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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.

Network55.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
55.0.0.0
Broadcast address
55.127.255.255
First usable
55.0.0.1
Last usable
55.127.255.254
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 37000000 · Integer 922746880 to 931135487
Reverse DNS zones
0.55.in-addr.arpa
1.55.in-addr.arpa
2.55.in-addr.arpa
3.55.in-addr.arpa
4.55.in-addr.arpa
5.55.in-addr.arpa
6.55.in-addr.arpa
7.55.in-addr.arpa
8.55.in-addr.arpa
9.55.in-addr.arpa
10.55.in-addr.arpa
11.55.in-addr.arpa
12.55.in-addr.arpa
13.55.in-addr.arpa
14.55.in-addr.arpa
15.55.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
Address00110111.00000000.00000000.0000000055.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00110111.00000000.00000000.0000000055.0.0.0
Broadcast00110111.01111111.11111111.1111111155.127.255.255
Split into smaller subnets/18
/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)

55.0.0.0/9 makes 512 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
155.0.0.0/1855.0.0.1 to 55.0.63.25455.0.63.25516,382
255.0.64.0/1855.0.64.1 to 55.0.127.25455.0.127.25516,382
355.0.128.0/1855.0.128.1 to 55.0.191.25455.0.191.25516,382
455.0.192.0/1855.0.192.1 to 55.0.255.25455.0.255.25516,382
555.1.0.0/1855.1.0.1 to 55.1.63.25455.1.63.25516,382
655.1.64.0/1855.1.64.1 to 55.1.127.25455.1.127.25516,382
755.1.128.0/1855.1.128.1 to 55.1.191.25455.1.191.25516,382
855.1.192.0/1855.1.192.1 to 55.1.255.25455.1.255.25516,382
955.2.0.0/1855.2.0.1 to 55.2.63.25455.2.63.25516,382
1055.2.64.0/1855.2.64.1 to 55.2.127.25455.2.127.25516,382
1155.2.128.0/1855.2.128.1 to 55.2.191.25455.2.191.25516,382
1255.2.192.0/1855.2.192.1 to 55.2.255.25455.2.255.25516,382
1355.3.0.0/1855.3.0.1 to 55.3.63.25455.3.63.25516,382
1455.3.64.0/1855.3.64.1 to 55.3.127.25455.3.127.25516,382
1555.3.128.0/1855.3.128.1 to 55.3.191.25455.3.191.25516,382
1655.3.192.0/1855.3.192.1 to 55.3.255.25455.3.255.25516,382
1755.4.0.0/1855.4.0.1 to 55.4.63.25455.4.63.25516,382
1855.4.64.0/1855.4.64.1 to 55.4.127.25455.4.127.25516,382
1955.4.128.0/1855.4.128.1 to 55.4.191.25455.4.191.25516,382
2055.4.192.0/1855.4.192.1 to 55.4.255.25455.4.255.25516,382
2155.5.0.0/1855.5.0.1 to 55.5.63.25455.5.63.25516,382
2255.5.64.0/1855.5.64.1 to 55.5.127.25455.5.127.25516,382
2355.5.128.0/1855.5.128.1 to 55.5.191.25455.5.191.25516,382
2455.5.192.0/1855.5.192.1 to 55.5.255.25455.5.255.25516,382
2555.6.0.0/1855.6.0.1 to 55.6.63.25455.6.63.25516,382
2655.6.64.0/1855.6.64.1 to 55.6.127.25455.6.127.25516,382
2755.6.128.0/1855.6.128.1 to 55.6.191.25455.6.191.25516,382
2855.6.192.0/1855.6.192.1 to 55.6.255.25455.6.255.25516,382
2955.7.0.0/1855.7.0.1 to 55.7.63.25455.7.63.25516,382
3055.7.64.0/1855.7.64.1 to 55.7.127.25455.7.127.25516,382
