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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.

Network28.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
28.0.0.0
Broadcast address
29.255.255.255
First usable
28.0.0.1
Last usable
29.255.255.254
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
A (default /8)
As numbers
Hex 1C000000 · Integer 469762048 to 503316479
Reverse DNS zones
28.in-addr.arpa
29.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
Address00011100.00000000.00000000.0000000028.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network00011100.00000000.00000000.0000000028.0.0.0
Broadcast00011101.11111111.11111111.1111111129.255.255.255
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)

28.0.0.0/7 makes 256 subnets of /15.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
128.0.0.0/1528.0.0.1 to 28.1.255.25428.1.255.255131,070
228.2.0.0/1528.2.0.1 to 28.3.255.25428.3.255.255131,070
328.4.0.0/1528.4.0.1 to 28.5.255.25428.5.255.255131,070
428.6.0.0/1528.6.0.1 to 28.7.255.25428.7.255.255131,070
528.8.0.0/1528.8.0.1 to 28.9.255.25428.9.255.255131,070
628.10.0.0/1528.10.0.1 to 28.11.255.25428.11.255.255131,070
728.12.0.0/1528.12.0.1 to 28.13.255.25428.13.255.255131,070
828.14.0.0/1528.14.0.1 to 28.15.255.25428.15.255.255131,070
928.16.0.0/1528.16.0.1 to 28.17.255.25428.17.255.255131,070
1028.18.0.0/1528.18.0.1 to 28.19.255.25428.19.255.255131,070
1128.20.0.0/1528.20.0.1 to 28.21.255.25428.21.255.255131,070
1228.22.0.0/1528.22.0.1 to 28.23.255.25428.23.255.255131,070
1328.24.0.0/1528.24.0.1 to 28.25.255.25428.25.255.255131,070
1428.26.0.0/1528.26.0.1 to 28.27.255.25428.27.255.255131,070
1528.28.0.0/1528.28.0.1 to 28.29.255.25428.29.255.255131,070
1628.30.0.0/1528.30.0.1 to 28.31.255.25428.31.255.255131,070
1728.32.0.0/1528.32.0.1 to 28.33.255.25428.33.255.255131,070
1828.34.0.0/1528.34.0.1 to 28.35.255.25428.35.255.255131,070
1928.36.0.0/1528.36.0.1 to 28.37.255.25428.37.255.255131,070
2028.38.0.0/1528.38.0.1 to 28.39.255.25428.39.255.255131,070
2128.40.0.0/1528.40.0.1 to 28.41.255.25428.41.255.255131,070
2228.42.0.0/1528.42.0.1 to 28.43.255.25428.43.255.255131,070
2328.44.0.0/1528.44.0.1 to 28.45.255.25428.45.255.255131,070
2428.46.0.0/1528.46.0.1 to 28.47.255.25428.47.255.255131,070
2528.48.0.0/1528.48.0.1 to 28.49.255.25428.49.255.255131,070
2628.50.0.0/1528.50.0.1 to 28.51.255.25428.51.255.255131,070
2728.52.0.0/1528.52.0.1 to 28.53.255.25428.53.255.255131,070
2828.54.0.0/1528.54.0.1 to 28.55.255.25428.55.255.255131,070
2928.56.0.0/1528.56.0.1 to 28.57.255.25428.57.255.255131,070
3028.58.0.0/1528.58.0.1 to 28.59.255.25428.59.255.255131,070
3128.60.0.0/1528.60.0.1 to 28.61.255.25428.61.255.255131,070
3228.62.0.0/1528.62.0.1 to 28.63.255.25428.63.255.255131,070
3328.64.0.0/1528.64.0.1 to 28.65.255.25428.65.255.255131,070
3428.66.0.0/1528.66.0.1 to 28.67.255.25428.67.255.255131,070
