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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.

Network15.7.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
15.7.0.0
Broadcast address
15.7.63.255
First usable
15.7.0.1
Last usable
15.7.63.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Public public
Old class
A (default /8)
As numbers
Hex 0F070000 · Integer 252116992 to 252133375
Reverse DNS zones
0.7.15.in-addr.arpa
1.7.15.in-addr.arpa
2.7.15.in-addr.arpa
3.7.15.in-addr.arpa
4.7.15.in-addr.arpa
5.7.15.in-addr.arpa
6.7.15.in-addr.arpa
7.7.15.in-addr.arpa
8.7.15.in-addr.arpa
9.7.15.in-addr.arpa
10.7.15.in-addr.arpa
11.7.15.in-addr.arpa
12.7.15.in-addr.arpa
13.7.15.in-addr.arpa
14.7.15.in-addr.arpa
15.7.15.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001111.00000111.00000000.0000000015.7.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00001111.00000111.00000000.0000000015.7.0.0
Broadcast00001111.00000111.00111111.1111111115.7.63.255
Split into smaller subnets/26
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

15.7.0.0/18 makes 256 subnets of /26.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
115.7.0.0/2615.7.0.1 to 15.7.0.6215.7.0.6362
215.7.0.64/2615.7.0.65 to 15.7.0.12615.7.0.12762
315.7.0.128/2615.7.0.129 to 15.7.0.19015.7.0.19162
415.7.0.192/2615.7.0.193 to 15.7.0.25415.7.0.25562
515.7.1.0/2615.7.1.1 to 15.7.1.6215.7.1.6362
615.7.1.64/2615.7.1.65 to 15.7.1.12615.7.1.12762
715.7.1.128/2615.7.1.129 to 15.7.1.19015.7.1.19162
815.7.1.192/2615.7.1.193 to 15.7.1.25415.7.1.25562
915.7.2.0/2615.7.2.1 to 15.7.2.6215.7.2.6362
1015.7.2.64/2615.7.2.65 to 15.7.2.12615.7.2.12762
1115.7.2.128/2615.7.2.129 to 15.7.2.19015.7.2.19162
1215.7.2.192/2615.7.2.193 to 15.7.2.25415.7.2.25562
1315.7.3.0/2615.7.3.1 to 15.7.3.6215.7.3.6362
1415.7.3.64/2615.7.3.65 to 15.7.3.12615.7.3.12762
1515.7.3.128/2615.7.3.129 to 15.7.3.19015.7.3.19162
1615.7.3.192/2615.7.3.193 to 15.7.3.25415.7.3.25562
1715.7.4.0/2615.7.4.1 to 15.7.4.6215.7.4.6362
1815.7.4.64/2615.7.4.65 to 15.7.4.12615.7.4.12762
1915.7.4.128/2615.7.4.129 to 15.7.4.19015.7.4.19162
2015.7.4.192/2615.7.4.193 to 15.7.4.25415.7.4.25562
2115.7.5.0/2615.7.5.1 to 15.7.5.6215.7.5.6362
2215.7.5.64/2615.7.5.65 to 15.7.5.12615.7.5.12762
2315.7.5.128/2615.7.5.129 to 15.7.5.19015.7.5.19162
2415.7.5.192/2615.7.5.193 to 15.7.5.25415.7.5.25562
2515.7.6.0/2615.7.6.1 to 15.7.6.6215.7.6.6362
2615.7.6.64/2615.7.6.65 to 15.7.6.12615.7.6.12762
2715.7.6.128/2615.7.6.129 to 15.7.6.19015.7.6.19162
