0.35.254191.0.35.255510
19191.0.36.0/23191.0.36.1 to 191.0.37.254191.0.37.255510
20191.0.38.0/23191.0.38.1 to 191.0.39.254191.0.39.255510
21191.0.40.0/23191.0.40.1 to 191.0.41.254191.0.41.255510
22191.0.42.0/23191.0.42.1 to 191.0.43.254191.0.43.255510
23191.0.44.0/23191.0.44.1 to 191.0.45.254191.0.45.255510
24191.0.46.0/23191.0.46.1 to 191.0.47.254191.0.47.255510
25191.0.48.0/23191.0.48.1 to 191.0.49.254191.0.49.255510
26191.0.50.0/23191.0.50.1 to 191.0.51.254191.0.51.255510
27191.0.52.0/23191.0.52.1 to 191.0.53.254191.0.53.255510
28191.0.54.0/23191.0.54.1 to 191.0.55.254191.0.55.255510
29191.0.56.0/23191.0.56.1 to 191.0.57.254191.0.57.255510
30191.0.58.0/23191.0.58.1 to 191.0.59.254191.0.59.255510
31191.0.60.0/23191.0.60.1 to 191.0.61.254191.0.61.255510
32191.0.62.0/23191.0.62.1 to 191.0.63.254191.0.63.255510
33191.0.64.0/23191.0.64.1 to 191.0.65.254191.0.65.255510
34191.0.66.0/23191.0.66.1 to 191.0.67.254191.0.67.255510
35191.0.68.0/23191.0.68.1 to 191.0.69.254191.0.69.255510
36191.0.70.0/23191.0.70.1 to 191.0.71.254191.0.71.255510
37191.0.72.0/23191.0.72.1 to 191.0.73.254191.0.73.255510
38191.0.74.0/23191.0.74.1 to 191.0.75.254191.0.75.255510
39191.0.76.0/23191.0.76.1 to 191.0.77.254191.0.77.255510
40191.0.78.0/23191.0.78.1 to 191.0.79.254191.0.79.255510
41191.0.80.0/23191.0.80.1 to 191.0.81.254191.0.81.255510
42191.0.82.0/23191.0.82.1 to 191.0.83.254191.0.83.255510
43191.0.84.0/23191.0.84.1 to 191.0.85.254191.0.85.255510
44191.0.86.0/23191.0.86.1 to 191.0.87.254191.0.87.255510
45191.0.88.0/23191.0.88.1 to 191.0.89.254191.0.89.255510
46191.0.90.0/23191.0.90.1 to 191.0.91.254191.0.91.255510
47191.0.92.0/23191.0.92.1 to 191.0.93.254191.0.93.255510
48191.0.94.0/23191.0.94.1 to 191.0.95.254191.0.95.255510
49191.0.96.0/23191.0.96.1 to 191.0.97.254191.0.97.255510
50191.0.98.0/23191.0.98.1 to 191.0.99.254191.0.99.255510
51191.0.100.0/23191.0.100.1 to 191.0.101.254191.0.101.255510
52191.0.102.0/23191.0.102.1 to 191.0.103.254191.0.103.255510
53191.0.104.0/23191.0.104.1 to 191.0.105.254191.0.105.255510
54191.0.106.0/23191.0.106.1 to 191.0.107.254191.0.107.255510
55191.0.108.0/23191.0.108.1 to 191.0.109.254191.0.109.255510
56191.0.110.0/23191.0.110.1 to 191.0.111.254191.0.111.255510
57191.0.112.0/23191.0.112.1 to 191.0.113.254191.0.113.255510
58191.0.114.0/23191.0.114.1 to 191.0.115.254191.0.115.255510
59191.0.116.0/23191.0.116.1 to 191.0.117.254191.0.117.255510
60191.0.118.0/23191.0.118.1 to 191.0.119.254191.0.119.255510
61191.0.120.0/23191.0.120.1 to 191.0.121.254191.0.121.255510
62191.0.122.0/23191.0.122.1 to 191.0.123.254191.0.123.255510
63191.0.124.0/23191.0.124.1 to 191.0.125.254191.0.125.255510
64191.0.126.0/23191.0.126.1 to 191.0.127.254191.0.127.255510
65191.0.128.0/23191.0.128.1 to 191.0.129.254191.0.129.255510
66191.0.130.0/23191.0.130.1 to 191.0.131.254191.0.131.255510
67191.0.132.0/23191.0.132.1 to 191.0.133.254191.0.133.255510
