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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.

Network15.2.0.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
15.2.0.0
Broadcast address
15.2.31.255
First usable
15.2.0.1
Last usable
15.2.31.254
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 0F020000 · Integer 251789312 to 251797503
Reverse DNS zones
0.2.15.in-addr.arpa
1.2.15.in-addr.arpa
2.2.15.in-addr.arpa
3.2.15.in-addr.arpa
4.2.15.in-addr.arpa
5.2.15.in-addr.arpa
6.2.15.in-addr.arpa
7.2.15.in-addr.arpa
8.2.15.in-addr.arpa
9.2.15.in-addr.arpa
10.2.15.in-addr.arpa
11.2.15.in-addr.arpa
12.2.15.in-addr.arpa
13.2.15.in-addr.arpa
14.2.15.in-addr.arpa
15.2.15.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
Address00001111.00000010.00000000.0000000015.2.0.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00001111.00000010.00000000.0000000015.2.0.0
Broadcast00001111.00000010.00011111.1111111115.2.31.255
Split into smaller subnets/29
/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)

15.2.0.0/19 makes 1,024 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
115.2.0.0/2915.2.0.1 to 15.2.0.615.2.0.76
215.2.0.8/2915.2.0.9 to 15.2.0.1415.2.0.156
315.2.0.16/2915.2.0.17 to 15.2.0.2215.2.0.236
415.2.0.24/2915.2.0.25 to 15.2.0.3015.2.0.316
515.2.0.32/2915.2.0.33 to 15.2.0.3815.2.0.396
615.2.0.40/2915.2.0.41 to 15.2.0.4615.2.0.476
715.2.0.48/2915.2.0.49 to 15.2.0.5415.2.0.556
815.2.0.56/2915.2.0.57 to 15.2.0.6215.2.0.636
915.2.0.64/2915.2.0.65 to 15.2.0.7015.2.0.716
1015.2.0.72/2915.2.0.73 to 15.2.0.7815.2.0.796
1115.2.0.80/2915.2.0.81 to 15.2.0.8615.2.0.876
1215.2.0.88/2915.2.0.89 to 15.2.0.9415.2.0.956
1315.2.0.96/2915.2.0.97 to 15.2.0.10215.2.0.1036
1415.2.0.104/2915.2.0.105 to 15.2.0.11015.2.0.1116
1515.2.0.112/2915.2.0.113 to 15.2.0.11815.2.0.1196
1615.2.0.120/2915.2.0.121 to 15.2.0.12615.2.0.1276
1715.2.0.128/2915.2.0.129 to 15.2.0.13415.2.0.1356
1815.2.0.136/2915.2.0.137 to 15.2.0.14215.2.0.1436
1915.2.0.144/2915.2.0.145 to 15.2.0.15015.2.0.1516
2015.2.0.152/2915.2.0.153 to 15.2.0.15815.2.0.1596
2115.2.0.160/2915.2.0.161 to 15.2.0.16615.2.0.1676
2215.2.0.168/2915.2.0.169 to 15.2.0.17415.2.0.1756
2315.2.0.176/2915.2.0.177 to 15.2.0.18215.2.0.1836
2415.2.0.184/2915.2.0.185 to 15.2.0.19015.2.0.1916
2515.2.0.192/2915.2.0.193 to 15.2.0.19815.2.0.1996