2815.7.6.192/2615.7.6.193 to 15.7.6.25415.7.6.25562
2915.7.7.0/2615.7.7.1 to 15.7.7.6215.7.7.6362
3015.7.7.64/2615.7.7.65 to 15.7.7.12615.7.7.12762
3115.7.7.128/2615.7.7.129 to 15.7.7.19015.7.7.19162
3215.7.7.192/2615.7.7.193 to 15.7.7.25415.7.7.25562
3315.7.8.0/2615.7.8.1 to 15.7.8.6215.7.8.6362
3415.7.8.64/2615.7.8.65 to 15.7.8.12615.7.8.12762
3515.7.8.128/2615.7.8.129 to 15.7.8.19015.7.8.19162
3615.7.8.192/2615.7.8.193 to 15.7.8.25415.7.8.25562
3715.7.9.0/2615.7.9.1 to 15.7.9.6215.7.9.6362
3815.7.9.64/2615.7.9.65 to 15.7.9.12615.7.9.12762
3915.7.9.128/2615.7.9.129 to 15.7.9.19015.7.9.19162
4015.7.9.192/2615.7.9.193 to 15.7.9.25415.7.9.25562
4115.7.10.0/2615.7.10.1 to 15.7.10.6215.7.10.6362
4215.7.10.64/2615.7.10.65 to 15.7.10.12615.7.10.12762
4315.7.10.128/2615.7.10.129 to 15.7.10.19015.7.10.19162
4415.7.10.192/2615.7.10.193 to 15.7.10.25415.7.10.25562
4515.7.11.0/2615.7.11.1 to 15.7.11.6215.7.11.6362
4615.7.11.64/2615.7.11.65 to 15.7.11.12615.7.11.12762
4715.7.11.128/2615.7.11.129 to 15.7.11.19015.7.11.19162
4815.7.11.192/2615.7.11.193 to 15.7.11.25415.7.11.25562
4915.7.12.0/2615.7.12.1 to 15.7.12.6215.7.12.6362
5015.7.12.64/2615.7.12.65 to 15.7.12.12615.7.12.12762
5115.7.12.128/2615.7.12.129 to 15.7.12.19015.7.12.19162
5215.7.12.192/2615.7.12.193 to 15.7.12.25415.7.12.25562
5315.7.13.0/2615.7.13.1 to 15.7.13.6215.7.13.6362
5415.7.13.64/2615.7.13.65 to 15.7.13.12615.7.13.12762
5515.7.13.128/2615.7.13.129 to 15.7.13.19015.7.13.19162
5615.7.13.192/2615.7.13.193 to 15.7.13.25415.7.13.25562
5715.7.14.0/2615.7.14.1 to 15.7.14.6215.7.14.6362
5815.7.14.64/2615.7.14.65 to 15.7.14.12615.7.14.12762
5915.7.14.128/2615.7.14.129 to 15.7.14.19015.7.14.19162
6015.7.14.192/2615.7.14.193 to 15.7.14.25415.7.14.25562
6115.7.15.0/2615.7.15.1 to 15.7.15.6215.7.15.6362
6215.7.15.64/2615.7.15.65 to 15.7.15.12615.7.15.12762
6315.7.15.128/2615.7.15.129 to 15.7.15.19015.7.15.19162
6415.7.15.192/2615.7.15.193 to 15.7.15.25415.7.15.25562
6515.7.16.0/2615.7.16.1 to 15.7.16.6215.7.16.6362
6615.7.16.64/2615.7.16.65 to 15.7.16.12615.7.16.12762
6715.7.16.128/2615.7.16.129 to 15.7.16.19015.7.16.19162
6815.7.16.192/2615.7.16.193 to 15.7.16.25415.7.16.25562
6915.7.17.0/2615.7.17.1 to 15.7.17.6215.7.17.6362
7015.7.17.64/2615.7.17.65 to 15.7.17.12615.7.17.12762
7115.7.17.128/2615.7.17.129 to 15.7.17.19015.7.17.19162
7215.7.17.192/2615.7.17.193 to 15.7.17.25415.7.17.25562
7315.7.18.0/2615.7.18.1 to 15.7.18.6215.7.18.6362
7415.7.18.64/2615.7.18.65 to 15.7.18.12615.7.18.12762
7515.7.18.128/2615.7.18.129 to 15.7.18.19015.7.18.19162
