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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.

Network13.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
13.0.0.0
Broadcast address
13.255.255.255
First usable
13.0.0.1
Last usable
13.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
A (default /8)
As numbers
Hex 0D000000 · Integer 218103808 to 234881023
Reverse DNS zone
13.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001101..00000000.00000000.0000000013.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00001101..00000000.00000000.0000000013.0.0.0
Broadcast00001101..11111111.11111111.1111111113.255.255.255
Split into smaller subnets/16
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

13.0.0.0/8 makes 256 subnets of /16.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
113.0.0.0/1613.0.0.1 to 13.0.255.25413.0.255.25565,534
213.1.0.0/1613.1.0.1 to 13.1.255.25413.1.255.25565,534
313.2.0.0/1613.2.0.1 to 13.2.255.25413.2.255.25565,534
413.3.0.0/1613.3.0.1 to 13.3.255.25413.3.255.25565,534
513.4.0.0/1613.4.0.1 to 13.4.255.25413.4.255.25565,534
613.5.0.0/1613.5.0.1 to 13.5.255.25413.5.255.25565,534
713.6.0.0/1613.6.0.1 to 13.6.255.25413.6.255.25565,534
813.7.0.0/1613.7.0.1 to 13.7.255.25413.7.255.25565,534
913.8.0.0/1613.8.0.1 to 13.8.255.25413.8.255.25565,534
1013.9.0.0/1613.9.0.1 to 13.9.255.25413.9.255.25565,534
1113.10.0.0/1613.10.0.1 to 13.10.255.25413.10.255.25565,534
1213.11.0.0/1613.11.0.1 to 13.11.255.25413.11.255.25565,534
1313.12.0.0/1613.12.0.1 to 13.12.255.25413.12.255.25565,534
1413.13.0.0/1613.13.0.1 to 13.13.255.25413.13.255.25565,534
1513.14.0.0/1613.14.0.1 to 13.14.255.25413.14.255.25565,534
1613.15.0.0/1613.15.0.1 to 13.15.255.25413.15.255.25565,534
1713.16.0.0/1613.16.0.1 to 13.16.255.25413.16.255.25565,534
1813.17.0.0/1613.17.0.1 to 13.17.255.25413.17.255.25565,534
1913.18.0.0/1613.18.0.1 to 13.18.255.25413.18.255.25565,534
2013.19.0.0/1613.19.0.1 to 13.19.255.25413.19.255.25565,534
2113.20.0.0/1613.20.0.1 to 13.20.255.25413.20.255.25565,534
2213.21.0.0/1613.21.0.1 to 13.21.255.25413.21.255.25565,534
2313.22.0.0/1613.22.0.1 to 13.22.255.25413.22.255.25565,534
2413.23.0.0/1613.23.0.1 to 13.23.255.25413.23.255.25565,534
2513.24.0.0/1613.24.0.1 to 13.24.255.25413.24.255.25565,534
2613.25.0.0/1613.25.0.1 to 13.25.255.25413.25.255.25565,534
2713.26.0.0/1613.26.0.1 to 13.26.255.25413.26.255.25565,534
2813.27.0.0/1613.27.0.1 to 13.27.255.25413.27.255.25565,534
2913.28.0.0/1613.28.0.1 to 13.28.255.25413.28.255.25565,534
3013.29.0.0/1613.29.0.1 to 13.29.255.25413.29.255.25565,534
3113.30.0.0/1613.30.0.1 to 13.30.255.25413.30.255.25565,534
3213.31.0.0/1613.31.0.1 to 13.31.255.25413.31.255.25565,534
3313.32.0.0/1613.32.0.1 to 13.32.255.25413.32.255.25565,534
3413.33.0.0/1613.33.0.1 to 13.33.255.25413.33.255.25565,534
