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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.

Network70.4.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
70.4.0.0
Broadcast address
70.4.31.255
First usable
70.4.0.1
Last usable
70.4.31.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
A (default /8)
As numbers
Hex 46040000 · Integer 1174667264 to 1174675455
Reverse DNS zones
0.4.70.in-addr.arpa
1.4.70.in-addr.arpa
2.4.70.in-addr.arpa
3.4.70.in-addr.arpa
4.4.70.in-addr.arpa
5.4.70.in-addr.arpa
6.4.70.in-addr.arpa
7.4.70.in-addr.arpa
8.4.70.in-addr.arpa
9.4.70.in-addr.arpa
10.4.70.in-addr.arpa
11.4.70.in-addr.arpa
12.4.70.in-addr.arpa
13.4.70.in-addr.arpa
14.4.70.in-addr.arpa
15.4.70.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01000110.00000100.00000000.0000000070.4.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network01000110.00000100.00000000.0000000070.4.0.0
Broadcast01000110.00000100.00011111.1111111170.4.31.255
Split into smaller subnets/28
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

70.4.0.0/19 makes 512 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
170.4.0.0/2870.4.0.1 to 70.4.0.1470.4.0.1514
270.4.0.16/2870.4.0.17 to 70.4.0.3070.4.0.3114
370.4.0.32/2870.4.0.33 to 70.4.0.4670.4.0.4714
470.4.0.48/2870.4.0.49 to 70.4.0.6270.4.0.6314
570.4.0.64/2870.4.0.65 to 70.4.0.7870.4.0.7914
670.4.0.80/2870.4.0.81 to 70.4.0.9470.4.0.9514
770.4.0.96/2870.4.0.97 to 70.4.0.11070.4.0.11114
870.4.0.112/2870.4.0.113 to 70.4.0.12670.4.0.12714
970.4.0.128/2870.4.0.129 to 70.4.0.14270.4.0.14314
1070.4.0.144/2870.4.0.145 to 70.4.0.15870.4.0.15914
1170.4.0.160/2870.4.0.161 to 70.4.0.17470.4.0.17514
1270.4.0.176/2870.4.0.177 to 70.4.0.19070.4.0.19114
1370.4.0.192/2870.4.0.193 to 70.4.0.20670.4.0.20714
1470.4.0.208/2870.4.0.209 to 70.4.0.22270.4.0.22314
1570.4.0.224/2870.4.0.225 to 70.4.0.23870.4.0.23914
1670.4.0.240/2870.4.0.241 to 70.4.0.25470.4.0.25514
1770.4.1.0/2870.4.1.1 to 70.4.1.1470.4.1.1514
1870.4.1.16/2870.4.1.17 to 70.4.1.3070.4.1.3114
1970.4.1.32/2870.4.1.33 to 70.4.1.4670.4.1.4714
2070.4.1.48/2870.4.1.49 to 70.4.1.6270.4.1.6314
2170.4.1.64/2870.4.1.65 to 70.4.1.7870.4.1.7914
2270.4.1.80/2870.4.1.81 to 70.4.1.9470.4.1.9514
2370.4.1.96/2870.4.1.97 to 70.4.1.11070.4.1.11114
2470.4.1.112/2870.4.1.113 to 70.4.1.12670.4.1.12714
2570.4.1.128/2870.4.1.129 to 70.4.1.14270.4.1.14314
2670.4.1.144/2870.4.1.145 to 70.4.1.15870.4.1.15914
