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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.

Network61.4.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
61.4.64.0
Broadcast address
61.4.95.255
First usable
61.4.64.1
Last usable
61.4.95.254
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 3D044000 · Integer 1023688704 to 1023696895
Reverse DNS zones
64.4.61.in-addr.arpa
65.4.61.in-addr.arpa
66.4.61.in-addr.arpa
67.4.61.in-addr.arpa
68.4.61.in-addr.arpa
69.4.61.in-addr.arpa
70.4.61.in-addr.arpa
71.4.61.in-addr.arpa
72.4.61.in-addr.arpa
73.4.61.in-addr.arpa
74.4.61.in-addr.arpa
75.4.61.in-addr.arpa
76.4.61.in-addr.arpa
77.4.61.in-addr.arpa
78.4.61.in-addr.arpa
79.4.61.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
Address00111101.00000100.01000000.0000000061.4.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network00111101.00000100.01000000.0000000061.4.64.0
Broadcast00111101.00000100.01011111.1111111161.4.95.255
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)

61.4.64.0/19 makes 1,024 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
161.4.64.0/2961.4.64.1 to 61.4.64.661.4.64.76
261.4.64.8/2961.4.64.9 to 61.4.64.1461.4.64.156
361.4.64.16/2961.4.64.17 to 61.4.64.2261.4.64.236
461.4.64.24/2961.4.64.25 to 61.4.64.3061.4.64.316
561.4.64.32/2961.4.64.33 to 61.4.64.3861.4.64.396
661.4.64.40/2961.4.64.41 to 61.4.64.4661.4.64.476
761.4.64.48/2961.4.64.49 to 61.4.64.5461.4.64.556
861.4.64.56/2961.4.64.57 to 61.4.64.6261.4.64.636
961.4.64.64/2961.4.64.65 to 61.4.64.7061.4.64.716
1061.4.64.72/2961.4.64.73 to 61.4.64.7861.4.64.796
1161.4.64.80/2961.4.64.81 to 61.4.64.8661.4.64.876
1261.4.64.88/2961.4.64.89 to 61.4.64.9461.4.64.956
1361.4.64.96/2961.4.64.97 to 61.4.64.10261.4.64.1036
1461.4.64.104/2961.4.64.105 to 61.4.64.11061.4.64.1116
1561.4.64.112/2961.4.64.113 to 61.4.64.11861.4.64.1196
1661.4.64.120/2961.4.64.121 to 61.4.64.12661.4.64.1276
1761.4.64.128/2961.4.64.129 to 61.4.64.13461.4.64.1356
1861.4.64.136/2961.4.64.137 to 61.4.64.14261.4.64.1436
1961.4.64.144/2961.4.64.145 to 61.4.64.15061.4.64.1516
2061.4.64.152/2961.4.64.153 to 61.4.64.15861.4.64.1596
2161.4.64.160/2961.4.64.161 to 61.4.64.16661.4.64.1676
2261.4.64.168/2961.4.64.169 to 61.4.64.17461.4.64.1756
2361.4.64.176/2961.4.64.177 to 61.4.64.18261.4.64.1836
2461.4.64.184/2961.4.64.185 to 61.4.64.19061.4.64.1916
2561.4.64.192/2961.4.64.193 to 61.4.64.19861.4.64.1996
2661.4.64.200/2961.4.64.201 to 61.4.64.20661.4.64.2076