3513.34.0.0/1613.34.0.1 to 13.34.255.25413.34.255.25565,534
3613.35.0.0/1613.35.0.1 to 13.35.255.25413.35.255.25565,534
3713.36.0.0/1613.36.0.1 to 13.36.255.25413.36.255.25565,534
3813.37.0.0/1613.37.0.1 to 13.37.255.25413.37.255.25565,534
3913.38.0.0/1613.38.0.1 to 13.38.255.25413.38.255.25565,534
4013.39.0.0/1613.39.0.1 to 13.39.255.25413.39.255.25565,534
4113.40.0.0/1613.40.0.1 to 13.40.255.25413.40.255.25565,534
4213.41.0.0/1613.41.0.1 to 13.41.255.25413.41.255.25565,534
4313.42.0.0/1613.42.0.1 to 13.42.255.25413.42.255.25565,534
4413.43.0.0/1613.43.0.1 to 13.43.255.25413.43.255.25565,534
4513.44.0.0/1613.44.0.1 to 13.44.255.25413.44.255.25565,534
4613.45.0.0/1613.45.0.1 to 13.45.255.25413.45.255.25565,534
4713.46.0.0/1613.46.0.1 to 13.46.255.25413.46.255.25565,534
4813.47.0.0/1613.47.0.1 to 13.47.255.25413.47.255.25565,534
4913.48.0.0/1613.48.0.1 to 13.48.255.25413.48.255.25565,534
5013.49.0.0/1613.49.0.1 to 13.49.255.25413.49.255.25565,534
5113.50.0.0/1613.50.0.1 to 13.50.255.25413.50.255.25565,534
5213.51.0.0/1613.51.0.1 to 13.51.255.25413.51.255.25565,534
5313.52.0.0/1613.52.0.1 to 13.52.255.25413.52.255.25565,534
5413.53.0.0/1613.53.0.1 to 13.53.255.25413.53.255.25565,534
5513.54.0.0/1613.54.0.1 to 13.54.255.25413.54.255.25565,534
5613.55.0.0/1613.55.0.1 to 13.55.255.25413.55.255.25565,534
5713.56.0.0/1613.56.0.1 to 13.56.255.25413.56.255.25565,534
5813.57.0.0/1613.57.0.1 to 13.57.255.25413.57.255.25565,534
5913.58.0.0/1613.58.0.1 to 13.58.255.25413.58.255.25565,534
6013.59.0.0/1613.59.0.1 to 13.59.255.25413.59.255.25565,534
6113.60.0.0/1613.60.0.1 to 13.60.255.25413.60.255.25565,534
6213.61.0.0/1613.61.0.1 to 13.61.255.25413.61.255.25565,534
6313.62.0.0/1613.62.0.1 to 13.62.255.25413.62.255.25565,534
6413.63.0.0/1613.63.0.1 to 13.63.255.25413.63.255.25565,534
6513.64.0.0/1613.64.0.1 to 13.64.255.25413.64.255.25565,534
6613.65.0.0/1613.65.0.1 to 13.65.255.25413.65.255.25565,534
6713.66.0.0/1613.66.0.1 to 13.66.255.25413.66.255.25565,534
6813.67.0.0/1613.67.0.1 to 13.67.255.25413.67.255.25565,534
6913.68.0.0/1613.68.0.1 to 13.68.255.25413.68.255.25565,534
7013.69.0.0/1613.69.0.1 to 13.69.255.25413.69.255.25565,534
7113.70.0.0/1613.70.0.1 to 13.70.255.25413.70.255.25565,534
7213.71.0.0/1613.71.0.1 to 13.71.255.25413.71.255.25565,534
7313.72.0.0/1613.72.0.1 to 13.72.255.25413.72.255.25565,534
7413.73.0.0/1613.73.0.1 to 13.73.255.25413.73.255.25565,534
7513.74.0.0/1613.74.0.1 to 13.74.255.25413.74.255.25565,534
7613.75.0.0/1613.75.0.1 to 13.75.255.25413.75.255.25565,534
7713.76.0.0/1613.76.0.1 to 13.76.255.25413.76.255.25565,534
7813.77.0.0/1613.77.0.1 to 13.77.255.25413.77.255.25565,534
7913.78.0.0/1613.78.0.1 to 13.78.255.25413.78.255.25565,534
8013.79.0.0/1613.79.0.1 to 13.79.255.25413.79.255.25565,534
8113.80.0.0/1613.80.0.1 to 13.80.255.25413.80.255.25565,534