3155.7.128.0/1855.7.128.1 to 55.7.191.25455.7.191.25516,382
3255.7.192.0/1855.7.192.1 to 55.7.255.25455.7.255.25516,382
3355.8.0.0/1855.8.0.1 to 55.8.63.25455.8.63.25516,382
3455.8.64.0/1855.8.64.1 to 55.8.127.25455.8.127.25516,382
3555.8.128.0/1855.8.128.1 to 55.8.191.25455.8.191.25516,382
3655.8.192.0/1855.8.192.1 to 55.8.255.25455.8.255.25516,382
3755.9.0.0/1855.9.0.1 to 55.9.63.25455.9.63.25516,382
3855.9.64.0/1855.9.64.1 to 55.9.127.25455.9.127.25516,382
3955.9.128.0/1855.9.128.1 to 55.9.191.25455.9.191.25516,382
4055.9.192.0/1855.9.192.1 to 55.9.255.25455.9.255.25516,382
4155.10.0.0/1855.10.0.1 to 55.10.63.25455.10.63.25516,382
4255.10.64.0/1855.10.64.1 to 55.10.127.25455.10.127.25516,382
4355.10.128.0/1855.10.128.1 to 55.10.191.25455.10.191.25516,382
4455.10.192.0/1855.10.192.1 to 55.10.255.25455.10.255.25516,382
4555.11.0.0/1855.11.0.1 to 55.11.63.25455.11.63.25516,382
4655.11.64.0/1855.11.64.1 to 55.11.127.25455.11.127.25516,382
4755.11.128.0/1855.11.128.1 to 55.11.191.25455.11.191.25516,382
4855.11.192.0/1855.11.192.1 to 55.11.255.25455.11.255.25516,382
4955.12.0.0/1855.12.0.1 to 55.12.63.25455.12.63.25516,382
5055.12.64.0/1855.12.64.1 to 55.12.127.25455.12.127.25516,382
5155.12.128.0/1855.12.128.1 to 55.12.191.25455.12.191.25516,382
5255.12.192.0/1855.12.192.1 to 55.12.255.25455.12.255.25516,382
5355.13.0.0/1855.13.0.1 to 55.13.63.25455.13.63.25516,382
5455.13.64.0/1855.13.64.1 to 55.13.127.25455.13.127.25516,382
5555.13.128.0/1855.13.128.1 to 55.13.191.25455.13.191.25516,382
5655.13.192.0/1855.13.192.1 to 55.13.255.25455.13.255.25516,382
5755.14.0.0/1855.14.0.1 to 55.14.63.25455.14.63.25516,382
5855.14.64.0/1855.14.64.1 to 55.14.127.25455.14.127.25516,382
5955.14.128.0/1855.14.128.1 to 55.14.191.25455.14.191.25516,382
6055.14.192.0/1855.14.192.1 to 55.14.255.25455.14.255.25516,382
6155.15.0.0/1855.15.0.1 to 55.15.63.25455.15.63.25516,382
6255.15.64.0/1855.15.64.1 to 55.15.127.25455.15.127.25516,382
6355.15.128.0/1855.15.128.1 to 55.15.191.25455.15.191.25516,382
6455.15.192.0/1855.15.192.1 to 55.15.255.25455.15.255.25516,382
6555.16.0.0/1855.16.0.1 to 55.16.63.25455.16.63.25516,382
6655.16.64.0/1855.16.64.1 to 55.16.127.25455.16.127.25516,382
6755.16.128.0/1855.16.128.1 to 55.16.191.25455.16.191.25516,382
6855.16.192.0/1855.16.192.1 to 55.16.255.25455.16.255.25516,382
6955.17.0.0/1855.17.0.1 to 55.17.63.25455.17.63.25516,382
7055.17.64.0/1855.17.64.1 to 55.17.127.25455.17.127.25516,382
7155.17.128.0/1855.17.128.1 to 55.17.191.25455.17.191.25516,382
7255.17.192.0/1855.17.192.1 to 55.17.255.25455.17.255.25516,382
7355.18.0.0/1855.18.0.1 to 55.18.63.25455.18.63.25516,382
7455.18.64.0/1855.18.64.1 to 55.18.127.25455.18.127.25516,382
7555.18.128.0/1855.18.128.1 to 55.18.191.25455.18.191.25516,382
7655.18.192.0/1855.18.192.1 to 55.18.255.25455.18.255.25516,382
7755.19.0.0/1855.19.0.1 to 55.19.63.25455.19.63.25516,382