3528.68.0.0/1528.68.0.1 to 28.69.255.25428.69.255.255131,070
3628.70.0.0/1528.70.0.1 to 28.71.255.25428.71.255.255131,070
3728.72.0.0/1528.72.0.1 to 28.73.255.25428.73.255.255131,070
3828.74.0.0/1528.74.0.1 to 28.75.255.25428.75.255.255131,070
3928.76.0.0/1528.76.0.1 to 28.77.255.25428.77.255.255131,070
4028.78.0.0/1528.78.0.1 to 28.79.255.25428.79.255.255131,070
4128.80.0.0/1528.80.0.1 to 28.81.255.25428.81.255.255131,070
4228.82.0.0/1528.82.0.1 to 28.83.255.25428.83.255.255131,070
4328.84.0.0/1528.84.0.1 to 28.85.255.25428.85.255.255131,070
4428.86.0.0/1528.86.0.1 to 28.87.255.25428.87.255.255131,070
4528.88.0.0/1528.88.0.1 to 28.89.255.25428.89.255.255131,070
4628.90.0.0/1528.90.0.1 to 28.91.255.25428.91.255.255131,070
4728.92.0.0/1528.92.0.1 to 28.93.255.25428.93.255.255131,070
4828.94.0.0/1528.94.0.1 to 28.95.255.25428.95.255.255131,070
4928.96.0.0/1528.96.0.1 to 28.97.255.25428.97.255.255131,070
5028.98.0.0/1528.98.0.1 to 28.99.255.25428.99.255.255131,070
5128.100.0.0/1528.100.0.1 to 28.101.255.25428.101.255.255131,070
5228.102.0.0/1528.102.0.1 to 28.103.255.25428.103.255.255131,070
5328.104.0.0/1528.104.0.1 to 28.105.255.25428.105.255.255131,070
5428.106.0.0/1528.106.0.1 to 28.107.255.25428.107.255.255131,070
5528.108.0.0/1528.108.0.1 to 28.109.255.25428.109.255.255131,070
5628.110.0.0/1528.110.0.1 to 28.111.255.25428.111.255.255131,070
5728.112.0.0/1528.112.0.1 to 28.113.255.25428.113.255.255131,070
5828.114.0.0/1528.114.0.1 to 28.115.255.25428.115.255.255131,070
5928.116.0.0/1528.116.0.1 to 28.117.255.25428.117.255.255131,070
6028.118.0.0/1528.118.0.1 to 28.119.255.25428.119.255.255131,070
6128.120.0.0/1528.120.0.1 to 28.121.255.25428.121.255.255131,070
6228.122.0.0/1528.122.0.1 to 28.123.255.25428.123.255.255131,070
6328.124.0.0/1528.124.0.1 to 28.125.255.25428.125.255.255131,070
6428.126.0.0/1528.126.0.1 to 28.127.255.25428.127.255.255131,070
6528.128.0.0/1528.128.0.1 to 28.129.255.25428.129.255.255131,070
6628.130.0.0/1528.130.0.1 to 28.131.255.25428.131.255.255131,070
6728.132.0.0/1528.132.0.1 to 28.133.255.25428.133.255.255131,070
6828.134.0.0/1528.134.0.1 to 28.135.255.25428.135.255.255131,070
6928.136.0.0/1528.136.0.1 to 28.137.255.25428.137.255.255131,070
7028.138.0.0/1528.138.0.1 to 28.139.255.25428.139.255.255131,070
7128.140.0.0/1528.140.0.1 to 28.141.255.25428.141.255.255131,070
7228.142.0.0/1528.142.0.1 to 28.143.255.25428.143.255.255131,070
7328.144.0.0/1528.144.0.1 to 28.145.255.25428.145.255.255131,070
7428.146.0.0/1528.146.0.1 to 28.147.255.25428.147.255.255131,070
7528.148.0.0/1528.148.0.1 to 28.149.255.25428.149.255.255131,070
7628.150.0.0/1528.150.0.1 to 28.151.255.25428.151.255.255131,070
7728.152.0.0/1528.152.0.1 to 28.153.255.25428.153.255.255131,070
7828.154.0.0/1528.154.0.1 to 28.155.255.25428.155.255.255131,070
7928.156.0.0/1528.156.0.1 to 28.157.255.25428.157.255.255131,070