2761.4.64.208/2961.4.64.209 to 61.4.64.21461.4.64.2156
2861.4.64.216/2961.4.64.217 to 61.4.64.22261.4.64.2236
2961.4.64.224/2961.4.64.225 to 61.4.64.23061.4.64.2316
3061.4.64.232/2961.4.64.233 to 61.4.64.23861.4.64.2396
3161.4.64.240/2961.4.64.241 to 61.4.64.24661.4.64.2476
3261.4.64.248/2961.4.64.249 to 61.4.64.25461.4.64.2556
3361.4.65.0/2961.4.65.1 to 61.4.65.661.4.65.76
3461.4.65.8/2961.4.65.9 to 61.4.65.1461.4.65.156
3561.4.65.16/2961.4.65.17 to 61.4.65.2261.4.65.236
3661.4.65.24/2961.4.65.25 to 61.4.65.3061.4.65.316
3761.4.65.32/2961.4.65.33 to 61.4.65.3861.4.65.396
3861.4.65.40/2961.4.65.41 to 61.4.65.4661.4.65.476
3961.4.65.48/2961.4.65.49 to 61.4.65.5461.4.65.556
4061.4.65.56/2961.4.65.57 to 61.4.65.6261.4.65.636
4161.4.65.64/2961.4.65.65 to 61.4.65.7061.4.65.716
4261.4.65.72/2961.4.65.73 to 61.4.65.7861.4.65.796
4361.4.65.80/2961.4.65.81 to 61.4.65.8661.4.65.876
4461.4.65.88/2961.4.65.89 to 61.4.65.9461.4.65.956
4561.4.65.96/2961.4.65.97 to 61.4.65.10261.4.65.1036
4661.4.65.104/2961.4.65.105 to 61.4.65.11061.4.65.1116
4761.4.65.112/2961.4.65.113 to 61.4.65.11861.4.65.1196
4861.4.65.120/2961.4.65.121 to 61.4.65.12661.4.65.1276
4961.4.65.128/2961.4.65.129 to 61.4.65.13461.4.65.1356
5061.4.65.136/2961.4.65.137 to 61.4.65.14261.4.65.1436
5161.4.65.144/2961.4.65.145 to 61.4.65.15061.4.65.1516
5261.4.65.152/2961.4.65.153 to 61.4.65.15861.4.65.1596
5361.4.65.160/2961.4.65.161 to 61.4.65.16661.4.65.1676
5461.4.65.168/2961.4.65.169 to 61.4.65.17461.4.65.1756
5561.4.65.176/2961.4.65.177 to 61.4.65.18261.4.65.1836
5661.4.65.184/2961.4.65.185 to 61.4.65.19061.4.65.1916
5761.4.65.192/2961.4.65.193 to 61.4.65.19861.4.65.1996
5861.4.65.200/2961.4.65.201 to 61.4.65.20661.4.65.2076
5961.4.65.208/2961.4.65.209 to 61.4.65.21461.4.65.2156
6061.4.65.216/2961.4.65.217 to 61.4.65.22261.4.65.2236
6161.4.65.224/2961.4.65.225 to 61.4.65.23061.4.65.2316
6261.4.65.232/2961.4.65.233 to 61.4.65.23861.4.65.2396
6361.4.65.240/2961.4.65.241 to 61.4.65.24661.4.65.2476
6461.4.65.248/2961.4.65.249 to 61.4.65.25461.4.65.2556
6561.4.66.0/2961.4.66.1 to 61.4.66.661.4.66.76
6661.4.66.8/2961.4.66.9 to 61.4.66.1461.4.66.156
6761.4.66.16/2961.4.66.17 to 61.4.66.2261.4.66.236
6861.4.66.24/2961.4.66.25 to 61.4.66.3061.4.66.316
6961.4.66.32/2961.4.66.33 to 61.4.66.3861.4.66.396
7061.4.66.40/2961.4.66.41 to 61.4.66.4661.4.66.476
7161.4.66.48/2961.4.66.49 to 61.4.66.5461.4.66.556
7261.4.66.56/2961.4.66.57 to 61.4.66.6261.4.66.636
7361.4.66.64/2961.4.66.65 to 61.4.66.7061.4.66.716
7461.4.66.72/2961.4.66.73 to 61.4.66.7861.4.66.796