7855.19.64.0/1855.19.64.1 to 55.19.127.25455.19.127.25516,382
7955.19.128.0/1855.19.128.1 to 55.19.191.25455.19.191.25516,382
8055.19.192.0/1855.19.192.1 to 55.19.255.25455.19.255.25516,382
8155.20.0.0/1855.20.0.1 to 55.20.63.25455.20.63.25516,382
8255.20.64.0/1855.20.64.1 to 55.20.127.25455.20.127.25516,382
8355.20.128.0/1855.20.128.1 to 55.20.191.25455.20.191.25516,382
8455.20.192.0/1855.20.192.1 to 55.20.255.25455.20.255.25516,382
8555.21.0.0/1855.21.0.1 to 55.21.63.25455.21.63.25516,382
8655.21.64.0/1855.21.64.1 to 55.21.127.25455.21.127.25516,382
8755.21.128.0/1855.21.128.1 to 55.21.191.25455.21.191.25516,382
8855.21.192.0/1855.21.192.1 to 55.21.255.25455.21.255.25516,382
8955.22.0.0/1855.22.0.1 to 55.22.63.25455.22.63.25516,382
9055.22.64.0/1855.22.64.1 to 55.22.127.25455.22.127.25516,382
9155.22.128.0/1855.22.128.1 to 55.22.191.25455.22.191.25516,382
9255.22.192.0/1855.22.192.1 to 55.22.255.25455.22.255.25516,382
9355.23.0.0/1855.23.0.1 to 55.23.63.25455.23.63.25516,382
9455.23.64.0/1855.23.64.1 to 55.23.127.25455.23.127.25516,382
9555.23.128.0/1855.23.128.1 to 55.23.191.25455.23.191.25516,382
9655.23.192.0/1855.23.192.1 to 55.23.255.25455.23.255.25516,382
9755.24.0.0/1855.24.0.1 to 55.24.63.25455.24.63.25516,382
9855.24.64.0/1855.24.64.1 to 55.24.127.25455.24.127.25516,382
9955.24.128.0/1855.24.128.1 to 55.24.191.25455.24.191.25516,382
10055.24.192.0/1855.24.192.1 to 55.24.255.25455.24.255.25516,382
10155.25.0.0/1855.25.0.1 to 55.25.63.25455.25.63.25516,382
10255.25.64.0/1855.25.64.1 to 55.25.127.25455.25.127.25516,382
10355.25.128.0/1855.25.128.1 to 55.25.191.25455.25.191.25516,382
10455.25.192.0/1855.25.192.1 to 55.25.255.25455.25.255.25516,382
10555.26.0.0/1855.26.0.1 to 55.26.63.25455.26.63.25516,382
10655.26.64.0/1855.26.64.1 to 55.26.127.25455.26.127.25516,382
10755.26.128.0/1855.26.128.1 to 55.26.191.25455.26.191.25516,382
10855.26.192.0/1855.26.192.1 to 55.26.255.25455.26.255.25516,382
10955.27.0.0/1855.27.0.1 to 55.27.63.25455.27.63.25516,382
11055.27.64.0/1855.27.64.1 to 55.27.127.25455.27.127.25516,382
11155.27.128.0/1855.27.128.1 to 55.27.191.25455.27.191.25516,382
11255.27.192.0/1855.27.192.1 to 55.27.255.25455.27.255.25516,382
11355.28.0.0/1855.28.0.1 to 55.28.63.25455.28.63.25516,382
11455.28.64.0/1855.28.64.1 to 55.28.127.25455.28.127.25516,382
11555.28.128.0/1855.28.128.1 to 55.28.191.25455.28.191.25516,382
11655.28.192.0/1855.28.192.1 to 55.28.255.25455.28.255.25516,382
11755.29.0.0/1855.29.0.1 to 55.29.63.25455.29.63.25516,382
11855.29.64.0/1855.29.64.1 to 55.29.127.25455.29.127.25516,382
11955.29.128.0/1855.29.128.1 to 55.29.191.25455.29.191.25516,382
12055.29.192.0/1855.29.192.1 to 55.29.255.25455.29.255.25516,382
12155.30.0.0/1855.30.0.1 to 55.30.63.25455.30.63.25516,382
12255.30.64.0/1855.30.64.1 to 55.30.127.25455.30.127.25516,382
