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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.

Network57.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
57.0.0.0
Broadcast address
57.127.255.255
First usable
57.0.0.1
Last usable
57.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 39000000 · Integer 956301312 to 964689919
Reverse DNS zones
0.57.in-addr.arpa
1.57.in-addr.arpa
2.57.in-addr.arpa
3.57.in-addr.arpa
4.57.in-addr.arpa
5.57.in-addr.arpa
6.57.in-addr.arpa
7.57.in-addr.arpa
8.57.in-addr.arpa
9.57.in-addr.arpa
10.57.in-addr.arpa
11.57.in-addr.arpa
12.57.in-addr.arpa
13.57.in-addr.arpa
14.57.in-addr.arpa
15.57.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111001.00000000.00000000.0000000057.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00111001.00000000.00000000.0000000057.0.0.0
Broadcast00111001.01111111.11111111.1111111157.127.255.255
Split into smaller subnets/19
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

57.0.0.0/9 makes 1,024 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
157.0.0.0/1957.0.0.1 to 57.0.31.25457.0.31.2558,190
257.0.32.0/1957.0.32.1 to 57.0.63.25457.0.63.2558,190
357.0.64.0/1957.0.64.1 to 57.0.95.25457.0.95.2558,190
457.0.96.0/1957.0.96.1 to 57.0.127.25457.0.127.2558,190
557.0.128.0/1957.0.128.1 to 57.0.159.25457.0.159.2558,190
657.0.160.0/1957.0.160.1 to 57.0.191.25457.0.191.2558,190
757.0.192.0/1957.0.192.1 to 57.0.223.25457.0.223.2558,190
857.0.224.0/1957.0.224.1 to 57.0.255.25457.0.255.2558,190
957.1.0.0/1957.1.0.1 to 57.1.31.25457.1.31.2558,190
1057.1.32.0/1957.1.32.1 to 57.1.63.25457.1.63.2558,190
1157.1.64.0/1957.1.64.1 to 57.1.95.25457.1.95.2558,190
1257.1.96.0/1957.1.96.1 to 57.1.127.25457.1.127.2558,190
1357.1.128.0/1957.1.128.1 to 57.1.159.25457.1.159.2558,190
1457.1.160.0/1957.1.160.1 to 57.1.191.25457.1.191.2558,190
1557.1.192.0/1957.1.192.1 to 57.1.223.25457.1.223.2558,190
1657.1.224.0/1957.1.224.1 to 57.1.255.25457.1.255.2558,190
1757.2.0.0/1957.2.0.1 to 57.2.31.25457.2.31.2558,190
1857.2.32.0/1957.2.32.1 to 57.2.63.25457.2.63.2558,190
1957.2.64.0/1957.2.64.1 to 57.2.95.25457.2.95.2558,190
2057.2.96.0/1957.2.96.1 to 57.2.127.25457.2.127.2558,190
2157.2.128.0/1957.2.128.1 to 57.2.159.25457.2.159.2558,190
2257.2.160.0/1957.2.160.1 to 57.2.191.25457.2.191.2558,190
2357.2.192.0/1957.2.192.1 to 57.2.223.25457.2.223.2558,190
2457.2.224.0/1957.2.224.1 to 57.2.255.25457.2.255.2558,190
2557.3.0.0/1957.3.0.1 to 57.3.31.25457.3.31.2558,190
2657.3.32.0/1957.3.32.1 to 57.3.63.25457.3.63.2558,190
2757.3.64.0/1957.3.64.1 to 57.3.95.25457.3.95.2558,190
2857.3.96.0/1957.3.96.1 to 57.3.127.25457.3.127.2558,190
2957.3.128.0/1957.3.128.1 to 57.3.159.25457.3.159.2558,190
3057.3.160.0/1957.3.160.1 to 57.3.191.25457.3.191.2558,190
