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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.

Network57.2.48.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
57.2.48.0
Broadcast address
57.2.63.255
First usable
57.2.48.1
Last usable
57.2.63.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Public public
Old class
A (default /8)
As numbers
Hex 39023000 · Integer 956444672 to 956448767
Reverse DNS zones
48.2.57.in-addr.arpa
49.2.57.in-addr.arpa
50.2.57.in-addr.arpa
51.2.57.in-addr.arpa
52.2.57.in-addr.arpa
53.2.57.in-addr.arpa
54.2.57.in-addr.arpa
55.2.57.in-addr.arpa
56.2.57.in-addr.arpa
57.2.57.in-addr.arpa
58.2.57.in-addr.arpa
59.2.57.in-addr.arpa
60.2.57.in-addr.arpa
61.2.57.in-addr.arpa
62.2.57.in-addr.arpa
63.2.57.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00111001.00000010.00110000.0000000057.2.48.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network00111001.00000010.00110000.0000000057.2.48.0
Broadcast00111001.00000010.00111111.1111111157.2.63.255
Split into smaller subnets/30
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

57.2.48.0/20 makes 1,024 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
157.2.48.0/3057.2.48.1 to 57.2.48.257.2.48.32
257.2.48.4/3057.2.48.5 to 57.2.48.657.2.48.72
357.2.48.8/3057.2.48.9 to 57.2.48.1057.2.48.112
457.2.48.12/3057.2.48.13 to 57.2.48.1457.2.48.152
557.2.48.16/3057.2.48.17 to 57.2.48.1857.2.48.192
657.2.48.20/3057.2.48.21 to 57.2.48.2257.2.48.232
757.2.48.24/3057.2.48.25 to 57.2.48.2657.2.48.272
857.2.48.28/3057.2.48.29 to 57.2.48.3057.2.48.312
957.2.48.32/3057.2.48.33 to 57.2.48.3457.2.48.352
1057.2.48.36/3057.2.48.37 to 57.2.48.3857.2.48.392
1157.2.48.40/3057.2.48.41 to 57.2.48.4257.2.48.432
1257.2.48.44/3057.2.48.45 to 57.2.48.4657.2.48.472
1357.2.48.48/3057.2.48.49 to 57.2.48.5057.2.48.512
1457.2.48.52/3057.2.48.53 to 57.2.48.5457.2.48.552
1557.2.48.56/3057.2.48.57 to 57.2.48.5857.2.48.592
1657.2.48.60/3057.2.48.61 to 57.2.48.6257.2.48.632
1757.2.48.64/3057.2.48.65 to 57.2.48.6657.2.48.672
1857.2.48.68/3057.2.48.69 to 57.2.48.7057.2.48.712
1957.2.48.72/3057.2.48.73 to 57.2.48.7457.2.48.752
2057.2.48.76/3057.2.48.77 to 57.2.48.7857.2.48.792
2157.2.48.80/3057.2.48.81 to 57.2.48.8257.2.48.832
2257.2.48.84/3057.2.48.85 to 57.2.48.8657.2.48.872
2357.2.48.88/3057.2.48.89 to 57.2.48.9057.2.48.912
2457.2.48.92/3057.2.48.93 to 57.2.48.9457.2.48.952
2557.2.48.96/3057.2.48.97 to 57.2.48.9857.2.48.992
2657.2.48.100/3057.2.48.101 to 57.2.48.10257.2.48.1032