8028.158.0.0/1528.158.0.1 to 28.159.255.25428.159.255.255131,070
8128.160.0.0/1528.160.0.1 to 28.161.255.25428.161.255.255131,070
8228.162.0.0/1528.162.0.1 to 28.163.255.25428.163.255.255131,070
8328.164.0.0/1528.164.0.1 to 28.165.255.25428.165.255.255131,070
8428.166.0.0/1528.166.0.1 to 28.167.255.25428.167.255.255131,070
8528.168.0.0/1528.168.0.1 to 28.169.255.25428.169.255.255131,070
8628.170.0.0/1528.170.0.1 to 28.171.255.25428.171.255.255131,070
8728.172.0.0/1528.172.0.1 to 28.173.255.25428.173.255.255131,070
8828.174.0.0/1528.174.0.1 to 28.175.255.25428.175.255.255131,070
8928.176.0.0/1528.176.0.1 to 28.177.255.25428.177.255.255131,070
9028.178.0.0/1528.178.0.1 to 28.179.255.25428.179.255.255131,070
9128.180.0.0/1528.180.0.1 to 28.181.255.25428.181.255.255131,070
9228.182.0.0/1528.182.0.1 to 28.183.255.25428.183.255.255131,070
9328.184.0.0/1528.184.0.1 to 28.185.255.25428.185.255.255131,070
9428.186.0.0/1528.186.0.1 to 28.187.255.25428.187.255.255131,070
9528.188.0.0/1528.188.0.1 to 28.189.255.25428.189.255.255131,070
9628.190.0.0/1528.190.0.1 to 28.191.255.25428.191.255.255131,070
9728.192.0.0/1528.192.0.1 to 28.193.255.25428.193.255.255131,070
9828.194.0.0/1528.194.0.1 to 28.195.255.25428.195.255.255131,070
9928.196.0.0/1528.196.0.1 to 28.197.255.25428.197.255.255131,070
10028.198.0.0/1528.198.0.1 to 28.199.255.25428.199.255.255131,070
10128.200.0.0/1528.200.0.1 to 28.201.255.25428.201.255.255131,070
10228.202.0.0/1528.202.0.1 to 28.203.255.25428.203.255.255131,070
10328.204.0.0/1528.204.0.1 to 28.205.255.25428.205.255.255131,070
10428.206.0.0/1528.206.0.1 to 28.207.255.25428.207.255.255131,070
10528.208.0.0/1528.208.0.1 to 28.209.255.25428.209.255.255131,070
10628.210.0.0/1528.210.0.1 to 28.211.255.25428.211.255.255131,070
10728.212.0.0/1528.212.0.1 to 28.213.255.25428.213.255.255131,070
10828.214.0.0/1528.214.0.1 to 28.215.255.25428.215.255.255131,070
10928.216.0.0/1528.216.0.1 to 28.217.255.25428.217.255.255131,070
11028.218.0.0/1528.218.0.1 to 28.219.255.25428.219.255.255131,070
11128.220.0.0/1528.220.0.1 to 28.221.255.25428.221.255.255131,070
11228.222.0.0/1528.222.0.1 to 28.223.255.25428.223.255.255131,070
11328.224.0.0/1528.224.0.1 to 28.225.255.25428.225.255.255131,070
11428.226.0.0/1528.226.0.1 to 28.227.255.25428.227.255.255131,070
11528.228.0.0/1528.228.0.1 to 28.229.255.25428.229.255.255131,070
11628.230.0.0/1528.230.0.1 to 28.231.255.25428.231.255.255131,070
11728.232.0.0/1528.232.0.1 to 28.233.255.25428.233.255.255131,070
11828.234.0.0/1528.234.0.1 to 28.235.255.25428.235.255.255131,070
11928.236.0.0/1528.236.0.1 to 28.237.255.25428.237.255.255131,070
12028.238.0.0/1528.238.0.1 to 28.239.255.25428.239.255.255131,070
12128.240.0.0/1528.240.0.1 to 28.241.255.25428.241.255.255131,070
12228.242.0.0/1528.242.0.1 to 28.243.255.25428.243.255.255131,070
12328.244.0.0/1528.244.0.1 to 28.245.255.25428.245.255.255131,070