3157.3.192.0/1957.3.192.1 to 57.3.223.25457.3.223.2558,190
3257.3.224.0/1957.3.224.1 to 57.3.255.25457.3.255.2558,190
3357.4.0.0/1957.4.0.1 to 57.4.31.25457.4.31.2558,190
3457.4.32.0/1957.4.32.1 to 57.4.63.25457.4.63.2558,190
3557.4.64.0/1957.4.64.1 to 57.4.95.25457.4.95.2558,190
3657.4.96.0/1957.4.96.1 to 57.4.127.25457.4.127.2558,190
3757.4.128.0/1957.4.128.1 to 57.4.159.25457.4.159.2558,190
3857.4.160.0/1957.4.160.1 to 57.4.191.25457.4.191.2558,190
3957.4.192.0/1957.4.192.1 to 57.4.223.25457.4.223.2558,190
4057.4.224.0/1957.4.224.1 to 57.4.255.25457.4.255.2558,190
4157.5.0.0/1957.5.0.1 to 57.5.31.25457.5.31.2558,190
4257.5.32.0/1957.5.32.1 to 57.5.63.25457.5.63.2558,190
4357.5.64.0/1957.5.64.1 to 57.5.95.25457.5.95.2558,190
4457.5.96.0/1957.5.96.1 to 57.5.127.25457.5.127.2558,190
4557.5.128.0/1957.5.128.1 to 57.5.159.25457.5.159.2558,190
4657.5.160.0/1957.5.160.1 to 57.5.191.25457.5.191.2558,190
4757.5.192.0/1957.5.192.1 to 57.5.223.25457.5.223.2558,190
4857.5.224.0/1957.5.224.1 to 57.5.255.25457.5.255.2558,190
4957.6.0.0/1957.6.0.1 to 57.6.31.25457.6.31.2558,190
5057.6.32.0/1957.6.32.1 to 57.6.63.25457.6.63.2558,190
5157.6.64.0/1957.6.64.1 to 57.6.95.25457.6.95.2558,190
5257.6.96.0/1957.6.96.1 to 57.6.127.25457.6.127.2558,190
5357.6.128.0/1957.6.128.1 to 57.6.159.25457.6.159.2558,190
5457.6.160.0/1957.6.160.1 to 57.6.191.25457.6.191.2558,190
5557.6.192.0/1957.6.192.1 to 57.6.223.25457.6.223.2558,190
5657.6.224.0/1957.6.224.1 to 57.6.255.25457.6.255.2558,190
5757.7.0.0/1957.7.0.1 to 57.7.31.25457.7.31.2558,190
5857.7.32.0/1957.7.32.1 to 57.7.63.25457.7.63.2558,190
5957.7.64.0/1957.7.64.1 to 57.7.95.25457.7.95.2558,190
6057.7.96.0/1957.7.96.1 to 57.7.127.25457.7.127.2558,190
6157.7.128.0/1957.7.128.1 to 57.7.159.25457.7.159.2558,190
6257.7.160.0/1957.7.160.1 to 57.7.191.25457.7.191.2558,190
6357.7.192.0/1957.7.192.1 to 57.7.223.25457.7.223.2558,190
6457.7.224.0/1957.7.224.1 to 57.7.255.25457.7.255.2558,190
6557.8.0.0/1957.8.0.1 to 57.8.31.25457.8.31.2558,190
6657.8.32.0/1957.8.32.1 to 57.8.63.25457.8.63.2558,190
6757.8.64.0/1957.8.64.1 to 57.8.95.25457.8.95.2558,190
6857.8.96.0/1957.8.96.1 to 57.8.127.25457.8.127.2558,190
6957.8.128.0/1957.8.128.1 to 57.8.159.25457.8.159.2558,190
7057.8.160.0/1957.8.160.1 to 57.8.191.25457.8.191.2558,190
7157.8.192.0/1957.8.192.1 to 57.8.223.25457.8.223.2558,190
7257.8.224.0/1957.8.224.1 to 57.8.255.25457.8.255.2558,190
7357.9.0.0/1957.9.0.1 to 57.9.31.25457.9.31.2558,190
7457.9.32.0/1957.9.32.1 to 57.9.63.25457.9.63.2558,190
7557.9.64.0/1957.9.64.1 to 57.9.95.25457.9.95.2558,190
7657.9.96.0/1957.9.96.1 to 57.9.127.25457.9.127.2558,190
7757.9.128.0/1957.9.128.1 to 57.9.159.25457.9.159.2558,190
7857.9.160.0/1957.9.160.1 to 57.9.191.25457.9.191.2558,190
7957.9.192.0/1957.9.192.1 to 57.9.223.25457.9.223.2558,190
