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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.

Network55.41.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
55.41.64.0
Broadcast address
55.41.127.255
First usable
55.41.64.1
Last usable
55.41.127.254
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 37294000 · Integer 925450240 to 925466623
Reverse DNS zones
64.41.55.in-addr.arpa
65.41.55.in-addr.arpa
66.41.55.in-addr.arpa
67.41.55.in-addr.arpa
68.41.55.in-addr.arpa
69.41.55.in-addr.arpa
70.41.55.in-addr.arpa
71.41.55.in-addr.arpa
72.41.55.in-addr.arpa
73.41.55.in-addr.arpa
74.41.55.in-addr.arpa
75.41.55.in-addr.arpa
76.41.55.in-addr.arpa
77.41.55.in-addr.arpa
78.41.55.in-addr.arpa
79.41.55.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
Address00110111.00101001.01000000.0000000055.41.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00110111.00101001.01000000.0000000055.41.64.0
Broadcast00110111.00101001.01111111.1111111155.41.127.255
Split into smaller subnets/29
/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)

55.41.64.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
155.41.64.0/2955.41.64.1 to 55.41.64.655.41.64.76
255.41.64.8/2955.41.64.9 to 55.41.64.1455.41.64.156
355.41.64.16/2955.41.64.17 to 55.41.64.2255.41.64.236
455.41.64.24/2955.41.64.25 to 55.41.64.3055.41.64.316
555.41.64.32/2955.41.64.33 to 55.41.64.3855.41.64.396
655.41.64.40/2955.41.64.41 to 55.41.64.4655.41.64.476
755.41.64.48/2955.41.64.49 to 55.41.64.5455.41.64.556
855.41.64.56/2955.41.64.57 to 55.41.64.6255.41.64.636
955.41.64.64/2955.41.64.65 to 55.41.64.7055.41.64.716
1055.41.64.72/2955.41.64.73 to 55.41.64.7855.41.64.796
1155.41.64.80/2955.41.64.81 to 55.41.64.8655.41.64.876
1255.41.64.88/2955.41.64.89 to 55.41.64.9455.41.64.956
1355.41.64.96/2955.41.64.97 to 55.41.64.10255.41.64.1036
1455.41.64.104/2955.41.64.105 to 55.41.64.11055.41.64.1116
1555.41.64.112/2955.41.64.113 to 55.41.64.11855.41.64.1196
1655.41.64.120/2955.41.64.121 to 55.41.64.12655.41.64.1276
1755.41.64.128/2955.41.64.129 to 55.41.64.13455.41.64.1356
1855.41.64.136/2955.41.64.137 to 55.41.64.14255.41.64.1436
1955.41.64.144/2955.41.64.145 to 55.41.64.15055.41.64.1516
2055.41.64.152/2955.41.64.153 to 55.41.64.15855.41.64.1596
2155.41.64.160/2955.41.64.161 to 55.41.64.16655.41.64.1676
2255.41.64.168/2955.41.64.169 to 55.41.64.17455.41.64.1756
2355.41.64.176/2955.41.64.177 to 55.41.64.18255.41.64.1836
2455.41.64.184/2955.41.64.185 to 55.41.64.19055.41.64.1916
2555.41.64.192/2955.41.64.193 to 55.41.64.19855.41.64.1996
2655.41.64.200/2955.41.64.201 to 55.41.64.20655.41.64.2076
2755.41.64.208/2955.41.64.209 to 55.41.64.21455.41.64.2156