2757.2.48.104/3057.2.48.105 to 57.2.48.10657.2.48.1072
2857.2.48.108/3057.2.48.109 to 57.2.48.11057.2.48.1112
2957.2.48.112/3057.2.48.113 to 57.2.48.11457.2.48.1152
3057.2.48.116/3057.2.48.117 to 57.2.48.11857.2.48.1192
3157.2.48.120/3057.2.48.121 to 57.2.48.12257.2.48.1232
3257.2.48.124/3057.2.48.125 to 57.2.48.12657.2.48.1272
3357.2.48.128/3057.2.48.129 to 57.2.48.13057.2.48.1312
3457.2.48.132/3057.2.48.133 to 57.2.48.13457.2.48.1352
3557.2.48.136/3057.2.48.137 to 57.2.48.13857.2.48.1392
3657.2.48.140/3057.2.48.141 to 57.2.48.14257.2.48.1432
3757.2.48.144/3057.2.48.145 to 57.2.48.14657.2.48.1472
3857.2.48.148/3057.2.48.149 to 57.2.48.15057.2.48.1512
3957.2.48.152/3057.2.48.153 to 57.2.48.15457.2.48.1552
4057.2.48.156/3057.2.48.157 to 57.2.48.15857.2.48.1592
4157.2.48.160/3057.2.48.161 to 57.2.48.16257.2.48.1632
4257.2.48.164/3057.2.48.165 to 57.2.48.16657.2.48.1672
4357.2.48.168/3057.2.48.169 to 57.2.48.17057.2.48.1712
4457.2.48.172/3057.2.48.173 to 57.2.48.17457.2.48.1752
4557.2.48.176/3057.2.48.177 to 57.2.48.17857.2.48.1792
4657.2.48.180/3057.2.48.181 to 57.2.48.18257.2.48.1832
4757.2.48.184/3057.2.48.185 to 57.2.48.18657.2.48.1872
4857.2.48.188/3057.2.48.189 to 57.2.48.19057.2.48.1912
4957.2.48.192/3057.2.48.193 to 57.2.48.19457.2.48.1952
5057.2.48.196/3057.2.48.197 to 57.2.48.19857.2.48.1992
5157.2.48.200/3057.2.48.201 to 57.2.48.20257.2.48.2032
5257.2.48.204/3057.2.48.205 to 57.2.48.20657.2.48.2072
5357.2.48.208/3057.2.48.209 to 57.2.48.21057.2.48.2112
5457.2.48.212/3057.2.48.213 to 57.2.48.21457.2.48.2152
5557.2.48.216/3057.2.48.217 to 57.2.48.21857.2.48.2192
5657.2.48.220/3057.2.48.221 to 57.2.48.22257.2.48.2232
5757.2.48.224/3057.2.48.225 to 57.2.48.22657.2.48.2272
5857.2.48.228/3057.2.48.229 to 57.2.48.23057.2.48.2312
5957.2.48.232/3057.2.48.233 to 57.2.48.23457.2.48.2352
6057.2.48.236/3057.2.48.237 to 57.2.48.23857.2.48.2392
6157.2.48.240/3057.2.48.241 to 57.2.48.24257.2.48.2432
6257.2.48.244/3057.2.48.245 to 57.2.48.24657.2.48.2472
6357.2.48.248/3057.2.48.249 to 57.2.48.25057.2.48.2512
6457.2.48.252/3057.2.48.253 to 57.2.48.25457.2.48.2552
6557.2.49.0/3057.2.49.1 to 57.2.49.257.2.49.32
6657.2.49.4/3057.2.49.5 to 57.2.49.657.2.49.72
6757.2.49.8/3057.2.49.9 to 57.2.49.1057.2.49.112
6857.2.49.12/3057.2.49.13 to 57.2.49.1457.2.49.152
6957.2.49.16/3057.2.49.17 to 57.2.49.1857.2.49.192
7057.2.49.20/3057.2.49.21 to 57.2.49.2257.2.49.232
7157.2.49.24/3057.2.49.25 to 57.2.49.2657.2.49.272
7257.2.49.28/3057.2.49.29 to 57.2.49.3057.2.49.312
7357.2.49.32/3057.2.49.33 to 57.2.49.3457.2.49.352