12428.246.0.0/1528.246.0.1 to 28.247.255.25428.247.255.255131,070
12528.248.0.0/1528.248.0.1 to 28.249.255.25428.249.255.255131,070
12628.250.0.0/1528.250.0.1 to 28.251.255.25428.251.255.255131,070
12728.252.0.0/1528.252.0.1 to 28.253.255.25428.253.255.255131,070
12828.254.0.0/1528.254.0.1 to 28.255.255.25428.255.255.255131,070
12929.0.0.0/1529.0.0.1 to 29.1.255.25429.1.255.255131,070
13029.2.0.0/1529.2.0.1 to 29.3.255.25429.3.255.255131,070
13129.4.0.0/1529.4.0.1 to 29.5.255.25429.5.255.255131,070
13229.6.0.0/1529.6.0.1 to 29.7.255.25429.7.255.255131,070
13329.8.0.0/1529.8.0.1 to 29.9.255.25429.9.255.255131,070
13429.10.0.0/1529.10.0.1 to 29.11.255.25429.11.255.255131,070
13529.12.0.0/1529.12.0.1 to 29.13.255.25429.13.255.255131,070
13629.14.0.0/1529.14.0.1 to 29.15.255.25429.15.255.255131,070
13729.16.0.0/1529.16.0.1 to 29.17.255.25429.17.255.255131,070
13829.18.0.0/1529.18.0.1 to 29.19.255.25429.19.255.255131,070
13929.20.0.0/1529.20.0.1 to 29.21.255.25429.21.255.255131,070
14029.22.0.0/1529.22.0.1 to 29.23.255.25429.23.255.255131,070
14129.24.0.0/1529.24.0.1 to 29.25.255.25429.25.255.255131,070
14229.26.0.0/1529.26.0.1 to 29.27.255.25429.27.255.255131,070
14329.28.0.0/1529.28.0.1 to 29.29.255.25429.29.255.255131,070
14429.30.0.0/1529.30.0.1 to 29.31.255.25429.31.255.255131,070
14529.32.0.0/1529.32.0.1 to 29.33.255.25429.33.255.255131,070
14629.34.0.0/1529.34.0.1 to 29.35.255.25429.35.255.255131,070
14729.36.0.0/1529.36.0.1 to 29.37.255.25429.37.255.255131,070
14829.38.0.0/1529.38.0.1 to 29.39.255.25429.39.255.255131,070
14929.40.0.0/1529.40.0.1 to 29.41.255.25429.41.255.255131,070
15029.42.0.0/1529.42.0.1 to 29.43.255.25429.43.255.255131,070
15129.44.0.0/1529.44.0.1 to 29.45.255.25429.45.255.255131,070
15229.46.0.0/1529.46.0.1 to 29.47.255.25429.47.255.255131,070
15329.48.0.0/1529.48.0.1 to 29.49.255.25429.49.255.255131,070
15429.50.0.0/1529.50.0.1 to 29.51.255.25429.51.255.255131,070
15529.52.0.0/1529.52.0.1 to 29.53.255.25429.53.255.255131,070
15629.54.0.0/1529.54.0.1 to 29.55.255.25429.55.255.255131,070
15729.56.0.0/1529.56.0.1 to 29.57.255.25429.57.255.255131,070
15829.58.0.0/1529.58.0.1 to 29.59.255.25429.59.255.255131,070
15929.60.0.0/1529.60.0.1 to 29.61.255.25429.61.255.255131,070
16029.62.0.0/1529.62.0.1 to 29.63.255.25429.63.255.255131,070
16129.64.0.0/1529.64.0.1 to 29.65.255.25429.65.255.255131,070
16229.66.0.0/1529.66.0.1 to 29.67.255.25429.67.255.255131,070
16329.68.0.0/1529.68.0.1 to 29.69.255.25429.69.255.255131,070
16429.70.0.0/1529.70.0.1 to 29.71.255.25429.71.255.255131,070
16529.72.0.0/1529.72.0.1 to 29.73.255.25429.73.255.255131,070
16629.74.0.0/1529.74.0.1 to 29.75.255.25429.75.255.255131,070
16729.76.0.0/1529.76.0.1 to 29.77.255.25429.77.255.255131,070
16829.78.0.0/1529.78.0.1 to 29.79.255.25429.79.255.255131,070
16929.80.0.0/1529.80.0.1 to 29.81.255.25429.81.255.255131,070