2855.41.64.216/2955.41.64.217 to 55.41.64.22255.41.64.2236
2955.41.64.224/2955.41.64.225 to 55.41.64.23055.41.64.2316
3055.41.64.232/2955.41.64.233 to 55.41.64.23855.41.64.2396
3155.41.64.240/2955.41.64.241 to 55.41.64.24655.41.64.2476
3255.41.64.248/2955.41.64.249 to 55.41.64.25455.41.64.2556
3355.41.65.0/2955.41.65.1 to 55.41.65.655.41.65.76
3455.41.65.8/2955.41.65.9 to 55.41.65.1455.41.65.156
3555.41.65.16/2955.41.65.17 to 55.41.65.2255.41.65.236
3655.41.65.24/2955.41.65.25 to 55.41.65.3055.41.65.316
3755.41.65.32/2955.41.65.33 to 55.41.65.3855.41.65.396
3855.41.65.40/2955.41.65.41 to 55.41.65.4655.41.65.476
3955.41.65.48/2955.41.65.49 to 55.41.65.5455.41.65.556
4055.41.65.56/2955.41.65.57 to 55.41.65.6255.41.65.636
4155.41.65.64/2955.41.65.65 to 55.41.65.7055.41.65.716
4255.41.65.72/2955.41.65.73 to 55.41.65.7855.41.65.796
4355.41.65.80/2955.41.65.81 to 55.41.65.8655.41.65.876
4455.41.65.88/2955.41.65.89 to 55.41.65.9455.41.65.956
4555.41.65.96/2955.41.65.97 to 55.41.65.10255.41.65.1036
4655.41.65.104/2955.41.65.105 to 55.41.65.11055.41.65.1116
4755.41.65.112/2955.41.65.113 to 55.41.65.11855.41.65.1196
4855.41.65.120/2955.41.65.121 to 55.41.65.12655.41.65.1276
4955.41.65.128/2955.41.65.129 to 55.41.65.13455.41.65.1356
5055.41.65.136/2955.41.65.137 to 55.41.65.14255.41.65.1436
5155.41.65.144/2955.41.65.145 to 55.41.65.15055.41.65.1516
5255.41.65.152/2955.41.65.153 to 55.41.65.15855.41.65.1596
5355.41.65.160/2955.41.65.161 to 55.41.65.16655.41.65.1676
5455.41.65.168/2955.41.65.169 to 55.41.65.17455.41.65.1756
5555.41.65.176/2955.41.65.177 to 55.41.65.18255.41.65.1836
5655.41.65.184/2955.41.65.185 to 55.41.65.19055.41.65.1916
5755.41.65.192/2955.41.65.193 to 55.41.65.19855.41.65.1996
5855.41.65.200/2955.41.65.201 to 55.41.65.20655.41.65.2076
5955.41.65.208/2955.41.65.209 to 55.41.65.21455.41.65.2156
6055.41.65.216/2955.41.65.217 to 55.41.65.22255.41.65.2236
6155.41.65.224/2955.41.65.225 to 55.41.65.23055.41.65.2316
6255.41.65.232/2955.41.65.233 to 55.41.65.23855.41.65.2396
6355.41.65.240/2955.41.65.241 to 55.41.65.24655.41.65.2476
6455.41.65.248/2955.41.65.249 to 55.41.65.25455.41.65.2556
6555.41.66.0/2955.41.66.1 to 55.41.66.655.41.66.76
6655.41.66.8/2955.41.66.9 to 55.41.66.1455.41.66.156
6755.41.66.16/2955.41.66.17 to 55.41.66.2255.41.66.236
6855.41.66.24/2955.41.66.25 to 55.41.66.3055.41.66.316
6955.41.66.32/2955.41.66.33 to 55.41.66.3855.41.66.396
7055.41.66.40/2955.41.66.41 to 55.41.66.4655.41.66.476
7155.41.66.48/2955.41.66.49 to 55.41.66.5455.41.66.556
7255.41.66.56/2955.41.66.57 to 55.41.66.6255.41.66.636
7355.41.66.64/2955.41.66.65 to 55.41.66.7055.41.66.716
7455.41.66.72/2955.41.66.73 to 55.41.66.7855.41.66.796