8057.9.224.0/1957.9.224.1 to 57.9.255.25457.9.255.2558,190
8157.10.0.0/1957.10.0.1 to 57.10.31.25457.10.31.2558,190
8257.10.32.0/1957.10.32.1 to 57.10.63.25457.10.63.2558,190
8357.10.64.0/1957.10.64.1 to 57.10.95.25457.10.95.2558,190
8457.10.96.0/1957.10.96.1 to 57.10.127.25457.10.127.2558,190
8557.10.128.0/1957.10.128.1 to 57.10.159.25457.10.159.2558,190
8657.10.160.0/1957.10.160.1 to 57.10.191.25457.10.191.2558,190
8757.10.192.0/1957.10.192.1 to 57.10.223.25457.10.223.2558,190
8857.10.224.0/1957.10.224.1 to 57.10.255.25457.10.255.2558,190
8957.11.0.0/1957.11.0.1 to 57.11.31.25457.11.31.2558,190
9057.11.32.0/1957.11.32.1 to 57.11.63.25457.11.63.2558,190
9157.11.64.0/1957.11.64.1 to 57.11.95.25457.11.95.2558,190
9257.11.96.0/1957.11.96.1 to 57.11.127.25457.11.127.2558,190
9357.11.128.0/1957.11.128.1 to 57.11.159.25457.11.159.2558,190
9457.11.160.0/1957.11.160.1 to 57.11.191.25457.11.191.2558,190
9557.11.192.0/1957.11.192.1 to 57.11.223.25457.11.223.2558,190
9657.11.224.0/1957.11.224.1 to 57.11.255.25457.11.255.2558,190
9757.12.0.0/1957.12.0.1 to 57.12.31.25457.12.31.2558,190
9857.12.32.0/1957.12.32.1 to 57.12.63.25457.12.63.2558,190
9957.12.64.0/1957.12.64.1 to 57.12.95.25457.12.95.2558,190
10057.12.96.0/1957.12.96.1 to 57.12.127.25457.12.127.2558,190
10157.12.128.0/1957.12.128.1 to 57.12.159.25457.12.159.2558,190
10257.12.160.0/1957.12.160.1 to 57.12.191.25457.12.191.2558,190
10357.12.192.0/1957.12.192.1 to 57.12.223.25457.12.223.2558,190
10457.12.224.0/1957.12.224.1 to 57.12.255.25457.12.255.2558,190
10557.13.0.0/1957.13.0.1 to 57.13.31.25457.13.31.2558,190
10657.13.32.0/1957.13.32.1 to 57.13.63.25457.13.63.2558,190
10757.13.64.0/1957.13.64.1 to 57.13.95.25457.13.95.2558,190
10857.13.96.0/1957.13.96.1 to 57.13.127.25457.13.127.2558,190
10957.13.128.0/1957.13.128.1 to 57.13.159.25457.13.159.2558,190
11057.13.160.0/1957.13.160.1 to 57.13.191.25457.13.191.2558,190
11157.13.192.0/1957.13.192.1 to 57.13.223.25457.13.223.2558,190
11257.13.224.0/1957.13.224.1 to 57.13.255.25457.13.255.2558,190
11357.14.0.0/1957.14.0.1 to 57.14.31.25457.14.31.2558,190
11457.14.32.0/1957.14.32.1 to 57.14.63.25457.14.63.2558,190
11557.14.64.0/1957.14.64.1 to 57.14.95.25457.14.95.2558,190
11657.14.96.0/1957.14.96.1 to 57.14.127.25457.14.127.2558,190
11757.14.128.0/1957.14.128.1 to 57.14.159.25457.14.159.2558,190
11857.14.160.0/1957.14.160.1 to 57.14.191.25457.14.191.2558,190
11957.14.192.0/1957.14.192.1 to 57.14.223.25457.14.223.2558,190
12057.14.224.0/1957.14.224.1 to 57.14.255.25457.14.255.2558,190
12157.15.0.0/1957.15.0.1 to 57.15.31.25457.15.31.2558,190
12257.15.32.0/1957.15.32.1 to 57.15.63.25457.15.63.2558,190
12357.15.64.0/1957.15.64.1 to 57.15.95.25457.15.95.2558,190
12457.15.96.0/1957.15.96.1 to 57.15.127.25457.15.127.2558,190