8213.81.0.0/1613.81.0.1 to 13.81.255.25413.81.255.25565,534
8313.82.0.0/1613.82.0.1 to 13.82.255.25413.82.255.25565,534
8413.83.0.0/1613.83.0.1 to 13.83.255.25413.83.255.25565,534
8513.84.0.0/1613.84.0.1 to 13.84.255.25413.84.255.25565,534
8613.85.0.0/1613.85.0.1 to 13.85.255.25413.85.255.25565,534
8713.86.0.0/1613.86.0.1 to 13.86.255.25413.86.255.25565,534
8813.87.0.0/1613.87.0.1 to 13.87.255.25413.87.255.25565,534
8913.88.0.0/1613.88.0.1 to 13.88.255.25413.88.255.25565,534
9013.89.0.0/1613.89.0.1 to 13.89.255.25413.89.255.25565,534
9113.90.0.0/1613.90.0.1 to 13.90.255.25413.90.255.25565,534
9213.91.0.0/1613.91.0.1 to 13.91.255.25413.91.255.25565,534
9313.92.0.0/1613.92.0.1 to 13.92.255.25413.92.255.25565,534
9413.93.0.0/1613.93.0.1 to 13.93.255.25413.93.255.25565,534
9513.94.0.0/1613.94.0.1 to 13.94.255.25413.94.255.25565,534
9613.95.0.0/1613.95.0.1 to 13.95.255.25413.95.255.25565,534
9713.96.0.0/1613.96.0.1 to 13.96.255.25413.96.255.25565,534
9813.97.0.0/1613.97.0.1 to 13.97.255.25413.97.255.25565,534
9913.98.0.0/1613.98.0.1 to 13.98.255.25413.98.255.25565,534
10013.99.0.0/1613.99.0.1 to 13.99.255.25413.99.255.25565,534
10113.100.0.0/1613.100.0.1 to 13.100.255.25413.100.255.25565,534
10213.101.0.0/1613.101.0.1 to 13.101.255.25413.101.255.25565,534
10313.102.0.0/1613.102.0.1 to 13.102.255.25413.102.255.25565,534
10413.103.0.0/1613.103.0.1 to 13.103.255.25413.103.255.25565,534
10513.104.0.0/1613.104.0.1 to 13.104.255.25413.104.255.25565,534
10613.105.0.0/1613.105.0.1 to 13.105.255.25413.105.255.25565,534
10713.106.0.0/1613.106.0.1 to 13.106.255.25413.106.255.25565,534
10813.107.0.0/1613.107.0.1 to 13.107.255.25413.107.255.25565,534
10913.108.0.0/1613.108.0.1 to 13.108.255.25413.108.255.25565,534
11013.109.0.0/1613.109.0.1 to 13.109.255.25413.109.255.25565,534
11113.110.0.0/1613.110.0.1 to 13.110.255.25413.110.255.25565,534
11213.111.0.0/1613.111.0.1 to 13.111.255.25413.111.255.25565,534
11313.112.0.0/1613.112.0.1 to 13.112.255.25413.112.255.25565,534
11413.113.0.0/1613.113.0.1 to 13.113.255.25413.113.255.25565,534
11513.114.0.0/1613.114.0.1 to 13.114.255.25413.114.255.25565,534
11613.115.0.0/1613.115.0.1 to 13.115.255.25413.115.255.25565,534
11713.116.0.0/1613.116.0.1 to 13.116.255.25413.116.255.25565,534
11813.117.0.0/1613.117.0.1 to 13.117.255.25413.117.255.25565,534
11913.118.0.0/1613.118.0.1 to 13.118.255.25413.118.255.25565,534
12013.119.0.0/1613.119.0.1 to 13.119.255.25413.119.255.25565,534
12113.120.0.0/1613.120.0.1 to 13.120.255.25413.120.255.25565,534
12213.121.0.0/1613.121.0.1 to 13.121.255.25413.121.255.25565,534
12313.122.0.0/1613.122.0.1 to 13.122.255.25413.122.255.25565,534
12413.123.0.0/1613.123.0.1 to 13.123.255.25413.123.255.25565,534
12513.124.0.0/1613.124.0.1 to 13.124.255.25413.124.255.25565,534
12613.125.0.0/1613.125.0.1 to 13.125.255.25413.125.255.25565,534
