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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.

Network38.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
38.0.0.0
Broadcast address
38.63.255.255
First usable
38.0.0.1
Last usable
38.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Public public
Old class
A (default /8)
As numbers
Hex 26000000 · Integer 637534208 to 641728511
Reverse DNS zones
0.38.in-addr.arpa
1.38.in-addr.arpa
2.38.in-addr.arpa
3.38.in-addr.arpa
4.38.in-addr.arpa
5.38.in-addr.arpa
6.38.in-addr.arpa
7.38.in-addr.arpa
8.38.in-addr.arpa
9.38.in-addr.arpa
10.38.in-addr.arpa
11.38.in-addr.arpa
12.38.in-addr.arpa
13.38.in-addr.arpa
14.38.in-addr.arpa
15.38.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100110.00000000.00000000.0000000038.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network00100110.00000000.00000000.0000000038.0.0.0
Broadcast00100110.00111111.11111111.1111111138.63.255.255
Split into smaller subnets/18
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

38.0.0.0/10 makes 256 subnets of /18.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
138.0.0.0/1838.0.0.1 to 38.0.63.25438.0.63.25516,382
238.0.64.0/1838.0.64.1 to 38.0.127.25438.0.127.25516,382
338.0.128.0/1838.0.128.1 to 38.0.191.25438.0.191.25516,382
438.0.192.0/1838.0.192.1 to 38.0.255.25438.0.255.25516,382
538.1.0.0/1838.1.0.1 to 38.1.63.25438.1.63.25516,382
638.1.64.0/1838.1.64.1 to 38.1.127.25438.1.127.25516,382
738.1.128.0/1838.1.128.1 to 38.1.191.25438.1.191.25516,382
838.1.192.0/1838.1.192.1 to 38.1.255.25438.1.255.25516,382
938.2.0.0/1838.2.0.1 to 38.2.63.25438.2.63.25516,382
1038.2.64.0/1838.2.64.1 to 38.2.127.25438.2.127.25516,382
1138.2.128.0/1838.2.128.1 to 38.2.191.25438.2.191.25516,382
1238.2.192.0/1838.2.192.1 to 38.2.255.25438.2.255.25516,382
1338.3.0.0/1838.3.0.1 to 38.3.63.25438.3.63.25516,382
1438.3.64.0/1838.3.64.1 to 38.3.127.25438.3.127.25516,382
1538.3.128.0/1838.3.128.1 to 38.3.191.25438.3.191.25516,382
1638.3.192.0/1838.3.192.1 to 38.3.255.25438.3.255.25516,382
1738.4.0.0/1838.4.0.1 to 38.4.63.25438.4.63.25516,382
1838.4.64.0/1838.4.64.1 to 38.4.127.25438.4.127.25516,382
1938.4.128.0/1838.4.128.1 to 38.4.191.25438.4.191.25516,382
2038.4.192.0/1838.4.192.1 to 38.4.255.25438.4.255.25516,382
2138.5.0.0/1838.5.0.1 to 38.5.63.25438.5.63.25516,382
2238.5.64.0/1838.5.64.1 to 38.5.127.25438.5.127.25516,382
2338.5.128.0/1838.5.128.1 to 38.5.191.25438.5.191.25516,382
2438.5.192.0/1838.5.192.1 to 38.5.255.25438.5.255.25516,382
2538.6.0.0/1838.6.0.1 to 38.6.63.25438.6.63.25516,382
2638.6.64.0/1838.6.64.1 to 38.6.127.25438.6.127.25516,382
2738.6.128.0/1838.6.128.1 to 38.6.191.25438.6.191.25516,382
2838.6.192.0/1838.6.192.1 to 38.6.255.25438.6.255.25516,382
2938.7.0.0/1838.7.0.1 to 38.7.63.25438.7.63.25516,382
3038.7.64.0/1838.7.64.1 to 38.7.127.25438.7.127.25516,382