12557.15.128.0/1957.15.128.1 to 57.15.159.25457.15.159.2558,190
12657.15.160.0/1957.15.160.1 to 57.15.191.25457.15.191.2558,190
12757.15.192.0/1957.15.192.1 to 57.15.223.25457.15.223.2558,190
12857.15.224.0/1957.15.224.1 to 57.15.255.25457.15.255.2558,190
12957.16.0.0/1957.16.0.1 to 57.16.31.25457.16.31.2558,190
13057.16.32.0/1957.16.32.1 to 57.16.63.25457.16.63.2558,190
13157.16.64.0/1957.16.64.1 to 57.16.95.25457.16.95.2558,190
13257.16.96.0/1957.16.96.1 to 57.16.127.25457.16.127.2558,190
13357.16.128.0/1957.16.128.1 to 57.16.159.25457.16.159.2558,190
13457.16.160.0/1957.16.160.1 to 57.16.191.25457.16.191.2558,190
13557.16.192.0/1957.16.192.1 to 57.16.223.25457.16.223.2558,190
13657.16.224.0/1957.16.224.1 to 57.16.255.25457.16.255.2558,190
13757.17.0.0/1957.17.0.1 to 57.17.31.25457.17.31.2558,190
13857.17.32.0/1957.17.32.1 to 57.17.63.25457.17.63.2558,190
13957.17.64.0/1957.17.64.1 to 57.17.95.25457.17.95.2558,190
14057.17.96.0/1957.17.96.1 to 57.17.127.25457.17.127.2558,190
14157.17.128.0/1957.17.128.1 to 57.17.159.25457.17.159.2558,190
14257.17.160.0/1957.17.160.1 to 57.17.191.25457.17.191.2558,190
14357.17.192.0/1957.17.192.1 to 57.17.223.25457.17.223.2558,190
14457.17.224.0/1957.17.224.1 to 57.17.255.25457.17.255.2558,190
14557.18.0.0/1957.18.0.1 to 57.18.31.25457.18.31.2558,190
14657.18.32.0/1957.18.32.1 to 57.18.63.25457.18.63.2558,190
14757.18.64.0/1957.18.64.1 to 57.18.95.25457.18.95.2558,190
14857.18.96.0/1957.18.96.1 to 57.18.127.25457.18.127.2558,190
14957.18.128.0/1957.18.128.1 to 57.18.159.25457.18.159.2558,190
15057.18.160.0/1957.18.160.1 to 57.18.191.25457.18.191.2558,190
15157.18.192.0/1957.18.192.1 to 57.18.223.25457.18.223.2558,190
15257.18.224.0/1957.18.224.1 to 57.18.255.25457.18.255.2558,190
15357.19.0.0/1957.19.0.1 to 57.19.31.25457.19.31.2558,190
15457.19.32.0/1957.19.32.1 to 57.19.63.25457.19.63.2558,190
15557.19.64.0/1957.19.64.1 to 57.19.95.25457.19.95.2558,190
15657.19.96.0/1957.19.96.1 to 57.19.127.25457.19.127.2558,190
15757.19.128.0/1957.19.128.1 to 57.19.159.25457.19.159.2558,190
15857.19.160.0/1957.19.160.1 to 57.19.191.25457.19.191.2558,190
15957.19.192.0/1957.19.192.1 to 57.19.223.25457.19.223.2558,190
16057.19.224.0/1957.19.224.1 to 57.19.255.25457.19.255.2558,190
16157.20.0.0/1957.20.0.1 to 57.20.31.25457.20.31.2558,190
16257.20.32.0/1957.20.32.1 to 57.20.63.25457.20.63.2558,190
16357.20.64.0/1957.20.64.1 to 57.20.95.25457.20.95.2558,190
16457.20.96.0/1957.20.96.1 to 57.20.127.25457.20.127.2558,190
16557.20.128.0/1957.20.128.1 to 57.20.159.25457.20.159.2558,190
16657.20.160.0/1957.20.160.1 to 57.20.191.25457.20.191.2558,190
16757.20.192.0/1957.20.192.1 to 57.20.223.25457.20.223.2558,190
16857.20.224.0/1957.20.224.1 to 57.20.255.25457.20.255.2558,190