2770.4.1.160/2870.4.1.161 to 70.4.1.17470.4.1.17514
2870.4.1.176/2870.4.1.177 to 70.4.1.19070.4.1.19114
2970.4.1.192/2870.4.1.193 to 70.4.1.20670.4.1.20714
3070.4.1.208/2870.4.1.209 to 70.4.1.22270.4.1.22314
3170.4.1.224/2870.4.1.225 to 70.4.1.23870.4.1.23914
3270.4.1.240/2870.4.1.241 to 70.4.1.25470.4.1.25514
3370.4.2.0/2870.4.2.1 to 70.4.2.1470.4.2.1514
3470.4.2.16/2870.4.2.17 to 70.4.2.3070.4.2.3114
3570.4.2.32/2870.4.2.33 to 70.4.2.4670.4.2.4714
3670.4.2.48/2870.4.2.49 to 70.4.2.6270.4.2.6314
3770.4.2.64/2870.4.2.65 to 70.4.2.7870.4.2.7914
3870.4.2.80/2870.4.2.81 to 70.4.2.9470.4.2.9514
3970.4.2.96/2870.4.2.97 to 70.4.2.11070.4.2.11114
4070.4.2.112/2870.4.2.113 to 70.4.2.12670.4.2.12714
4170.4.2.128/2870.4.2.129 to 70.4.2.14270.4.2.14314
4270.4.2.144/2870.4.2.145 to 70.4.2.15870.4.2.15914
4370.4.2.160/2870.4.2.161 to 70.4.2.17470.4.2.17514
4470.4.2.176/2870.4.2.177 to 70.4.2.19070.4.2.19114
4570.4.2.192/2870.4.2.193 to 70.4.2.20670.4.2.20714
4670.4.2.208/2870.4.2.209 to 70.4.2.22270.4.2.22314
4770.4.2.224/2870.4.2.225 to 70.4.2.23870.4.2.23914
4870.4.2.240/2870.4.2.241 to 70.4.2.25470.4.2.25514
4970.4.3.0/2870.4.3.1 to 70.4.3.1470.4.3.1514
5070.4.3.16/2870.4.3.17 to 70.4.3.3070.4.3.3114
5170.4.3.32/2870.4.3.33 to 70.4.3.4670.4.3.4714
5270.4.3.48/2870.4.3.49 to 70.4.3.6270.4.3.6314
5370.4.3.64/2870.4.3.65 to 70.4.3.7870.4.3.7914
5470.4.3.80/2870.4.3.81 to 70.4.3.9470.4.3.9514
5570.4.3.96/2870.4.3.97 to 70.4.3.11070.4.3.11114
5670.4.3.112/2870.4.3.113 to 70.4.3.12670.4.3.12714
5770.4.3.128/2870.4.3.129 to 70.4.3.14270.4.3.14314
5870.4.3.144/2870.4.3.145 to 70.4.3.15870.4.3.15914
5970.4.3.160/2870.4.3.161 to 70.4.3.17470.4.3.17514
6070.4.3.176/2870.4.3.177 to 70.4.3.19070.4.3.19114
6170.4.3.192/2870.4.3.193 to 70.4.3.20670.4.3.20714
6270.4.3.208/2870.4.3.209 to 70.4.3.22270.4.3.22314
6370.4.3.224/2870.4.3.225 to 70.4.3.23870.4.3.23914
6470.4.3.240/2870.4.3.241 to 70.4.3.25470.4.3.25514
6570.4.4.0/2870.4.4.1 to 70.4.4.1470.4.4.1514
6670.4.4.16/2870.4.4.17 to 70.4.4.3070.4.4.3114
6770.4.4.32/2870.4.4.33 to 70.4.4.4670.4.4.4714
6870.4.4.48/2870.4.4.49 to 70.4.4.6270.4.4.6314
6970.4.4.64/2870.4.4.65 to 70.4.4.7870.4.4.7914
7070.4.4.80/2870.4.4.81 to 70.4.4.9470.4.4.9514
7170.4.4.96/2870.4.4.97 to 70.4.4.11070.4.4.11114
7270.4.4.112/2870.4.4.113 to 70.4.4.12670.4.4.12714
7370.4.4.128/2870.4.4.129 to 70.4.4.14270.4.4.14314
7470.4.4.144/2870.4.4.145 to 70.4.4.15870.4.4.15914
7570.4.4.160/2870.4.4.161 to 70.4.4.17470.4.4.17514