3138.7.128.0/1838.7.128.1 to 38.7.191.25438.7.191.25516,382
3238.7.192.0/1838.7.192.1 to 38.7.255.25438.7.255.25516,382
3338.8.0.0/1838.8.0.1 to 38.8.63.25438.8.63.25516,382
3438.8.64.0/1838.8.64.1 to 38.8.127.25438.8.127.25516,382
3538.8.128.0/1838.8.128.1 to 38.8.191.25438.8.191.25516,382
3638.8.192.0/1838.8.192.1 to 38.8.255.25438.8.255.25516,382
3738.9.0.0/1838.9.0.1 to 38.9.63.25438.9.63.25516,382
3838.9.64.0/1838.9.64.1 to 38.9.127.25438.9.127.25516,382
3938.9.128.0/1838.9.128.1 to 38.9.191.25438.9.191.25516,382
4038.9.192.0/1838.9.192.1 to 38.9.255.25438.9.255.25516,382
4138.10.0.0/1838.10.0.1 to 38.10.63.25438.10.63.25516,382
4238.10.64.0/1838.10.64.1 to 38.10.127.25438.10.127.25516,382
4338.10.128.0/1838.10.128.1 to 38.10.191.25438.10.191.25516,382
4438.10.192.0/1838.10.192.1 to 38.10.255.25438.10.255.25516,382
4538.11.0.0/1838.11.0.1 to 38.11.63.25438.11.63.25516,382
4638.11.64.0/1838.11.64.1 to 38.11.127.25438.11.127.25516,382
4738.11.128.0/1838.11.128.1 to 38.11.191.25438.11.191.25516,382
4838.11.192.0/1838.11.192.1 to 38.11.255.25438.11.255.25516,382
4938.12.0.0/1838.12.0.1 to 38.12.63.25438.12.63.25516,382
5038.12.64.0/1838.12.64.1 to 38.12.127.25438.12.127.25516,382
5138.12.128.0/1838.12.128.1 to 38.12.191.25438.12.191.25516,382
5238.12.192.0/1838.12.192.1 to 38.12.255.25438.12.255.25516,382
5338.13.0.0/1838.13.0.1 to 38.13.63.25438.13.63.25516,382
5438.13.64.0/1838.13.64.1 to 38.13.127.25438.13.127.25516,382
5538.13.128.0/1838.13.128.1 to 38.13.191.25438.13.191.25516,382
5638.13.192.0/1838.13.192.1 to 38.13.255.25438.13.255.25516,382
5738.14.0.0/1838.14.0.1 to 38.14.63.25438.14.63.25516,382
5838.14.64.0/1838.14.64.1 to 38.14.127.25438.14.127.25516,382
5938.14.128.0/1838.14.128.1 to 38.14.191.25438.14.191.25516,382
6038.14.192.0/1838.14.192.1 to 38.14.255.25438.14.255.25516,382
6138.15.0.0/1838.15.0.1 to 38.15.63.25438.15.63.25516,382
6238.15.64.0/1838.15.64.1 to 38.15.127.25438.15.127.25516,382
6338.15.128.0/1838.15.128.1 to 38.15.191.25438.15.191.25516,382
6438.15.192.0/1838.15.192.1 to 38.15.255.25438.15.255.25516,382
6538.16.0.0/1838.16.0.1 to 38.16.63.25438.16.63.25516,382
6638.16.64.0/1838.16.64.1 to 38.16.127.25438.16.127.25516,382
6738.16.128.0/1838.16.128.1 to 38.16.191.25438.16.191.25516,382
6838.16.192.0/1838.16.192.1 to 38.16.255.25438.16.255.25516,382
6938.17.0.0/1838.17.0.1 to 38.17.63.25438.17.63.25516,382
7038.17.64.0/1838.17.64.1 to 38.17.127.25438.17.127.25516,382
7138.17.128.0/1838.17.128.1 to 38.17.191.25438.17.191.25516,382
7238.17.192.0/1838.17.192.1 to 38.17.255.25438.17.255.25516,382
7338.18.0.0/1838.18.0.1 to 38.18.63.25438.18.63.25516,382
7438.18.64.0/1838.18.64.1 to 38.18.127.25438.18.127.25516,382
7538.18.128.0/1838.18.128.1 to 38.18.191.25438.18.191.25516,382
7638.18.192.0/1838.18.192.1 to 38.18.255.25438.18.255.25516,382