16957.21.0.0/1957.21.0.1 to 57.21.31.25457.21.31.2558,190
17057.21.32.0/1957.21.32.1 to 57.21.63.25457.21.63.2558,190
17157.21.64.0/1957.21.64.1 to 57.21.95.25457.21.95.2558,190
17257.21.96.0/1957.21.96.1 to 57.21.127.25457.21.127.2558,190
17357.21.128.0/1957.21.128.1 to 57.21.159.25457.21.159.2558,190
17457.21.160.0/1957.21.160.1 to 57.21.191.25457.21.191.2558,190
17557.21.192.0/1957.21.192.1 to 57.21.223.25457.21.223.2558,190
17657.21.224.0/1957.21.224.1 to 57.21.255.25457.21.255.2558,190
17757.22.0.0/1957.22.0.1 to 57.22.31.25457.22.31.2558,190
17857.22.32.0/1957.22.32.1 to 57.22.63.25457.22.63.2558,190
17957.22.64.0/1957.22.64.1 to 57.22.95.25457.22.95.2558,190
18057.22.96.0/1957.22.96.1 to 57.22.127.25457.22.127.2558,190
18157.22.128.0/1957.22.128.1 to 57.22.159.25457.22.159.2558,190
18257.22.160.0/1957.22.160.1 to 57.22.191.25457.22.191.2558,190
18357.22.192.0/1957.22.192.1 to 57.22.223.25457.22.223.2558,190
18457.22.224.0/1957.22.224.1 to 57.22.255.25457.22.255.2558,190
18557.23.0.0/1957.23.0.1 to 57.23.31.25457.23.31.2558,190
18657.23.32.0/1957.23.32.1 to 57.23.63.25457.23.63.2558,190
18757.23.64.0/1957.23.64.1 to 57.23.95.25457.23.95.2558,190
18857.23.96.0/1957.23.96.1 to 57.23.127.25457.23.127.2558,190
18957.23.128.0/1957.23.128.1 to 57.23.159.25457.23.159.2558,190
19057.23.160.0/1957.23.160.1 to 57.23.191.25457.23.191.2558,190
19157.23.192.0/1957.23.192.1 to 57.23.223.25457.23.223.2558,190
19257.23.224.0/1957.23.224.1 to 57.23.255.25457.23.255.2558,190
19357.24.0.0/1957.24.0.1 to 57.24.31.25457.24.31.2558,190
19457.24.32.0/1957.24.32.1 to 57.24.63.25457.24.63.2558,190
19557.24.64.0/1957.24.64.1 to 57.24.95.25457.24.95.2558,190
19657.24.96.0/1957.24.96.1 to 57.24.127.25457.24.127.2558,190
19757.24.128.0/1957.24.128.1 to 57.24.159.25457.24.159.2558,190
19857.24.160.0/1957.24.160.1 to 57.24.191.25457.24.191.2558,190
19957.24.192.0/1957.24.192.1 to 57.24.223.25457.24.223.2558,190
20057.24.224.0/1957.24.224.1 to 57.24.255.25457.24.255.2558,190
20157.25.0.0/1957.25.0.1 to 57.25.31.25457.25.31.2558,190
20257.25.32.0/1957.25.32.1 to 57.25.63.25457.25.63.2558,190
20357.25.64.0/1957.25.64.1 to 57.25.95.25457.25.95.2558,190
20457.25.96.0/1957.25.96.1 to 57.25.127.25457.25.127.2558,190
20557.25.128.0/1957.25.128.1 to 57.25.159.25457.25.159.2558,190
20657.25.160.0/1957.25.160.1 to 57.25.191.25457.25.191.2558,190
20757.25.192.0/1957.25.192.1 to 57.25.223.25457.25.223.2558,190
20857.25.224.0/1957.25.224.1 to 57.25.255.25457.25.255.2558,190
20957.26.0.0/1957.26.0.1 to 57.26.31.25457.26.31.2558,190
21057.26.32.0/1957.26.32.1 to 57.26.63.25457.26.63.2558,190
21157.26.64.0/1957.26.64.1 to 57.26.95.25457.26.95.2558,190
21257.26.96.0/1957.26.96.1 to 57.26.127.25457.26.127.2558,190
21357.26.128.0/1957.26.128.1 to 57.26.159.25457.26.159.2558,190