7561.4.66.80/2961.4.66.81 to 61.4.66.8661.4.66.876
7661.4.66.88/2961.4.66.89 to 61.4.66.9461.4.66.956
7761.4.66.96/2961.4.66.97 to 61.4.66.10261.4.66.1036
7861.4.66.104/2961.4.66.105 to 61.4.66.11061.4.66.1116
7961.4.66.112/2961.4.66.113 to 61.4.66.11861.4.66.1196
8061.4.66.120/2961.4.66.121 to 61.4.66.12661.4.66.1276
8161.4.66.128/2961.4.66.129 to 61.4.66.13461.4.66.1356
8261.4.66.136/2961.4.66.137 to 61.4.66.14261.4.66.1436
8361.4.66.144/2961.4.66.145 to 61.4.66.15061.4.66.1516
8461.4.66.152/2961.4.66.153 to 61.4.66.15861.4.66.1596
8561.4.66.160/2961.4.66.161 to 61.4.66.16661.4.66.1676
8661.4.66.168/2961.4.66.169 to 61.4.66.17461.4.66.1756
8761.4.66.176/2961.4.66.177 to 61.4.66.18261.4.66.1836
8861.4.66.184/2961.4.66.185 to 61.4.66.19061.4.66.1916
8961.4.66.192/2961.4.66.193 to 61.4.66.19861.4.66.1996
9061.4.66.200/2961.4.66.201 to 61.4.66.20661.4.66.2076
9161.4.66.208/2961.4.66.209 to 61.4.66.21461.4.66.2156
9261.4.66.216/2961.4.66.217 to 61.4.66.22261.4.66.2236
9361.4.66.224/2961.4.66.225 to 61.4.66.23061.4.66.2316
9461.4.66.232/2961.4.66.233 to 61.4.66.23861.4.66.2396
9561.4.66.240/2961.4.66.241 to 61.4.66.24661.4.66.2476
9661.4.66.248/2961.4.66.249 to 61.4.66.25461.4.66.2556
9761.4.67.0/2961.4.67.1 to 61.4.67.661.4.67.76
9861.4.67.8/2961.4.67.9 to 61.4.67.1461.4.67.156
9961.4.67.16/2961.4.67.17 to 61.4.67.2261.4.67.236
10061.4.67.24/2961.4.67.25 to 61.4.67.3061.4.67.316
10161.4.67.32/2961.4.67.33 to 61.4.67.3861.4.67.396
10261.4.67.40/2961.4.67.41 to 61.4.67.4661.4.67.476
10361.4.67.48/2961.4.67.49 to 61.4.67.5461.4.67.556
10461.4.67.56/2961.4.67.57 to 61.4.67.6261.4.67.636
10561.4.67.64/2961.4.67.65 to 61.4.67.7061.4.67.716
10661.4.67.72/2961.4.67.73 to 61.4.67.7861.4.67.796
10761.4.67.80/2961.4.67.81 to 61.4.67.8661.4.67.876
10861.4.67.88/2961.4.67.89 to 61.4.67.9461.4.67.956
10961.4.67.96/2961.4.67.97 to 61.4.67.10261.4.67.1036
11061.4.67.104/2961.4.67.105 to 61.4.67.11061.4.67.1116
11161.4.67.112/2961.4.67.113 to 61.4.67.11861.4.67.1196
11261.4.67.120/2961.4.67.121 to 61.4.67.12661.4.67.1276
11361.4.67.128/2961.4.67.129 to 61.4.67.13461.4.67.1356
11461.4.67.136/2961.4.67.137 to 61.4.67.14261.4.67.1436
11561.4.67.144/2961.4.67.145 to 61.4.67.15061.4.67.1516
11661.4.67.152/2961.4.67.153 to 61.4.67.15861.4.67.1596
11761.4.67.160/2961.4.67.161 to 61.4.67.16661.4.67.1676
11861.4.67.168/2961.4.67.169 to 61.4.67.17461.4.67.1756
11961.4.67.176/2961.4.67.177 to 61.4.67.18261.4.67.1836
12061.4.67.184/2961.4.67.185 to 61.4.67.19061.4.67.1916
