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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.

Network57.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
57.0.0.0
Broadcast address
57.255.255.255
First usable
57.0.0.1
Last usable
57.255.255.254
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 39000000 · Integer 956301312 to 973078527
Reverse DNS zone
57.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111001..00000000.00000000.0000000057.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network00111001..00000000.00000000.0000000057.0.0.0
Broadcast00111001..11111111.11111111.1111111157.255.255.255
Split into smaller subnets/20
/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)

57.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
157.0.0.0/2057.0.0.1 to 57.0.15.25457.0.15.2554,094
257.0.16.0/2057.0.16.1 to 57.0.31.25457.0.31.2554,094
357.0.32.0/2057.0.32.1 to 57.0.47.25457.0.47.2554,094
457.0.48.0/2057.0.48.1 to 57.0.63.25457.0.63.2554,094
557.0.64.0/2057.0.64.1 to 57.0.79.25457.0.79.2554,094
657.0.80.0/2057.0.80.1 to 57.0.95.25457.0.95.2554,094
757.0.96.0/2057.0.96.1 to 57.0.111.25457.0.111.2554,094
857.0.112.0/2057.0.112.1 to 57.0.127.25457.0.127.2554,094
957.0.128.0/2057.0.128.1 to 57.0.143.25457.0.143.2554,094
1057.0.144.0/2057.0.144.1 to 57.0.159.25457.0.159.2554,094
1157.0.160.0/2057.0.160.1 to 57.0.175.25457.0.175.2554,094
1257.0.176.0/2057.0.176.1 to 57.0.191.25457.0.191.2554,094
1357.0.192.0/2057.0.192.1 to 57.0.207.25457.0.207.2554,094
1457.0.208.0/2057.0.208.1 to 57.0.223.25457.0.223.2554,094
1557.0.224.0/2057.0.224.1 to 57.0.239.25457.0.239.2554,094
1657.0.240.0/2057.0.240.1 to 57.0.255.25457.0.255.2554,094
1757.1.0.0/2057.1.0.1 to 57.1.15.25457.1.15.2554,094
1857.1.16.0/2057.1.16.1 to 57.1.31.25457.1.31.2554,094
1957.1.32.0/2057.1.32.1 to 57.1.47.25457.1.47.2554,094
2057.1.48.0/2057.1.48.1 to 57.1.63.25457.1.63.2554,094
2157.1.64.0/2057.1.64.1 to 57.1.79.25457.1.79.2554,094
2257.1.80.0/2057.1.80.1 to 57.1.95.25457.1.95.2554,094
2357.1.96.0/2057.1.96.1 to 57.1.111.25457.1.111.2554,094
2457.1.112.0/2057.1.112.1 to 57.1.127.25457.1.127.2554,094
2557.1.128.0/2057.1.128.1 to 57.1.143.25457.1.143.2554,094
2657.1.144.0/2057.1.144.1 to 57.1.159.25457.1.159.2554,094
2757.1.160.0/2057.1.160.1 to 57.1.175.25457.1.175.2554,094
2857.1.176.0/2057.1.176.1 to 57.1.191.25457.1.191.2554,094
2957.1.192.0/2057.1.192.1 to 57.1.207.25457.1.207.2554,094
3057.1.208.0/2057.1.208.1 to 57.1.223.25457.1.223.2554,094
3157.1.224.0/2057.1.224.1 to 57.1.239.25457.1.239.2554,094
3257.1.240.0/2057.1.240.1 to 57.1.255.25457.1.255.2554,094
3357.2.0.0/2057.2.0.1 to 57.2.15.25457.2.15.2554,094
