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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.

Network130.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
130.0.0.0
Broadcast address
131.255.255.255
First usable
130.0.0.1
Last usable
131.255.255.254
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 82000000 · Integer 2181038080 to 2214592511
Reverse DNS zones
130.in-addr.arpa
131.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
Address10000010.00000000.00000000.00000000130.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10000010.00000000.00000000.00000000130.0.0.0
Broadcast10000011.11111111.11111111.11111111131.255.255.255
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)

130.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1130.0.0.0/15130.0.0.1 to 130.1.255.254130.1.255.255131,070
2130.2.0.0/15130.2.0.1 to 130.3.255.254130.3.255.255131,070
3130.4.0.0/15130.4.0.1 to 130.5.255.254130.5.255.255131,070
4130.6.0.0/15130.6.0.1 to 130.7.255.254130.7.255.255131,070
5130.8.0.0/15130.8.0.1 to 130.9.255.254130.9.255.255131,070
6130.10.0.0/15130.10.0.1 to 130.11.255.254130.11.255.255131,070
7130.12.0.0/15130.12.0.1 to 130.13.255.254130.13.255.255131,070
8130.14.0.0/15130.14.0.1 to 130.15.255.254130.15.255.255131,070
9130.16.0.0/15130.16.0.1 to 130.17.255.254130.17.255.255131,070
10130.18.0.0/15130.18.0.1 to 130.19.255.254130.19.255.255131,070
11130.20.0.0/15130.20.0.1 to 130.21.255.254130.21.255.255131,070
12130.22.0.0/15130.22.0.1 to 130.23.255.254130.23.255.255131,070
13130.24.0.0/15130.24.0.1 to 130.25.255.254130.25.255.255131,070
14130.26.0.0/15130.26.0.1 to 130.27.255.254130.27.255.255131,070
15130.28.0.0/15130.28.0.1 to 130.29.255.254130.29.255.255131,070
16130.30.0.0/15130.30.0.1 to 130.31.255.254130.31.255.255131,070
17130.32.0.0/15130.32.0.1 to 130.33.255.254130.33.255.255131,070
18130.34.0.0/15130.34.0.1 to 130.35.255.254130.35.255.255131,070
19130.36.0.0/15130.36.0.1 to 130.37.255.254130.37.255.255131,070
20130.38.0.0/15130.38.0.1 to 130.39.255.254130.39.255.255131,070
21130.40.0.0/15130.40.0.1 to 130.41.255.254130.41.255.255131,070
22130.42.0.0/15130.42.0.1 to 130.43.255.254130.43.255.255131,070
23130.44.0.0/15130.44.0.1 to 130.45.255.254130.45.255.255131,070
24130.46.0.0/15130.46.0.1 to 130.47.255.254130.47.255.255131,070
25130.48.0.0/15130.48.0.1 to 130.49.255.254130.49.255.255131,070
26130.50.0.0/15130.50.0.1 to 130.51.255.254130.51.255.255131,070
27130.52.0.0/15130.52.0.1 to 130.53.255.254130.53.255.255131,070
28130.54.0.0/15130.54.0.1 to 130.55.255.254130.55.255.255131,070
29130.56.0.0/15130.56.0.1 to 130.57.255.254130.57.255.255131,070
30130.58.0.0/15130.58.0.1 to 130.59.255.254130.59.255.255131,070
31130.60.0.0/15130.60.0.1 to 130.61.255.254130.61.255.255131,070
32130.62.0.0/15130.62.0.1 to 130.63.255.254130.63.255.255131,070
33130.64.0.0/15130.64.0.1 to 130.65.255.254130.65.255.255131,070
34130.66.0.0/15130.66.0.1 to 130.67.255.254130.67.255.255131,070
35130.68.0.0/15130.68.0.1 to 130.69.255.254130.69.255.255131,070