12713.126.0.0/1613.126.0.1 to 13.126.255.25413.126.255.25565,534
12813.127.0.0/1613.127.0.1 to 13.127.255.25413.127.255.25565,534
12913.128.0.0/1613.128.0.1 to 13.128.255.25413.128.255.25565,534
13013.129.0.0/1613.129.0.1 to 13.129.255.25413.129.255.25565,534
13113.130.0.0/1613.130.0.1 to 13.130.255.25413.130.255.25565,534
13213.131.0.0/1613.131.0.1 to 13.131.255.25413.131.255.25565,534
13313.132.0.0/1613.132.0.1 to 13.132.255.25413.132.255.25565,534
13413.133.0.0/1613.133.0.1 to 13.133.255.25413.133.255.25565,534
13513.134.0.0/1613.134.0.1 to 13.134.255.25413.134.255.25565,534
13613.135.0.0/1613.135.0.1 to 13.135.255.25413.135.255.25565,534
13713.136.0.0/1613.136.0.1 to 13.136.255.25413.136.255.25565,534
13813.137.0.0/1613.137.0.1 to 13.137.255.25413.137.255.25565,534
13913.138.0.0/1613.138.0.1 to 13.138.255.25413.138.255.25565,534
14013.139.0.0/1613.139.0.1 to 13.139.255.25413.139.255.25565,534
14113.140.0.0/1613.140.0.1 to 13.140.255.25413.140.255.25565,534
14213.141.0.0/1613.141.0.1 to 13.141.255.25413.141.255.25565,534
14313.142.0.0/1613.142.0.1 to 13.142.255.25413.142.255.25565,534
14413.143.0.0/1613.143.0.1 to 13.143.255.25413.143.255.25565,534
14513.144.0.0/1613.144.0.1 to 13.144.255.25413.144.255.25565,534
14613.145.0.0/1613.145.0.1 to 13.145.255.25413.145.255.25565,534
14713.146.0.0/1613.146.0.1 to 13.146.255.25413.146.255.25565,534
14813.147.0.0/1613.147.0.1 to 13.147.255.25413.147.255.25565,534
14913.148.0.0/1613.148.0.1 to 13.148.255.25413.148.255.25565,534
15013.149.0.0/1613.149.0.1 to 13.149.255.25413.149.255.25565,534
15113.150.0.0/1613.150.0.1 to 13.150.255.25413.150.255.25565,534
15213.151.0.0/1613.151.0.1 to 13.151.255.25413.151.255.25565,534
15313.152.0.0/1613.152.0.1 to 13.152.255.25413.152.255.25565,534
15413.153.0.0/1613.153.0.1 to 13.153.255.25413.153.255.25565,534
15513.154.0.0/1613.154.0.1 to 13.154.255.25413.154.255.25565,534
15613.155.0.0/1613.155.0.1 to 13.155.255.25413.155.255.25565,534
15713.156.0.0/1613.156.0.1 to 13.156.255.25413.156.255.25565,534
15813.157.0.0/1613.157.0.1 to 13.157.255.25413.157.255.25565,534
15913.158.0.0/1613.158.0.1 to 13.158.255.25413.158.255.25565,534
16013.159.0.0/1613.159.0.1 to 13.159.255.25413.159.255.25565,534
16113.160.0.0/1613.160.0.1 to 13.160.255.25413.160.255.25565,534
16213.161.0.0/1613.161.0.1 to 13.161.255.25413.161.255.25565,534
16313.162.0.0/1613.162.0.1 to 13.162.255.25413.162.255.25565,534
16413.163.0.0/1613.163.0.1 to 13.163.255.25413.163.255.25565,534
16513.164.0.0/1613.164.0.1 to 13.164.255.25413.164.255.25565,534
16613.165.0.0/1613.165.0.1 to 13.165.255.25413.165.255.25565,534
16713.166.0.0/1613.166.0.1 to 13.166.255.25413.166.255.25565,534
16813.167.0.0/1613.167.0.1 to 13.167.255.25413.167.255.25565,534
16913.168.0.0/1613.168.0.1 to 13.168.255.25413.168.255.25565,534
17013.169.0.0/1613.169.0.1 to 13.169.255.25413.169.255.25565,534