7555.41.66.80/2955.41.66.81 to 55.41.66.8655.41.66.876
7655.41.66.88/2955.41.66.89 to 55.41.66.9455.41.66.956
7755.41.66.96/2955.41.66.97 to 55.41.66.10255.41.66.1036
7855.41.66.104/2955.41.66.105 to 55.41.66.11055.41.66.1116
7955.41.66.112/2955.41.66.113 to 55.41.66.11855.41.66.1196
8055.41.66.120/2955.41.66.121 to 55.41.66.12655.41.66.1276
8155.41.66.128/2955.41.66.129 to 55.41.66.13455.41.66.1356
8255.41.66.136/2955.41.66.137 to 55.41.66.14255.41.66.1436
8355.41.66.144/2955.41.66.145 to 55.41.66.15055.41.66.1516
8455.41.66.152/2955.41.66.153 to 55.41.66.15855.41.66.1596
8555.41.66.160/2955.41.66.161 to 55.41.66.16655.41.66.1676
8655.41.66.168/2955.41.66.169 to 55.41.66.17455.41.66.1756
8755.41.66.176/2955.41.66.177 to 55.41.66.18255.41.66.1836
8855.41.66.184/2955.41.66.185 to 55.41.66.19055.41.66.1916
8955.41.66.192/2955.41.66.193 to 55.41.66.19855.41.66.1996
9055.41.66.200/2955.41.66.201 to 55.41.66.20655.41.66.2076
9155.41.66.208/2955.41.66.209 to 55.41.66.21455.41.66.2156
9255.41.66.216/2955.41.66.217 to 55.41.66.22255.41.66.2236
9355.41.66.224/2955.41.66.225 to 55.41.66.23055.41.66.2316
9455.41.66.232/2955.41.66.233 to 55.41.66.23855.41.66.2396
9555.41.66.240/2955.41.66.241 to 55.41.66.24655.41.66.2476
9655.41.66.248/2955.41.66.249 to 55.41.66.25455.41.66.2556
9755.41.67.0/2955.41.67.1 to 55.41.67.655.41.67.76
9855.41.67.8/2955.41.67.9 to 55.41.67.1455.41.67.156
9955.41.67.16/2955.41.67.17 to 55.41.67.2255.41.67.236
10055.41.67.24/2955.41.67.25 to 55.41.67.3055.41.67.316
10155.41.67.32/2955.41.67.33 to 55.41.67.3855.41.67.396
10255.41.67.40/2955.41.67.41 to 55.41.67.4655.41.67.476
10355.41.67.48/2955.41.67.49 to 55.41.67.5455.41.67.556
10455.41.67.56/2955.41.67.57 to 55.41.67.6255.41.67.636
10555.41.67.64/2955.41.67.65 to 55.41.67.7055.41.67.716
10655.41.67.72/2955.41.67.73 to 55.41.67.7855.41.67.796
10755.41.67.80/2955.41.67.81 to 55.41.67.8655.41.67.876
10855.41.67.88/2955.41.67.89 to 55.41.67.9455.41.67.956
10955.41.67.96/2955.41.67.97 to 55.41.67.10255.41.67.1036
11055.41.67.104/2955.41.67.105 to 55.41.67.11055.41.67.1116
11155.41.67.112/2955.41.67.113 to 55.41.67.11855.41.67.1196
11255.41.67.120/2955.41.67.121 to 55.41.67.12655.41.67.1276
11355.41.67.128/2955.41.67.129 to 55.41.67.13455.41.67.1356
11455.41.67.136/2955.41.67.137 to 55.41.67.14255.41.67.1436
11555.41.67.144/2955.41.67.145 to 55.41.67.15055.41.67.1516
11655.41.67.152/2955.41.67.153 to 55.41.67.15855.41.67.1596
11755.41.67.160/2955.41.67.161 to 55.41.67.16655.41.67.1676
11855.41.67.168/2955.41.67.169 to 55.41.67.17455.41.67.1756
11955.41.67.176/2955.41.67.177 to 55.41.67.18255.41.67.1836
12055.41.67.184/2955.41.67.185 to 55.41.67.19055.41.67.1916