36130.70.0.0/15130.70.0.1 to 130.71.255.254130.71.255.255131,070
37130.72.0.0/15130.72.0.1 to 130.73.255.254130.73.255.255131,070
38130.74.0.0/15130.74.0.1 to 130.75.255.254130.75.255.255131,070
39130.76.0.0/15130.76.0.1 to 130.77.255.254130.77.255.255131,070
40130.78.0.0/15130.78.0.1 to 130.79.255.254130.79.255.255131,070
41130.80.0.0/15130.80.0.1 to 130.81.255.254130.81.255.255131,070
42130.82.0.0/15130.82.0.1 to 130.83.255.254130.83.255.255131,070
43130.84.0.0/15130.84.0.1 to 130.85.255.254130.85.255.255131,070
44130.86.0.0/15130.86.0.1 to 130.87.255.254130.87.255.255131,070
45130.88.0.0/15130.88.0.1 to 130.89.255.254130.89.255.255131,070
46130.90.0.0/15130.90.0.1 to 130.91.255.254130.91.255.255131,070
47130.92.0.0/15130.92.0.1 to 130.93.255.254130.93.255.255131,070
48130.94.0.0/15130.94.0.1 to 130.95.255.254130.95.255.255131,070
49130.96.0.0/15130.96.0.1 to 130.97.255.254130.97.255.255131,070
50130.98.0.0/15130.98.0.1 to 130.99.255.254130.99.255.255131,070
51130.100.0.0/15130.100.0.1 to 130.101.255.254130.101.255.255131,070
52130.102.0.0/15130.102.0.1 to 130.103.255.254130.103.255.255131,070
53130.104.0.0/15130.104.0.1 to 130.105.255.254130.105.255.255131,070
54130.106.0.0/15130.106.0.1 to 130.107.255.254130.107.255.255131,070
55130.108.0.0/15130.108.0.1 to 130.109.255.254130.109.255.255131,070
56130.110.0.0/15130.110.0.1 to 130.111.255.254130.111.255.255131,070
57130.112.0.0/15130.112.0.1 to 130.113.255.254130.113.255.255131,070
58130.114.0.0/15130.114.0.1 to 130.115.255.254130.115.255.255131,070
59130.116.0.0/15130.116.0.1 to 130.117.255.254130.117.255.255131,070
60130.118.0.0/15130.118.0.1 to 130.119.255.254130.119.255.255131,070
61130.120.0.0/15130.120.0.1 to 130.121.255.254130.121.255.255131,070
62130.122.0.0/15130.122.0.1 to 130.123.255.254130.123.255.255131,070
63130.124.0.0/15130.124.0.1 to 130.125.255.254130.125.255.255131,070
64130.126.0.0/15130.126.0.1 to 130.127.255.254130.127.255.255131,070
65130.128.0.0/15130.128.0.1 to 130.129.255.254130.129.255.255131,070
66130.130.0.0/15130.130.0.1 to 130.131.255.254130.131.255.255131,070
67130.132.0.0/15130.132.0.1 to 130.133.255.254130.133.255.255131,070
68130.134.0.0/15130.134.0.1 to 130.135.255.254130.135.255.255131,070
69130.136.0.0/15130.136.0.1 to 130.137.255.254130.137.255.255131,070
70130.138.0.0/15130.138.0.1 to 130.139.255.254130.139.255.255131,070
71130.140.0.0/15130.140.0.1 to 130.141.255.254130.141.255.255131,070
72130.142.0.0/15130.142.0.1 to 130.143.255.254130.143.255.255131,070
73130.144.0.0/15130.144.0.1 to 130.145.255.254130.145.255.255131,070
74130.146.0.0/15130.146.0.1 to 130.147.255.254130.147.255.255131,070
75130.148.0.0/15130.148.0.1 to 130.149.255.254130.149.255.255131,070
76130.150.0.0/15130.150.0.1 to 130.151.255.254130.151.255.255131,070
77130.152.0.0/15130.152.0.1 to 130.153.255.254130.153.255.255131,070
78130.154.0.0/15130.154.0.1 to 130.155.255.254130.155.255.255131,070
79130.156.0.0/15130.156.0.1 to 130.157.255.254130.157.255.255131,070
80130.158.0.0/15130.158.0.1 to 130.159.255.254130.159.255.255131,070