17113.170.0.0/1613.170.0.1 to 13.170.255.25413.170.255.25565,534
17213.171.0.0/1613.171.0.1 to 13.171.255.25413.171.255.25565,534
17313.172.0.0/1613.172.0.1 to 13.172.255.25413.172.255.25565,534
17413.173.0.0/1613.173.0.1 to 13.173.255.25413.173.255.25565,534
17513.174.0.0/1613.174.0.1 to 13.174.255.25413.174.255.25565,534
17613.175.0.0/1613.175.0.1 to 13.175.255.25413.175.255.25565,534
17713.176.0.0/1613.176.0.1 to 13.176.255.25413.176.255.25565,534
17813.177.0.0/1613.177.0.1 to 13.177.255.25413.177.255.25565,534
17913.178.0.0/1613.178.0.1 to 13.178.255.25413.178.255.25565,534
18013.179.0.0/1613.179.0.1 to 13.179.255.25413.179.255.25565,534
18113.180.0.0/1613.180.0.1 to 13.180.255.25413.180.255.25565,534
18213.181.0.0/1613.181.0.1 to 13.181.255.25413.181.255.25565,534
18313.182.0.0/1613.182.0.1 to 13.182.255.25413.182.255.25565,534
18413.183.0.0/1613.183.0.1 to 13.183.255.25413.183.255.25565,534
18513.184.0.0/1613.184.0.1 to 13.184.255.25413.184.255.25565,534
18613.185.0.0/1613.185.0.1 to 13.185.255.25413.185.255.25565,534
18713.186.0.0/1613.186.0.1 to 13.186.255.25413.186.255.25565,534
18813.187.0.0/1613.187.0.1 to 13.187.255.25413.187.255.25565,534
18913.188.0.0/1613.188.0.1 to 13.188.255.25413.188.255.25565,534
19013.189.0.0/1613.189.0.1 to 13.189.255.25413.189.255.25565,534
19113.190.0.0/1613.190.0.1 to 13.190.255.25413.190.255.25565,534
19213.191.0.0/1613.191.0.1 to 13.191.255.25413.191.255.25565,534
19313.192.0.0/1613.192.0.1 to 13.192.255.25413.192.255.25565,534
19413.193.0.0/1613.193.0.1 to 13.193.255.25413.193.255.25565,534
19513.194.0.0/1613.194.0.1 to 13.194.255.25413.194.255.25565,534
19613.195.0.0/1613.195.0.1 to 13.195.255.25413.195.255.25565,534
19713.196.0.0/1613.196.0.1 to 13.196.255.25413.196.255.25565,534
19813.197.0.0/1613.197.0.1 to 13.197.255.25413.197.255.25565,534
19913.198.0.0/1613.198.0.1 to 13.198.255.25413.198.255.25565,534
20013.199.0.0/1613.199.0.1 to 13.199.255.25413.199.255.25565,534
20113.200.0.0/1613.200.0.1 to 13.200.255.25413.200.255.25565,534
20213.201.0.0/1613.201.0.1 to 13.201.255.25413.201.255.25565,534
20313.202.0.0/1613.202.0.1 to 13.202.255.25413.202.255.25565,534
20413.203.0.0/1613.203.0.1 to 13.203.255.25413.203.255.25565,534
20513.204.0.0/1613.204.0.1 to 13.204.255.25413.204.255.25565,534
20613.205.0.0/1613.205.0.1 to 13.205.255.25413.205.255.25565,534
20713.206.0.0/1613.206.0.1 to 13.206.255.25413.206.255.25565,534
20813.207.0.0/1613.207.0.1 to 13.207.255.25413.207.255.25565,534
20913.208.0.0/1613.208.0.1 to 13.208.255.25413.208.255.25565,534
21013.209.0.0/1613.209.0.1 to 13.209.255.25413.209.255.25565,534
21113.210.0.0/1613.210.0.1 to 13.210.255.25413.210.255.25565,534
21213.211.0.0/1613.211.0.1 to 13.211.255.25413.211.255.25565,534
21313.212.0.0/1613.212.0.1 to 13.212.255.25413.212.255.25565,534