7738.19.0.0/1838.19.0.1 to 38.19.63.25438.19.63.25516,382
7838.19.64.0/1838.19.64.1 to 38.19.127.25438.19.127.25516,382
7938.19.128.0/1838.19.128.1 to 38.19.191.25438.19.191.25516,382
8038.19.192.0/1838.19.192.1 to 38.19.255.25438.19.255.25516,382
8138.20.0.0/1838.20.0.1 to 38.20.63.25438.20.63.25516,382
8238.20.64.0/1838.20.64.1 to 38.20.127.25438.20.127.25516,382
8338.20.128.0/1838.20.128.1 to 38.20.191.25438.20.191.25516,382
8438.20.192.0/1838.20.192.1 to 38.20.255.25438.20.255.25516,382
8538.21.0.0/1838.21.0.1 to 38.21.63.25438.21.63.25516,382
8638.21.64.0/1838.21.64.1 to 38.21.127.25438.21.127.25516,382
8738.21.128.0/1838.21.128.1 to 38.21.191.25438.21.191.25516,382
8838.21.192.0/1838.21.192.1 to 38.21.255.25438.21.255.25516,382
8938.22.0.0/1838.22.0.1 to 38.22.63.25438.22.63.25516,382
9038.22.64.0/1838.22.64.1 to 38.22.127.25438.22.127.25516,382
9138.22.128.0/1838.22.128.1 to 38.22.191.25438.22.191.25516,382
9238.22.192.0/1838.22.192.1 to 38.22.255.25438.22.255.25516,382
9338.23.0.0/1838.23.0.1 to 38.23.63.25438.23.63.25516,382
9438.23.64.0/1838.23.64.1 to 38.23.127.25438.23.127.25516,382
9538.23.128.0/1838.23.128.1 to 38.23.191.25438.23.191.25516,382
9638.23.192.0/1838.23.192.1 to 38.23.255.25438.23.255.25516,382
9738.24.0.0/1838.24.0.1 to 38.24.63.25438.24.63.25516,382
9838.24.64.0/1838.24.64.1 to 38.24.127.25438.24.127.25516,382
9938.24.128.0/1838.24.128.1 to 38.24.191.25438.24.191.25516,382
10038.24.192.0/1838.24.192.1 to 38.24.255.25438.24.255.25516,382
10138.25.0.0/1838.25.0.1 to 38.25.63.25438.25.63.25516,382
10238.25.64.0/1838.25.64.1 to 38.25.127.25438.25.127.25516,382
10338.25.128.0/1838.25.128.1 to 38.25.191.25438.25.191.25516,382
10438.25.192.0/1838.25.192.1 to 38.25.255.25438.25.255.25516,382
10538.26.0.0/1838.26.0.1 to 38.26.63.25438.26.63.25516,382
10638.26.64.0/1838.26.64.1 to 38.26.127.25438.26.127.25516,382
10738.26.128.0/1838.26.128.1 to 38.26.191.25438.26.191.25516,382
10838.26.192.0/1838.26.192.1 to 38.26.255.25438.26.255.25516,382
10938.27.0.0/1838.27.0.1 to 38.27.63.25438.27.63.25516,382
11038.27.64.0/1838.27.64.1 to 38.27.127.25438.27.127.25516,382
11138.27.128.0/1838.27.128.1 to 38.27.191.25438.27.191.25516,382
11238.27.192.0/1838.27.192.1 to 38.27.255.25438.27.255.25516,382
11338.28.0.0/1838.28.0.1 to 38.28.63.25438.28.63.25516,382
11438.28.64.0/1838.28.64.1 to 38.28.127.25438.28.127.25516,382
11538.28.128.0/1838.28.128.1 to 38.28.191.25438.28.191.25516,382
11638.28.192.0/1838.28.192.1 to 38.28.255.25438.28.255.25516,382
11738.29.0.0/1838.29.0.1 to 38.29.63.25438.29.63.25516,382
11838.29.64.0/1838.29.64.1 to 38.29.127.25438.29.127.25516,382
11938.29.128.0/1838.29.128.1 to 38.29.191.25438.29.191.25516,382
12038.29.192.0/1838.29.192.1 to 38.29.255.25438.29.255.25516,382
12138.30.0.0/1838.30.0.1 to 38.30.63.25438.30.63.25516,382
12238.30.64.0/1838.30.64.1 to 38.30.127.25438.30.127.25516,382