2615.2.0.200/2915.2.0.201 to 15.2.0.20615.2.0.2076
2715.2.0.208/2915.2.0.209 to 15.2.0.21415.2.0.2156
2815.2.0.216/2915.2.0.217 to 15.2.0.22215.2.0.2236
2915.2.0.224/2915.2.0.225 to 15.2.0.23015.2.0.2316
3015.2.0.232/2915.2.0.233 to 15.2.0.23815.2.0.2396
3115.2.0.240/2915.2.0.241 to 15.2.0.24615.2.0.2476
3215.2.0.248/2915.2.0.249 to 15.2.0.25415.2.0.2556
3315.2.1.0/2915.2.1.1 to 15.2.1.615.2.1.76
3415.2.1.8/2915.2.1.9 to 15.2.1.1415.2.1.156
3515.2.1.16/2915.2.1.17 to 15.2.1.2215.2.1.236
3615.2.1.24/2915.2.1.25 to 15.2.1.3015.2.1.316
3715.2.1.32/2915.2.1.33 to 15.2.1.3815.2.1.396
3815.2.1.40/2915.2.1.41 to 15.2.1.4615.2.1.476
3915.2.1.48/2915.2.1.49 to 15.2.1.5415.2.1.556
4015.2.1.56/2915.2.1.57 to 15.2.1.6215.2.1.636
4115.2.1.64/2915.2.1.65 to 15.2.1.7015.2.1.716
4215.2.1.72/2915.2.1.73 to 15.2.1.7815.2.1.796
4315.2.1.80/2915.2.1.81 to 15.2.1.8615.2.1.876
4415.2.1.88/2915.2.1.89 to 15.2.1.9415.2.1.956
4515.2.1.96/2915.2.1.97 to 15.2.1.10215.2.1.1036
4615.2.1.104/2915.2.1.105 to 15.2.1.11015.2.1.1116
4715.2.1.112/2915.2.1.113 to 15.2.1.11815.2.1.1196
4815.2.1.120/2915.2.1.121 to 15.2.1.12615.2.1.1276
4915.2.1.128/2915.2.1.129 to 15.2.1.13415.2.1.1356
5015.2.1.136/2915.2.1.137 to 15.2.1.14215.2.1.1436
5115.2.1.144/2915.2.1.145 to 15.2.1.15015.2.1.1516
5215.2.1.152/2915.2.1.153 to 15.2.1.15815.2.1.1596
5315.2.1.160/2915.2.1.161 to 15.2.1.16615.2.1.1676
5415.2.1.168/2915.2.1.169 to 15.2.1.17415.2.1.1756
5515.2.1.176/2915.2.1.177 to 15.2.1.18215.2.1.1836
5615.2.1.184/2915.2.1.185 to 15.2.1.19015.2.1.1916
5715.2.1.192/2915.2.1.193 to 15.2.1.19815.2.1.1996
5815.2.1.200/2915.2.1.201 to 15.2.1.20615.2.1.2076
5915.2.1.208/2915.2.1.209 to 15.2.1.21415.2.1.2156
6015.2.1.216/2915.2.1.217 to 15.2.1.22215.2.1.2236
6115.2.1.224/2915.2.1.225 to 15.2.1.23015.2.1.2316
6215.2.1.232/2915.2.1.233 to 15.2.1.23815.2.1.2396
6315.2.1.240/2915.2.1.241 to 15.2.1.24615.2.1.2476
6415.2.1.248/2915.2.1.249 to 15.2.1.25415.2.1.2556
6515.2.2.0/2915.2.2.1 to 15.2.2.615.2.2.76
6615.2.2.8/2915.2.2.9 to 15.2.2.1415.2.2.156
6715.2.2.16/2915.2.2.17 to 15.2.2.2215.2.2.236
6815.2.2.24/2915.2.2.25 to 15.2.2.3015.2.2.316
6915.2.2.32/2915.2.2.33 to 15.2.2.3815.2.2.396
7015.2.2.40/2915.2.2.41 to 15.2.2.4615.2.2.476
7115.2.2.48/2915.2.2.49 to 15.2.2.5415.2.2.556
7215.2.2.56/2915.2.2.57 to 15.2.2.6215.2.2.636