12161.4.67.192/2961.4.67.193 to 61.4.67.19861.4.67.1996
12261.4.67.200/2961.4.67.201 to 61.4.67.20661.4.67.2076
12361.4.67.208/2961.4.67.209 to 61.4.67.21461.4.67.2156
12461.4.67.216/2961.4.67.217 to 61.4.67.22261.4.67.2236
12561.4.67.224/2961.4.67.225 to 61.4.67.23061.4.67.2316
12661.4.67.232/2961.4.67.233 to 61.4.67.23861.4.67.2396
12761.4.67.240/2961.4.67.241 to 61.4.67.24661.4.67.2476
12861.4.67.248/2961.4.67.249 to 61.4.67.25461.4.67.2556
12961.4.68.0/2961.4.68.1 to 61.4.68.661.4.68.76
13061.4.68.8/2961.4.68.9 to 61.4.68.1461.4.68.156
13161.4.68.16/2961.4.68.17 to 61.4.68.2261.4.68.236
13261.4.68.24/2961.4.68.25 to 61.4.68.3061.4.68.316
13361.4.68.32/2961.4.68.33 to 61.4.68.3861.4.68.396
13461.4.68.40/2961.4.68.41 to 61.4.68.4661.4.68.476
13561.4.68.48/2961.4.68.49 to 61.4.68.5461.4.68.556
13661.4.68.56/2961.4.68.57 to 61.4.68.6261.4.68.636
13761.4.68.64/2961.4.68.65 to 61.4.68.7061.4.68.716
13861.4.68.72/2961.4.68.73 to 61.4.68.7861.4.68.796
13961.4.68.80/2961.4.68.81 to 61.4.68.8661.4.68.876
14061.4.68.88/2961.4.68.89 to 61.4.68.9461.4.68.956
14161.4.68.96/2961.4.68.97 to 61.4.68.10261.4.68.1036
14261.4.68.104/2961.4.68.105 to 61.4.68.11061.4.68.1116
14361.4.68.112/2961.4.68.113 to 61.4.68.11861.4.68.1196
14461.4.68.120/2961.4.68.121 to 61.4.68.12661.4.68.1276
14561.4.68.128/2961.4.68.129 to 61.4.68.13461.4.68.1356
14661.4.68.136/2961.4.68.137 to 61.4.68.14261.4.68.1436
14761.4.68.144/2961.4.68.145 to 61.4.68.15061.4.68.1516
14861.4.68.152/2961.4.68.153 to 61.4.68.15861.4.68.1596
14961.4.68.160/2961.4.68.161 to 61.4.68.16661.4.68.1676
15061.4.68.168/2961.4.68.169 to 61.4.68.17461.4.68.1756
15161.4.68.176/2961.4.68.177 to 61.4.68.18261.4.68.1836
15261.4.68.184/2961.4.68.185 to 61.4.68.19061.4.68.1916
15361.4.68.192/2961.4.68.193 to 61.4.68.19861.4.68.1996
15461.4.68.200/2961.4.68.201 to 61.4.68.20661.4.68.2076
15561.4.68.208/2961.4.68.209 to 61.4.68.21461.4.68.2156
15661.4.68.216/2961.4.68.217 to 61.4.68.22261.4.68.2236
15761.4.68.224/2961.4.68.225 to 61.4.68.23061.4.68.2316
15861.4.68.232/2961.4.68.233 to 61.4.68.23861.4.68.2396
15961.4.68.240/2961.4.68.241 to 61.4.68.24661.4.68.2476
16061.4.68.248/2961.4.68.249 to 61.4.68.25461.4.68.2556
16161.4.69.0/2961.4.69.1 to 61.4.69.661.4.69.76
16261.4.69.8/2961.4.69.9 to 61.4.69.1461.4.69.156
16361.4.69.16/2961.4.69.17 to 61.4.69.2261.4.69.236
16461.4.69.24/2961.4.69.25 to 61.4.69.3061.4.69.316
16561.4.69.32/2961.4.69.33 to 61.4.69.3861.4.69.396
16661.4.69.40/2961.4.69.41 to 61.4.69.4661.4.69.476