7615.7.18.192/2615.7.18.193 to 15.7.18.25415.7.18.25562
7715.7.19.0/2615.7.19.1 to 15.7.19.6215.7.19.6362
7815.7.19.64/2615.7.19.65 to 15.7.19.12615.7.19.12762
7915.7.19.128/2615.7.19.129 to 15.7.19.19015.7.19.19162
8015.7.19.192/2615.7.19.193 to 15.7.19.25415.7.19.25562
8115.7.20.0/2615.7.20.1 to 15.7.20.6215.7.20.6362
8215.7.20.64/2615.7.20.65 to 15.7.20.12615.7.20.12762
8315.7.20.128/2615.7.20.129 to 15.7.20.19015.7.20.19162
8415.7.20.192/2615.7.20.193 to 15.7.20.25415.7.20.25562
8515.7.21.0/2615.7.21.1 to 15.7.21.6215.7.21.6362
8615.7.21.64/2615.7.21.65 to 15.7.21.12615.7.21.12762
8715.7.21.128/2615.7.21.129 to 15.7.21.19015.7.21.19162
8815.7.21.192/2615.7.21.193 to 15.7.21.25415.7.21.25562
8915.7.22.0/2615.7.22.1 to 15.7.22.6215.7.22.6362
9015.7.22.64/2615.7.22.65 to 15.7.22.12615.7.22.12762
9115.7.22.128/2615.7.22.129 to 15.7.22.19015.7.22.19162
9215.7.22.192/2615.7.22.193 to 15.7.22.25415.7.22.25562
9315.7.23.0/2615.7.23.1 to 15.7.23.6215.7.23.6362
9415.7.23.64/2615.7.23.65 to 15.7.23.12615.7.23.12762
9515.7.23.128/2615.7.23.129 to 15.7.23.19015.7.23.19162
9615.7.23.192/2615.7.23.193 to 15.7.23.25415.7.23.25562
9715.7.24.0/2615.7.24.1 to 15.7.24.6215.7.24.6362
9815.7.24.64/2615.7.24.65 to 15.7.24.12615.7.24.12762
9915.7.24.128/2615.7.24.129 to 15.7.24.19015.7.24.19162
10015.7.24.192/2615.7.24.193 to 15.7.24.25415.7.24.25562
10115.7.25.0/2615.7.25.1 to 15.7.25.6215.7.25.6362
10215.7.25.64/2615.7.25.65 to 15.7.25.12615.7.25.12762
10315.7.25.128/2615.7.25.129 to 15.7.25.19015.7.25.19162
10415.7.25.192/2615.7.25.193 to 15.7.25.25415.7.25.25562
10515.7.26.0/2615.7.26.1 to 15.7.26.6215.7.26.6362
10615.7.26.64/2615.7.26.65 to 15.7.26.12615.7.26.12762
10715.7.26.128/2615.7.26.129 to 15.7.26.19015.7.26.19162
10815.7.26.192/2615.7.26.193 to 15.7.26.25415.7.26.25562
10915.7.27.0/2615.7.27.1 to 15.7.27.6215.7.27.6362
11015.7.27.64/2615.7.27.65 to 15.7.27.12615.7.27.12762
11115.7.27.128/2615.7.27.129 to 15.7.27.19015.7.27.19162
11215.7.27.192/2615.7.27.193 to 15.7.27.25415.7.27.25562
11315.7.28.0/2615.7.28.1 to 15.7.28.6215.7.28.6362
11415.7.28.64/2615.7.28.65 to 15.7.28.12615.7.28.12762
11515.7.28.128/2615.7.28.129 to 15.7.28.19015.7.28.19162
11615.7.28.192/2615.7.28.193 to 15.7.28.25415.7.28.25562
11715.7.29.0/2615.7.29.1 to 15.7.29.6215.7.29.6362
11815.7.29.64/2615.7.29.65 to 15.7.29.12615.7.29.12762
11915.7.29.128/2615.7.29.129 to 15.7.29.19015.7.29.19162
12015.7.29.192/2615.7.29.193 to 15.7.29.25415.7.29.25562