21457.26.160.0/1957.26.160.1 to 57.26.191.25457.26.191.2558,190
21557.26.192.0/1957.26.192.1 to 57.26.223.25457.26.223.2558,190
21657.26.224.0/1957.26.224.1 to 57.26.255.25457.26.255.2558,190
21757.27.0.0/1957.27.0.1 to 57.27.31.25457.27.31.2558,190
21857.27.32.0/1957.27.32.1 to 57.27.63.25457.27.63.2558,190
21957.27.64.0/1957.27.64.1 to 57.27.95.25457.27.95.2558,190
22057.27.96.0/1957.27.96.1 to 57.27.127.25457.27.127.2558,190
22157.27.128.0/1957.27.128.1 to 57.27.159.25457.27.159.2558,190
22257.27.160.0/1957.27.160.1 to 57.27.191.25457.27.191.2558,190
22357.27.192.0/1957.27.192.1 to 57.27.223.25457.27.223.2558,190
22457.27.224.0/1957.27.224.1 to 57.27.255.25457.27.255.2558,190
22557.28.0.0/1957.28.0.1 to 57.28.31.25457.28.31.2558,190
22657.28.32.0/1957.28.32.1 to 57.28.63.25457.28.63.2558,190
22757.28.64.0/1957.28.64.1 to 57.28.95.25457.28.95.2558,190
22857.28.96.0/1957.28.96.1 to 57.28.127.25457.28.127.2558,190
22957.28.128.0/1957.28.128.1 to 57.28.159.25457.28.159.2558,190
23057.28.160.0/1957.28.160.1 to 57.28.191.25457.28.191.2558,190
23157.28.192.0/1957.28.192.1 to 57.28.223.25457.28.223.2558,190
23257.28.224.0/1957.28.224.1 to 57.28.255.25457.28.255.2558,190
23357.29.0.0/1957.29.0.1 to 57.29.31.25457.29.31.2558,190
23457.29.32.0/1957.29.32.1 to 57.29.63.25457.29.63.2558,190
23557.29.64.0/1957.29.64.1 to 57.29.95.25457.29.95.2558,190
23657.29.96.0/1957.29.96.1 to 57.29.127.25457.29.127.2558,190
23757.29.128.0/1957.29.128.1 to 57.29.159.25457.29.159.2558,190
23857.29.160.0/1957.29.160.1 to 57.29.191.25457.29.191.2558,190
23957.29.192.0/1957.29.192.1 to 57.29.223.25457.29.223.2558,190
24057.29.224.0/1957.29.224.1 to 57.29.255.25457.29.255.2558,190
24157.30.0.0/1957.30.0.1 to 57.30.31.25457.30.31.2558,190
24257.30.32.0/1957.30.32.1 to 57.30.63.25457.30.63.2558,190
24357.30.64.0/1957.30.64.1 to 57.30.95.25457.30.95.2558,190
24457.30.96.0/1957.30.96.1 to 57.30.127.25457.30.127.2558,190
24557.30.128.0/1957.30.128.1 to 57.30.159.25457.30.159.2558,190
24657.30.160.0/1957.30.160.1 to 57.30.191.25457.30.191.2558,190
24757.30.192.0/1957.30.192.1 to 57.30.223.25457.30.223.2558,190
24857.30.224.0/1957.30.224.1 to 57.30.255.25457.30.255.2558,190
24957.31.0.0/1957.31.0.1 to 57.31.31.25457.31.31.2558,190
25057.31.32.0/1957.31.32.1 to 57.31.63.25457.31.63.2558,190
25157.31.64.0/1957.31.64.1 to 57.31.95.25457.31.95.2558,190
25257.31.96.0/1957.31.96.1 to 57.31.127.25457.31.127.2558,190
25357.31.128.0/1957.31.128.1 to 57.31.159.25457.31.159.2558,190
25457.31.160.0/1957.31.160.1 to 57.31.191.25457.31.191.2558,190
25557.31.192.0/1957.31.192.1 to 57.31.223.25457.31.223.2558,190
25657.31.224.0/1957.31.224.1 to 57.31.255.25457.31.255.2558,190

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.