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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.

Network57.2.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
57.2.64.0
Broadcast address
57.2.127.255
First usable
57.2.64.1
Last usable
57.2.127.254
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 39024000 · Integer 956448768 to 956465151
Reverse DNS zones
64.2.57.in-addr.arpa
65.2.57.in-addr.arpa
66.2.57.in-addr.arpa
67.2.57.in-addr.arpa
68.2.57.in-addr.arpa
69.2.57.in-addr.arpa
70.2.57.in-addr.arpa
71.2.57.in-addr.arpa
72.2.57.in-addr.arpa
73.2.57.in-addr.arpa
74.2.57.in-addr.arpa
75.2.57.in-addr.arpa
76.2.57.in-addr.arpa
77.2.57.in-addr.arpa
78.2.57.in-addr.arpa
79.2.57.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
Address00111001.00000010.01000000.0000000057.2.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network00111001.00000010.01000000.0000000057.2.64.0
Broadcast00111001.00000010.01111111.1111111157.2.127.255
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)

57.2.64.0/18 makes 2,048 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
157.2.64.0/2957.2.64.1 to 57.2.64.657.2.64.76
257.2.64.8/2957.2.64.9 to 57.2.64.1457.2.64.156
357.2.64.16/2957.2.64.17 to 57.2.64.2257.2.64.236
457.2.64.24/2957.2.64.25 to 57.2.64.3057.2.64.316
557.2.64.32/2957.2.64.33 to 57.2.64.3857.2.64.396
657.2.64.40/2957.2.64.41 to 57.2.64.4657.2.64.476
757.2.64.48/2957.2.64.49 to 57.2.64.5457.2.64.556
857.2.64.56/2957.2.64.57 to 57.2.64.6257.2.64.636
957.2.64.64/2957.2.64.65 to 57.2.64.7057.2.64.716
1057.2.64.72/2957.2.64.73 to 57.2.64.7857.2.64.796
1157.2.64.80/2957.2.64.81 to 57.2.64.8657.2.64.876
1257.2.64.88/2957.2.64.89 to 57.2.64.9457.2.64.956
1357.2.64.96/2957.2.64.97 to 57.2.64.10257.2.64.1036
1457.2.64.104/2957.2.64.105 to 57.2.64.11057.2.64.1116
1557.2.64.112/2957.2.64.113 to 57.2.64.11857.2.64.1196
1657.2.64.120/2957.2.64.121 to 57.2.64.12657.2.64.1276
1757.2.64.128/2957.2.64.129 to 57.2.64.13457.2.64.1356
1857.2.64.136/2957.2.64.137 to 57.2.64.14257.2.64.1436
1957.2.64.144/2957.2.64.145 to 57.2.64.15057.2.64.1516
2057.2.64.152/2957.2.64.153 to 57.2.64.15857.2.64.1596
2157.2.64.160/2957.2.64.161 to 57.2.64.16657.2.64.1676
2257.2.64.168/2957.2.64.169 to 57.2.64.17457.2.64.1756
2357.2.64.176/2957.2.64.177 to 57.2.64.18257.2.64.1836
2457.2.64.184/2957.2.64.185 to 57.2.64.19057.2.64.1916
2557.2.64.192/2957.2.64.193 to 57.2.64.19857.2.64.1996
2657.2.64.200/2957.2.64.201 to 57.2.64.20657.2.64.2076