12115.7.30.0/2615.7.30.1 to 15.7.30.6215.7.30.6362
12215.7.30.64/2615.7.30.65 to 15.7.30.12615.7.30.12762
12315.7.30.128/2615.7.30.129 to 15.7.30.19015.7.30.19162
12415.7.30.192/2615.7.30.193 to 15.7.30.25415.7.30.25562
12515.7.31.0/2615.7.31.1 to 15.7.31.6215.7.31.6362
12615.7.31.64/2615.7.31.65 to 15.7.31.12615.7.31.12762
12715.7.31.128/2615.7.31.129 to 15.7.31.19015.7.31.19162
12815.7.31.192/2615.7.31.193 to 15.7.31.25415.7.31.25562
12915.7.32.0/2615.7.32.1 to 15.7.32.6215.7.32.6362
13015.7.32.64/2615.7.32.65 to 15.7.32.12615.7.32.12762
13115.7.32.128/2615.7.32.129 to 15.7.32.19015.7.32.19162
13215.7.32.192/2615.7.32.193 to 15.7.32.25415.7.32.25562
13315.7.33.0/2615.7.33.1 to 15.7.33.6215.7.33.6362
13415.7.33.64/2615.7.33.65 to 15.7.33.12615.7.33.12762
13515.7.33.128/2615.7.33.129 to 15.7.33.19015.7.33.19162
13615.7.33.192/2615.7.33.193 to 15.7.33.25415.7.33.25562
13715.7.34.0/2615.7.34.1 to 15.7.34.6215.7.34.6362
13815.7.34.64/2615.7.34.65 to 15.7.34.12615.7.34.12762
13915.7.34.128/2615.7.34.129 to 15.7.34.19015.7.34.19162
14015.7.34.192/2615.7.34.193 to 15.7.34.25415.7.34.25562
14115.7.35.0/2615.7.35.1 to 15.7.35.6215.7.35.6362
14215.7.35.64/2615.7.35.65 to 15.7.35.12615.7.35.12762
14315.7.35.128/2615.7.35.129 to 15.7.35.19015.7.35.19162
14415.7.35.192/2615.7.35.193 to 15.7.35.25415.7.35.25562
14515.7.36.0/2615.7.36.1 to 15.7.36.6215.7.36.6362
14615.7.36.64/2615.7.36.65 to 15.7.36.12615.7.36.12762
14715.7.36.128/2615.7.36.129 to 15.7.36.19015.7.36.19162
14815.7.36.192/2615.7.36.193 to 15.7.36.25415.7.36.25562
14915.7.37.0/2615.7.37.1 to 15.7.37.6215.7.37.6362
15015.7.37.64/2615.7.37.65 to 15.7.37.12615.7.37.12762
15115.7.37.128/2615.7.37.129 to 15.7.37.19015.7.37.19162
15215.7.37.192/2615.7.37.193 to 15.7.37.25415.7.37.25562
15315.7.38.0/2615.7.38.1 to 15.7.38.6215.7.38.6362
15415.7.38.64/2615.7.38.65 to 15.7.38.12615.7.38.12762
15515.7.38.128/2615.7.38.129 to 15.7.38.19015.7.38.19162
15615.7.38.192/2615.7.38.193 to 15.7.38.25415.7.38.25562
15715.7.39.0/2615.7.39.1 to 15.7.39.6215.7.39.6362
15815.7.39.64/2615.7.39.65 to 15.7.39.12615.7.39.12762
15915.7.39.128/2615.7.39.129 to 15.7.39.19015.7.39.19162
16015.7.39.192/2615.7.39.193 to 15.7.39.25415.7.39.25562
16115.7.40.0/2615.7.40.1 to 15.7.40.6215.7.40.6362
16215.7.40.64/2615.7.40.65 to 15.7.40.12615.7.40.12762
16315.7.40.128/2615.7.40.129 to 15.7.40.19015.7.40.19162
16415.7.40.192/2615.7.40.193 to 15.7.40.25415.7.40.25562
16515.7.41.0/2615.7.41.1 to 15.7.41.6215.7.41.6362
16615.7.41.64/2615.7.41.65 to 15.7.41.12615.7.41.12762