12338.30.128.0/1838.30.128.1 to 38.30.191.25438.30.191.25516,382
12438.30.192.0/1838.30.192.1 to 38.30.255.25438.30.255.25516,382
12538.31.0.0/1838.31.0.1 to 38.31.63.25438.31.63.25516,382
12638.31.64.0/1838.31.64.1 to 38.31.127.25438.31.127.25516,382
12738.31.128.0/1838.31.128.1 to 38.31.191.25438.31.191.25516,382
12838.31.192.0/1838.31.192.1 to 38.31.255.25438.31.255.25516,382
12938.32.0.0/1838.32.0.1 to 38.32.63.25438.32.63.25516,382
13038.32.64.0/1838.32.64.1 to 38.32.127.25438.32.127.25516,382
13138.32.128.0/1838.32.128.1 to 38.32.191.25438.32.191.25516,382
13238.32.192.0/1838.32.192.1 to 38.32.255.25438.32.255.25516,382
13338.33.0.0/1838.33.0.1 to 38.33.63.25438.33.63.25516,382
13438.33.64.0/1838.33.64.1 to 38.33.127.25438.33.127.25516,382
13538.33.128.0/1838.33.128.1 to 38.33.191.25438.33.191.25516,382
13638.33.192.0/1838.33.192.1 to 38.33.255.25438.33.255.25516,382
13738.34.0.0/1838.34.0.1 to 38.34.63.25438.34.63.25516,382
13838.34.64.0/1838.34.64.1 to 38.34.127.25438.34.127.25516,382
13938.34.128.0/1838.34.128.1 to 38.34.191.25438.34.191.25516,382
14038.34.192.0/1838.34.192.1 to 38.34.255.25438.34.255.25516,382
14138.35.0.0/1838.35.0.1 to 38.35.63.25438.35.63.25516,382
14238.35.64.0/1838.35.64.1 to 38.35.127.25438.35.127.25516,382
14338.35.128.0/1838.35.128.1 to 38.35.191.25438.35.191.25516,382
14438.35.192.0/1838.35.192.1 to 38.35.255.25438.35.255.25516,382
14538.36.0.0/1838.36.0.1 to 38.36.63.25438.36.63.25516,382
14638.36.64.0/1838.36.64.1 to 38.36.127.25438.36.127.25516,382
14738.36.128.0/1838.36.128.1 to 38.36.191.25438.36.191.25516,382
14838.36.192.0/1838.36.192.1 to 38.36.255.25438.36.255.25516,382
14938.37.0.0/1838.37.0.1 to 38.37.63.25438.37.63.25516,382
15038.37.64.0/1838.37.64.1 to 38.37.127.25438.37.127.25516,382
15138.37.128.0/1838.37.128.1 to 38.37.191.25438.37.191.25516,382
15238.37.192.0/1838.37.192.1 to 38.37.255.25438.37.255.25516,382
15338.38.0.0/1838.38.0.1 to 38.38.63.25438.38.63.25516,382
15438.38.64.0/1838.38.64.1 to 38.38.127.25438.38.127.25516,382
15538.38.128.0/1838.38.128.1 to 38.38.191.25438.38.191.25516,382
15638.38.192.0/1838.38.192.1 to 38.38.255.25438.38.255.25516,382
15738.39.0.0/1838.39.0.1 to 38.39.63.25438.39.63.25516,382
15838.39.64.0/1838.39.64.1 to 38.39.127.25438.39.127.25516,382
15938.39.128.0/1838.39.128.1 to 38.39.191.25438.39.191.25516,382
16038.39.192.0/1838.39.192.1 to 38.39.255.25438.39.255.25516,382
16138.40.0.0/1838.40.0.1 to 38.40.63.25438.40.63.25516,382
16238.40.64.0/1838.40.64.1 to 38.40.127.25438.40.127.25516,382
16338.40.128.0/1838.40.128.1 to 38.40.191.25438.40.191.25516,382
16438.40.192.0/1838.40.192.1 to 38.40.255.25438.40.255.25516,382
16538.41.0.0/1838.41.0.1 to 38.41.63.25438.41.63.25516,382
16638.41.64.0/1838.41.64.1 to 38.41.127.25438.41.127.25516,382
16738.41.128.0/1838.41.128.1 to 38.41.191.25438.41.191.25516,382