7457.2.49.36/3057.2.49.37 to 57.2.49.3857.2.49.392
7557.2.49.40/3057.2.49.41 to 57.2.49.4257.2.49.432
7657.2.49.44/3057.2.49.45 to 57.2.49.4657.2.49.472
7757.2.49.48/3057.2.49.49 to 57.2.49.5057.2.49.512
7857.2.49.52/3057.2.49.53 to 57.2.49.5457.2.49.552
7957.2.49.56/3057.2.49.57 to 57.2.49.5857.2.49.592
8057.2.49.60/3057.2.49.61 to 57.2.49.6257.2.49.632
8157.2.49.64/3057.2.49.65 to 57.2.49.6657.2.49.672
8257.2.49.68/3057.2.49.69 to 57.2.49.7057.2.49.712
8357.2.49.72/3057.2.49.73 to 57.2.49.7457.2.49.752
8457.2.49.76/3057.2.49.77 to 57.2.49.7857.2.49.792
8557.2.49.80/3057.2.49.81 to 57.2.49.8257.2.49.832
8657.2.49.84/3057.2.49.85 to 57.2.49.8657.2.49.872
8757.2.49.88/3057.2.49.89 to 57.2.49.9057.2.49.912
8857.2.49.92/3057.2.49.93 to 57.2.49.9457.2.49.952
8957.2.49.96/3057.2.49.97 to 57.2.49.9857.2.49.992
9057.2.49.100/3057.2.49.101 to 57.2.49.10257.2.49.1032
9157.2.49.104/3057.2.49.105 to 57.2.49.10657.2.49.1072
9257.2.49.108/3057.2.49.109 to 57.2.49.11057.2.49.1112
9357.2.49.112/3057.2.49.113 to 57.2.49.11457.2.49.1152
9457.2.49.116/3057.2.49.117 to 57.2.49.11857.2.49.1192
9557.2.49.120/3057.2.49.121 to 57.2.49.12257.2.49.1232
9657.2.49.124/3057.2.49.125 to 57.2.49.12657.2.49.1272
9757.2.49.128/3057.2.49.129 to 57.2.49.13057.2.49.1312
9857.2.49.132/3057.2.49.133 to 57.2.49.13457.2.49.1352
9957.2.49.136/3057.2.49.137 to 57.2.49.13857.2.49.1392
10057.2.49.140/3057.2.49.141 to 57.2.49.14257.2.49.1432
10157.2.49.144/3057.2.49.145 to 57.2.49.14657.2.49.1472
10257.2.49.148/3057.2.49.149 to 57.2.49.15057.2.49.1512
10357.2.49.152/3057.2.49.153 to 57.2.49.15457.2.49.1552
10457.2.49.156/3057.2.49.157 to 57.2.49.15857.2.49.1592
10557.2.49.160/3057.2.49.161 to 57.2.49.16257.2.49.1632
10657.2.49.164/3057.2.49.165 to 57.2.49.16657.2.49.1672
10757.2.49.168/3057.2.49.169 to 57.2.49.17057.2.49.1712
10857.2.49.172/3057.2.49.173 to 57.2.49.17457.2.49.1752
10957.2.49.176/3057.2.49.177 to 57.2.49.17857.2.49.1792
11057.2.49.180/3057.2.49.181 to 57.2.49.18257.2.49.1832
11157.2.49.184/3057.2.49.185 to 57.2.49.18657.2.49.1872
11257.2.49.188/3057.2.49.189 to 57.2.49.19057.2.49.1912
11357.2.49.192/3057.2.49.193 to 57.2.49.19457.2.49.1952
11457.2.49.196/3057.2.49.197 to 57.2.49.19857.2.49.1992
11557.2.49.200/3057.2.49.201 to 57.2.49.20257.2.49.2032
11657.2.49.204/3057.2.49.205 to 57.2.49.20657.2.49.2072
11757.2.49.208/3057.2.49.209 to 57.2.49.21057.2.49.2112
11857.2.49.212/3057.2.49.213 to 57.2.49.21457.2.49.2152
11957.2.49.216/3057.2.49.217 to 57.2.49.21857.2.49.2192
