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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.

Network13.112.0.0/12
Usable hosts1,048,574
Subnet mask255.240.0.0
Addresses1,048,576
Network address
13.112.0.0
Broadcast address
13.127.255.255
First usable
13.112.0.1
Last usable
13.127.255.254
Usable hosts
1,048,574 (1,048,576 less the network and broadcast addresses)
Subnet mask
255.240.0.0
Wildcard mask
0.15.255.255 (Cisco ACLs, OSPF)
Prefix length
/12
Type
Public public
Old class
A (default /8)
As numbers
Hex 0D700000 · Integer 225443840 to 226492415
Reverse DNS zones
112.13.in-addr.arpa
113.13.in-addr.arpa
114.13.in-addr.arpa
115.13.in-addr.arpa
116.13.in-addr.arpa
117.13.in-addr.arpa
118.13.in-addr.arpa
119.13.in-addr.arpa
120.13.in-addr.arpa
121.13.in-addr.arpa
122.13.in-addr.arpa
123.13.in-addr.arpa
124.13.in-addr.arpa
125.13.in-addr.arpa
126.13.in-addr.arpa
127.13.in-addr.arpa
/12 is not on a 8-bit boundary, so it takes 16 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00001101.01110000.00000000.0000000013.112.0.0
Subnet mask11111111.11110000.00000000.00000000255.240.0.0
Network00001101.01110000.00000000.0000000013.112.0.0
Broadcast00001101.01111111.11111111.1111111113.127.255.255
Split into smaller subnets/20
/13 (2)/14 (4)/15 (8)/16 (16)/17 (32)/18 (64)/19 (128)/20 (256)/21 (512)/22 (1,024)/23 (2,048)/24 (4,096)

13.112.0.0/12 makes 256 subnets of /20.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
113.112.0.0/2013.112.0.1 to 13.112.15.25413.112.15.2554,094
213.112.16.0/2013.112.16.1 to 13.112.31.25413.112.31.2554,094
313.112.32.0/2013.112.32.1 to 13.112.47.25413.112.47.2554,094
413.112.48.0/2013.112.48.1 to 13.112.63.25413.112.63.2554,094
513.112.64.0/2013.112.64.1 to 13.112.79.25413.112.79.2554,094
613.112.80.0/2013.112.80.1 to 13.112.95.25413.112.95.2554,094
713.112.96.0/2013.112.96.1 to 13.112.111.25413.112.111.2554,094
813.112.112.0/2013.112.112.1 to 13.112.127.25413.112.127.2554,094
913.112.128.0/2013.112.128.1 to 13.112.143.25413.112.143.2554,094
1013.112.144.0/2013.112.144.1 to 13.112.159.25413.112.159.2554,094
1113.112.160.0/2013.112.160.1 to 13.112.175.25413.112.175.2554,094
1213.112.176.0/2013.112.176.1 to 13.112.191.25413.112.191.2554,094
1313.112.192.0/2013.112.192.1 to 13.112.207.25413.112.207.2554,094
1413.112.208.0/2013.112.208.1 to 13.112.223.25413.112.223.2554,094
1513.112.224.0/2013.112.224.1 to 13.112.239.25413.112.239.2554,094
1613.112.240.0/2013.112.240.1 to 13.112.255.25413.112.255.2554,094
1713.113.0.0/2013.113.0.1 to 13.113.15.25413.113.15.2554,094
1813.113.16.0/2013.113.16.1 to 13.113.31.25413.113.31.2554,094
1913.113.32.0/2013.113.32.1 to 13.113.47.25413.113.47.2554,094
2013.113.48.0/2013.113.48.1 to 13.113.63.25413.113.63.2554,094
2113.113.64.0/2013.113.64.1 to 13.113.79.25413.113.79.2554,094
2213.113.80.0/2013.113.80.1 to 13.113.95.25413.113.95.2554,094