7315.2.2.64/2915.2.2.65 to 15.2.2.7015.2.2.716
7415.2.2.72/2915.2.2.73 to 15.2.2.7815.2.2.796
7515.2.2.80/2915.2.2.81 to 15.2.2.8615.2.2.876
7615.2.2.88/2915.2.2.89 to 15.2.2.9415.2.2.956
7715.2.2.96/2915.2.2.97 to 15.2.2.10215.2.2.1036
7815.2.2.104/2915.2.2.105 to 15.2.2.11015.2.2.1116
7915.2.2.112/2915.2.2.113 to 15.2.2.11815.2.2.1196
8015.2.2.120/2915.2.2.121 to 15.2.2.12615.2.2.1276
8115.2.2.128/2915.2.2.129 to 15.2.2.13415.2.2.1356
8215.2.2.136/2915.2.2.137 to 15.2.2.14215.2.2.1436
8315.2.2.144/2915.2.2.145 to 15.2.2.15015.2.2.1516
8415.2.2.152/2915.2.2.153 to 15.2.2.15815.2.2.1596
8515.2.2.160/2915.2.2.161 to 15.2.2.16615.2.2.1676
8615.2.2.168/2915.2.2.169 to 15.2.2.17415.2.2.1756
8715.2.2.176/2915.2.2.177 to 15.2.2.18215.2.2.1836
8815.2.2.184/2915.2.2.185 to 15.2.2.19015.2.2.1916
8915.2.2.192/2915.2.2.193 to 15.2.2.19815.2.2.1996
9015.2.2.200/2915.2.2.201 to 15.2.2.20615.2.2.2076
9115.2.2.208/2915.2.2.209 to 15.2.2.21415.2.2.2156
9215.2.2.216/2915.2.2.217 to 15.2.2.22215.2.2.2236
9315.2.2.224/2915.2.2.225 to 15.2.2.23015.2.2.2316
9415.2.2.232/2915.2.2.233 to 15.2.2.23815.2.2.2396
9515.2.2.240/2915.2.2.241 to 15.2.2.24615.2.2.2476
9615.2.2.248/2915.2.2.249 to 15.2.2.25415.2.2.2556
9715.2.3.0/2915.2.3.1 to 15.2.3.615.2.3.76
9815.2.3.8/2915.2.3.9 to 15.2.3.1415.2.3.156
9915.2.3.16/2915.2.3.17 to 15.2.3.2215.2.3.236
10015.2.3.24/2915.2.3.25 to 15.2.3.3015.2.3.316
10115.2.3.32/2915.2.3.33 to 15.2.3.3815.2.3.396
10215.2.3.40/2915.2.3.41 to 15.2.3.4615.2.3.476
10315.2.3.48/2915.2.3.49 to 15.2.3.5415.2.3.556
10415.2.3.56/2915.2.3.57 to 15.2.3.6215.2.3.636
10515.2.3.64/2915.2.3.65 to 15.2.3.7015.2.3.716
10615.2.3.72/2915.2.3.73 to 15.2.3.7815.2.3.796
10715.2.3.80/2915.2.3.81 to 15.2.3.8615.2.3.876
10815.2.3.88/2915.2.3.89 to 15.2.3.9415.2.3.956
10915.2.3.96/2915.2.3.97 to 15.2.3.10215.2.3.1036
11015.2.3.104/2915.2.3.105 to 15.2.3.11015.2.3.1116
11115.2.3.112/2915.2.3.113 to 15.2.3.11815.2.3.1196
11215.2.3.120/2915.2.3.121 to 15.2.3.12615.2.3.1276
11315.2.3.128/2915.2.3.129 to 15.2.3.13415.2.3.1356
11415.2.3.136/2915.2.3.137 to 15.2.3.14215.2.3.1436
11515.2.3.144/2915.2.3.145 to 15.2.3.15015.2.3.1516
11615.2.3.152/2915.2.3.153 to 15.2.3.15815.2.3.1596
11715.2.3.160/2915.2.3.161 to 15.2.3.16615.2.3.1676
11815.2.3.168/2915.2.3.169 to 15.2.3.17415.2.3.1756
11915.2.3.176/2915.2.3.177 to 15.2.3.18215.2.3.1836