2757.2.64.208/2957.2.64.209 to 57.2.64.21457.2.64.2156
2857.2.64.216/2957.2.64.217 to 57.2.64.22257.2.64.2236
2957.2.64.224/2957.2.64.225 to 57.2.64.23057.2.64.2316
3057.2.64.232/2957.2.64.233 to 57.2.64.23857.2.64.2396
3157.2.64.240/2957.2.64.241 to 57.2.64.24657.2.64.2476
3257.2.64.248/2957.2.64.249 to 57.2.64.25457.2.64.2556
3357.2.65.0/2957.2.65.1 to 57.2.65.657.2.65.76
3457.2.65.8/2957.2.65.9 to 57.2.65.1457.2.65.156
3557.2.65.16/2957.2.65.17 to 57.2.65.2257.2.65.236
3657.2.65.24/2957.2.65.25 to 57.2.65.3057.2.65.316
3757.2.65.32/2957.2.65.33 to 57.2.65.3857.2.65.396
3857.2.65.40/2957.2.65.41 to 57.2.65.4657.2.65.476
3957.2.65.48/2957.2.65.49 to 57.2.65.5457.2.65.556
4057.2.65.56/2957.2.65.57 to 57.2.65.6257.2.65.636
4157.2.65.64/2957.2.65.65 to 57.2.65.7057.2.65.716
4257.2.65.72/2957.2.65.73 to 57.2.65.7857.2.65.796
4357.2.65.80/2957.2.65.81 to 57.2.65.8657.2.65.876
4457.2.65.88/2957.2.65.89 to 57.2.65.9457.2.65.956
4557.2.65.96/2957.2.65.97 to 57.2.65.10257.2.65.1036
4657.2.65.104/2957.2.65.105 to 57.2.65.11057.2.65.1116
4757.2.65.112/2957.2.65.113 to 57.2.65.11857.2.65.1196
4857.2.65.120/2957.2.65.121 to 57.2.65.12657.2.65.1276
4957.2.65.128/2957.2.65.129 to 57.2.65.13457.2.65.1356
5057.2.65.136/2957.2.65.137 to 57.2.65.14257.2.65.1436
5157.2.65.144/2957.2.65.145 to 57.2.65.15057.2.65.1516
5257.2.65.152/2957.2.65.153 to 57.2.65.15857.2.65.1596
5357.2.65.160/2957.2.65.161 to 57.2.65.16657.2.65.1676
5457.2.65.168/2957.2.65.169 to 57.2.65.17457.2.65.1756
5557.2.65.176/2957.2.65.177 to 57.2.65.18257.2.65.1836
5657.2.65.184/2957.2.65.185 to 57.2.65.19057.2.65.1916
5757.2.65.192/2957.2.65.193 to 57.2.65.19857.2.65.1996
5857.2.65.200/2957.2.65.201 to 57.2.65.20657.2.65.2076
5957.2.65.208/2957.2.65.209 to 57.2.65.21457.2.65.2156
6057.2.65.216/2957.2.65.217 to 57.2.65.22257.2.65.2236
6157.2.65.224/2957.2.65.225 to 57.2.65.23057.2.65.2316
6257.2.65.232/2957.2.65.233 to 57.2.65.23857.2.65.2396
6357.2.65.240/2957.2.65.241 to 57.2.65.24657.2.65.2476
6457.2.65.248/2957.2.65.249 to 57.2.65.25457.2.65.2556
6557.2.66.0/2957.2.66.1 to 57.2.66.657.2.66.76
6657.2.66.8/2957.2.66.9 to 57.2.66.1457.2.66.156
6757.2.66.16/2957.2.66.17 to 57.2.66.2257.2.66.236
6857.2.66.24/2957.2.66.25 to 57.2.66.3057.2.66.316
6957.2.66.32/2957.2.66.33 to 57.2.66.3857.2.66.396
7057.2.66.40/2957.2.66.41 to 57.2.66.4657.2.66.476
7157.2.66.48/2957.2.66.49 to 57.2.66.5457.2.66.556
7257.2.66.56/2957.2.66.57 to 57.2.66.6257.2.66.636
7357.2.66.64/2957.2.66.65 to 57.2.66.7057.2.66.716
7457.2.66.72/2957.2.66.73 to 57.2.66.7857.2.66.796