16715.7.41.128/2615.7.41.129 to 15.7.41.19015.7.41.19162
16815.7.41.192/2615.7.41.193 to 15.7.41.25415.7.41.25562
16915.7.42.0/2615.7.42.1 to 15.7.42.6215.7.42.6362
17015.7.42.64/2615.7.42.65 to 15.7.42.12615.7.42.12762
17115.7.42.128/2615.7.42.129 to 15.7.42.19015.7.42.19162
17215.7.42.192/2615.7.42.193 to 15.7.42.25415.7.42.25562
17315.7.43.0/2615.7.43.1 to 15.7.43.6215.7.43.6362
17415.7.43.64/2615.7.43.65 to 15.7.43.12615.7.43.12762
17515.7.43.128/2615.7.43.129 to 15.7.43.19015.7.43.19162
17615.7.43.192/2615.7.43.193 to 15.7.43.25415.7.43.25562
17715.7.44.0/2615.7.44.1 to 15.7.44.6215.7.44.6362
17815.7.44.64/2615.7.44.65 to 15.7.44.12615.7.44.12762
17915.7.44.128/2615.7.44.129 to 15.7.44.19015.7.44.19162
18015.7.44.192/2615.7.44.193 to 15.7.44.25415.7.44.25562
18115.7.45.0/2615.7.45.1 to 15.7.45.6215.7.45.6362
18215.7.45.64/2615.7.45.65 to 15.7.45.12615.7.45.12762
18315.7.45.128/2615.7.45.129 to 15.7.45.19015.7.45.19162
18415.7.45.192/2615.7.45.193 to 15.7.45.25415.7.45.25562
18515.7.46.0/2615.7.46.1 to 15.7.46.6215.7.46.6362
18615.7.46.64/2615.7.46.65 to 15.7.46.12615.7.46.12762
18715.7.46.128/2615.7.46.129 to 15.7.46.19015.7.46.19162
18815.7.46.192/2615.7.46.193 to 15.7.46.25415.7.46.25562
18915.7.47.0/2615.7.47.1 to 15.7.47.6215.7.47.6362
19015.7.47.64/2615.7.47.65 to 15.7.47.12615.7.47.12762
19115.7.47.128/2615.7.47.129 to 15.7.47.19015.7.47.19162
19215.7.47.192/2615.7.47.193 to 15.7.47.25415.7.47.25562
19315.7.48.0/2615.7.48.1 to 15.7.48.6215.7.48.6362
19415.7.48.64/2615.7.48.65 to 15.7.48.12615.7.48.12762
19515.7.48.128/2615.7.48.129 to 15.7.48.19015.7.48.19162
19615.7.48.192/2615.7.48.193 to 15.7.48.25415.7.48.25562
19715.7.49.0/2615.7.49.1 to 15.7.49.6215.7.49.6362
19815.7.49.64/2615.7.49.65 to 15.7.49.12615.7.49.12762
19915.7.49.128/2615.7.49.129 to 15.7.49.19015.7.49.19162
20015.7.49.192/2615.7.49.193 to 15.7.49.25415.7.49.25562
20115.7.50.0/2615.7.50.1 to 15.7.50.6215.7.50.6362
20215.7.50.64/2615.7.50.65 to 15.7.50.12615.7.50.12762
20315.7.50.128/2615.7.50.129 to 15.7.50.19015.7.50.19162
20415.7.50.192/2615.7.50.193 to 15.7.50.25415.7.50.25562
20515.7.51.0/2615.7.51.1 to 15.7.51.6215.7.51.6362
20615.7.51.64/2615.7.51.65 to 15.7.51.12615.7.51.12762
20715.7.51.128/2615.7.51.129 to 15.7.51.19015.7.51.19162
20815.7.51.192/2615.7.51.193 to 15.7.51.25415.7.51.25562
20915.7.52.0/2615.7.52.1 to 15.7.52.6215.7.52.6362
21015.7.52.64/2615.7.52.65 to 15.7.52.12615.7.52.12762
21115.7.52.128/2615.7.52.129 to 15.7.52.19015.7.52.19162