16761.4.69.48/2961.4.69.49 to 61.4.69.5461.4.69.556
16861.4.69.56/2961.4.69.57 to 61.4.69.6261.4.69.636
16961.4.69.64/2961.4.69.65 to 61.4.69.7061.4.69.716
17061.4.69.72/2961.4.69.73 to 61.4.69.7861.4.69.796
17161.4.69.80/2961.4.69.81 to 61.4.69.8661.4.69.876
17261.4.69.88/2961.4.69.89 to 61.4.69.9461.4.69.956
17361.4.69.96/2961.4.69.97 to 61.4.69.10261.4.69.1036
17461.4.69.104/2961.4.69.105 to 61.4.69.11061.4.69.1116
17561.4.69.112/2961.4.69.113 to 61.4.69.11861.4.69.1196
17661.4.69.120/2961.4.69.121 to 61.4.69.12661.4.69.1276
17761.4.69.128/2961.4.69.129 to 61.4.69.13461.4.69.1356
17861.4.69.136/2961.4.69.137 to 61.4.69.14261.4.69.1436
17961.4.69.144/2961.4.69.145 to 61.4.69.15061.4.69.1516
18061.4.69.152/2961.4.69.153 to 61.4.69.15861.4.69.1596
18161.4.69.160/2961.4.69.161 to 61.4.69.16661.4.69.1676
18261.4.69.168/2961.4.69.169 to 61.4.69.17461.4.69.1756
18361.4.69.176/2961.4.69.177 to 61.4.69.18261.4.69.1836
18461.4.69.184/2961.4.69.185 to 61.4.69.19061.4.69.1916
18561.4.69.192/2961.4.69.193 to 61.4.69.19861.4.69.1996
18661.4.69.200/2961.4.69.201 to 61.4.69.20661.4.69.2076
18761.4.69.208/2961.4.69.209 to 61.4.69.21461.4.69.2156
18861.4.69.216/2961.4.69.217 to 61.4.69.22261.4.69.2236
18961.4.69.224/2961.4.69.225 to 61.4.69.23061.4.69.2316
19061.4.69.232/2961.4.69.233 to 61.4.69.23861.4.69.2396
19161.4.69.240/2961.4.69.241 to 61.4.69.24661.4.69.2476
19261.4.69.248/2961.4.69.249 to 61.4.69.25461.4.69.2556
19361.4.70.0/2961.4.70.1 to 61.4.70.661.4.70.76
19461.4.70.8/2961.4.70.9 to 61.4.70.1461.4.70.156
19561.4.70.16/2961.4.70.17 to 61.4.70.2261.4.70.236
19661.4.70.24/2961.4.70.25 to 61.4.70.3061.4.70.316
19761.4.70.32/2961.4.70.33 to 61.4.70.3861.4.70.396
19861.4.70.40/2961.4.70.41 to 61.4.70.4661.4.70.476
19961.4.70.48/2961.4.70.49 to 61.4.70.5461.4.70.556
20061.4.70.56/2961.4.70.57 to 61.4.70.6261.4.70.636
20161.4.70.64/2961.4.70.65 to 61.4.70.7061.4.70.716
20261.4.70.72/2961.4.70.73 to 61.4.70.7861.4.70.796
20361.4.70.80/2961.4.70.81 to 61.4.70.8661.4.70.876
20461.4.70.88/2961.4.70.89 to 61.4.70.9461.4.70.956
20561.4.70.96/2961.4.70.97 to 61.4.70.10261.4.70.1036
20661.4.70.104/2961.4.70.105 to 61.4.70.11061.4.70.1116
20761.4.70.112/2961.4.70.113 to 61.4.70.11861.4.70.1196
20861.4.70.120/2961.4.70.121 to 61.4.70.12661.4.70.1276
20961.4.70.128/2961.4.70.129 to 61.4.70.13461.4.70.1356
21061.4.70.136/2961.4.70.137 to 61.4.70.14261.4.70.1436
21161.4.70.144/2961.4.70.145 to 61.4.70.15061.4.70.1516
21261.4.70.152/2961.4.70.153 to 61.4.70.15861.4.70.1596