3457.2.16.0/2057.2.16.1 to 57.2.31.25457.2.31.2554,094
3557.2.32.0/2057.2.32.1 to 57.2.47.25457.2.47.2554,094
3657.2.48.0/2057.2.48.1 to 57.2.63.25457.2.63.2554,094
3757.2.64.0/2057.2.64.1 to 57.2.79.25457.2.79.2554,094
3857.2.80.0/2057.2.80.1 to 57.2.95.25457.2.95.2554,094
3957.2.96.0/2057.2.96.1 to 57.2.111.25457.2.111.2554,094
4057.2.112.0/2057.2.112.1 to 57.2.127.25457.2.127.2554,094
4157.2.128.0/2057.2.128.1 to 57.2.143.25457.2.143.2554,094
4257.2.144.0/2057.2.144.1 to 57.2.159.25457.2.159.2554,094
4357.2.160.0/2057.2.160.1 to 57.2.175.25457.2.175.2554,094
4457.2.176.0/2057.2.176.1 to 57.2.191.25457.2.191.2554,094
4557.2.192.0/2057.2.192.1 to 57.2.207.25457.2.207.2554,094
4657.2.208.0/2057.2.208.1 to 57.2.223.25457.2.223.2554,094
4757.2.224.0/2057.2.224.1 to 57.2.239.25457.2.239.2554,094
4857.2.240.0/2057.2.240.1 to 57.2.255.25457.2.255.2554,094
4957.3.0.0/2057.3.0.1 to 57.3.15.25457.3.15.2554,094
5057.3.16.0/2057.3.16.1 to 57.3.31.25457.3.31.2554,094
5157.3.32.0/2057.3.32.1 to 57.3.47.25457.3.47.2554,094
5257.3.48.0/2057.3.48.1 to 57.3.63.25457.3.63.2554,094
5357.3.64.0/2057.3.64.1 to 57.3.79.25457.3.79.2554,094
5457.3.80.0/2057.3.80.1 to 57.3.95.25457.3.95.2554,094
5557.3.96.0/2057.3.96.1 to 57.3.111.25457.3.111.2554,094
5657.3.112.0/2057.3.112.1 to 57.3.127.25457.3.127.2554,094
5757.3.128.0/2057.3.128.1 to 57.3.143.25457.3.143.2554,094
5857.3.144.0/2057.3.144.1 to 57.3.159.25457.3.159.2554,094
5957.3.160.0/2057.3.160.1 to 57.3.175.25457.3.175.2554,094
6057.3.176.0/2057.3.176.1 to 57.3.191.25457.3.191.2554,094
6157.3.192.0/2057.3.192.1 to 57.3.207.25457.3.207.2554,094
6257.3.208.0/2057.3.208.1 to 57.3.223.25457.3.223.2554,094
6357.3.224.0/2057.3.224.1 to 57.3.239.25457.3.239.2554,094
6457.3.240.0/2057.3.240.1 to 57.3.255.25457.3.255.2554,094
6557.4.0.0/2057.4.0.1 to 57.4.15.25457.4.15.2554,094
6657.4.16.0/2057.4.16.1 to 57.4.31.25457.4.31.2554,094
6757.4.32.0/2057.4.32.1 to 57.4.47.25457.4.47.2554,094
6857.4.48.0/2057.4.48.1 to 57.4.63.25457.4.63.2554,094
6957.4.64.0/2057.4.64.1 to 57.4.79.25457.4.79.2554,094
7057.4.80.0/2057.4.80.1 to 57.4.95.25457.4.95.2554,094
7157.4.96.0/2057.4.96.1 to 57.4.111.25457.4.111.2554,094
7257.4.112.0/2057.4.112.1 to 57.4.127.25457.4.127.2554,094
7357.4.128.0/2057.4.128.1 to 57.4.143.25457.4.143.2554,094
7457.4.144.0/2057.4.144.1 to 57.4.159.25457.4.159.2554,094
7557.4.160.0/2057.4.160.1 to 57.4.175.25457.4.175.2554,094
7657.4.176.0/2057.4.176.1 to 57.4.191.25457.4.191.2554,094
7757.4.192.0/2057.4.192.1 to 57.4.207.25457.4.207.2554,094
7857.4.208.0/2057.4.208.1 to 57.4.223.25457.4.223.2554,094
7957.4.224.0/2057.4.224.1 to 57.4.239.25457.4.239.2554,094
8057.4.240.0/2057.4.240.1 to 57.4.255.25457.4.255.2554,094