7557.2.66.80/2957.2.66.81 to 57.2.66.8657.2.66.876
7657.2.66.88/2957.2.66.89 to 57.2.66.9457.2.66.956
7757.2.66.96/2957.2.66.97 to 57.2.66.10257.2.66.1036
7857.2.66.104/2957.2.66.105 to 57.2.66.11057.2.66.1116
7957.2.66.112/2957.2.66.113 to 57.2.66.11857.2.66.1196
8057.2.66.120/2957.2.66.121 to 57.2.66.12657.2.66.1276
8157.2.66.128/2957.2.66.129 to 57.2.66.13457.2.66.1356
8257.2.66.136/2957.2.66.137 to 57.2.66.14257.2.66.1436
8357.2.66.144/2957.2.66.145 to 57.2.66.15057.2.66.1516
8457.2.66.152/2957.2.66.153 to 57.2.66.15857.2.66.1596
8557.2.66.160/2957.2.66.161 to 57.2.66.16657.2.66.1676
8657.2.66.168/2957.2.66.169 to 57.2.66.17457.2.66.1756
8757.2.66.176/2957.2.66.177 to 57.2.66.18257.2.66.1836
8857.2.66.184/2957.2.66.185 to 57.2.66.19057.2.66.1916
8957.2.66.192/2957.2.66.193 to 57.2.66.19857.2.66.1996
9057.2.66.200/2957.2.66.201 to 57.2.66.20657.2.66.2076
9157.2.66.208/2957.2.66.209 to 57.2.66.21457.2.66.2156
9257.2.66.216/2957.2.66.217 to 57.2.66.22257.2.66.2236
9357.2.66.224/2957.2.66.225 to 57.2.66.23057.2.66.2316
9457.2.66.232/2957.2.66.233 to 57.2.66.23857.2.66.2396
9557.2.66.240/2957.2.66.241 to 57.2.66.24657.2.66.2476
9657.2.66.248/2957.2.66.249 to 57.2.66.25457.2.66.2556
9757.2.67.0/2957.2.67.1 to 57.2.67.657.2.67.76
9857.2.67.8/2957.2.67.9 to 57.2.67.1457.2.67.156
9957.2.67.16/2957.2.67.17 to 57.2.67.2257.2.67.236
10057.2.67.24/2957.2.67.25 to 57.2.67.3057.2.67.316
10157.2.67.32/2957.2.67.33 to 57.2.67.3857.2.67.396
10257.2.67.40/2957.2.67.41 to 57.2.67.4657.2.67.476
10357.2.67.48/2957.2.67.49 to 57.2.67.5457.2.67.556
10457.2.67.56/2957.2.67.57 to 57.2.67.6257.2.67.636
10557.2.67.64/2957.2.67.65 to 57.2.67.7057.2.67.716
10657.2.67.72/2957.2.67.73 to 57.2.67.7857.2.67.796
10757.2.67.80/2957.2.67.81 to 57.2.67.8657.2.67.876
10857.2.67.88/2957.2.67.89 to 57.2.67.9457.2.67.956
10957.2.67.96/2957.2.67.97 to 57.2.67.10257.2.67.1036
11057.2.67.104/2957.2.67.105 to 57.2.67.11057.2.67.1116
11157.2.67.112/2957.2.67.113 to 57.2.67.11857.2.67.1196
11257.2.67.120/2957.2.67.121 to 57.2.67.12657.2.67.1276
11357.2.67.128/2957.2.67.129 to 57.2.67.13457.2.67.1356
11457.2.67.136/2957.2.67.137 to 57.2.67.14257.2.67.1436
11557.2.67.144/2957.2.67.145 to 57.2.67.15057.2.67.1516
11657.2.67.152/2957.2.67.153 to 57.2.67.15857.2.67.1596
11757.2.67.160/2957.2.67.161 to 57.2.67.16657.2.67.1676
11857.2.67.168/2957.2.67.169 to 57.2.67.17457.2.67.1756
11957.2.67.176/2957.2.67.177 to 57.2.67.18257.2.67.1836
12057.2.67.184/2957.2.67.185 to 57.2.67.19057.2.67.1916