12015.2.3.184/2915.2.3.185 to 15.2.3.19015.2.3.1916
12115.2.3.192/2915.2.3.193 to 15.2.3.19815.2.3.1996
12215.2.3.200/2915.2.3.201 to 15.2.3.20615.2.3.2076
12315.2.3.208/2915.2.3.209 to 15.2.3.21415.2.3.2156
12415.2.3.216/2915.2.3.217 to 15.2.3.22215.2.3.2236
12515.2.3.224/2915.2.3.225 to 15.2.3.23015.2.3.2316
12615.2.3.232/2915.2.3.233 to 15.2.3.23815.2.3.2396
12715.2.3.240/2915.2.3.241 to 15.2.3.24615.2.3.2476
12815.2.3.248/2915.2.3.249 to 15.2.3.25415.2.3.2556
12915.2.4.0/2915.2.4.1 to 15.2.4.615.2.4.76
13015.2.4.8/2915.2.4.9 to 15.2.4.1415.2.4.156
13115.2.4.16/2915.2.4.17 to 15.2.4.2215.2.4.236
13215.2.4.24/2915.2.4.25 to 15.2.4.3015.2.4.316
13315.2.4.32/2915.2.4.33 to 15.2.4.3815.2.4.396
13415.2.4.40/2915.2.4.41 to 15.2.4.4615.2.4.476
13515.2.4.48/2915.2.4.49 to 15.2.4.5415.2.4.556
13615.2.4.56/2915.2.4.57 to 15.2.4.6215.2.4.636
13715.2.4.64/2915.2.4.65 to 15.2.4.7015.2.4.716
13815.2.4.72/2915.2.4.73 to 15.2.4.7815.2.4.796
13915.2.4.80/2915.2.4.81 to 15.2.4.8615.2.4.876
14015.2.4.88/2915.2.4.89 to 15.2.4.9415.2.4.956
14115.2.4.96/2915.2.4.97 to 15.2.4.10215.2.4.1036
14215.2.4.104/2915.2.4.105 to 15.2.4.11015.2.4.1116
14315.2.4.112/2915.2.4.113 to 15.2.4.11815.2.4.1196
14415.2.4.120/2915.2.4.121 to 15.2.4.12615.2.4.1276
14515.2.4.128/2915.2.4.129 to 15.2.4.13415.2.4.1356
14615.2.4.136/2915.2.4.137 to 15.2.4.14215.2.4.1436
14715.2.4.144/2915.2.4.145 to 15.2.4.15015.2.4.1516
14815.2.4.152/2915.2.4.153 to 15.2.4.15815.2.4.1596
14915.2.4.160/2915.2.4.161 to 15.2.4.16615.2.4.1676
15015.2.4.168/2915.2.4.169 to 15.2.4.17415.2.4.1756
15115.2.4.176/2915.2.4.177 to 15.2.4.18215.2.4.1836
15215.2.4.184/2915.2.4.185 to 15.2.4.19015.2.4.1916
15315.2.4.192/2915.2.4.193 to 15.2.4.19815.2.4.1996
15415.2.4.200/2915.2.4.201 to 15.2.4.20615.2.4.2076
15515.2.4.208/2915.2.4.209 to 15.2.4.21415.2.4.2156
15615.2.4.216/2915.2.4.217 to 15.2.4.22215.2.4.2236
15715.2.4.224/2915.2.4.225 to 15.2.4.23015.2.4.2316
15815.2.4.232/2915.2.4.233 to 15.2.4.23815.2.4.2396
15915.2.4.240/2915.2.4.241 to 15.2.4.24615.2.4.2476
16015.2.4.248/2915.2.4.249 to 15.2.4.25415.2.4.2556
16115.2.5.0/2915.2.5.1 to 15.2.5.615.2.5.76
16215.2.5.8/2915.2.5.9 to 15.2.5.1415.2.5.156
16315.2.5.16/2915.2.5.17 to 15.2.5.2215.2.5.236
16415.2.5.24/2915.2.5.25 to 15.2.5.3015.2.5.316
16515.2.5.32/2915.2.5.33 to 15.2.5.3815.2.5.396