12355.30.128.0/1855.30.128.1 to 55.30.191.25455.30.191.25516,382
12455.30.192.0/1855.30.192.1 to 55.30.255.25455.30.255.25516,382
12555.31.0.0/1855.31.0.1 to 55.31.63.25455.31.63.25516,382
12655.31.64.0/1855.31.64.1 to 55.31.127.25455.31.127.25516,382
12755.31.128.0/1855.31.128.1 to 55.31.191.25455.31.191.25516,382
12855.31.192.0/1855.31.192.1 to 55.31.255.25455.31.255.25516,382
12955.32.0.0/1855.32.0.1 to 55.32.63.25455.32.63.25516,382
13055.32.64.0/1855.32.64.1 to 55.32.127.25455.32.127.25516,382
13155.32.128.0/1855.32.128.1 to 55.32.191.25455.32.191.25516,382
13255.32.192.0/1855.32.192.1 to 55.32.255.25455.32.255.25516,382
13355.33.0.0/1855.33.0.1 to 55.33.63.25455.33.63.25516,382
13455.33.64.0/1855.33.64.1 to 55.33.127.25455.33.127.25516,382
13555.33.128.0/1855.33.128.1 to 55.33.191.25455.33.191.25516,382
13655.33.192.0/1855.33.192.1 to 55.33.255.25455.33.255.25516,382
13755.34.0.0/1855.34.0.1 to 55.34.63.25455.34.63.25516,382
13855.34.64.0/1855.34.64.1 to 55.34.127.25455.34.127.25516,382
13955.34.128.0/1855.34.128.1 to 55.34.191.25455.34.191.25516,382
14055.34.192.0/1855.34.192.1 to 55.34.255.25455.34.255.25516,382
14155.35.0.0/1855.35.0.1 to 55.35.63.25455.35.63.25516,382
14255.35.64.0/1855.35.64.1 to 55.35.127.25455.35.127.25516,382
14355.35.128.0/1855.35.128.1 to 55.35.191.25455.35.191.25516,382
14455.35.192.0/1855.35.192.1 to 55.35.255.25455.35.255.25516,382
14555.36.0.0/1855.36.0.1 to 55.36.63.25455.36.63.25516,382
14655.36.64.0/1855.36.64.1 to 55.36.127.25455.36.127.25516,382
14755.36.128.0/1855.36.128.1 to 55.36.191.25455.36.191.25516,382
14855.36.192.0/1855.36.192.1 to 55.36.255.25455.36.255.25516,382
14955.37.0.0/1855.37.0.1 to 55.37.63.25455.37.63.25516,382
15055.37.64.0/1855.37.64.1 to 55.37.127.25455.37.127.25516,382
15155.37.128.0/1855.37.128.1 to 55.37.191.25455.37.191.25516,382
15255.37.192.0/1855.37.192.1 to 55.37.255.25455.37.255.25516,382
15355.38.0.0/1855.38.0.1 to 55.38.63.25455.38.63.25516,382
15455.38.64.0/1855.38.64.1 to 55.38.127.25455.38.127.25516,382
15555.38.128.0/1855.38.128.1 to 55.38.191.25455.38.191.25516,382
15655.38.192.0/1855.38.192.1 to 55.38.255.25455.38.255.25516,382
15755.39.0.0/1855.39.0.1 to 55.39.63.25455.39.63.25516,382
15855.39.64.0/1855.39.64.1 to 55.39.127.25455.39.127.25516,382
15955.39.128.0/1855.39.128.1 to 55.39.191.25455.39.191.25516,382
16055.39.192.0/1855.39.192.1 to 55.39.255.25455.39.255.25516,382
16155.40.0.0/1855.40.0.1 to 55.40.63.25455.40.63.25516,382
16255.40.64.0/1855.40.64.1 to 55.40.127.25455.40.127.25516,382
16355.40.128.0/1855.40.128.1 to 55.40.191.25455.40.191.25516,382
16455.40.192.0/1855.40.192.1 to 55.40.255.25455.40.255.25516,382
16555.41.0.0/1855.41.0.1 to 55.41.63.25455.41.63.25516,382
16655.41.64.0/1855.41.64.1 to 55.41.127.25455.41.127.25516,382
16755.41.128.0/1855.41.128.1 to 55.41.191.25455.41.191.25516,382