12057.2.49.220/3057.2.49.221 to 57.2.49.22257.2.49.2232
12157.2.49.224/3057.2.49.225 to 57.2.49.22657.2.49.2272
12257.2.49.228/3057.2.49.229 to 57.2.49.23057.2.49.2312
12357.2.49.232/3057.2.49.233 to 57.2.49.23457.2.49.2352
12457.2.49.236/3057.2.49.237 to 57.2.49.23857.2.49.2392
12557.2.49.240/3057.2.49.241 to 57.2.49.24257.2.49.2432
12657.2.49.244/3057.2.49.245 to 57.2.49.24657.2.49.2472
12757.2.49.248/3057.2.49.249 to 57.2.49.25057.2.49.2512
12857.2.49.252/3057.2.49.253 to 57.2.49.25457.2.49.2552
12957.2.50.0/3057.2.50.1 to 57.2.50.257.2.50.32
13057.2.50.4/3057.2.50.5 to 57.2.50.657.2.50.72
13157.2.50.8/3057.2.50.9 to 57.2.50.1057.2.50.112
13257.2.50.12/3057.2.50.13 to 57.2.50.1457.2.50.152
13357.2.50.16/3057.2.50.17 to 57.2.50.1857.2.50.192
13457.2.50.20/3057.2.50.21 to 57.2.50.2257.2.50.232
13557.2.50.24/3057.2.50.25 to 57.2.50.2657.2.50.272
13657.2.50.28/3057.2.50.29 to 57.2.50.3057.2.50.312
13757.2.50.32/3057.2.50.33 to 57.2.50.3457.2.50.352
13857.2.50.36/3057.2.50.37 to 57.2.50.3857.2.50.392
13957.2.50.40/3057.2.50.41 to 57.2.50.4257.2.50.432
14057.2.50.44/3057.2.50.45 to 57.2.50.4657.2.50.472
14157.2.50.48/3057.2.50.49 to 57.2.50.5057.2.50.512
14257.2.50.52/3057.2.50.53 to 57.2.50.5457.2.50.552
14357.2.50.56/3057.2.50.57 to 57.2.50.5857.2.50.592
14457.2.50.60/3057.2.50.61 to 57.2.50.6257.2.50.632
14557.2.50.64/3057.2.50.65 to 57.2.50.6657.2.50.672
14657.2.50.68/3057.2.50.69 to 57.2.50.7057.2.50.712
14757.2.50.72/3057.2.50.73 to 57.2.50.7457.2.50.752
14857.2.50.76/3057.2.50.77 to 57.2.50.7857.2.50.792
14957.2.50.80/3057.2.50.81 to 57.2.50.8257.2.50.832
15057.2.50.84/3057.2.50.85 to 57.2.50.8657.2.50.872
15157.2.50.88/3057.2.50.89 to 57.2.50.9057.2.50.912
15257.2.50.92/3057.2.50.93 to 57.2.50.9457.2.50.952
15357.2.50.96/3057.2.50.97 to 57.2.50.9857.2.50.992
15457.2.50.100/3057.2.50.101 to 57.2.50.10257.2.50.1032
15557.2.50.104/3057.2.50.105 to 57.2.50.10657.2.50.1072
15657.2.50.108/3057.2.50.109 to 57.2.50.11057.2.50.1112
15757.2.50.112/3057.2.50.113 to 57.2.50.11457.2.50.1152
15857.2.50.116/3057.2.50.117 to 57.2.50.11857.2.50.1192
15957.2.50.120/3057.2.50.121 to 57.2.50.12257.2.50.1232
16057.2.50.124/3057.2.50.125 to 57.2.50.12657.2.50.1272
16157.2.50.128/3057.2.50.129 to 57.2.50.13057.2.50.1312
16257.2.50.132/3057.2.50.133 to 57.2.50.13457.2.50.1352
16357.2.50.136/3057.2.50.137 to 57.2.50.13857.2.50.1392
16457.2.50.140/3057.2.50.141 to 57.2.50.14257.2.50.1432
16557.2.50.144/3057.2.50.145 to 57.2.50.14657.2.50.1472
16657.2.50.148/3057.2.50.149 to 57.2.50.15057.2.50.1512