8157.5.0.0/2057.5.0.1 to 57.5.15.25457.5.15.2554,094
8257.5.16.0/2057.5.16.1 to 57.5.31.25457.5.31.2554,094
8357.5.32.0/2057.5.32.1 to 57.5.47.25457.5.47.2554,094
8457.5.48.0/2057.5.48.1 to 57.5.63.25457.5.63.2554,094
8557.5.64.0/2057.5.64.1 to 57.5.79.25457.5.79.2554,094
8657.5.80.0/2057.5.80.1 to 57.5.95.25457.5.95.2554,094
8757.5.96.0/2057.5.96.1 to 57.5.111.25457.5.111.2554,094
8857.5.112.0/2057.5.112.1 to 57.5.127.25457.5.127.2554,094
8957.5.128.0/2057.5.128.1 to 57.5.143.25457.5.143.2554,094
9057.5.144.0/2057.5.144.1 to 57.5.159.25457.5.159.2554,094
9157.5.160.0/2057.5.160.1 to 57.5.175.25457.5.175.2554,094
9257.5.176.0/2057.5.176.1 to 57.5.191.25457.5.191.2554,094
9357.5.192.0/2057.5.192.1 to 57.5.207.25457.5.207.2554,094
9457.5.208.0/2057.5.208.1 to 57.5.223.25457.5.223.2554,094
9557.5.224.0/2057.5.224.1 to 57.5.239.25457.5.239.2554,094
9657.5.240.0/2057.5.240.1 to 57.5.255.25457.5.255.2554,094
9757.6.0.0/2057.6.0.1 to 57.6.15.25457.6.15.2554,094
9857.6.16.0/2057.6.16.1 to 57.6.31.25457.6.31.2554,094
9957.6.32.0/2057.6.32.1 to 57.6.47.25457.6.47.2554,094
10057.6.48.0/2057.6.48.1 to 57.6.63.25457.6.63.2554,094
10157.6.64.0/2057.6.64.1 to 57.6.79.25457.6.79.2554,094
10257.6.80.0/2057.6.80.1 to 57.6.95.25457.6.95.2554,094
10357.6.96.0/2057.6.96.1 to 57.6.111.25457.6.111.2554,094
10457.6.112.0/2057.6.112.1 to 57.6.127.25457.6.127.2554,094
10557.6.128.0/2057.6.128.1 to 57.6.143.25457.6.143.2554,094
10657.6.144.0/2057.6.144.1 to 57.6.159.25457.6.159.2554,094
10757.6.160.0/2057.6.160.1 to 57.6.175.25457.6.175.2554,094
10857.6.176.0/2057.6.176.1 to 57.6.191.25457.6.191.2554,094
10957.6.192.0/2057.6.192.1 to 57.6.207.25457.6.207.2554,094
11057.6.208.0/2057.6.208.1 to 57.6.223.25457.6.223.2554,094
11157.6.224.0/2057.6.224.1 to 57.6.239.25457.6.239.2554,094
11257.6.240.0/2057.6.240.1 to 57.6.255.25457.6.255.2554,094
11357.7.0.0/2057.7.0.1 to 57.7.15.25457.7.15.2554,094
11457.7.16.0/2057.7.16.1 to 57.7.31.25457.7.31.2554,094
11557.7.32.0/2057.7.32.1 to 57.7.47.25457.7.47.2554,094
11657.7.48.0/2057.7.48.1 to 57.7.63.25457.7.63.2554,094
11757.7.64.0/2057.7.64.1 to 57.7.79.25457.7.79.2554,094
11857.7.80.0/2057.7.80.1 to 57.7.95.25457.7.95.2554,094
11957.7.96.0/2057.7.96.1 to 57.7.111.25457.7.111.2554,094
12057.7.112.0/2057.7.112.1 to 57.7.127.25457.7.127.2554,094
12157.7.128.0/2057.7.128.1 to 57.7.143.25457.7.143.2554,094
12257.7.144.0/2057.7.144.1 to 57.7.159.25457.7.159.2554,094
12357.7.160.0/2057.7.160.1 to 57.7.175.25457.7.175.2554,094
12457.7.176.0/2057.7.176.1 to 57.7.191.25457.7.191.2554,094
12557.7.192.0/2057.7.192.1 to 57.7.207.25457.7.207.2554,094
12657.7.208.0/2057.7.208.1 to 57.7.223.25457.7.223.2554,094