16838.41.192.0/1838.41.192.1 to 38.41.255.25438.41.255.25516,382
16938.42.0.0/1838.42.0.1 to 38.42.63.25438.42.63.25516,382
17038.42.64.0/1838.42.64.1 to 38.42.127.25438.42.127.25516,382
17138.42.128.0/1838.42.128.1 to 38.42.191.25438.42.191.25516,382
17238.42.192.0/1838.42.192.1 to 38.42.255.25438.42.255.25516,382
17338.43.0.0/1838.43.0.1 to 38.43.63.25438.43.63.25516,382
17438.43.64.0/1838.43.64.1 to 38.43.127.25438.43.127.25516,382
17538.43.128.0/1838.43.128.1 to 38.43.191.25438.43.191.25516,382
17638.43.192.0/1838.43.192.1 to 38.43.255.25438.43.255.25516,382
17738.44.0.0/1838.44.0.1 to 38.44.63.25438.44.63.25516,382
17838.44.64.0/1838.44.64.1 to 38.44.127.25438.44.127.25516,382
17938.44.128.0/1838.44.128.1 to 38.44.191.25438.44.191.25516,382
18038.44.192.0/1838.44.192.1 to 38.44.255.25438.44.255.25516,382
18138.45.0.0/1838.45.0.1 to 38.45.63.25438.45.63.25516,382
18238.45.64.0/1838.45.64.1 to 38.45.127.25438.45.127.25516,382
18338.45.128.0/1838.45.128.1 to 38.45.191.25438.45.191.25516,382
18438.45.192.0/1838.45.192.1 to 38.45.255.25438.45.255.25516,382
18538.46.0.0/1838.46.0.1 to 38.46.63.25438.46.63.25516,382
18638.46.64.0/1838.46.64.1 to 38.46.127.25438.46.127.25516,382
18738.46.128.0/1838.46.128.1 to 38.46.191.25438.46.191.25516,382
18838.46.192.0/1838.46.192.1 to 38.46.255.25438.46.255.25516,382
18938.47.0.0/1838.47.0.1 to 38.47.63.25438.47.63.25516,382
19038.47.64.0/1838.47.64.1 to 38.47.127.25438.47.127.25516,382
19138.47.128.0/1838.47.128.1 to 38.47.191.25438.47.191.25516,382
19238.47.192.0/1838.47.192.1 to 38.47.255.25438.47.255.25516,382
19338.48.0.0/1838.48.0.1 to 38.48.63.25438.48.63.25516,382
19438.48.64.0/1838.48.64.1 to 38.48.127.25438.48.127.25516,382
19538.48.128.0/1838.48.128.1 to 38.48.191.25438.48.191.25516,382
19638.48.192.0/1838.48.192.1 to 38.48.255.25438.48.255.25516,382
19738.49.0.0/1838.49.0.1 to 38.49.63.25438.49.63.25516,382
19838.49.64.0/1838.49.64.1 to 38.49.127.25438.49.127.25516,382
19938.49.128.0/1838.49.128.1 to 38.49.191.25438.49.191.25516,382
20038.49.192.0/1838.49.192.1 to 38.49.255.25438.49.255.25516,382
20138.50.0.0/1838.50.0.1 to 38.50.63.25438.50.63.25516,382
20238.50.64.0/1838.50.64.1 to 38.50.127.25438.50.127.25516,382
20338.50.128.0/1838.50.128.1 to 38.50.191.25438.50.191.25516,382
20438.50.192.0/1838.50.192.1 to 38.50.255.25438.50.255.25516,382
20538.51.0.0/1838.51.0.1 to 38.51.63.25438.51.63.25516,382
20638.51.64.0/1838.51.64.1 to 38.51.127.25438.51.127.25516,382
20738.51.128.0/1838.51.128.1 to 38.51.191.25438.51.191.25516,382
20838.51.192.0/1838.51.192.1 to 38.51.255.25438.51.255.25516,382
20938.52.0.0/1838.52.0.1 to 38.52.63.25438.52.63.25516,382
21038.52.64.0/1838.52.64.1 to 38.52.127.25438.52.127.25516,382
21138.52.128.0/1838.52.128.1 to 38.52.191.25438.52.191.25516,382
21238.52.192.0/1838.52.192.1 to 38.52.255.25438.52.255.25516,382