7670.4.4.176/2870.4.4.177 to 70.4.4.19070.4.4.19114
7770.4.4.192/2870.4.4.193 to 70.4.4.20670.4.4.20714
7870.4.4.208/2870.4.4.209 to 70.4.4.22270.4.4.22314
7970.4.4.224/2870.4.4.225 to 70.4.4.23870.4.4.23914
8070.4.4.240/2870.4.4.241 to 70.4.4.25470.4.4.25514
8170.4.5.0/2870.4.5.1 to 70.4.5.1470.4.5.1514
8270.4.5.16/2870.4.5.17 to 70.4.5.3070.4.5.3114
8370.4.5.32/2870.4.5.33 to 70.4.5.4670.4.5.4714
8470.4.5.48/2870.4.5.49 to 70.4.5.6270.4.5.6314
8570.4.5.64/2870.4.5.65 to 70.4.5.7870.4.5.7914
8670.4.5.80/2870.4.5.81 to 70.4.5.9470.4.5.9514
8770.4.5.96/2870.4.5.97 to 70.4.5.11070.4.5.11114
8870.4.5.112/2870.4.5.113 to 70.4.5.12670.4.5.12714
8970.4.5.128/2870.4.5.129 to 70.4.5.14270.4.5.14314
9070.4.5.144/2870.4.5.145 to 70.4.5.15870.4.5.15914
9170.4.5.160/2870.4.5.161 to 70.4.5.17470.4.5.17514
9270.4.5.176/2870.4.5.177 to 70.4.5.19070.4.5.19114
9370.4.5.192/2870.4.5.193 to 70.4.5.20670.4.5.20714
9470.4.5.208/2870.4.5.209 to 70.4.5.22270.4.5.22314
9570.4.5.224/2870.4.5.225 to 70.4.5.23870.4.5.23914
9670.4.5.240/2870.4.5.241 to 70.4.5.25470.4.5.25514
9770.4.6.0/2870.4.6.1 to 70.4.6.1470.4.6.1514
9870.4.6.16/2870.4.6.17 to 70.4.6.3070.4.6.3114
9970.4.6.32/2870.4.6.33 to 70.4.6.4670.4.6.4714
10070.4.6.48/2870.4.6.49 to 70.4.6.6270.4.6.6314
10170.4.6.64/2870.4.6.65 to 70.4.6.7870.4.6.7914
10270.4.6.80/2870.4.6.81 to 70.4.6.9470.4.6.9514
10370.4.6.96/2870.4.6.97 to 70.4.6.11070.4.6.11114
10470.4.6.112/2870.4.6.113 to 70.4.6.12670.4.6.12714
10570.4.6.128/2870.4.6.129 to 70.4.6.14270.4.6.14314
10670.4.6.144/2870.4.6.145 to 70.4.6.15870.4.6.15914
10770.4.6.160/2870.4.6.161 to 70.4.6.17470.4.6.17514
10870.4.6.176/2870.4.6.177 to 70.4.6.19070.4.6.19114
10970.4.6.192/2870.4.6.193 to 70.4.6.20670.4.6.20714
11070.4.6.208/2870.4.6.209 to 70.4.6.22270.4.6.22314
11170.4.6.224/2870.4.6.225 to 70.4.6.23870.4.6.23914
11270.4.6.240/2870.4.6.241 to 70.4.6.25470.4.6.25514
11370.4.7.0/2870.4.7.1 to 70.4.7.1470.4.7.1514
11470.4.7.16/2870.4.7.17 to 70.4.7.3070.4.7.3114
11570.4.7.32/2870.4.7.33 to 70.4.7.4670.4.7.4714
11670.4.7.48/2870.4.7.49 to 70.4.7.6270.4.7.6314
11770.4.7.64/2870.4.7.65 to 70.4.7.7870.4.7.7914
11870.4.7.80/2870.4.7.81 to 70.4.7.9470.4.7.9514
11970.4.7.96/2870.4.7.97 to 70.4.7.11070.4.7.11114
12070.4.7.112/2870.4.7.113 to 70.4.7.12670.4.7.12714
12170.4.7.128/2870.4.7.129 to 70.4.7.14270.4.7.14314
12270.4.7.144/2870.4.7.145 to 70.4.7.15870.4.7.15914
12370.4.7.160/2870.4.7.161 to 70.4.7.17470.4.7.17514