17029.82.0.0/1529.82.0.1 to 29.83.255.25429.83.255.255131,070
17129.84.0.0/1529.84.0.1 to 29.85.255.25429.85.255.255131,070
17229.86.0.0/1529.86.0.1 to 29.87.255.25429.87.255.255131,070
17329.88.0.0/1529.88.0.1 to 29.89.255.25429.89.255.255131,070
17429.90.0.0/1529.90.0.1 to 29.91.255.25429.91.255.255131,070
17529.92.0.0/1529.92.0.1 to 29.93.255.25429.93.255.255131,070
17629.94.0.0/1529.94.0.1 to 29.95.255.25429.95.255.255131,070
17729.96.0.0/1529.96.0.1 to 29.97.255.25429.97.255.255131,070
17829.98.0.0/1529.98.0.1 to 29.99.255.25429.99.255.255131,070
17929.100.0.0/1529.100.0.1 to 29.101.255.25429.101.255.255131,070
18029.102.0.0/1529.102.0.1 to 29.103.255.25429.103.255.255131,070
18129.104.0.0/1529.104.0.1 to 29.105.255.25429.105.255.255131,070
18229.106.0.0/1529.106.0.1 to 29.107.255.25429.107.255.255131,070
18329.108.0.0/1529.108.0.1 to 29.109.255.25429.109.255.255131,070
18429.110.0.0/1529.110.0.1 to 29.111.255.25429.111.255.255131,070
18529.112.0.0/1529.112.0.1 to 29.113.255.25429.113.255.255131,070
18629.114.0.0/1529.114.0.1 to 29.115.255.25429.115.255.255131,070
18729.116.0.0/1529.116.0.1 to 29.117.255.25429.117.255.255131,070
18829.118.0.0/1529.118.0.1 to 29.119.255.25429.119.255.255131,070
18929.120.0.0/1529.120.0.1 to 29.121.255.25429.121.255.255131,070
19029.122.0.0/1529.122.0.1 to 29.123.255.25429.123.255.255131,070
19129.124.0.0/1529.124.0.1 to 29.125.255.25429.125.255.255131,070
19229.126.0.0/1529.126.0.1 to 29.127.255.25429.127.255.255131,070
19329.128.0.0/1529.128.0.1 to 29.129.255.25429.129.255.255131,070
19429.130.0.0/1529.130.0.1 to 29.131.255.25429.131.255.255131,070
19529.132.0.0/1529.132.0.1 to 29.133.255.25429.133.255.255131,070
19629.134.0.0/1529.134.0.1 to 29.135.255.25429.135.255.255131,070
19729.136.0.0/1529.136.0.1 to 29.137.255.25429.137.255.255131,070
19829.138.0.0/1529.138.0.1 to 29.139.255.25429.139.255.255131,070
19929.140.0.0/1529.140.0.1 to 29.141.255.25429.141.255.255131,070
20029.142.0.0/1529.142.0.1 to 29.143.255.25429.143.255.255131,070
20129.144.0.0/1529.144.0.1 to 29.145.255.25429.145.255.255131,070
20229.146.0.0/1529.146.0.1 to 29.147.255.25429.147.255.255131,070
20329.148.0.0/1529.148.0.1 to 29.149.255.25429.149.255.255131,070
20429.150.0.0/1529.150.0.1 to 29.151.255.25429.151.255.255131,070
20529.152.0.0/1529.152.0.1 to 29.153.255.25429.153.255.255131,070
20629.154.0.0/1529.154.0.1 to 29.155.255.25429.155.255.255131,070
20729.156.0.0/1529.156.0.1 to 29.157.255.25429.157.255.255131,070
20829.158.0.0/1529.158.0.1 to 29.159.255.25429.159.255.255131,070
20929.160.0.0/1529.160.0.1 to 29.161.255.25429.161.255.255131,070
21029.162.0.0/1529.162.0.1 to 29.163.255.25429.163.255.255131,070
21129.164.0.0/1529.164.0.1 to 29.165.255.25429.165.255.255131,070
21229.166.0.0/1529.166.0.1 to 29.167.255.25429.167.255.255131,070
21329.168.0.0/1529.168.0.1 to 29.169.255.25429.169.255.255131,070