81130.160.0.0/15130.160.0.1 to 130.161.255.254130.161.255.255131,070
82130.162.0.0/15130.162.0.1 to 130.163.255.254130.163.255.255131,070
83130.164.0.0/15130.164.0.1 to 130.165.255.254130.165.255.255131,070
84130.166.0.0/15130.166.0.1 to 130.167.255.254130.167.255.255131,070
85130.168.0.0/15130.168.0.1 to 130.169.255.254130.169.255.255131,070
86130.170.0.0/15130.170.0.1 to 130.171.255.254130.171.255.255131,070
87130.172.0.0/15130.172.0.1 to 130.173.255.254130.173.255.255131,070
88130.174.0.0/15130.174.0.1 to 130.175.255.254130.175.255.255131,070
89130.176.0.0/15130.176.0.1 to 130.177.255.254130.177.255.255131,070
90130.178.0.0/15130.178.0.1 to 130.179.255.254130.179.255.255131,070
91130.180.0.0/15130.180.0.1 to 130.181.255.254130.181.255.255131,070
92130.182.0.0/15130.182.0.1 to 130.183.255.254130.183.255.255131,070
93130.184.0.0/15130.184.0.1 to 130.185.255.254130.185.255.255131,070
94130.186.0.0/15130.186.0.1 to 130.187.255.254130.187.255.255131,070
95130.188.0.0/15130.188.0.1 to 130.189.255.254130.189.255.255131,070
96130.190.0.0/15130.190.0.1 to 130.191.255.254130.191.255.255131,070
97130.192.0.0/15130.192.0.1 to 130.193.255.254130.193.255.255131,070
98130.194.0.0/15130.194.0.1 to 130.195.255.254130.195.255.255131,070
99130.196.0.0/15130.196.0.1 to 130.197.255.254130.197.255.255131,070
100130.198.0.0/15130.198.0.1 to 130.199.255.254130.199.255.255131,070
101130.200.0.0/15130.200.0.1 to 130.201.255.254130.201.255.255131,070
102130.202.0.0/15130.202.0.1 to 130.203.255.254130.203.255.255131,070
103130.204.0.0/15130.204.0.1 to 130.205.255.254130.205.255.255131,070
104130.206.0.0/15130.206.0.1 to 130.207.255.254130.207.255.255131,070
105130.208.0.0/15130.208.0.1 to 130.209.255.254130.209.255.255131,070
106130.210.0.0/15130.210.0.1 to 130.211.255.254130.211.255.255131,070
107130.212.0.0/15130.212.0.1 to 130.213.255.254130.213.255.255131,070
108130.214.0.0/15130.214.0.1 to 130.215.255.254130.215.255.255131,070
109130.216.0.0/15130.216.0.1 to 130.217.255.254130.217.255.255131,070
110130.218.0.0/15130.218.0.1 to 130.219.255.254130.219.255.255131,070
111130.220.0.0/15130.220.0.1 to 130.221.255.254130.221.255.255131,070
112130.222.0.0/15130.222.0.1 to 130.223.255.254130.223.255.255131,070
113130.224.0.0/15130.224.0.1 to 130.225.255.254130.225.255.255131,070
114130.226.0.0/15130.226.0.1 to 130.227.255.254130.227.255.255131,070
115130.228.0.0/15130.228.0.1 to 130.229.255.254130.229.255.255131,070
116130.230.0.0/15130.230.0.1 to 130.231.255.254130.231.255.255131,070
117130.232.0.0/15130.232.0.1 to 130.233.255.254130.233.255.255131,070
118130.234.0.0/15130.234.0.1 to 130.235.255.254130.235.255.255131,070
119130.236.0.0/15130.236.0.1 to 130.237.255.254130.237.255.255131,070
120130.238.0.0/15130.238.0.1 to 130.239.255.254130.239.255.255131,070
121130.240.0.0/15130.240.0.1 to 130.241.255.254130.241.255.255131,070
122130.242.0.0/15130.242.0.1 to 130.243.255.254130.243.255.255131,070
123130.244.0.0/15130.244.0.1 to 130.245.255.254130.245.255.255131,070
124130.246.0.0/15130.246.0.1 to 130.247.255.254130.247.255.255131,070