12757.7.224.0/2057.7.224.1 to 57.7.239.25457.7.239.2554,094
12857.7.240.0/2057.7.240.1 to 57.7.255.25457.7.255.2554,094
12957.8.0.0/2057.8.0.1 to 57.8.15.25457.8.15.2554,094
13057.8.16.0/2057.8.16.1 to 57.8.31.25457.8.31.2554,094
13157.8.32.0/2057.8.32.1 to 57.8.47.25457.8.47.2554,094
13257.8.48.0/2057.8.48.1 to 57.8.63.25457.8.63.2554,094
13357.8.64.0/2057.8.64.1 to 57.8.79.25457.8.79.2554,094
13457.8.80.0/2057.8.80.1 to 57.8.95.25457.8.95.2554,094
13557.8.96.0/2057.8.96.1 to 57.8.111.25457.8.111.2554,094
13657.8.112.0/2057.8.112.1 to 57.8.127.25457.8.127.2554,094
13757.8.128.0/2057.8.128.1 to 57.8.143.25457.8.143.2554,094
13857.8.144.0/2057.8.144.1 to 57.8.159.25457.8.159.2554,094
13957.8.160.0/2057.8.160.1 to 57.8.175.25457.8.175.2554,094
14057.8.176.0/2057.8.176.1 to 57.8.191.25457.8.191.2554,094
14157.8.192.0/2057.8.192.1 to 57.8.207.25457.8.207.2554,094
14257.8.208.0/2057.8.208.1 to 57.8.223.25457.8.223.2554,094
14357.8.224.0/2057.8.224.1 to 57.8.239.25457.8.239.2554,094
14457.8.240.0/2057.8.240.1 to 57.8.255.25457.8.255.2554,094
14557.9.0.0/2057.9.0.1 to 57.9.15.25457.9.15.2554,094
14657.9.16.0/2057.9.16.1 to 57.9.31.25457.9.31.2554,094
14757.9.32.0/2057.9.32.1 to 57.9.47.25457.9.47.2554,094
14857.9.48.0/2057.9.48.1 to 57.9.63.25457.9.63.2554,094
14957.9.64.0/2057.9.64.1 to 57.9.79.25457.9.79.2554,094
15057.9.80.0/2057.9.80.1 to 57.9.95.25457.9.95.2554,094
15157.9.96.0/2057.9.96.1 to 57.9.111.25457.9.111.2554,094
15257.9.112.0/2057.9.112.1 to 57.9.127.25457.9.127.2554,094
15357.9.128.0/2057.9.128.1 to 57.9.143.25457.9.143.2554,094
15457.9.144.0/2057.9.144.1 to 57.9.159.25457.9.159.2554,094
15557.9.160.0/2057.9.160.1 to 57.9.175.25457.9.175.2554,094
15657.9.176.0/2057.9.176.1 to 57.9.191.25457.9.191.2554,094
15757.9.192.0/2057.9.192.1 to 57.9.207.25457.9.207.2554,094
15857.9.208.0/2057.9.208.1 to 57.9.223.25457.9.223.2554,094
15957.9.224.0/2057.9.224.1 to 57.9.239.25457.9.239.2554,094
16057.9.240.0/2057.9.240.1 to 57.9.255.25457.9.255.2554,094
16157.10.0.0/2057.10.0.1 to 57.10.15.25457.10.15.2554,094
16257.10.16.0/2057.10.16.1 to 57.10.31.25457.10.31.2554,094
16357.10.32.0/2057.10.32.1 to 57.10.47.25457.10.47.2554,094
16457.10.48.0/2057.10.48.1 to 57.10.63.25457.10.63.2554,094
16557.10.64.0/2057.10.64.1 to 57.10.79.25457.10.79.2554,094
16657.10.80.0/2057.10.80.1 to 57.10.95.25457.10.95.2554,094
16757.10.96.0/2057.10.96.1 to 57.10.111.25457.10.111.2554,094
16857.10.112.0/2057.10.112.1 to 57.10.127.25457.10.127.2554,094
16957.10.128.0/2057.10.128.1 to 57.10.143.25457.10.143.2554,094
17057.10.144.0/2057.10.144.1 to 57.10.159.25457.10.159.2554,094
17157.10.160.0/2057.10.160.1 to 57.10.175.25457.10.175.2554,094