16855.41.192.0/1855.41.192.1 to 55.41.255.25455.41.255.25516,382
16955.42.0.0/1855.42.0.1 to 55.42.63.25455.42.63.25516,382
17055.42.64.0/1855.42.64.1 to 55.42.127.25455.42.127.25516,382
17155.42.128.0/1855.42.128.1 to 55.42.191.25455.42.191.25516,382
17255.42.192.0/1855.42.192.1 to 55.42.255.25455.42.255.25516,382
17355.43.0.0/1855.43.0.1 to 55.43.63.25455.43.63.25516,382
17455.43.64.0/1855.43.64.1 to 55.43.127.25455.43.127.25516,382
17555.43.128.0/1855.43.128.1 to 55.43.191.25455.43.191.25516,382
17655.43.192.0/1855.43.192.1 to 55.43.255.25455.43.255.25516,382
17755.44.0.0/1855.44.0.1 to 55.44.63.25455.44.63.25516,382
17855.44.64.0/1855.44.64.1 to 55.44.127.25455.44.127.25516,382
17955.44.128.0/1855.44.128.1 to 55.44.191.25455.44.191.25516,382
18055.44.192.0/1855.44.192.1 to 55.44.255.25455.44.255.25516,382
18155.45.0.0/1855.45.0.1 to 55.45.63.25455.45.63.25516,382
18255.45.64.0/1855.45.64.1 to 55.45.127.25455.45.127.25516,382
18355.45.128.0/1855.45.128.1 to 55.45.191.25455.45.191.25516,382
18455.45.192.0/1855.45.192.1 to 55.45.255.25455.45.255.25516,382
18555.46.0.0/1855.46.0.1 to 55.46.63.25455.46.63.25516,382
18655.46.64.0/1855.46.64.1 to 55.46.127.25455.46.127.25516,382
18755.46.128.0/1855.46.128.1 to 55.46.191.25455.46.191.25516,382
18855.46.192.0/1855.46.192.1 to 55.46.255.25455.46.255.25516,382
18955.47.0.0/1855.47.0.1 to 55.47.63.25455.47.63.25516,382
19055.47.64.0/1855.47.64.1 to 55.47.127.25455.47.127.25516,382
19155.47.128.0/1855.47.128.1 to 55.47.191.25455.47.191.25516,382
19255.47.192.0/1855.47.192.1 to 55.47.255.25455.47.255.25516,382
19355.48.0.0/1855.48.0.1 to 55.48.63.25455.48.63.25516,382
19455.48.64.0/1855.48.64.1 to 55.48.127.25455.48.127.25516,382
19555.48.128.0/1855.48.128.1 to 55.48.191.25455.48.191.25516,382
19655.48.192.0/1855.48.192.1 to 55.48.255.25455.48.255.25516,382
19755.49.0.0/1855.49.0.1 to 55.49.63.25455.49.63.25516,382
19855.49.64.0/1855.49.64.1 to 55.49.127.25455.49.127.25516,382
19955.49.128.0/1855.49.128.1 to 55.49.191.25455.49.191.25516,382
20055.49.192.0/1855.49.192.1 to 55.49.255.25455.49.255.25516,382
20155.50.0.0/1855.50.0.1 to 55.50.63.25455.50.63.25516,382
20255.50.64.0/1855.50.64.1 to 55.50.127.25455.50.127.25516,382
20355.50.128.0/1855.50.128.1 to 55.50.191.25455.50.191.25516,382
20455.50.192.0/1855.50.192.1 to 55.50.255.25455.50.255.25516,382
20555.51.0.0/1855.51.0.1 to 55.51.63.25455.51.63.25516,382
20655.51.64.0/1855.51.64.1 to 55.51.127.25455.51.127.25516,382
20755.51.128.0/1855.51.128.1 to 55.51.191.25455.51.191.25516,382
20855.51.192.0/1855.51.192.1 to 55.51.255.25455.51.255.25516,382
20955.52.0.0/1855.52.0.1 to 55.52.63.25455.52.63.25516,382
21055.52.64.0/1855.52.64.1 to 55.52.127.25455.52.127.25516,382
21155.52.128.0/1855.52.128.1 to 55.52.191.25455.52.191.25516,382
21255.52.192.0/1855.52.192.1 to 55.52.255.25455.52.255.25516,382