2313.113.96.0/2013.113.96.1 to 13.113.111.25413.113.111.2554,094
2413.113.112.0/2013.113.112.1 to 13.113.127.25413.113.127.2554,094
2513.113.128.0/2013.113.128.1 to 13.113.143.25413.113.143.2554,094
2613.113.144.0/2013.113.144.1 to 13.113.159.25413.113.159.2554,094
2713.113.160.0/2013.113.160.1 to 13.113.175.25413.113.175.2554,094
2813.113.176.0/2013.113.176.1 to 13.113.191.25413.113.191.2554,094
2913.113.192.0/2013.113.192.1 to 13.113.207.25413.113.207.2554,094
3013.113.208.0/2013.113.208.1 to 13.113.223.25413.113.223.2554,094
3113.113.224.0/2013.113.224.1 to 13.113.239.25413.113.239.2554,094
3213.113.240.0/2013.113.240.1 to 13.113.255.25413.113.255.2554,094
3313.114.0.0/2013.114.0.1 to 13.114.15.25413.114.15.2554,094
3413.114.16.0/2013.114.16.1 to 13.114.31.25413.114.31.2554,094
3513.114.32.0/2013.114.32.1 to 13.114.47.25413.114.47.2554,094
3613.114.48.0/2013.114.48.1 to 13.114.63.25413.114.63.2554,094
3713.114.64.0/2013.114.64.1 to 13.114.79.25413.114.79.2554,094
3813.114.80.0/2013.114.80.1 to 13.114.95.25413.114.95.2554,094
3913.114.96.0/2013.114.96.1 to 13.114.111.25413.114.111.2554,094
4013.114.112.0/2013.114.112.1 to 13.114.127.25413.114.127.2554,094
4113.114.128.0/2013.114.128.1 to 13.114.143.25413.114.143.2554,094
4213.114.144.0/2013.114.144.1 to 13.114.159.25413.114.159.2554,094
4313.114.160.0/2013.114.160.1 to 13.114.175.25413.114.175.2554,094
4413.114.176.0/2013.114.176.1 to 13.114.191.25413.114.191.2554,094
4513.114.192.0/2013.114.192.1 to 13.114.207.25413.114.207.2554,094
4613.114.208.0/2013.114.208.1 to 13.114.223.25413.114.223.2554,094
4713.114.224.0/2013.114.224.1 to 13.114.239.25413.114.239.2554,094
4813.114.240.0/2013.114.240.1 to 13.114.255.25413.114.255.2554,094
4913.115.0.0/2013.115.0.1 to 13.115.15.25413.115.15.2554,094
5013.115.16.0/2013.115.16.1 to 13.115.31.25413.115.31.2554,094
5113.115.32.0/2013.115.32.1 to 13.115.47.25413.115.47.2554,094
5213.115.48.0/2013.115.48.1 to 13.115.63.25413.115.63.2554,094
5313.115.64.0/2013.115.64.1 to 13.115.79.25413.115.79.2554,094
5413.115.80.0/2013.115.80.1 to 13.115.95.25413.115.95.2554,094
5513.115.96.0/2013.115.96.1 to 13.115.111.25413.115.111.2554,094
5613.115.112.0/2013.115.112.1 to 13.115.127.25413.115.127.2554,094
5713.115.128.0/2013.115.128.1 to 13.115.143.25413.115.143.2554,094
5813.115.144.0/2013.115.144.1 to 13.115.159.25413.115.159.2554,094
5913.115.160.0/2013.115.160.1 to 13.115.175.25413.115.175.2554,094
6013.115.176.0/2013.115.176.1 to 13.115.191.25413.115.191.2554,094
6113.115.192.0/2013.115.192.1 to 13.115.207.25413.115.207.2554,094
6213.115.208.0/2013.115.208.1 to 13.115.223.25413.115.223.2554,094
6313.115.224.0/2013.115.224.1 to 13.115.239.25413.115.239.2554,094
6413.115.240.0/2013.115.240.1 to 13.115.255.25413.115.255.2554,094
6513.116.0.0/2013.116.0.1 to 13.116.15.25413.116.15.2554,094
6613.116.16.0/2013.116.16.1 to 13.116.31.25413.116.31.2554,094