17257.10.176.0/2057.10.176.1 to 57.10.191.25457.10.191.2554,094
17357.10.192.0/2057.10.192.1 to 57.10.207.25457.10.207.2554,094
17457.10.208.0/2057.10.208.1 to 57.10.223.25457.10.223.2554,094
17557.10.224.0/2057.10.224.1 to 57.10.239.25457.10.239.2554,094
17657.10.240.0/2057.10.240.1 to 57.10.255.25457.10.255.2554,094
17757.11.0.0/2057.11.0.1 to 57.11.15.25457.11.15.2554,094
17857.11.16.0/2057.11.16.1 to 57.11.31.25457.11.31.2554,094
17957.11.32.0/2057.11.32.1 to 57.11.47.25457.11.47.2554,094
18057.11.48.0/2057.11.48.1 to 57.11.63.25457.11.63.2554,094
18157.11.64.0/2057.11.64.1 to 57.11.79.25457.11.79.2554,094
18257.11.80.0/2057.11.80.1 to 57.11.95.25457.11.95.2554,094
18357.11.96.0/2057.11.96.1 to 57.11.111.25457.11.111.2554,094
18457.11.112.0/2057.11.112.1 to 57.11.127.25457.11.127.2554,094
18557.11.128.0/2057.11.128.1 to 57.11.143.25457.11.143.2554,094
18657.11.144.0/2057.11.144.1 to 57.11.159.25457.11.159.2554,094
18757.11.160.0/2057.11.160.1 to 57.11.175.25457.11.175.2554,094
18857.11.176.0/2057.11.176.1 to 57.11.191.25457.11.191.2554,094
18957.11.192.0/2057.11.192.1 to 57.11.207.25457.11.207.2554,094
19057.11.208.0/2057.11.208.1 to 57.11.223.25457.11.223.2554,094
19157.11.224.0/2057.11.224.1 to 57.11.239.25457.11.239.2554,094
19257.11.240.0/2057.11.240.1 to 57.11.255.25457.11.255.2554,094
19357.12.0.0/2057.12.0.1 to 57.12.15.25457.12.15.2554,094
19457.12.16.0/2057.12.16.1 to 57.12.31.25457.12.31.2554,094
19557.12.32.0/2057.12.32.1 to 57.12.47.25457.12.47.2554,094
19657.12.48.0/2057.12.48.1 to 57.12.63.25457.12.63.2554,094
19757.12.64.0/2057.12.64.1 to 57.12.79.25457.12.79.2554,094
19857.12.80.0/2057.12.80.1 to 57.12.95.25457.12.95.2554,094
19957.12.96.0/2057.12.96.1 to 57.12.111.25457.12.111.2554,094
20057.12.112.0/2057.12.112.1 to 57.12.127.25457.12.127.2554,094
20157.12.128.0/2057.12.128.1 to 57.12.143.25457.12.143.2554,094
20257.12.144.0/2057.12.144.1 to 57.12.159.25457.12.159.2554,094
20357.12.160.0/2057.12.160.1 to 57.12.175.25457.12.175.2554,094
20457.12.176.0/2057.12.176.1 to 57.12.191.25457.12.191.2554,094
20557.12.192.0/2057.12.192.1 to 57.12.207.25457.12.207.2554,094
20657.12.208.0/2057.12.208.1 to 57.12.223.25457.12.223.2554,094
20757.12.224.0/2057.12.224.1 to 57.12.239.25457.12.239.2554,094
20857.12.240.0/2057.12.240.1 to 57.12.255.25457.12.255.2554,094
20957.13.0.0/2057.13.0.1 to 57.13.15.25457.13.15.2554,094
21057.13.16.0/2057.13.16.1 to 57.13.31.25457.13.31.2554,094
21157.13.32.0/2057.13.32.1 to 57.13.47.25457.13.47.2554,094
21257.13.48.0/2057.13.48.1 to 57.13.63.25457.13.63.2554,094
21357.13.64.0/2057.13.64.1 to 57.13.79.25457.13.79.2554,094
21457.13.80.0/2057.13.80.1 to 57.13.95.25457.13.95.2554,094