12155.41.67.192/2955.41.67.193 to 55.41.67.19855.41.67.1996
12255.41.67.200/2955.41.67.201 to 55.41.67.20655.41.67.2076
12355.41.67.208/2955.41.67.209 to 55.41.67.21455.41.67.2156
12455.41.67.216/2955.41.67.217 to 55.41.67.22255.41.67.2236
12555.41.67.224/2955.41.67.225 to 55.41.67.23055.41.67.2316
12655.41.67.232/2955.41.67.233 to 55.41.67.23855.41.67.2396
12755.41.67.240/2955.41.67.241 to 55.41.67.24655.41.67.2476
12855.41.67.248/2955.41.67.249 to 55.41.67.25455.41.67.2556
12955.41.68.0/2955.41.68.1 to 55.41.68.655.41.68.76
13055.41.68.8/2955.41.68.9 to 55.41.68.1455.41.68.156
13155.41.68.16/2955.41.68.17 to 55.41.68.2255.41.68.236
13255.41.68.24/2955.41.68.25 to 55.41.68.3055.41.68.316
13355.41.68.32/2955.41.68.33 to 55.41.68.3855.41.68.396
13455.41.68.40/2955.41.68.41 to 55.41.68.4655.41.68.476
13555.41.68.48/2955.41.68.49 to 55.41.68.5455.41.68.556
13655.41.68.56/2955.41.68.57 to 55.41.68.6255.41.68.636
13755.41.68.64/2955.41.68.65 to 55.41.68.7055.41.68.716
13855.41.68.72/2955.41.68.73 to 55.41.68.7855.41.68.796
13955.41.68.80/2955.41.68.81 to 55.41.68.8655.41.68.876
14055.41.68.88/2955.41.68.89 to 55.41.68.9455.41.68.956
14155.41.68.96/2955.41.68.97 to 55.41.68.10255.41.68.1036
14255.41.68.104/2955.41.68.105 to 55.41.68.11055.41.68.1116
14355.41.68.112/2955.41.68.113 to 55.41.68.11855.41.68.1196
14455.41.68.120/2955.41.68.121 to 55.41.68.12655.41.68.1276
14555.41.68.128/2955.41.68.129 to 55.41.68.13455.41.68.1356
14655.41.68.136/2955.41.68.137 to 55.41.68.14255.41.68.1436
14755.41.68.144/2955.41.68.145 to 55.41.68.15055.41.68.1516
14855.41.68.152/2955.41.68.153 to 55.41.68.15855.41.68.1596
14955.41.68.160/2955.41.68.161 to 55.41.68.16655.41.68.1676
15055.41.68.168/2955.41.68.169 to 55.41.68.17455.41.68.1756
15155.41.68.176/2955.41.68.177 to 55.41.68.18255.41.68.1836
15255.41.68.184/2955.41.68.185 to 55.41.68.19055.41.68.1916
15355.41.68.192/2955.41.68.193 to 55.41.68.19855.41.68.1996
15455.41.68.200/2955.41.68.201 to 55.41.68.20655.41.68.2076
15555.41.68.208/2955.41.68.209 to 55.41.68.21455.41.68.2156
15655.41.68.216/2955.41.68.217 to 55.41.68.22255.41.68.2236
15755.41.68.224/2955.41.68.225 to 55.41.68.23055.41.68.2316
15855.41.68.232/2955.41.68.233 to 55.41.68.23855.41.68.2396
15955.41.68.240/2955.41.68.241 to 55.41.68.24655.41.68.2476
16055.41.68.248/2955.41.68.249 to 55.41.68.25455.41.68.2556
16155.41.69.0/2955.41.69.1 to 55.41.69.655.41.69.76
16255.41.69.8/2955.41.69.9 to 55.41.69.1455.41.69.156
16355.41.69.16/2955.41.69.17 to 55.41.69.2255.41.69.236
16455.41.69.24/2955.41.69.25 to 55.41.69.3055.41.69.316
16555.41.69.32/2955.41.69.33 to 55.41.69.3855.41.69.396
16655.41.69.40/2955.41.69.41 to 55.41.69.4655.41.69.476