16615.2.5.40/2915.2.5.41 to 15.2.5.4615.2.5.476
16715.2.5.48/2915.2.5.49 to 15.2.5.5415.2.5.556
16815.2.5.56/2915.2.5.57 to 15.2.5.6215.2.5.636
16915.2.5.64/2915.2.5.65 to 15.2.5.7015.2.5.716
17015.2.5.72/2915.2.5.73 to 15.2.5.7815.2.5.796
17115.2.5.80/2915.2.5.81 to 15.2.5.8615.2.5.876
17215.2.5.88/2915.2.5.89 to 15.2.5.9415.2.5.956
17315.2.5.96/2915.2.5.97 to 15.2.5.10215.2.5.1036
17415.2.5.104/2915.2.5.105 to 15.2.5.11015.2.5.1116
17515.2.5.112/2915.2.5.113 to 15.2.5.11815.2.5.1196
17615.2.5.120/2915.2.5.121 to 15.2.5.12615.2.5.1276
17715.2.5.128/2915.2.5.129 to 15.2.5.13415.2.5.1356
17815.2.5.136/2915.2.5.137 to 15.2.5.14215.2.5.1436
17915.2.5.144/2915.2.5.145 to 15.2.5.15015.2.5.1516
18015.2.5.152/2915.2.5.153 to 15.2.5.15815.2.5.1596
18115.2.5.160/2915.2.5.161 to 15.2.5.16615.2.5.1676
18215.2.5.168/2915.2.5.169 to 15.2.5.17415.2.5.1756
18315.2.5.176/2915.2.5.177 to 15.2.5.18215.2.5.1836
18415.2.5.184/2915.2.5.185 to 15.2.5.19015.2.5.1916
18515.2.5.192/2915.2.5.193 to 15.2.5.19815.2.5.1996
18615.2.5.200/2915.2.5.201 to 15.2.5.20615.2.5.2076
18715.2.5.208/2915.2.5.209 to 15.2.5.21415.2.5.2156
18815.2.5.216/2915.2.5.217 to 15.2.5.22215.2.5.2236
18915.2.5.224/2915.2.5.225 to 15.2.5.23015.2.5.2316
19015.2.5.232/2915.2.5.233 to 15.2.5.23815.2.5.2396
19115.2.5.240/2915.2.5.241 to 15.2.5.24615.2.5.2476
19215.2.5.248/2915.2.5.249 to 15.2.5.25415.2.5.2556
19315.2.6.0/2915.2.6.1 to 15.2.6.615.2.6.76
19415.2.6.8/2915.2.6.9 to 15.2.6.1415.2.6.156
19515.2.6.16/2915.2.6.17 to 15.2.6.2215.2.6.236
19615.2.6.24/2915.2.6.25 to 15.2.6.3015.2.6.316
19715.2.6.32/2915.2.6.33 to 15.2.6.3815.2.6.396
19815.2.6.40/2915.2.6.41 to 15.2.6.4615.2.6.476
19915.2.6.48/2915.2.6.49 to 15.2.6.5415.2.6.556
20015.2.6.56/2915.2.6.57 to 15.2.6.6215.2.6.636
20115.2.6.64/2915.2.6.65 to 15.2.6.7015.2.6.716
20215.2.6.72/2915.2.6.73 to 15.2.6.7815.2.6.796
20315.2.6.80/2915.2.6.81 to 15.2.6.8615.2.6.876
20415.2.6.88/2915.2.6.89 to 15.2.6.9415.2.6.956
20515.2.6.96/2915.2.6.97 to 15.2.6.10215.2.6.1036
20615.2.6.104/2915.2.6.105 to 15.2.6.11015.2.6.1116
20715.2.6.112/2915.2.6.113 to 15.2.6.11815.2.6.1196
20815.2.6.120/2915.2.6.121 to 15.2.6.12615.2.6.1276
20915.2.6.128/2915.2.6.129 to 15.2.6.13415.2.6.1356
21015.2.6.136/2915.2.6.137 to 15.2.6.14215.2.6.1436
21115.2.6.144/2915.2.6.145 to 15.2.6.15015.2.6.1516