12157.2.67.192/2957.2.67.193 to 57.2.67.19857.2.67.1996
12257.2.67.200/2957.2.67.201 to 57.2.67.20657.2.67.2076
12357.2.67.208/2957.2.67.209 to 57.2.67.21457.2.67.2156
12457.2.67.216/2957.2.67.217 to 57.2.67.22257.2.67.2236
12557.2.67.224/2957.2.67.225 to 57.2.67.23057.2.67.2316
12657.2.67.232/2957.2.67.233 to 57.2.67.23857.2.67.2396
12757.2.67.240/2957.2.67.241 to 57.2.67.24657.2.67.2476
12857.2.67.248/2957.2.67.249 to 57.2.67.25457.2.67.2556
12957.2.68.0/2957.2.68.1 to 57.2.68.657.2.68.76
13057.2.68.8/2957.2.68.9 to 57.2.68.1457.2.68.156
13157.2.68.16/2957.2.68.17 to 57.2.68.2257.2.68.236
13257.2.68.24/2957.2.68.25 to 57.2.68.3057.2.68.316
13357.2.68.32/2957.2.68.33 to 57.2.68.3857.2.68.396
13457.2.68.40/2957.2.68.41 to 57.2.68.4657.2.68.476
13557.2.68.48/2957.2.68.49 to 57.2.68.5457.2.68.556
13657.2.68.56/2957.2.68.57 to 57.2.68.6257.2.68.636
13757.2.68.64/2957.2.68.65 to 57.2.68.7057.2.68.716
13857.2.68.72/2957.2.68.73 to 57.2.68.7857.2.68.796
13957.2.68.80/2957.2.68.81 to 57.2.68.8657.2.68.876
14057.2.68.88/2957.2.68.89 to 57.2.68.9457.2.68.956
14157.2.68.96/2957.2.68.97 to 57.2.68.10257.2.68.1036
14257.2.68.104/2957.2.68.105 to 57.2.68.11057.2.68.1116
14357.2.68.112/2957.2.68.113 to 57.2.68.11857.2.68.1196
14457.2.68.120/2957.2.68.121 to 57.2.68.12657.2.68.1276
14557.2.68.128/2957.2.68.129 to 57.2.68.13457.2.68.1356
14657.2.68.136/2957.2.68.137 to 57.2.68.14257.2.68.1436
14757.2.68.144/2957.2.68.145 to 57.2.68.15057.2.68.1516
14857.2.68.152/2957.2.68.153 to 57.2.68.15857.2.68.1596
14957.2.68.160/2957.2.68.161 to 57.2.68.16657.2.68.1676
15057.2.68.168/2957.2.68.169 to 57.2.68.17457.2.68.1756
15157.2.68.176/2957.2.68.177 to 57.2.68.18257.2.68.1836
15257.2.68.184/2957.2.68.185 to 57.2.68.19057.2.68.1916
15357.2.68.192/2957.2.68.193 to 57.2.68.19857.2.68.1996
15457.2.68.200/2957.2.68.201 to 57.2.68.20657.2.68.2076
15557.2.68.208/2957.2.68.209 to 57.2.68.21457.2.68.2156
15657.2.68.216/2957.2.68.217 to 57.2.68.22257.2.68.2236
15757.2.68.224/2957.2.68.225 to 57.2.68.23057.2.68.2316
15857.2.68.232/2957.2.68.233 to 57.2.68.23857.2.68.2396
15957.2.68.240/2957.2.68.241 to 57.2.68.24657.2.68.2476
16057.2.68.248/2957.2.68.249 to 57.2.68.25457.2.68.2556
16157.2.69.0/2957.2.69.1 to 57.2.69.657.2.69.76
16257.2.69.8/2957.2.69.9 to 57.2.69.1457.2.69.156
16357.2.69.16/2957.2.69.17 to 57.2.69.2257.2.69.236
16457.2.69.24/2957.2.69.25 to 57.2.69.3057.2.69.316
16557.2.69.32/2957.2.69.33 to 57.2.69.3857.2.69.396
16657.2.69.40/2957.2.69.41 to 57.2.69.4657.2.69.476