21413.213.0.0/1613.213.0.1 to 13.213.255.25413.213.255.25565,534
21513.214.0.0/1613.214.0.1 to 13.214.255.25413.214.255.25565,534
21613.215.0.0/1613.215.0.1 to 13.215.255.25413.215.255.25565,534
21713.216.0.0/1613.216.0.1 to 13.216.255.25413.216.255.25565,534
21813.217.0.0/1613.217.0.1 to 13.217.255.25413.217.255.25565,534
21913.218.0.0/1613.218.0.1 to 13.218.255.25413.218.255.25565,534
22013.219.0.0/1613.219.0.1 to 13.219.255.25413.219.255.25565,534
22113.220.0.0/1613.220.0.1 to 13.220.255.25413.220.255.25565,534
22213.221.0.0/1613.221.0.1 to 13.221.255.25413.221.255.25565,534
22313.222.0.0/1613.222.0.1 to 13.222.255.25413.222.255.25565,534
22413.223.0.0/1613.223.0.1 to 13.223.255.25413.223.255.25565,534
22513.224.0.0/1613.224.0.1 to 13.224.255.25413.224.255.25565,534
22613.225.0.0/1613.225.0.1 to 13.225.255.25413.225.255.25565,534
22713.226.0.0/1613.226.0.1 to 13.226.255.25413.226.255.25565,534
22813.227.0.0/1613.227.0.1 to 13.227.255.25413.227.255.25565,534
22913.228.0.0/1613.228.0.1 to 13.228.255.25413.228.255.25565,534
23013.229.0.0/1613.229.0.1 to 13.229.255.25413.229.255.25565,534
23113.230.0.0/1613.230.0.1 to 13.230.255.25413.230.255.25565,534
23213.231.0.0/1613.231.0.1 to 13.231.255.25413.231.255.25565,534
23313.232.0.0/1613.232.0.1 to 13.232.255.25413.232.255.25565,534
23413.233.0.0/1613.233.0.1 to 13.233.255.25413.233.255.25565,534
23513.234.0.0/1613.234.0.1 to 13.234.255.25413.234.255.25565,534
23613.235.0.0/1613.235.0.1 to 13.235.255.25413.235.255.25565,534
23713.236.0.0/1613.236.0.1 to 13.236.255.25413.236.255.25565,534
23813.237.0.0/1613.237.0.1 to 13.237.255.25413.237.255.25565,534
23913.238.0.0/1613.238.0.1 to 13.238.255.25413.238.255.25565,534
24013.239.0.0/1613.239.0.1 to 13.239.255.25413.239.255.25565,534
24113.240.0.0/1613.240.0.1 to 13.240.255.25413.240.255.25565,534
24213.241.0.0/1613.241.0.1 to 13.241.255.25413.241.255.25565,534
24313.242.0.0/1613.242.0.1 to 13.242.255.25413.242.255.25565,534
24413.243.0.0/1613.243.0.1 to 13.243.255.25413.243.255.25565,534
24513.244.0.0/1613.244.0.1 to 13.244.255.25413.244.255.25565,534
24613.245.0.0/1613.245.0.1 to 13.245.255.25413.245.255.25565,534
24713.246.0.0/1613.246.0.1 to 13.246.255.25413.246.255.25565,534
24813.247.0.0/1613.247.0.1 to 13.247.255.25413.247.255.25565,534
24913.248.0.0/1613.248.0.1 to 13.248.255.25413.248.255.25565,534
25013.249.0.0/1613.249.0.1 to 13.249.255.25413.249.255.25565,534
25113.250.0.0/1613.250.0.1 to 13.250.255.25413.250.255.25565,534
25213.251.0.0/1613.251.0.1 to 13.251.255.25413.251.255.25565,534
25313.252.0.0/1613.252.0.1 to 13.252.255.25413.252.255.25565,534
25413.253.0.0/1613.253.0.1 to 13.253.255.25413.253.255.25565,534
25513.254.0.0/1613.254.0.1 to 13.254.255.25413.254.255.25565,534
25613.255.0.0/1613.255.0.1 to 13.255.255.25413.255.255.25565,534

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.