16757.2.50.152/3057.2.50.153 to 57.2.50.15457.2.50.1552
16857.2.50.156/3057.2.50.157 to 57.2.50.15857.2.50.1592
16957.2.50.160/3057.2.50.161 to 57.2.50.16257.2.50.1632
17057.2.50.164/3057.2.50.165 to 57.2.50.16657.2.50.1672
17157.2.50.168/3057.2.50.169 to 57.2.50.17057.2.50.1712
17257.2.50.172/3057.2.50.173 to 57.2.50.17457.2.50.1752
17357.2.50.176/3057.2.50.177 to 57.2.50.17857.2.50.1792
17457.2.50.180/3057.2.50.181 to 57.2.50.18257.2.50.1832
17557.2.50.184/3057.2.50.185 to 57.2.50.18657.2.50.1872
17657.2.50.188/3057.2.50.189 to 57.2.50.19057.2.50.1912
17757.2.50.192/3057.2.50.193 to 57.2.50.19457.2.50.1952
17857.2.50.196/3057.2.50.197 to 57.2.50.19857.2.50.1992
17957.2.50.200/3057.2.50.201 to 57.2.50.20257.2.50.2032
18057.2.50.204/3057.2.50.205 to 57.2.50.20657.2.50.2072
18157.2.50.208/3057.2.50.209 to 57.2.50.21057.2.50.2112
18257.2.50.212/3057.2.50.213 to 57.2.50.21457.2.50.2152
18357.2.50.216/3057.2.50.217 to 57.2.50.21857.2.50.2192
18457.2.50.220/3057.2.50.221 to 57.2.50.22257.2.50.2232
18557.2.50.224/3057.2.50.225 to 57.2.50.22657.2.50.2272
18657.2.50.228/3057.2.50.229 to 57.2.50.23057.2.50.2312
18757.2.50.232/3057.2.50.233 to 57.2.50.23457.2.50.2352
18857.2.50.236/3057.2.50.237 to 57.2.50.23857.2.50.2392
18957.2.50.240/3057.2.50.241 to 57.2.50.24257.2.50.2432
19057.2.50.244/3057.2.50.245 to 57.2.50.24657.2.50.2472
19157.2.50.248/3057.2.50.249 to 57.2.50.25057.2.50.2512
19257.2.50.252/3057.2.50.253 to 57.2.50.25457.2.50.2552
19357.2.51.0/3057.2.51.1 to 57.2.51.257.2.51.32
19457.2.51.4/3057.2.51.5 to 57.2.51.657.2.51.72
19557.2.51.8/3057.2.51.9 to 57.2.51.1057.2.51.112
19657.2.51.12/3057.2.51.13 to 57.2.51.1457.2.51.152
19757.2.51.16/3057.2.51.17 to 57.2.51.1857.2.51.192
19857.2.51.20/3057.2.51.21 to 57.2.51.2257.2.51.232
19957.2.51.24/3057.2.51.25 to 57.2.51.2657.2.51.272
20057.2.51.28/3057.2.51.29 to 57.2.51.3057.2.51.312
20157.2.51.32/3057.2.51.33 to 57.2.51.3457.2.51.352
20257.2.51.36/3057.2.51.37 to 57.2.51.3857.2.51.392
20357.2.51.40/3057.2.51.41 to 57.2.51.4257.2.51.432
20457.2.51.44/3057.2.51.45 to 57.2.51.4657.2.51.472
20557.2.51.48/3057.2.51.49 to 57.2.51.5057.2.51.512
20657.2.51.52/3057.2.51.53 to 57.2.51.5457.2.51.552
20757.2.51.56/3057.2.51.57 to 57.2.51.5857.2.51.592
20857.2.51.60/3057.2.51.61 to 57.2.51.6257.2.51.632
20957.2.51.64/3057.2.51.65 to 57.2.51.6657.2.51.672
21057.2.51.68/3057.2.51.69 to 57.2.51.7057.2.51.712
21157.2.51.72/3057.2.51.73 to 57.2.51.7457.2.51.752
21257.2.51.76/3057.2.51.77 to 57.2.51.7857.2.51.792