125130.248.0.0/15130.248.0.1 to 130.249.255.254130.249.255.255131,070
126130.250.0.0/15130.250.0.1 to 130.251.255.254130.251.255.255131,070
127130.252.0.0/15130.252.0.1 to 130.253.255.254130.253.255.255131,070
128130.254.0.0/15130.254.0.1 to 130.255.255.254130.255.255.255131,070
129131.0.0.0/15131.0.0.1 to 131.1.255.254131.1.255.255131,070
130131.2.0.0/15131.2.0.1 to 131.3.255.254131.3.255.255131,070
131131.4.0.0/15131.4.0.1 to 131.5.255.254131.5.255.255131,070
132131.6.0.0/15131.6.0.1 to 131.7.255.254131.7.255.255131,070
133131.8.0.0/15131.8.0.1 to 131.9.255.254131.9.255.255131,070
134131.10.0.0/15131.10.0.1 to 131.11.255.254131.11.255.255131,070
135131.12.0.0/15131.12.0.1 to 131.13.255.254131.13.255.255131,070
136131.14.0.0/15131.14.0.1 to 131.15.255.254131.15.255.255131,070
137131.16.0.0/15131.16.0.1 to 131.17.255.254131.17.255.255131,070
138131.18.0.0/15131.18.0.1 to 131.19.255.254131.19.255.255131,070
139131.20.0.0/15131.20.0.1 to 131.21.255.254131.21.255.255131,070
140131.22.0.0/15131.22.0.1 to 131.23.255.254131.23.255.255131,070
141131.24.0.0/15131.24.0.1 to 131.25.255.254131.25.255.255131,070
142131.26.0.0/15131.26.0.1 to 131.27.255.254131.27.255.255131,070
143131.28.0.0/15131.28.0.1 to 131.29.255.254131.29.255.255131,070
144131.30.0.0/15131.30.0.1 to 131.31.255.254131.31.255.255131,070
145131.32.0.0/15131.32.0.1 to 131.33.255.254131.33.255.255131,070
146131.34.0.0/15131.34.0.1 to 131.35.255.254131.35.255.255131,070
147131.36.0.0/15131.36.0.1 to 131.37.255.254131.37.255.255131,070
148131.38.0.0/15131.38.0.1 to 131.39.255.254131.39.255.255131,070
149131.40.0.0/15131.40.0.1 to 131.41.255.254131.41.255.255131,070
150131.42.0.0/15131.42.0.1 to 131.43.255.254131.43.255.255131,070
151131.44.0.0/15131.44.0.1 to 131.45.255.254131.45.255.255131,070
152131.46.0.0/15131.46.0.1 to 131.47.255.254131.47.255.255131,070
153131.48.0.0/15131.48.0.1 to 131.49.255.254131.49.255.255131,070
154131.50.0.0/15131.50.0.1 to 131.51.255.254131.51.255.255131,070
155131.52.0.0/15131.52.0.1 to 131.53.255.254131.53.255.255131,070
156131.54.0.0/15131.54.0.1 to 131.55.255.254131.55.255.255131,070
157131.56.0.0/15131.56.0.1 to 131.57.255.254131.57.255.255131,070
158131.58.0.0/15131.58.0.1 to 131.59.255.254131.59.255.255131,070
159131.60.0.0/15131.60.0.1 to 131.61.255.254131.61.255.255131,070
160131.62.0.0/15131.62.0.1 to 131.63.255.254131.63.255.255131,070
161131.64.0.0/15131.64.0.1 to 131.65.255.254131.65.255.255131,070
162131.66.0.0/15131.66.0.1 to 131.67.255.254131.67.255.255131,070
163131.68.0.0/15131.68.0.1 to 131.69.255.254131.69.255.255131,070
164131.70.0.0/15131.70.0.1 to 131.71.255.254131.71.255.255131,070
165131.72.0.0/15131.72.0.1 to 131.73.255.254131.73.255.255131,070
166131.74.0.0/15131.74.0.1 to 131.75.255.254131.75.255.255131,070
167131.76.0.0/15131.76.0.1 to 131.77.255.254131.77.255.255131,070
168131.78.0.0/15131.78.0.1 to 131.79.255.254131.79.255.255131,070
169131.80.0.0/15131.80.0.1 to 131.81.255.254131.81.255.255131,070
170131.82.0.0/15131.82.0.1 to 131.83.255.254131.83.255.255131,070