21361.4.70.160/2961.4.70.161 to 61.4.70.16661.4.70.1676
21461.4.70.168/2961.4.70.169 to 61.4.70.17461.4.70.1756
21561.4.70.176/2961.4.70.177 to 61.4.70.18261.4.70.1836
21661.4.70.184/2961.4.70.185 to 61.4.70.19061.4.70.1916
21761.4.70.192/2961.4.70.193 to 61.4.70.19861.4.70.1996
21861.4.70.200/2961.4.70.201 to 61.4.70.20661.4.70.2076
21961.4.70.208/2961.4.70.209 to 61.4.70.21461.4.70.2156
22061.4.70.216/2961.4.70.217 to 61.4.70.22261.4.70.2236
22161.4.70.224/2961.4.70.225 to 61.4.70.23061.4.70.2316
22261.4.70.232/2961.4.70.233 to 61.4.70.23861.4.70.2396
22361.4.70.240/2961.4.70.241 to 61.4.70.24661.4.70.2476
22461.4.70.248/2961.4.70.249 to 61.4.70.25461.4.70.2556
22561.4.71.0/2961.4.71.1 to 61.4.71.661.4.71.76
22661.4.71.8/2961.4.71.9 to 61.4.71.1461.4.71.156
22761.4.71.16/2961.4.71.17 to 61.4.71.2261.4.71.236
22861.4.71.24/2961.4.71.25 to 61.4.71.3061.4.71.316
22961.4.71.32/2961.4.71.33 to 61.4.71.3861.4.71.396
23061.4.71.40/2961.4.71.41 to 61.4.71.4661.4.71.476
23161.4.71.48/2961.4.71.49 to 61.4.71.5461.4.71.556
23261.4.71.56/2961.4.71.57 to 61.4.71.6261.4.71.636
23361.4.71.64/2961.4.71.65 to 61.4.71.7061.4.71.716
23461.4.71.72/2961.4.71.73 to 61.4.71.7861.4.71.796
23561.4.71.80/2961.4.71.81 to 61.4.71.8661.4.71.876
23661.4.71.88/2961.4.71.89 to 61.4.71.9461.4.71.956
23761.4.71.96/2961.4.71.97 to 61.4.71.10261.4.71.1036
23861.4.71.104/2961.4.71.105 to 61.4.71.11061.4.71.1116
23961.4.71.112/2961.4.71.113 to 61.4.71.11861.4.71.1196
24061.4.71.120/2961.4.71.121 to 61.4.71.12661.4.71.1276
24161.4.71.128/2961.4.71.129 to 61.4.71.13461.4.71.1356
24261.4.71.136/2961.4.71.137 to 61.4.71.14261.4.71.1436
24361.4.71.144/2961.4.71.145 to 61.4.71.15061.4.71.1516
24461.4.71.152/2961.4.71.153 to 61.4.71.15861.4.71.1596
24561.4.71.160/2961.4.71.161 to 61.4.71.16661.4.71.1676
24661.4.71.168/2961.4.71.169 to 61.4.71.17461.4.71.1756
24761.4.71.176/2961.4.71.177 to 61.4.71.18261.4.71.1836
24861.4.71.184/2961.4.71.185 to 61.4.71.19061.4.71.1916
24961.4.71.192/2961.4.71.193 to 61.4.71.19861.4.71.1996
25061.4.71.200/2961.4.71.201 to 61.4.71.20661.4.71.2076
25161.4.71.208/2961.4.71.209 to 61.4.71.21461.4.71.2156
25261.4.71.216/2961.4.71.217 to 61.4.71.22261.4.71.2236
25361.4.71.224/2961.4.71.225 to 61.4.71.23061.4.71.2316
25461.4.71.232/2961.4.71.233 to 61.4.71.23861.4.71.2396
25561.4.71.240/2961.4.71.241 to 61.4.71.24661.4.71.2476
25661.4.71.248/2961.4.71.249 to 61.4.71.25461.4.71.2556

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.