21557.13.96.0/2057.13.96.1 to 57.13.111.25457.13.111.2554,094
21657.13.112.0/2057.13.112.1 to 57.13.127.25457.13.127.2554,094
21757.13.128.0/2057.13.128.1 to 57.13.143.25457.13.143.2554,094
21857.13.144.0/2057.13.144.1 to 57.13.159.25457.13.159.2554,094
21957.13.160.0/2057.13.160.1 to 57.13.175.25457.13.175.2554,094
22057.13.176.0/2057.13.176.1 to 57.13.191.25457.13.191.2554,094
22157.13.192.0/2057.13.192.1 to 57.13.207.25457.13.207.2554,094
22257.13.208.0/2057.13.208.1 to 57.13.223.25457.13.223.2554,094
22357.13.224.0/2057.13.224.1 to 57.13.239.25457.13.239.2554,094
22457.13.240.0/2057.13.240.1 to 57.13.255.25457.13.255.2554,094
22557.14.0.0/2057.14.0.1 to 57.14.15.25457.14.15.2554,094
22657.14.16.0/2057.14.16.1 to 57.14.31.25457.14.31.2554,094
22757.14.32.0/2057.14.32.1 to 57.14.47.25457.14.47.2554,094
22857.14.48.0/2057.14.48.1 to 57.14.63.25457.14.63.2554,094
22957.14.64.0/2057.14.64.1 to 57.14.79.25457.14.79.2554,094
23057.14.80.0/2057.14.80.1 to 57.14.95.25457.14.95.2554,094
23157.14.96.0/2057.14.96.1 to 57.14.111.25457.14.111.2554,094
23257.14.112.0/2057.14.112.1 to 57.14.127.25457.14.127.2554,094
23357.14.128.0/2057.14.128.1 to 57.14.143.25457.14.143.2554,094
23457.14.144.0/2057.14.144.1 to 57.14.159.25457.14.159.2554,094
23557.14.160.0/2057.14.160.1 to 57.14.175.25457.14.175.2554,094
23657.14.176.0/2057.14.176.1 to 57.14.191.25457.14.191.2554,094
23757.14.192.0/2057.14.192.1 to 57.14.207.25457.14.207.2554,094
23857.14.208.0/2057.14.208.1 to 57.14.223.25457.14.223.2554,094
23957.14.224.0/2057.14.224.1 to 57.14.239.25457.14.239.2554,094
24057.14.240.0/2057.14.240.1 to 57.14.255.25457.14.255.2554,094
24157.15.0.0/2057.15.0.1 to 57.15.15.25457.15.15.2554,094
24257.15.16.0/2057.15.16.1 to 57.15.31.25457.15.31.2554,094
24357.15.32.0/2057.15.32.1 to 57.15.47.25457.15.47.2554,094
24457.15.48.0/2057.15.48.1 to 57.15.63.25457.15.63.2554,094
24557.15.64.0/2057.15.64.1 to 57.15.79.25457.15.79.2554,094
24657.15.80.0/2057.15.80.1 to 57.15.95.25457.15.95.2554,094
24757.15.96.0/2057.15.96.1 to 57.15.111.25457.15.111.2554,094
24857.15.112.0/2057.15.112.1 to 57.15.127.25457.15.127.2554,094
24957.15.128.0/2057.15.128.1 to 57.15.143.25457.15.143.2554,094
25057.15.144.0/2057.15.144.1 to 57.15.159.25457.15.159.2554,094
25157.15.160.0/2057.15.160.1 to 57.15.175.25457.15.175.2554,094
25257.15.176.0/2057.15.176.1 to 57.15.191.25457.15.191.2554,094
25357.15.192.0/2057.15.192.1 to 57.15.207.25457.15.207.2554,094
25457.15.208.0/2057.15.208.1 to 57.15.223.25457.15.223.2554,094
25557.15.224.0/2057.15.224.1 to 57.15.239.25457.15.239.2554,094
25657.15.240.0/2057.15.240.1 to 57.15.255.25457.15.255.2554,094

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.