68191.0.134.0/23191.0.134.1 to 191.0.135.254191.0.135.255510
69191.0.136.0/23191.0.136.1 to 191.0.137.254191.0.137.255510
70191.0.138.0/23191.0.138.1 to 191.0.139.254191.0.139.255510
71191.0.140.0/23191.0.140.1 to 191.0.141.254191.0.141.255510
72191.0.142.0/23191.0.142.1 to 191.0.143.254191.0.143.255510
73191.0.144.0/23191.0.144.1 to 191.0.145.254191.0.145.255510
74191.0.146.0/23191.0.146.1 to 191.0.147.254191.0.147.255510
75191.0.148.0/23191.0.148.1 to 191.0.149.254191.0.149.255510
76191.0.150.0/23191.0.150.1 to 191.0.151.254191.0.151.255510
77191.0.152.0/23191.0.152.1 to 191.0.153.254191.0.153.255510
78191.0.154.0/23191.0.154.1 to 191.0.155.254191.0.155.255510
79191.0.156.0/23191.0.156.1 to 191.0.157.254191.0.157.255510
80191.0.158.0/23191.0.158.1 to 191.0.159.254191.0.159.255510
81191.0.160.0/23191.0.160.1 to 191.0.161.254191.0.161.255510
82191.0.162.0/23191.0.162.1 to 191.0.163.254191.0.163.255510
83191.0.164.0/23191.0.164.1 to 191.0.165.254191.0.165.255510
84191.0.166.0/23191.0.166.1 to 191.0.167.254191.0.167.255510
85191.0.168.0/23191.0.168.1 to 191.0.169.254191.0.169.255510
86191.0.170.0/23191.0.170.1 to 191.0.171.254191.0.171.255510
87191.0.172.0/23191.0.172.1 to 191.0.173.254191.0.173.255510
88191.0.174.0/23191.0.174.1 to 191.0.175.254191.0.175.255510
89191.0.176.0/23191.0.176.1 to 191.0.177.254191.0.177.255510
90191.0.178.0/23191.0.178.1 to 191.0.179.254191.0.179.255510
91191.0.180.0/23191.0.180.1 to 191.0.181.254191.0.181.255510
92191.0.182.0/23191.0.182.1 to 191.0.183.254191.0.183.255510
93191.0.184.0/23191.0.184.1 to 191.0.185.254191.0.185.255510
94191.0.186.0/23191.0.186.1 to 191.0.187.254191.0.187.255510
95191.0.188.0/23191.0.188.1 to 191.0.189.254191.0.189.255510
96191.0.190.0/23191.0.190.1 to 191.0.191.254191.0.191.255510
97191.0.192.0/23191.0.192.1 to 191.0.193.254191.0.193.255510
98191.0.194.0/23191.0.194.1 to 191.0.195.254191.0.195.255510
99191.0.196.0/23191.0.196.1 to 191.0.197.254191.0.197.255510
100191.0.198.0/23191.0.198.1 to 191.0.199.254191.0.199.255510
101191.0.200.0/23191.0.200.1 to 191.0.201.254191.0.201.255510
102191.0.202.0/23191.0.202.1 to 191.0.203.254191.0.203.255510
103191.0.204.0/23191.0.204.1 to 191.0.205.254191.0.205.255510
104191.0.206.0/23191.0.206.1 to 191.0.207.254191.0.207.255510
105191.0.208.0/23191.0.208.1 to 191.0.209.254191.0.209.255510
106191.0.210.0/23191.0.210.1 to 191.0.211.254191.0.211.255510
107191.0.212.0/23191.0.212.1 to 191.0.213.254191.0.213.255510
108191.0.214.0/23191.0.214.1 to 191.0.215.254191.0.215.255510
109191.0.216.0/23191.0.216.1 to 191.0.217.254191.0.217.255510
110191.0.218.0/23191.0.218.1 to 191.0.219.254191.0.219.255510
111191.0.220.0/23191.0.220.1 to 191.0.221.254191.0.221.255510
112191.0.222.0/23191.0.222.1 to 191.0.223.254191.0.223.255510
113191.0.224.0/23191.0.224.1 to 191.0.225.254191.0.225.255510
114191.0.226.0/23191.0.226.1 to 191.0.227.254191.0.227.255510