171131.84.0.0/15131.84.0.1 to 131.85.255.254131.85.255.255131,070
172131.86.0.0/15131.86.0.1 to 131.87.255.254131.87.255.255131,070
173131.88.0.0/15131.88.0.1 to 131.89.255.254131.89.255.255131,070
174131.90.0.0/15131.90.0.1 to 131.91.255.254131.91.255.255131,070
175131.92.0.0/15131.92.0.1 to 131.93.255.254131.93.255.255131,070
176131.94.0.0/15131.94.0.1 to 131.95.255.254131.95.255.255131,070
177131.96.0.0/15131.96.0.1 to 131.97.255.254131.97.255.255131,070
178131.98.0.0/15131.98.0.1 to 131.99.255.254131.99.255.255131,070
179131.100.0.0/15131.100.0.1 to 131.101.255.254131.101.255.255131,070
180131.102.0.0/15131.102.0.1 to 131.103.255.254131.103.255.255131,070
181131.104.0.0/15131.104.0.1 to 131.105.255.254131.105.255.255131,070
182131.106.0.0/15131.106.0.1 to 131.107.255.254131.107.255.255131,070
183131.108.0.0/15131.108.0.1 to 131.109.255.254131.109.255.255131,070
184131.110.0.0/15131.110.0.1 to 131.111.255.254131.111.255.255131,070
185131.112.0.0/15131.112.0.1 to 131.113.255.254131.113.255.255131,070
186131.114.0.0/15131.114.0.1 to 131.115.255.254131.115.255.255131,070
187131.116.0.0/15131.116.0.1 to 131.117.255.254131.117.255.255131,070
188131.118.0.0/15131.118.0.1 to 131.119.255.254131.119.255.255131,070
189131.120.0.0/15131.120.0.1 to 131.121.255.254131.121.255.255131,070
190131.122.0.0/15131.122.0.1 to 131.123.255.254131.123.255.255131,070
191131.124.0.0/15131.124.0.1 to 131.125.255.254131.125.255.255131,070
192131.126.0.0/15131.126.0.1 to 131.127.255.254131.127.255.255131,070
193131.128.0.0/15131.128.0.1 to 131.129.255.254131.129.255.255131,070
194131.130.0.0/15131.130.0.1 to 131.131.255.254131.131.255.255131,070
195131.132.0.0/15131.132.0.1 to 131.133.255.254131.133.255.255131,070
196131.134.0.0/15131.134.0.1 to 131.135.255.254131.135.255.255131,070
197131.136.0.0/15131.136.0.1 to 131.137.255.254131.137.255.255131,070
198131.138.0.0/15131.138.0.1 to 131.139.255.254131.139.255.255131,070
199131.140.0.0/15131.140.0.1 to 131.141.255.254131.141.255.255131,070
200131.142.0.0/15131.142.0.1 to 131.143.255.254131.143.255.255131,070
201131.144.0.0/15131.144.0.1 to 131.145.255.254131.145.255.255131,070
202131.146.0.0/15131.146.0.1 to 131.147.255.254131.147.255.255131,070
203131.148.0.0/15131.148.0.1 to 131.149.255.254131.149.255.255131,070
204131.150.0.0/15131.150.0.1 to 131.151.255.254131.151.255.255131,070
205131.152.0.0/15131.152.0.1 to 131.153.255.254131.153.255.255131,070
206131.154.0.0/15131.154.0.1 to 131.155.255.254131.155.255.255131,070
207131.156.0.0/15131.156.0.1 to 131.157.255.254131.157.255.255131,070
208131.158.0.0/15131.158.0.1 to 131.159.255.254131.159.255.255131,070
209131.160.0.0/15131.160.0.1 to 131.161.255.254131.161.255.255131,070
210131.162.0.0/15131.162.0.1 to 131.163.255.254131.163.255.255131,070
211131.164.0.0/15131.164.0.1 to 131.165.255.254131.165.255.255131,070
212131.166.0.0/15131.166.0.1 to 131.167.255.254131.167.255.255131,070
213131.168.0.0/15131.168.0.1 to 131.169.255.254131.169.255.255131,070