21355.53.0.0/1855.53.0.1 to 55.53.63.25455.53.63.25516,382
21455.53.64.0/1855.53.64.1 to 55.53.127.25455.53.127.25516,382
21555.53.128.0/1855.53.128.1 to 55.53.191.25455.53.191.25516,382
21655.53.192.0/1855.53.192.1 to 55.53.255.25455.53.255.25516,382
21755.54.0.0/1855.54.0.1 to 55.54.63.25455.54.63.25516,382
21855.54.64.0/1855.54.64.1 to 55.54.127.25455.54.127.25516,382
21955.54.128.0/1855.54.128.1 to 55.54.191.25455.54.191.25516,382
22055.54.192.0/1855.54.192.1 to 55.54.255.25455.54.255.25516,382
22155.55.0.0/1855.55.0.1 to 55.55.63.25455.55.63.25516,382
22255.55.64.0/1855.55.64.1 to 55.55.127.25455.55.127.25516,382
22355.55.128.0/1855.55.128.1 to 55.55.191.25455.55.191.25516,382
22455.55.192.0/1855.55.192.1 to 55.55.255.25455.55.255.25516,382
22555.56.0.0/1855.56.0.1 to 55.56.63.25455.56.63.25516,382
22655.56.64.0/1855.56.64.1 to 55.56.127.25455.56.127.25516,382
22755.56.128.0/1855.56.128.1 to 55.56.191.25455.56.191.25516,382
22855.56.192.0/1855.56.192.1 to 55.56.255.25455.56.255.25516,382
22955.57.0.0/1855.57.0.1 to 55.57.63.25455.57.63.25516,382
23055.57.64.0/1855.57.64.1 to 55.57.127.25455.57.127.25516,382
23155.57.128.0/1855.57.128.1 to 55.57.191.25455.57.191.25516,382
23255.57.192.0/1855.57.192.1 to 55.57.255.25455.57.255.25516,382
23355.58.0.0/1855.58.0.1 to 55.58.63.25455.58.63.25516,382
23455.58.64.0/1855.58.64.1 to 55.58.127.25455.58.127.25516,382
23555.58.128.0/1855.58.128.1 to 55.58.191.25455.58.191.25516,382
23655.58.192.0/1855.58.192.1 to 55.58.255.25455.58.255.25516,382
23755.59.0.0/1855.59.0.1 to 55.59.63.25455.59.63.25516,382
23855.59.64.0/1855.59.64.1 to 55.59.127.25455.59.127.25516,382
23955.59.128.0/1855.59.128.1 to 55.59.191.25455.59.191.25516,382
24055.59.192.0/1855.59.192.1 to 55.59.255.25455.59.255.25516,382
24155.60.0.0/1855.60.0.1 to 55.60.63.25455.60.63.25516,382
24255.60.64.0/1855.60.64.1 to 55.60.127.25455.60.127.25516,382
24355.60.128.0/1855.60.128.1 to 55.60.191.25455.60.191.25516,382
24455.60.192.0/1855.60.192.1 to 55.60.255.25455.60.255.25516,382
24555.61.0.0/1855.61.0.1 to 55.61.63.25455.61.63.25516,382
24655.61.64.0/1855.61.64.1 to 55.61.127.25455.61.127.25516,382
24755.61.128.0/1855.61.128.1 to 55.61.191.25455.61.191.25516,382
24855.61.192.0/1855.61.192.1 to 55.61.255.25455.61.255.25516,382
24955.62.0.0/1855.62.0.1 to 55.62.63.25455.62.63.25516,382
25055.62.64.0/1855.62.64.1 to 55.62.127.25455.62.127.25516,382
25155.62.128.0/1855.62.128.1 to 55.62.191.25455.62.191.25516,382
25255.62.192.0/1855.62.192.1 to 55.62.255.25455.62.255.25516,382
25355.63.0.0/1855.63.0.1 to 55.63.63.25455.63.63.25516,382
25455.63.64.0/1855.63.64.1 to 55.63.127.25455.63.127.25516,382
25555.63.128.0/1855.63.128.1 to 55.63.191.25455.63.191.25516,382
25655.63.192.0/1855.63.192.1 to 55.63.255.25455.63.255.25516,382

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.