21215.7.52.192/2615.7.52.193 to 15.7.52.25415.7.52.25562
21315.7.53.0/2615.7.53.1 to 15.7.53.6215.7.53.6362
21415.7.53.64/2615.7.53.65 to 15.7.53.12615.7.53.12762
21515.7.53.128/2615.7.53.129 to 15.7.53.19015.7.53.19162
21615.7.53.192/2615.7.53.193 to 15.7.53.25415.7.53.25562
21715.7.54.0/2615.7.54.1 to 15.7.54.6215.7.54.6362
21815.7.54.64/2615.7.54.65 to 15.7.54.12615.7.54.12762
21915.7.54.128/2615.7.54.129 to 15.7.54.19015.7.54.19162
22015.7.54.192/2615.7.54.193 to 15.7.54.25415.7.54.25562
22115.7.55.0/2615.7.55.1 to 15.7.55.6215.7.55.6362
22215.7.55.64/2615.7.55.65 to 15.7.55.12615.7.55.12762
22315.7.55.128/2615.7.55.129 to 15.7.55.19015.7.55.19162
22415.7.55.192/2615.7.55.193 to 15.7.55.25415.7.55.25562
22515.7.56.0/2615.7.56.1 to 15.7.56.6215.7.56.6362
22615.7.56.64/2615.7.56.65 to 15.7.56.12615.7.56.12762
22715.7.56.128/2615.7.56.129 to 15.7.56.19015.7.56.19162
22815.7.56.192/2615.7.56.193 to 15.7.56.25415.7.56.25562
22915.7.57.0/2615.7.57.1 to 15.7.57.6215.7.57.6362
23015.7.57.64/2615.7.57.65 to 15.7.57.12615.7.57.12762
23115.7.57.128/2615.7.57.129 to 15.7.57.19015.7.57.19162
23215.7.57.192/2615.7.57.193 to 15.7.57.25415.7.57.25562
23315.7.58.0/2615.7.58.1 to 15.7.58.6215.7.58.6362
23415.7.58.64/2615.7.58.65 to 15.7.58.12615.7.58.12762
23515.7.58.128/2615.7.58.129 to 15.7.58.19015.7.58.19162
23615.7.58.192/2615.7.58.193 to 15.7.58.25415.7.58.25562
23715.7.59.0/2615.7.59.1 to 15.7.59.6215.7.59.6362
23815.7.59.64/2615.7.59.65 to 15.7.59.12615.7.59.12762
23915.7.59.128/2615.7.59.129 to 15.7.59.19015.7.59.19162
24015.7.59.192/2615.7.59.193 to 15.7.59.25415.7.59.25562
24115.7.60.0/2615.7.60.1 to 15.7.60.6215.7.60.6362
24215.7.60.64/2615.7.60.65 to 15.7.60.12615.7.60.12762
24315.7.60.128/2615.7.60.129 to 15.7.60.19015.7.60.19162
24415.7.60.192/2615.7.60.193 to 15.7.60.25415.7.60.25562
24515.7.61.0/2615.7.61.1 to 15.7.61.6215.7.61.6362
24615.7.61.64/2615.7.61.65 to 15.7.61.12615.7.61.12762
24715.7.61.128/2615.7.61.129 to 15.7.61.19015.7.61.19162
24815.7.61.192/2615.7.61.193 to 15.7.61.25415.7.61.25562
24915.7.62.0/2615.7.62.1 to 15.7.62.6215.7.62.6362
25015.7.62.64/2615.7.62.65 to 15.7.62.12615.7.62.12762
25115.7.62.128/2615.7.62.129 to 15.7.62.19015.7.62.19162
25215.7.62.192/2615.7.62.193 to 15.7.62.25415.7.62.25562
25315.7.63.0/2615.7.63.1 to 15.7.63.6215.7.63.6362
25415.7.63.64/2615.7.63.65 to 15.7.63.12615.7.63.12762
25515.7.63.128/2615.7.63.129 to 15.7.63.19015.7.63.19162
25615.7.63.192/2615.7.63.193 to 15.7.63.25415.7.63.25562

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.