12470.4.7.176/2870.4.7.177 to 70.4.7.19070.4.7.19114
12570.4.7.192/2870.4.7.193 to 70.4.7.20670.4.7.20714
12670.4.7.208/2870.4.7.209 to 70.4.7.22270.4.7.22314
12770.4.7.224/2870.4.7.225 to 70.4.7.23870.4.7.23914
12870.4.7.240/2870.4.7.241 to 70.4.7.25470.4.7.25514
12970.4.8.0/2870.4.8.1 to 70.4.8.1470.4.8.1514
13070.4.8.16/2870.4.8.17 to 70.4.8.3070.4.8.3114
13170.4.8.32/2870.4.8.33 to 70.4.8.4670.4.8.4714
13270.4.8.48/2870.4.8.49 to 70.4.8.6270.4.8.6314
13370.4.8.64/2870.4.8.65 to 70.4.8.7870.4.8.7914
13470.4.8.80/2870.4.8.81 to 70.4.8.9470.4.8.9514
13570.4.8.96/2870.4.8.97 to 70.4.8.11070.4.8.11114
13670.4.8.112/2870.4.8.113 to 70.4.8.12670.4.8.12714
13770.4.8.128/2870.4.8.129 to 70.4.8.14270.4.8.14314
13870.4.8.144/2870.4.8.145 to 70.4.8.15870.4.8.15914
13970.4.8.160/2870.4.8.161 to 70.4.8.17470.4.8.17514
14070.4.8.176/2870.4.8.177 to 70.4.8.19070.4.8.19114
14170.4.8.192/2870.4.8.193 to 70.4.8.20670.4.8.20714
14270.4.8.208/2870.4.8.209 to 70.4.8.22270.4.8.22314
14370.4.8.224/2870.4.8.225 to 70.4.8.23870.4.8.23914
14470.4.8.240/2870.4.8.241 to 70.4.8.25470.4.8.25514
14570.4.9.0/2870.4.9.1 to 70.4.9.1470.4.9.1514
14670.4.9.16/2870.4.9.17 to 70.4.9.3070.4.9.3114
14770.4.9.32/2870.4.9.33 to 70.4.9.4670.4.9.4714
14870.4.9.48/2870.4.9.49 to 70.4.9.6270.4.9.6314
14970.4.9.64/2870.4.9.65 to 70.4.9.7870.4.9.7914
15070.4.9.80/2870.4.9.81 to 70.4.9.9470.4.9.9514
15170.4.9.96/2870.4.9.97 to 70.4.9.11070.4.9.11114
15270.4.9.112/2870.4.9.113 to 70.4.9.12670.4.9.12714
15370.4.9.128/2870.4.9.129 to 70.4.9.14270.4.9.14314
15470.4.9.144/2870.4.9.145 to 70.4.9.15870.4.9.15914
15570.4.9.160/2870.4.9.161 to 70.4.9.17470.4.9.17514
15670.4.9.176/2870.4.9.177 to 70.4.9.19070.4.9.19114
15770.4.9.192/2870.4.9.193 to 70.4.9.20670.4.9.20714
15870.4.9.208/2870.4.9.209 to 70.4.9.22270.4.9.22314
15970.4.9.224/2870.4.9.225 to 70.4.9.23870.4.9.23914
16070.4.9.240/2870.4.9.241 to 70.4.9.25470.4.9.25514
16170.4.10.0/2870.4.10.1 to 70.4.10.1470.4.10.1514
16270.4.10.16/2870.4.10.17 to 70.4.10.3070.4.10.3114
16370.4.10.32/2870.4.10.33 to 70.4.10.4670.4.10.4714
16470.4.10.48/2870.4.10.49 to 70.4.10.6270.4.10.6314
16570.4.10.64/2870.4.10.65 to 70.4.10.7870.4.10.7914
16670.4.10.80/2870.4.10.81 to 70.4.10.9470.4.10.9514
16770.4.10.96/2870.4.10.97 to 70.4.10.11070.4.10.11114
16870.4.10.112/2870.4.10.113 to 70.4.10.12670.4.10.12714
16970.4.10.128/2870.4.10.129 to 70.4.10.14270.4.10.14314