21429.170.0.0/1529.170.0.1 to 29.171.255.25429.171.255.255131,070
21529.172.0.0/1529.172.0.1 to 29.173.255.25429.173.255.255131,070
21629.174.0.0/1529.174.0.1 to 29.175.255.25429.175.255.255131,070
21729.176.0.0/1529.176.0.1 to 29.177.255.25429.177.255.255131,070
21829.178.0.0/1529.178.0.1 to 29.179.255.25429.179.255.255131,070
21929.180.0.0/1529.180.0.1 to 29.181.255.25429.181.255.255131,070
22029.182.0.0/1529.182.0.1 to 29.183.255.25429.183.255.255131,070
22129.184.0.0/1529.184.0.1 to 29.185.255.25429.185.255.255131,070
22229.186.0.0/1529.186.0.1 to 29.187.255.25429.187.255.255131,070
22329.188.0.0/1529.188.0.1 to 29.189.255.25429.189.255.255131,070
22429.190.0.0/1529.190.0.1 to 29.191.255.25429.191.255.255131,070
22529.192.0.0/1529.192.0.1 to 29.193.255.25429.193.255.255131,070
22629.194.0.0/1529.194.0.1 to 29.195.255.25429.195.255.255131,070
22729.196.0.0/1529.196.0.1 to 29.197.255.25429.197.255.255131,070
22829.198.0.0/1529.198.0.1 to 29.199.255.25429.199.255.255131,070
22929.200.0.0/1529.200.0.1 to 29.201.255.25429.201.255.255131,070
23029.202.0.0/1529.202.0.1 to 29.203.255.25429.203.255.255131,070
23129.204.0.0/1529.204.0.1 to 29.205.255.25429.205.255.255131,070
23229.206.0.0/1529.206.0.1 to 29.207.255.25429.207.255.255131,070
23329.208.0.0/1529.208.0.1 to 29.209.255.25429.209.255.255131,070
23429.210.0.0/1529.210.0.1 to 29.211.255.25429.211.255.255131,070
23529.212.0.0/1529.212.0.1 to 29.213.255.25429.213.255.255131,070
23629.214.0.0/1529.214.0.1 to 29.215.255.25429.215.255.255131,070
23729.216.0.0/1529.216.0.1 to 29.217.255.25429.217.255.255131,070
23829.218.0.0/1529.218.0.1 to 29.219.255.25429.219.255.255131,070
23929.220.0.0/1529.220.0.1 to 29.221.255.25429.221.255.255131,070
24029.222.0.0/1529.222.0.1 to 29.223.255.25429.223.255.255131,070
24129.224.0.0/1529.224.0.1 to 29.225.255.25429.225.255.255131,070
24229.226.0.0/1529.226.0.1 to 29.227.255.25429.227.255.255131,070
24329.228.0.0/1529.228.0.1 to 29.229.255.25429.229.255.255131,070
24429.230.0.0/1529.230.0.1 to 29.231.255.25429.231.255.255131,070
24529.232.0.0/1529.232.0.1 to 29.233.255.25429.233.255.255131,070
24629.234.0.0/1529.234.0.1 to 29.235.255.25429.235.255.255131,070
24729.236.0.0/1529.236.0.1 to 29.237.255.25429.237.255.255131,070
24829.238.0.0/1529.238.0.1 to 29.239.255.25429.239.255.255131,070
24929.240.0.0/1529.240.0.1 to 29.241.255.25429.241.255.255131,070
25029.242.0.0/1529.242.0.1 to 29.243.255.25429.243.255.255131,070
25129.244.0.0/1529.244.0.1 to 29.245.255.25429.245.255.255131,070
25229.246.0.0/1529.246.0.1 to 29.247.255.25429.247.255.255131,070
25329.248.0.0/1529.248.0.1 to 29.249.255.25429.249.255.255131,070
25429.250.0.0/1529.250.0.1 to 29.251.255.25429.251.255.255131,070
25529.252.0.0/1529.252.0.1 to 29.253.255.25429.253.255.255131,070
25629.254.0.0/1529.254.0.1 to 29.255.255.25429.255.255.255131,070

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.