21215.2.6.152/2915.2.6.153 to 15.2.6.15815.2.6.1596
21315.2.6.160/2915.2.6.161 to 15.2.6.16615.2.6.1676
21415.2.6.168/2915.2.6.169 to 15.2.6.17415.2.6.1756
21515.2.6.176/2915.2.6.177 to 15.2.6.18215.2.6.1836
21615.2.6.184/2915.2.6.185 to 15.2.6.19015.2.6.1916
21715.2.6.192/2915.2.6.193 to 15.2.6.19815.2.6.1996
21815.2.6.200/2915.2.6.201 to 15.2.6.20615.2.6.2076
21915.2.6.208/2915.2.6.209 to 15.2.6.21415.2.6.2156
22015.2.6.216/2915.2.6.217 to 15.2.6.22215.2.6.2236
22115.2.6.224/2915.2.6.225 to 15.2.6.23015.2.6.2316
22215.2.6.232/2915.2.6.233 to 15.2.6.23815.2.6.2396
22315.2.6.240/2915.2.6.241 to 15.2.6.24615.2.6.2476
22415.2.6.248/2915.2.6.249 to 15.2.6.25415.2.6.2556
22515.2.7.0/2915.2.7.1 to 15.2.7.615.2.7.76
22615.2.7.8/2915.2.7.9 to 15.2.7.1415.2.7.156
22715.2.7.16/2915.2.7.17 to 15.2.7.2215.2.7.236
22815.2.7.24/2915.2.7.25 to 15.2.7.3015.2.7.316
22915.2.7.32/2915.2.7.33 to 15.2.7.3815.2.7.396
23015.2.7.40/2915.2.7.41 to 15.2.7.4615.2.7.476
23115.2.7.48/2915.2.7.49 to 15.2.7.5415.2.7.556
23215.2.7.56/2915.2.7.57 to 15.2.7.6215.2.7.636
23315.2.7.64/2915.2.7.65 to 15.2.7.7015.2.7.716
23415.2.7.72/2915.2.7.73 to 15.2.7.7815.2.7.796
23515.2.7.80/2915.2.7.81 to 15.2.7.8615.2.7.876
23615.2.7.88/2915.2.7.89 to 15.2.7.9415.2.7.956
23715.2.7.96/2915.2.7.97 to 15.2.7.10215.2.7.1036
23815.2.7.104/2915.2.7.105 to 15.2.7.11015.2.7.1116
23915.2.7.112/2915.2.7.113 to 15.2.7.11815.2.7.1196
24015.2.7.120/2915.2.7.121 to 15.2.7.12615.2.7.1276
24115.2.7.128/2915.2.7.129 to 15.2.7.13415.2.7.1356
24215.2.7.136/2915.2.7.137 to 15.2.7.14215.2.7.1436
24315.2.7.144/2915.2.7.145 to 15.2.7.15015.2.7.1516
24415.2.7.152/2915.2.7.153 to 15.2.7.15815.2.7.1596
24515.2.7.160/2915.2.7.161 to 15.2.7.16615.2.7.1676
24615.2.7.168/2915.2.7.169 to 15.2.7.17415.2.7.1756
24715.2.7.176/2915.2.7.177 to 15.2.7.18215.2.7.1836
24815.2.7.184/2915.2.7.185 to 15.2.7.19015.2.7.1916
24915.2.7.192/2915.2.7.193 to 15.2.7.19815.2.7.1996
25015.2.7.200/2915.2.7.201 to 15.2.7.20615.2.7.2076
25115.2.7.208/2915.2.7.209 to 15.2.7.21415.2.7.2156
25215.2.7.216/2915.2.7.217 to 15.2.7.22215.2.7.2236
25315.2.7.224/2915.2.7.225 to 15.2.7.23015.2.7.2316
25415.2.7.232/2915.2.7.233 to 15.2.7.23815.2.7.2396
25515.2.7.240/2915.2.7.241 to 15.2.7.24615.2.7.2476
25615.2.7.248/2915.2.7.249 to 15.2.7.25415.2.7.2556

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.