17070.4.10.144/2870.4.10.145 to 70.4.10.15870.4.10.15914
17170.4.10.160/2870.4.10.161 to 70.4.10.17470.4.10.17514
17270.4.10.176/2870.4.10.177 to 70.4.10.19070.4.10.19114
17370.4.10.192/2870.4.10.193 to 70.4.10.20670.4.10.20714
17470.4.10.208/2870.4.10.209 to 70.4.10.22270.4.10.22314
17570.4.10.224/2870.4.10.225 to 70.4.10.23870.4.10.23914
17670.4.10.240/2870.4.10.241 to 70.4.10.25470.4.10.25514
17770.4.11.0/2870.4.11.1 to 70.4.11.1470.4.11.1514
17870.4.11.16/2870.4.11.17 to 70.4.11.3070.4.11.3114
17970.4.11.32/2870.4.11.33 to 70.4.11.4670.4.11.4714
18070.4.11.48/2870.4.11.49 to 70.4.11.6270.4.11.6314
18170.4.11.64/2870.4.11.65 to 70.4.11.7870.4.11.7914
18270.4.11.80/2870.4.11.81 to 70.4.11.9470.4.11.9514
18370.4.11.96/2870.4.11.97 to 70.4.11.11070.4.11.11114
18470.4.11.112/2870.4.11.113 to 70.4.11.12670.4.11.12714
18570.4.11.128/2870.4.11.129 to 70.4.11.14270.4.11.14314
18670.4.11.144/2870.4.11.145 to 70.4.11.15870.4.11.15914
18770.4.11.160/2870.4.11.161 to 70.4.11.17470.4.11.17514
18870.4.11.176/2870.4.11.177 to 70.4.11.19070.4.11.19114
18970.4.11.192/2870.4.11.193 to 70.4.11.20670.4.11.20714
19070.4.11.208/2870.4.11.209 to 70.4.11.22270.4.11.22314
19170.4.11.224/2870.4.11.225 to 70.4.11.23870.4.11.23914
19270.4.11.240/2870.4.11.241 to 70.4.11.25470.4.11.25514
19370.4.12.0/2870.4.12.1 to 70.4.12.1470.4.12.1514
19470.4.12.16/2870.4.12.17 to 70.4.12.3070.4.12.3114
19570.4.12.32/2870.4.12.33 to 70.4.12.4670.4.12.4714
19670.4.12.48/2870.4.12.49 to 70.4.12.6270.4.12.6314
19770.4.12.64/2870.4.12.65 to 70.4.12.7870.4.12.7914
19870.4.12.80/2870.4.12.81 to 70.4.12.9470.4.12.9514
19970.4.12.96/2870.4.12.97 to 70.4.12.11070.4.12.11114
20070.4.12.112/2870.4.12.113 to 70.4.12.12670.4.12.12714
20170.4.12.128/2870.4.12.129 to 70.4.12.14270.4.12.14314
20270.4.12.144/2870.4.12.145 to 70.4.12.15870.4.12.15914
20370.4.12.160/2870.4.12.161 to 70.4.12.17470.4.12.17514
20470.4.12.176/2870.4.12.177 to 70.4.12.19070.4.12.19114
20570.4.12.192/2870.4.12.193 to 70.4.12.20670.4.12.20714
20670.4.12.208/2870.4.12.209 to 70.4.12.22270.4.12.22314
20770.4.12.224/2870.4.12.225 to 70.4.12.23870.4.12.23914
20870.4.12.240/2870.4.12.241 to 70.4.12.25470.4.12.25514
20970.4.13.0/2870.4.13.1 to 70.4.13.1470.4.13.1514
21070.4.13.16/2870.4.13.17 to 70.4.13.3070.4.13.3114
21170.4.13.32/2870.4.13.33 to 70.4.13.4670.4.13.4714
21270.4.13.48/2870.4.13.49 to 70.4.13.6270.4.13.6314
21370.4.13.64/2870.4.13.65 to 70.4.13.7870.4.13.7914