115191.0.228.0/23191.0.228.1 to 191.0.229.254191.0.229.255510
116191.0.230.0/23191.0.230.1 to 191.0.231.254191.0.231.255510
117191.0.232.0/23191.0.232.1 to 191.0.233.254191.0.233.255510
118191.0.234.0/23191.0.234.1 to 191.0.235.254191.0.235.255510
119191.0.236.0/23191.0.236.1 to 191.0.237.254191.0.237.255510
120191.0.238.0/23191.0.238.1 to 191.0.239.254191.0.239.255510
121191.0.240.0/23191.0.240.1 to 191.0.241.254191.0.241.255510
122191.0.242.0/23191.0.242.1 to 191.0.243.254191.0.243.255510
123191.0.244.0/23191.0.244.1 to 191.0.245.254191.0.245.255510
124191.0.246.0/23191.0.246.1 to 191.0.247.254191.0.247.255510
125191.0.248.0/23191.0.248.1 to 191.0.249.254191.0.249.255510
126191.0.250.0/23191.0.250.1 to 191.0.251.254191.0.251.255510
127191.0.252.0/23191.0.252.1 to 191.0.253.254191.0.253.255510
128191.0.254.0/23191.0.254.1 to 191.0.255.254191.0.255.255510
129191.1.0.0/23191.1.0.1 to 191.1.1.254191.1.1.255510
130191.1.2.0/23191.1.2.1 to 191.1.3.254191.1.3.255510
131191.1.4.0/23191.1.4.1 to 191.1.5.254191.1.5.255510
132191.1.6.0/23191.1.6.1 to 191.1.7.254191.1.7.255510
133191.1.8.0/23191.1.8.1 to 191.1.9.254191.1.9.255510
134191.1.10.0/23191.1.10.1 to 191.1.11.254191.1.11.255510
135191.1.12.0/23191.1.12.1 to 191.1.13.254191.1.13.255510
136191.1.14.0/23191.1.14.1 to 191.1.15.254191.1.15.255510
137191.1.16.0/23191.1.16.1 to 191.1.17.254191.1.17.255510
138191.1.18.0/23191.1.18.1 to 191.1.19.254191.1.19.255510
139191.1.20.0/23191.1.20.1 to 191.1.21.254191.1.21.255510
140191.1.22.0/23191.1.22.1 to 191.1.23.254191.1.23.255510
141191.1.24.0/23191.1.24.1 to 191.1.25.254191.1.25.255510
142191.1.26.0/23191.1.26.1 to 191.1.27.254191.1.27.255510
143191.1.28.0/23191.1.28.1 to 191.1.29.254191.1.29.255510
144191.1.30.0/23191.1.30.1 to 191.1.31.254191.1.31.255510
145191.1.32.0/23191.1.32.1 to 191.1.33.254191.1.33.255510
146191.1.34.0/23191.1.34.1 to 191.1.35.254191.1.35.255510
147191.1.36.0/23191.1.36.1 to 191.1.37.254191.1.37.255510
148191.1.38.0/23191.1.38.1 to 191.1.39.254191.1.39.255510
149191.1.40.0/23191.1.40.1 to 191.1.41.254191.1.41.255510
150191.1.42.0/23191.1.42.1 to 191.1.43.254191.1.43.255510
151191.1.44.0/23191.1.44.1 to 191.1.45.254191.1.45.255510
152191.1.46.0/23191.1.46.1 to 191.1.47.254191.1.47.255510
153191.1.48.0/23191.1.48.1 to 191.1.49.254191.1.49.255510
154191.1.50.0/23191.1.50.1 to 191.1.51.254191.1.51.255510
155191.1.52.0/23191.1.52.1 to 191.1.53.254191.1.53.255510
156191.1.54.0/23191.1.54.1 to 191.1.55.254191.1.55.255510
157191.1.56.0/23191.1.56.1 to 191.1.57.254191.1.57.255510
158191.1.58.0/23191.1.58.1 to 191.1.59.254191.1.59.255510
159191.1.60.0/23191.1.60.1 to 191.1.61.254191.1.61.255510
160191.1.62.0/23191.1.62.1 to 191.1.63.254191.1.63.255510
161191.1.64.0/23191.1.64.1 to 191.1.65.254191.1.65.255510
162191.1.66.0/23191.1.66.1 to 191.1.67.254191.1.67.255510
163191.1.68.0/23191.1.68.1 to 191.1.69.254191.1.69.255510