6713.116.32.0/2013.116.32.1 to 13.116.47.25413.116.47.2554,094
6813.116.48.0/2013.116.48.1 to 13.116.63.25413.116.63.2554,094
6913.116.64.0/2013.116.64.1 to 13.116.79.25413.116.79.2554,094
7013.116.80.0/2013.116.80.1 to 13.116.95.25413.116.95.2554,094
7113.116.96.0/2013.116.96.1 to 13.116.111.25413.116.111.2554,094
7213.116.112.0/2013.116.112.1 to 13.116.127.25413.116.127.2554,094
7313.116.128.0/2013.116.128.1 to 13.116.143.25413.116.143.2554,094
7413.116.144.0/2013.116.144.1 to 13.116.159.25413.116.159.2554,094
7513.116.160.0/2013.116.160.1 to 13.116.175.25413.116.175.2554,094
7613.116.176.0/2013.116.176.1 to 13.116.191.25413.116.191.2554,094
7713.116.192.0/2013.116.192.1 to 13.116.207.25413.116.207.2554,094
7813.116.208.0/2013.116.208.1 to 13.116.223.25413.116.223.2554,094
7913.116.224.0/2013.116.224.1 to 13.116.239.25413.116.239.2554,094
8013.116.240.0/2013.116.240.1 to 13.116.255.25413.116.255.2554,094
8113.117.0.0/2013.117.0.1 to 13.117.15.25413.117.15.2554,094
8213.117.16.0/2013.117.16.1 to 13.117.31.25413.117.31.2554,094
8313.117.32.0/2013.117.32.1 to 13.117.47.25413.117.47.2554,094
8413.117.48.0/2013.117.48.1 to 13.117.63.25413.117.63.2554,094
8513.117.64.0/2013.117.64.1 to 13.117.79.25413.117.79.2554,094
8613.117.80.0/2013.117.80.1 to 13.117.95.25413.117.95.2554,094
8713.117.96.0/2013.117.96.1 to 13.117.111.25413.117.111.2554,094
8813.117.112.0/2013.117.112.1 to 13.117.127.25413.117.127.2554,094
8913.117.128.0/2013.117.128.1 to 13.117.143.25413.117.143.2554,094
9013.117.144.0/2013.117.144.1 to 13.117.159.25413.117.159.2554,094
9113.117.160.0/2013.117.160.1 to 13.117.175.25413.117.175.2554,094
9213.117.176.0/2013.117.176.1 to 13.117.191.25413.117.191.2554,094
9313.117.192.0/2013.117.192.1 to 13.117.207.25413.117.207.2554,094
9413.117.208.0/2013.117.208.1 to 13.117.223.25413.117.223.2554,094
9513.117.224.0/2013.117.224.1 to 13.117.239.25413.117.239.2554,094
9613.117.240.0/2013.117.240.1 to 13.117.255.25413.117.255.2554,094
9713.118.0.0/2013.118.0.1 to 13.118.15.25413.118.15.2554,094
9813.118.16.0/2013.118.16.1 to 13.118.31.25413.118.31.2554,094
9913.118.32.0/2013.118.32.1 to 13.118.47.25413.118.47.2554,094
10013.118.48.0/2013.118.48.1 to 13.118.63.25413.118.63.2554,094
10113.118.64.0/2013.118.64.1 to 13.118.79.25413.118.79.2554,094
10213.118.80.0/2013.118.80.1 to 13.118.95.25413.118.95.2554,094
10313.118.96.0/2013.118.96.1 to 13.118.111.25413.118.111.2554,094
10413.118.112.0/2013.118.112.1 to 13.118.127.25413.118.127.2554,094
10513.118.128.0/2013.118.128.1 to 13.118.143.25413.118.143.2554,094
10613.118.144.0/2013.118.144.1 to 13.118.159.25413.118.159.2554,094
10713.118.160.0/2013.118.160.1 to 13.118.175.25413.118.175.2554,094
10813.118.176.0/2013.118.176.1 to 13.118.191.25413.118.191.2554,094
10913.118.192.0/2013.118.192.1 to 13.118.207.25413.118.207.2554,094
11013.118.208.0/2013.118.208.1 to 13.118.223.25413.118.223.2554,094