21470.4.13.80/2870.4.13.81 to 70.4.13.9470.4.13.9514
21570.4.13.96/2870.4.13.97 to 70.4.13.11070.4.13.11114
21670.4.13.112/2870.4.13.113 to 70.4.13.12670.4.13.12714
21770.4.13.128/2870.4.13.129 to 70.4.13.14270.4.13.14314
21870.4.13.144/2870.4.13.145 to 70.4.13.15870.4.13.15914
21970.4.13.160/2870.4.13.161 to 70.4.13.17470.4.13.17514
22070.4.13.176/2870.4.13.177 to 70.4.13.19070.4.13.19114
22170.4.13.192/2870.4.13.193 to 70.4.13.20670.4.13.20714
22270.4.13.208/2870.4.13.209 to 70.4.13.22270.4.13.22314
22370.4.13.224/2870.4.13.225 to 70.4.13.23870.4.13.23914
22470.4.13.240/2870.4.13.241 to 70.4.13.25470.4.13.25514
22570.4.14.0/2870.4.14.1 to 70.4.14.1470.4.14.1514
22670.4.14.16/2870.4.14.17 to 70.4.14.3070.4.14.3114
22770.4.14.32/2870.4.14.33 to 70.4.14.4670.4.14.4714
22870.4.14.48/2870.4.14.49 to 70.4.14.6270.4.14.6314
22970.4.14.64/2870.4.14.65 to 70.4.14.7870.4.14.7914
23070.4.14.80/2870.4.14.81 to 70.4.14.9470.4.14.9514
23170.4.14.96/2870.4.14.97 to 70.4.14.11070.4.14.11114
23270.4.14.112/2870.4.14.113 to 70.4.14.12670.4.14.12714
23370.4.14.128/2870.4.14.129 to 70.4.14.14270.4.14.14314
23470.4.14.144/2870.4.14.145 to 70.4.14.15870.4.14.15914
23570.4.14.160/2870.4.14.161 to 70.4.14.17470.4.14.17514
23670.4.14.176/2870.4.14.177 to 70.4.14.19070.4.14.19114
23770.4.14.192/2870.4.14.193 to 70.4.14.20670.4.14.20714
23870.4.14.208/2870.4.14.209 to 70.4.14.22270.4.14.22314
23970.4.14.224/2870.4.14.225 to 70.4.14.23870.4.14.23914
24070.4.14.240/2870.4.14.241 to 70.4.14.25470.4.14.25514
24170.4.15.0/2870.4.15.1 to 70.4.15.1470.4.15.1514
24270.4.15.16/2870.4.15.17 to 70.4.15.3070.4.15.3114
24370.4.15.32/2870.4.15.33 to 70.4.15.4670.4.15.4714
24470.4.15.48/2870.4.15.49 to 70.4.15.6270.4.15.6314
24570.4.15.64/2870.4.15.65 to 70.4.15.7870.4.15.7914
24670.4.15.80/2870.4.15.81 to 70.4.15.9470.4.15.9514
24770.4.15.96/2870.4.15.97 to 70.4.15.11070.4.15.11114
24870.4.15.112/2870.4.15.113 to 70.4.15.12670.4.15.12714
24970.4.15.128/2870.4.15.129 to 70.4.15.14270.4.15.14314
25070.4.15.144/2870.4.15.145 to 70.4.15.15870.4.15.15914
25170.4.15.160/2870.4.15.161 to 70.4.15.17470.4.15.17514
25270.4.15.176/2870.4.15.177 to 70.4.15.19070.4.15.19114
25370.4.15.192/2870.4.15.193 to 70.4.15.20670.4.15.20714
25470.4.15.208/2870.4.15.209 to 70.4.15.22270.4.15.22314
25570.4.15.224/2870.4.15.225 to 70.4.15.23870.4.15.23914
25670.4.15.240/2870.4.15.241 to 70.4.15.25470.4.15.25514

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.