16755.41.69.48/2955.41.69.49 to 55.41.69.5455.41.69.556
16855.41.69.56/2955.41.69.57 to 55.41.69.6255.41.69.636
16955.41.69.64/2955.41.69.65 to 55.41.69.7055.41.69.716
17055.41.69.72/2955.41.69.73 to 55.41.69.7855.41.69.796
17155.41.69.80/2955.41.69.81 to 55.41.69.8655.41.69.876
17255.41.69.88/2955.41.69.89 to 55.41.69.9455.41.69.956
17355.41.69.96/2955.41.69.97 to 55.41.69.10255.41.69.1036
17455.41.69.104/2955.41.69.105 to 55.41.69.11055.41.69.1116
17555.41.69.112/2955.41.69.113 to 55.41.69.11855.41.69.1196
17655.41.69.120/2955.41.69.121 to 55.41.69.12655.41.69.1276
17755.41.69.128/2955.41.69.129 to 55.41.69.13455.41.69.1356
17855.41.69.136/2955.41.69.137 to 55.41.69.14255.41.69.1436
17955.41.69.144/2955.41.69.145 to 55.41.69.15055.41.69.1516
18055.41.69.152/2955.41.69.153 to 55.41.69.15855.41.69.1596
18155.41.69.160/2955.41.69.161 to 55.41.69.16655.41.69.1676
18255.41.69.168/2955.41.69.169 to 55.41.69.17455.41.69.1756
18355.41.69.176/2955.41.69.177 to 55.41.69.18255.41.69.1836
18455.41.69.184/2955.41.69.185 to 55.41.69.19055.41.69.1916
18555.41.69.192/2955.41.69.193 to 55.41.69.19855.41.69.1996
18655.41.69.200/2955.41.69.201 to 55.41.69.20655.41.69.2076
18755.41.69.208/2955.41.69.209 to 55.41.69.21455.41.69.2156
18855.41.69.216/2955.41.69.217 to 55.41.69.22255.41.69.2236
18955.41.69.224/2955.41.69.225 to 55.41.69.23055.41.69.2316
19055.41.69.232/2955.41.69.233 to 55.41.69.23855.41.69.2396
19155.41.69.240/2955.41.69.241 to 55.41.69.24655.41.69.2476
19255.41.69.248/2955.41.69.249 to 55.41.69.25455.41.69.2556
19355.41.70.0/2955.41.70.1 to 55.41.70.655.41.70.76
19455.41.70.8/2955.41.70.9 to 55.41.70.1455.41.70.156
19555.41.70.16/2955.41.70.17 to 55.41.70.2255.41.70.236
19655.41.70.24/2955.41.70.25 to 55.41.70.3055.41.70.316
19755.41.70.32/2955.41.70.33 to 55.41.70.3855.41.70.396
19855.41.70.40/2955.41.70.41 to 55.41.70.4655.41.70.476
19955.41.70.48/2955.41.70.49 to 55.41.70.5455.41.70.556
20055.41.70.56/2955.41.70.57 to 55.41.70.6255.41.70.636
20155.41.70.64/2955.41.70.65 to 55.41.70.7055.41.70.716
20255.41.70.72/2955.41.70.73 to 55.41.70.7855.41.70.796
20355.41.70.80/2955.41.70.81 to 55.41.70.8655.41.70.876
20455.41.70.88/2955.41.70.89 to 55.41.70.9455.41.70.956
20555.41.70.96/2955.41.70.97 to 55.41.70.10255.41.70.1036
20655.41.70.104/2955.41.70.105 to 55.41.70.11055.41.70.1116
20755.41.70.112/2955.41.70.113 to 55.41.70.11855.41.70.1196
20855.41.70.120/2955.41.70.121 to 55.41.70.12655.41.70.1276
20955.41.70.128/2955.41.70.129 to 55.41.70.13455.41.70.1356
21055.41.70.136/2955.41.70.137 to 55.41.70.14255.41.70.1436
21155.41.70.144/2955.41.70.145 to 55.41.70.15055.41.70.1516
21255.41.70.152/2955.41.70.153 to 55.41.70.15855.41.70.1596