16757.2.69.48/2957.2.69.49 to 57.2.69.5457.2.69.556
16857.2.69.56/2957.2.69.57 to 57.2.69.6257.2.69.636
16957.2.69.64/2957.2.69.65 to 57.2.69.7057.2.69.716
17057.2.69.72/2957.2.69.73 to 57.2.69.7857.2.69.796
17157.2.69.80/2957.2.69.81 to 57.2.69.8657.2.69.876
17257.2.69.88/2957.2.69.89 to 57.2.69.9457.2.69.956
17357.2.69.96/2957.2.69.97 to 57.2.69.10257.2.69.1036
17457.2.69.104/2957.2.69.105 to 57.2.69.11057.2.69.1116
17557.2.69.112/2957.2.69.113 to 57.2.69.11857.2.69.1196
17657.2.69.120/2957.2.69.121 to 57.2.69.12657.2.69.1276
17757.2.69.128/2957.2.69.129 to 57.2.69.13457.2.69.1356
17857.2.69.136/2957.2.69.137 to 57.2.69.14257.2.69.1436
17957.2.69.144/2957.2.69.145 to 57.2.69.15057.2.69.1516
18057.2.69.152/2957.2.69.153 to 57.2.69.15857.2.69.1596
18157.2.69.160/2957.2.69.161 to 57.2.69.16657.2.69.1676
18257.2.69.168/2957.2.69.169 to 57.2.69.17457.2.69.1756
18357.2.69.176/2957.2.69.177 to 57.2.69.18257.2.69.1836
18457.2.69.184/2957.2.69.185 to 57.2.69.19057.2.69.1916
18557.2.69.192/2957.2.69.193 to 57.2.69.19857.2.69.1996
18657.2.69.200/2957.2.69.201 to 57.2.69.20657.2.69.2076
18757.2.69.208/2957.2.69.209 to 57.2.69.21457.2.69.2156
18857.2.69.216/2957.2.69.217 to 57.2.69.22257.2.69.2236
18957.2.69.224/2957.2.69.225 to 57.2.69.23057.2.69.2316
19057.2.69.232/2957.2.69.233 to 57.2.69.23857.2.69.2396
19157.2.69.240/2957.2.69.241 to 57.2.69.24657.2.69.2476
19257.2.69.248/2957.2.69.249 to 57.2.69.25457.2.69.2556
19357.2.70.0/2957.2.70.1 to 57.2.70.657.2.70.76
19457.2.70.8/2957.2.70.9 to 57.2.70.1457.2.70.156
19557.2.70.16/2957.2.70.17 to 57.2.70.2257.2.70.236
19657.2.70.24/2957.2.70.25 to 57.2.70.3057.2.70.316
19757.2.70.32/2957.2.70.33 to 57.2.70.3857.2.70.396
19857.2.70.40/2957.2.70.41 to 57.2.70.4657.2.70.476
19957.2.70.48/2957.2.70.49 to 57.2.70.5457.2.70.556
20057.2.70.56/2957.2.70.57 to 57.2.70.6257.2.70.636
20157.2.70.64/2957.2.70.65 to 57.2.70.7057.2.70.716
20257.2.70.72/2957.2.70.73 to 57.2.70.7857.2.70.796
20357.2.70.80/2957.2.70.81 to 57.2.70.8657.2.70.876
20457.2.70.88/2957.2.70.89 to 57.2.70.9457.2.70.956
20557.2.70.96/2957.2.70.97 to 57.2.70.10257.2.70.1036
20657.2.70.104/2957.2.70.105 to 57.2.70.11057.2.70.1116
20757.2.70.112/2957.2.70.113 to 57.2.70.11857.2.70.1196
20857.2.70.120/2957.2.70.121 to 57.2.70.12657.2.70.1276
20957.2.70.128/2957.2.70.129 to 57.2.70.13457.2.70.1356
21057.2.70.136/2957.2.70.137 to 57.2.70.14257.2.70.1436
21157.2.70.144/2957.2.70.145 to 57.2.70.15057.2.70.1516
21257.2.70.152/2957.2.70.153 to 57.2.70.15857.2.70.1596