214131.170.0.0/15131.170.0.1 to 131.171.255.254131.171.255.255131,070
215131.172.0.0/15131.172.0.1 to 131.173.255.254131.173.255.255131,070
216131.174.0.0/15131.174.0.1 to 131.175.255.254131.175.255.255131,070
217131.176.0.0/15131.176.0.1 to 131.177.255.254131.177.255.255131,070
218131.178.0.0/15131.178.0.1 to 131.179.255.254131.179.255.255131,070
219131.180.0.0/15131.180.0.1 to 131.181.255.254131.181.255.255131,070
220131.182.0.0/15131.182.0.1 to 131.183.255.254131.183.255.255131,070
221131.184.0.0/15131.184.0.1 to 131.185.255.254131.185.255.255131,070
222131.186.0.0/15131.186.0.1 to 131.187.255.254131.187.255.255131,070
223131.188.0.0/15131.188.0.1 to 131.189.255.254131.189.255.255131,070
224131.190.0.0/15131.190.0.1 to 131.191.255.254131.191.255.255131,070
225131.192.0.0/15131.192.0.1 to 131.193.255.254131.193.255.255131,070
226131.194.0.0/15131.194.0.1 to 131.195.255.254131.195.255.255131,070
227131.196.0.0/15131.196.0.1 to 131.197.255.254131.197.255.255131,070
228131.198.0.0/15131.198.0.1 to 131.199.255.254131.199.255.255131,070
229131.200.0.0/15131.200.0.1 to 131.201.255.254131.201.255.255131,070
230131.202.0.0/15131.202.0.1 to 131.203.255.254131.203.255.255131,070
231131.204.0.0/15131.204.0.1 to 131.205.255.254131.205.255.255131,070
232131.206.0.0/15131.206.0.1 to 131.207.255.254131.207.255.255131,070
233131.208.0.0/15131.208.0.1 to 131.209.255.254131.209.255.255131,070
234131.210.0.0/15131.210.0.1 to 131.211.255.254131.211.255.255131,070
235131.212.0.0/15131.212.0.1 to 131.213.255.254131.213.255.255131,070
236131.214.0.0/15131.214.0.1 to 131.215.255.254131.215.255.255131,070
237131.216.0.0/15131.216.0.1 to 131.217.255.254131.217.255.255131,070
238131.218.0.0/15131.218.0.1 to 131.219.255.254131.219.255.255131,070
239131.220.0.0/15131.220.0.1 to 131.221.255.254131.221.255.255131,070
240131.222.0.0/15131.222.0.1 to 131.223.255.254131.223.255.255131,070
241131.224.0.0/15131.224.0.1 to 131.225.255.254131.225.255.255131,070
242131.226.0.0/15131.226.0.1 to 131.227.255.254131.227.255.255131,070
243131.228.0.0/15131.228.0.1 to 131.229.255.254131.229.255.255131,070
244131.230.0.0/15131.230.0.1 to 131.231.255.254131.231.255.255131,070
245131.232.0.0/15131.232.0.1 to 131.233.255.254131.233.255.255131,070
246131.234.0.0/15131.234.0.1 to 131.235.255.254131.235.255.255131,070
247131.236.0.0/15131.236.0.1 to 131.237.255.254131.237.255.255131,070
248131.238.0.0/15131.238.0.1 to 131.239.255.254131.239.255.255131,070
249131.240.0.0/15131.240.0.1 to 131.241.255.254131.241.255.255131,070
250131.242.0.0/15131.242.0.1 to 131.243.255.254131.243.255.255131,070
251131.244.0.0/15131.244.0.1 to 131.245.255.254131.245.255.255131,070
252131.246.0.0/15131.246.0.1 to 131.247.255.254131.247.255.255131,070
253131.248.0.0/15131.248.0.1 to 131.249.255.254131.249.255.255131,070
254131.250.0.0/15131.250.0.1 to 131.251.255.254131.251.255.255131,070
255131.252.0.0/15131.252.0.1 to 131.253.255.254131.253.255.255131,070
256131.254.0.0/15131.254.0.1 to 131.255.255.254131.255.255.255131,070

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.