21338.53.0.0/1838.53.0.1 to 38.53.63.25438.53.63.25516,382
21438.53.64.0/1838.53.64.1 to 38.53.127.25438.53.127.25516,382
21538.53.128.0/1838.53.128.1 to 38.53.191.25438.53.191.25516,382
21638.53.192.0/1838.53.192.1 to 38.53.255.25438.53.255.25516,382
21738.54.0.0/1838.54.0.1 to 38.54.63.25438.54.63.25516,382
21838.54.64.0/1838.54.64.1 to 38.54.127.25438.54.127.25516,382
21938.54.128.0/1838.54.128.1 to 38.54.191.25438.54.191.25516,382
22038.54.192.0/1838.54.192.1 to 38.54.255.25438.54.255.25516,382
22138.55.0.0/1838.55.0.1 to 38.55.63.25438.55.63.25516,382
22238.55.64.0/1838.55.64.1 to 38.55.127.25438.55.127.25516,382
22338.55.128.0/1838.55.128.1 to 38.55.191.25438.55.191.25516,382
22438.55.192.0/1838.55.192.1 to 38.55.255.25438.55.255.25516,382
22538.56.0.0/1838.56.0.1 to 38.56.63.25438.56.63.25516,382
22638.56.64.0/1838.56.64.1 to 38.56.127.25438.56.127.25516,382
22738.56.128.0/1838.56.128.1 to 38.56.191.25438.56.191.25516,382
22838.56.192.0/1838.56.192.1 to 38.56.255.25438.56.255.25516,382
22938.57.0.0/1838.57.0.1 to 38.57.63.25438.57.63.25516,382
23038.57.64.0/1838.57.64.1 to 38.57.127.25438.57.127.25516,382
23138.57.128.0/1838.57.128.1 to 38.57.191.25438.57.191.25516,382
23238.57.192.0/1838.57.192.1 to 38.57.255.25438.57.255.25516,382
23338.58.0.0/1838.58.0.1 to 38.58.63.25438.58.63.25516,382
23438.58.64.0/1838.58.64.1 to 38.58.127.25438.58.127.25516,382
23538.58.128.0/1838.58.128.1 to 38.58.191.25438.58.191.25516,382
23638.58.192.0/1838.58.192.1 to 38.58.255.25438.58.255.25516,382
23738.59.0.0/1838.59.0.1 to 38.59.63.25438.59.63.25516,382
23838.59.64.0/1838.59.64.1 to 38.59.127.25438.59.127.25516,382
23938.59.128.0/1838.59.128.1 to 38.59.191.25438.59.191.25516,382
24038.59.192.0/1838.59.192.1 to 38.59.255.25438.59.255.25516,382
24138.60.0.0/1838.60.0.1 to 38.60.63.25438.60.63.25516,382
24238.60.64.0/1838.60.64.1 to 38.60.127.25438.60.127.25516,382
24338.60.128.0/1838.60.128.1 to 38.60.191.25438.60.191.25516,382
24438.60.192.0/1838.60.192.1 to 38.60.255.25438.60.255.25516,382
24538.61.0.0/1838.61.0.1 to 38.61.63.25438.61.63.25516,382
24638.61.64.0/1838.61.64.1 to 38.61.127.25438.61.127.25516,382
24738.61.128.0/1838.61.128.1 to 38.61.191.25438.61.191.25516,382
24838.61.192.0/1838.61.192.1 to 38.61.255.25438.61.255.25516,382
24938.62.0.0/1838.62.0.1 to 38.62.63.25438.62.63.25516,382
25038.62.64.0/1838.62.64.1 to 38.62.127.25438.62.127.25516,382
25138.62.128.0/1838.62.128.1 to 38.62.191.25438.62.191.25516,382
25238.62.192.0/1838.62.192.1 to 38.62.255.25438.62.255.25516,382
25338.63.0.0/1838.63.0.1 to 38.63.63.25438.63.63.25516,382
25438.63.64.0/1838.63.64.1 to 38.63.127.25438.63.127.25516,382
25538.63.128.0/1838.63.128.1 to 38.63.191.25438.63.191.25516,382
25638.63.192.0/1838.63.192.1 to 38.63.255.25438.63.255.25516,382

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.