21357.2.70.160/2957.2.70.161 to 57.2.70.16657.2.70.1676
21457.2.70.168/2957.2.70.169 to 57.2.70.17457.2.70.1756
21557.2.70.176/2957.2.70.177 to 57.2.70.18257.2.70.1836
21657.2.70.184/2957.2.70.185 to 57.2.70.19057.2.70.1916
21757.2.70.192/2957.2.70.193 to 57.2.70.19857.2.70.1996
21857.2.70.200/2957.2.70.201 to 57.2.70.20657.2.70.2076
21957.2.70.208/2957.2.70.209 to 57.2.70.21457.2.70.2156
22057.2.70.216/2957.2.70.217 to 57.2.70.22257.2.70.2236
22157.2.70.224/2957.2.70.225 to 57.2.70.23057.2.70.2316
22257.2.70.232/2957.2.70.233 to 57.2.70.23857.2.70.2396
22357.2.70.240/2957.2.70.241 to 57.2.70.24657.2.70.2476
22457.2.70.248/2957.2.70.249 to 57.2.70.25457.2.70.2556
22557.2.71.0/2957.2.71.1 to 57.2.71.657.2.71.76
22657.2.71.8/2957.2.71.9 to 57.2.71.1457.2.71.156
22757.2.71.16/2957.2.71.17 to 57.2.71.2257.2.71.236
22857.2.71.24/2957.2.71.25 to 57.2.71.3057.2.71.316
22957.2.71.32/2957.2.71.33 to 57.2.71.3857.2.71.396
23057.2.71.40/2957.2.71.41 to 57.2.71.4657.2.71.476
23157.2.71.48/2957.2.71.49 to 57.2.71.5457.2.71.556
23257.2.71.56/2957.2.71.57 to 57.2.71.6257.2.71.636
23357.2.71.64/2957.2.71.65 to 57.2.71.7057.2.71.716
23457.2.71.72/2957.2.71.73 to 57.2.71.7857.2.71.796
23557.2.71.80/2957.2.71.81 to 57.2.71.8657.2.71.876
23657.2.71.88/2957.2.71.89 to 57.2.71.9457.2.71.956
23757.2.71.96/2957.2.71.97 to 57.2.71.10257.2.71.1036
23857.2.71.104/2957.2.71.105 to 57.2.71.11057.2.71.1116
23957.2.71.112/2957.2.71.113 to 57.2.71.11857.2.71.1196
24057.2.71.120/2957.2.71.121 to 57.2.71.12657.2.71.1276
24157.2.71.128/2957.2.71.129 to 57.2.71.13457.2.71.1356
24257.2.71.136/2957.2.71.137 to 57.2.71.14257.2.71.1436
24357.2.71.144/2957.2.71.145 to 57.2.71.15057.2.71.1516
24457.2.71.152/2957.2.71.153 to 57.2.71.15857.2.71.1596
24557.2.71.160/2957.2.71.161 to 57.2.71.16657.2.71.1676
24657.2.71.168/2957.2.71.169 to 57.2.71.17457.2.71.1756
24757.2.71.176/2957.2.71.177 to 57.2.71.18257.2.71.1836
24857.2.71.184/2957.2.71.185 to 57.2.71.19057.2.71.1916
24957.2.71.192/2957.2.71.193 to 57.2.71.19857.2.71.1996
25057.2.71.200/2957.2.71.201 to 57.2.71.20657.2.71.2076
25157.2.71.208/2957.2.71.209 to 57.2.71.21457.2.71.2156
25257.2.71.216/2957.2.71.217 to 57.2.71.22257.2.71.2236
25357.2.71.224/2957.2.71.225 to 57.2.71.23057.2.71.2316
25457.2.71.232/2957.2.71.233 to 57.2.71.23857.2.71.2396
25557.2.71.240/2957.2.71.241 to 57.2.71.24657.2.71.2476
25657.2.71.248/2957.2.71.249 to 57.2.71.25457.2.71.2556

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.