21357.2.51.80/3057.2.51.81 to 57.2.51.8257.2.51.832
21457.2.51.84/3057.2.51.85 to 57.2.51.8657.2.51.872
21557.2.51.88/3057.2.51.89 to 57.2.51.9057.2.51.912
21657.2.51.92/3057.2.51.93 to 57.2.51.9457.2.51.952
21757.2.51.96/3057.2.51.97 to 57.2.51.9857.2.51.992
21857.2.51.100/3057.2.51.101 to 57.2.51.10257.2.51.1032
21957.2.51.104/3057.2.51.105 to 57.2.51.10657.2.51.1072
22057.2.51.108/3057.2.51.109 to 57.2.51.11057.2.51.1112
22157.2.51.112/3057.2.51.113 to 57.2.51.11457.2.51.1152
22257.2.51.116/3057.2.51.117 to 57.2.51.11857.2.51.1192
22357.2.51.120/3057.2.51.121 to 57.2.51.12257.2.51.1232
22457.2.51.124/3057.2.51.125 to 57.2.51.12657.2.51.1272
22557.2.51.128/3057.2.51.129 to 57.2.51.13057.2.51.1312
22657.2.51.132/3057.2.51.133 to 57.2.51.13457.2.51.1352
22757.2.51.136/3057.2.51.137 to 57.2.51.13857.2.51.1392
22857.2.51.140/3057.2.51.141 to 57.2.51.14257.2.51.1432
22957.2.51.144/3057.2.51.145 to 57.2.51.14657.2.51.1472
23057.2.51.148/3057.2.51.149 to 57.2.51.15057.2.51.1512
23157.2.51.152/3057.2.51.153 to 57.2.51.15457.2.51.1552
23257.2.51.156/3057.2.51.157 to 57.2.51.15857.2.51.1592
23357.2.51.160/3057.2.51.161 to 57.2.51.16257.2.51.1632
23457.2.51.164/3057.2.51.165 to 57.2.51.16657.2.51.1672
23557.2.51.168/3057.2.51.169 to 57.2.51.17057.2.51.1712
23657.2.51.172/3057.2.51.173 to 57.2.51.17457.2.51.1752
23757.2.51.176/3057.2.51.177 to 57.2.51.17857.2.51.1792
23857.2.51.180/3057.2.51.181 to 57.2.51.18257.2.51.1832
23957.2.51.184/3057.2.51.185 to 57.2.51.18657.2.51.1872
24057.2.51.188/3057.2.51.189 to 57.2.51.19057.2.51.1912
24157.2.51.192/3057.2.51.193 to 57.2.51.19457.2.51.1952
24257.2.51.196/3057.2.51.197 to 57.2.51.19857.2.51.1992
24357.2.51.200/3057.2.51.201 to 57.2.51.20257.2.51.2032
24457.2.51.204/3057.2.51.205 to 57.2.51.20657.2.51.2072
24557.2.51.208/3057.2.51.209 to 57.2.51.21057.2.51.2112
24657.2.51.212/3057.2.51.213 to 57.2.51.21457.2.51.2152
24757.2.51.216/3057.2.51.217 to 57.2.51.21857.2.51.2192
24857.2.51.220/3057.2.51.221 to 57.2.51.22257.2.51.2232
24957.2.51.224/3057.2.51.225 to 57.2.51.22657.2.51.2272
25057.2.51.228/3057.2.51.229 to 57.2.51.23057.2.51.2312
25157.2.51.232/3057.2.51.233 to 57.2.51.23457.2.51.2352
25257.2.51.236/3057.2.51.237 to 57.2.51.23857.2.51.2392
25357.2.51.240/3057.2.51.241 to 57.2.51.24257.2.51.2432
25457.2.51.244/3057.2.51.245 to 57.2.51.24657.2.51.2472
25557.2.51.248/3057.2.51.249 to 57.2.51.25057.2.51.2512
25657.2.51.252/3057.2.51.253 to 57.2.51.25457.2.51.2552

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.