164191.1.70.0/23191.1.70.1 to 191.1.71.254191.1.71.255510
165191.1.72.0/23191.1.72.1 to 191.1.73.254191.1.73.255510
166191.1.74.0/23191.1.74.1 to 191.1.75.254191.1.75.255510
167191.1.76.0/23191.1.76.1 to 191.1.77.254191.1.77.255510
168191.1.78.0/23191.1.78.1 to 191.1.79.254191.1.79.255510
169191.1.80.0/23191.1.80.1 to 191.1.81.254191.1.81.255510
170191.1.82.0/23191.1.82.1 to 191.1.83.254191.1.83.255510
171191.1.84.0/23191.1.84.1 to 191.1.85.254191.1.85.255510
172191.1.86.0/23191.1.86.1 to 191.1.87.254191.1.87.255510
173191.1.88.0/23191.1.88.1 to 191.1.89.254191.1.89.255510
174191.1.90.0/23191.1.90.1 to 191.1.91.254191.1.91.255510
175191.1.92.0/23191.1.92.1 to 191.1.93.254191.1.93.255510
176191.1.94.0/23191.1.94.1 to 191.1.95.254191.1.95.255510
177191.1.96.0/23191.1.96.1 to 191.1.97.254191.1.97.255510
178191.1.98.0/23191.1.98.1 to 191.1.99.254191.1.99.255510
179191.1.100.0/23191.1.100.1 to 191.1.101.254191.1.101.255510
180191.1.102.0/23191.1.102.1 to 191.1.103.254191.1.103.255510
181191.1.104.0/23191.1.104.1 to 191.1.105.254191.1.105.255510
182191.1.106.0/23191.1.106.1 to 191.1.107.254191.1.107.255510
183191.1.108.0/23191.1.108.1 to 191.1.109.254191.1.109.255510
184191.1.110.0/23191.1.110.1 to 191.1.111.254191.1.111.255510
185191.1.112.0/23191.1.112.1 to 191.1.113.254191.1.113.255510
186191.1.114.0/23191.1.114.1 to 191.1.115.254191.1.115.255510
187191.1.116.0/23191.1.116.1 to 191.1.117.254191.1.117.255510
188191.1.118.0/23191.1.118.1 to 191.1.119.254191.1.119.255510
189191.1.120.0/23191.1.120.1 to 191.1.121.254191.1.121.255510
190191.1.122.0/23191.1.122.1 to 191.1.123.254191.1.123.255510
191191.1.124.0/23191.1.124.1 to 191.1.125.254191.1.125.255510
192191.1.126.0/23191.1.126.1 to 191.1.127.254191.1.127.255510
193191.1.128.0/23191.1.128.1 to 191.1.129.254191.1.129.255510
194191.1.130.0/23191.1.130.1 to 191.1.131.254191.1.131.255510
195191.1.132.0/23191.1.132.1 to 191.1.133.254191.1.133.255510
196191.1.134.0/23191.1.134.1 to 191.1.135.254191.1.135.255510
197191.1.136.0/23191.1.136.1 to 191.1.137.254191.1.137.255510
198191.1.138.0/23191.1.138.1 to 191.1.139.254191.1.139.255510
199191.1.140.0/23191.1.140.1 to 191.1.141.254191.1.141.255510
200191.1.142.0/23191.1.142.1 to 191.1.143.254191.1.143.255510
201191.1.144.0/23191.1.144.1 to 191.1.145.254191.1.145.255510
202191.1.146.0/23191.1.146.1 to 191.1.147.254191.1.147.255510
203191.1.148.0/23191.1.148.1 to 191.1.149.254191.1.149.255510
204191.1.150.0/23191.1.150.1 to 191.1.151.254191.1.151.255510
205191.1.152.0/23191.1.152.1 to 191.1.153.254191.1.153.255510
206191.1.154.0/23191.1.154.1 to 191.1.155.254191.1.155.255510
207191.1.156.0/23191.1.156.1 to 191.1.157.254191.1.157.255510
208191.1.158.0/23191.1.158.1 to 191.1.159.254191.1.159.255510
209191.1.160.0/23191.1.160.1 to 191.1.161.254191.1.161.255510
210191.1.162.0/23191.1.162.1 to 191.1.163.254191.1.163.255510