21355.41.70.160/2955.41.70.161 to 55.41.70.16655.41.70.1676
21455.41.70.168/2955.41.70.169 to 55.41.70.17455.41.70.1756
21555.41.70.176/2955.41.70.177 to 55.41.70.18255.41.70.1836
21655.41.70.184/2955.41.70.185 to 55.41.70.19055.41.70.1916
21755.41.70.192/2955.41.70.193 to 55.41.70.19855.41.70.1996
21855.41.70.200/2955.41.70.201 to 55.41.70.20655.41.70.2076
21955.41.70.208/2955.41.70.209 to 55.41.70.21455.41.70.2156
22055.41.70.216/2955.41.70.217 to 55.41.70.22255.41.70.2236
22155.41.70.224/2955.41.70.225 to 55.41.70.23055.41.70.2316
22255.41.70.232/2955.41.70.233 to 55.41.70.23855.41.70.2396
22355.41.70.240/2955.41.70.241 to 55.41.70.24655.41.70.2476
22455.41.70.248/2955.41.70.249 to 55.41.70.25455.41.70.2556
22555.41.71.0/2955.41.71.1 to 55.41.71.655.41.71.76
22655.41.71.8/2955.41.71.9 to 55.41.71.1455.41.71.156
22755.41.71.16/2955.41.71.17 to 55.41.71.2255.41.71.236
22855.41.71.24/2955.41.71.25 to 55.41.71.3055.41.71.316
22955.41.71.32/2955.41.71.33 to 55.41.71.3855.41.71.396
23055.41.71.40/2955.41.71.41 to 55.41.71.4655.41.71.476
23155.41.71.48/2955.41.71.49 to 55.41.71.5455.41.71.556
23255.41.71.56/2955.41.71.57 to 55.41.71.6255.41.71.636
23355.41.71.64/2955.41.71.65 to 55.41.71.7055.41.71.716
23455.41.71.72/2955.41.71.73 to 55.41.71.7855.41.71.796
23555.41.71.80/2955.41.71.81 to 55.41.71.8655.41.71.876
23655.41.71.88/2955.41.71.89 to 55.41.71.9455.41.71.956
23755.41.71.96/2955.41.71.97 to 55.41.71.10255.41.71.1036
23855.41.71.104/2955.41.71.105 to 55.41.71.11055.41.71.1116
23955.41.71.112/2955.41.71.113 to 55.41.71.11855.41.71.1196
24055.41.71.120/2955.41.71.121 to 55.41.71.12655.41.71.1276
24155.41.71.128/2955.41.71.129 to 55.41.71.13455.41.71.1356
24255.41.71.136/2955.41.71.137 to 55.41.71.14255.41.71.1436
24355.41.71.144/2955.41.71.145 to 55.41.71.15055.41.71.1516
24455.41.71.152/2955.41.71.153 to 55.41.71.15855.41.71.1596
24555.41.71.160/2955.41.71.161 to 55.41.71.16655.41.71.1676
24655.41.71.168/2955.41.71.169 to 55.41.71.17455.41.71.1756
24755.41.71.176/2955.41.71.177 to 55.41.71.18255.41.71.1836
24855.41.71.184/2955.41.71.185 to 55.41.71.19055.41.71.1916
24955.41.71.192/2955.41.71.193 to 55.41.71.19855.41.71.1996
25055.41.71.200/2955.41.71.201 to 55.41.71.20655.41.71.2076
25155.41.71.208/2955.41.71.209 to 55.41.71.21455.41.71.2156
25255.41.71.216/2955.41.71.217 to 55.41.71.22255.41.71.2236
25355.41.71.224/2955.41.71.225 to 55.41.71.23055.41.71.2316
25455.41.71.232/2955.41.71.233 to 55.41.71.23855.41.71.2396
25555.41.71.240/2955.41.71.241 to 55.41.71.24655.41.71.2476
25655.41.71.248/2955.41.71.249 to 55.41.71.25455.41.71.2556

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.