211191.1.164.0/23191.1.164.1 to 191.1.165.254191.1.165.255510
212191.1.166.0/23191.1.166.1 to 191.1.167.254191.1.167.255510
213191.1.168.0/23191.1.168.1 to 191.1.169.254191.1.169.255510
214191.1.170.0/23191.1.170.1 to 191.1.171.254191.1.171.255510
215191.1.172.0/23191.1.172.1 to 191.1.173.254191.1.173.255510
216191.1.174.0/23191.1.174.1 to 191.1.175.254191.1.175.255510
217191.1.176.0/23191.1.176.1 to 191.1.177.254191.1.177.255510
218191.1.178.0/23191.1.178.1 to 191.1.179.254191.1.179.255510
219191.1.180.0/23191.1.180.1 to 191.1.181.254191.1.181.255510
220191.1.182.0/23191.1.182.1 to 191.1.183.254191.1.183.255510
221191.1.184.0/23191.1.184.1 to 191.1.185.254191.1.185.255510
222191.1.186.0/23191.1.186.1 to 191.1.187.254191.1.187.255510
223191.1.188.0/23191.1.188.1 to 191.1.189.254191.1.189.255510
224191.1.190.0/23191.1.190.1 to 191.1.191.254191.1.191.255510
225191.1.192.0/23191.1.192.1 to 191.1.193.254191.1.193.255510
226191.1.194.0/23191.1.194.1 to 191.1.195.254191.1.195.255510
227191.1.196.0/23191.1.196.1 to 191.1.197.254191.1.197.255510
228191.1.198.0/23191.1.198.1 to 191.1.199.254191.1.199.255510
229191.1.200.0/23191.1.200.1 to 191.1.201.254191.1.201.255510
230191.1.202.0/23191.1.202.1 to 191.1.203.254191.1.203.255510
231191.1.204.0/23191.1.204.1 to 191.1.205.254191.1.205.255510
232191.1.206.0/23191.1.206.1 to 191.1.207.254191.1.207.255510
233191.1.208.0/23191.1.208.1 to 191.1.209.254191.1.209.255510
234191.1.210.0/23191.1.210.1 to 191.1.211.254191.1.211.255510
235191.1.212.0/23191.1.212.1 to 191.1.213.254191.1.213.255510
236191.1.214.0/23191.1.214.1 to 191.1.215.254191.1.215.255510
237191.1.216.0/23191.1.216.1 to 191.1.217.254191.1.217.255510
238191.1.218.0/23191.1.218.1 to 191.1.219.254191.1.219.255510
239191.1.220.0/23191.1.220.1 to 191.1.221.254191.1.221.255510
240191.1.222.0/23191.1.222.1 to 191.1.223.254191.1.223.255510
241191.1.224.0/23191.1.224.1 to 191.1.225.254191.1.225.255510
242191.1.226.0/23191.1.226.1 to 191.1.227.254191.1.227.255510
243191.1.228.0/23191.1.228.1 to 191.1.229.254191.1.229.255510
244191.1.230.0/23191.1.230.1 to 191.1.231.254191.1.231.255510
245191.1.232.0/23191.1.232.1 to 191.1.233.254191.1.233.255510
246191.1.234.0/23191.1.234.1 to 191.1.235.254191.1.235.255510
247191.1.236.0/23191.1.236.1 to 191.1.237.254191.1.237.255510
248191.1.238.0/23191.1.238.1 to 191.1.239.254191.1.239.255510
249191.1.240.0/23191.1.240.1 to 191.1.241.254191.1.241.255510
250191.1.242.0/23191.1.242.1 to 191.1.243.254191.1.243.255510
251191.1.244.0/23191.1.244.1 to 191.1.245.254191.1.245.255510
252191.1.246.0/23191.1.246.1 to 191.1.247.254191.1.247.255510
253191.1.248.0/23191.1.248.1 to 191.1.249.254191.1.249.255510
254191.1.250.0/23191.1.250.1 to 191.1.251.254191.1.251.255510
255191.1.252.0/23191.1.252.1 to 191.1.253.254191.1.253.255510
256191.1.254.0/23191.1.254.1 to 191.1.255.254191.1.255.255510

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.