11113.118.224.0/2013.118.224.1 to 13.118.239.25413.118.239.2554,094
11213.118.240.0/2013.118.240.1 to 13.118.255.25413.118.255.2554,094
11313.119.0.0/2013.119.0.1 to 13.119.15.25413.119.15.2554,094
11413.119.16.0/2013.119.16.1 to 13.119.31.25413.119.31.2554,094
11513.119.32.0/2013.119.32.1 to 13.119.47.25413.119.47.2554,094
11613.119.48.0/2013.119.48.1 to 13.119.63.25413.119.63.2554,094
11713.119.64.0/2013.119.64.1 to 13.119.79.25413.119.79.2554,094
11813.119.80.0/2013.119.80.1 to 13.119.95.25413.119.95.2554,094
11913.119.96.0/2013.119.96.1 to 13.119.111.25413.119.111.2554,094
12013.119.112.0/2013.119.112.1 to 13.119.127.25413.119.127.2554,094
12113.119.128.0/2013.119.128.1 to 13.119.143.25413.119.143.2554,094
12213.119.144.0/2013.119.144.1 to 13.119.159.25413.119.159.2554,094
12313.119.160.0/2013.119.160.1 to 13.119.175.25413.119.175.2554,094
12413.119.176.0/2013.119.176.1 to 13.119.191.25413.119.191.2554,094
12513.119.192.0/2013.119.192.1 to 13.119.207.25413.119.207.2554,094
12613.119.208.0/2013.119.208.1 to 13.119.223.25413.119.223.2554,094
12713.119.224.0/2013.119.224.1 to 13.119.239.25413.119.239.2554,094
12813.119.240.0/2013.119.240.1 to 13.119.255.25413.119.255.2554,094
12913.120.0.0/2013.120.0.1 to 13.120.15.25413.120.15.2554,094
13013.120.16.0/2013.120.16.1 to 13.120.31.25413.120.31.2554,094
13113.120.32.0/2013.120.32.1 to 13.120.47.25413.120.47.2554,094
13213.120.48.0/2013.120.48.1 to 13.120.63.25413.120.63.2554,094
13313.120.64.0/2013.120.64.1 to 13.120.79.25413.120.79.2554,094
13413.120.80.0/2013.120.80.1 to 13.120.95.25413.120.95.2554,094
13513.120.96.0/2013.120.96.1 to 13.120.111.25413.120.111.2554,094
13613.120.112.0/2013.120.112.1 to 13.120.127.25413.120.127.2554,094
13713.120.128.0/2013.120.128.1 to 13.120.143.25413.120.143.2554,094
13813.120.144.0/2013.120.144.1 to 13.120.159.25413.120.159.2554,094
13913.120.160.0/2013.120.160.1 to 13.120.175.25413.120.175.2554,094
14013.120.176.0/2013.120.176.1 to 13.120.191.25413.120.191.2554,094
14113.120.192.0/2013.120.192.1 to 13.120.207.25413.120.207.2554,094
14213.120.208.0/2013.120.208.1 to 13.120.223.25413.120.223.2554,094
14313.120.224.0/2013.120.224.1 to 13.120.239.25413.120.239.2554,094
14413.120.240.0/2013.120.240.1 to 13.120.255.25413.120.255.2554,094
14513.121.0.0/2013.121.0.1 to 13.121.15.25413.121.15.2554,094
14613.121.16.0/2013.121.16.1 to 13.121.31.25413.121.31.2554,094
14713.121.32.0/2013.121.32.1 to 13.121.47.25413.121.47.2554,094
14813.121.48.0/2013.121.48.1 to 13.121.63.25413.121.63.2554,094
14913.121.64.0/2013.121.64.1 to 13.121.79.25413.121.79.2554,094
15013.121.80.0/2013.121.80.1 to 13.121.95.25413.121.95.2554,094
15113.121.96.0/2013.121.96.1 to 13.121.111.25413.121.111.2554,094
15213.121.112.0/2013.121.112.1 to 13.121.127.25413.121.127.2554,094
15313.121.128.0/2013.121.128.1 to 13.121.143.25413.121.143.2554,094
15413.121.144.0/2013.121.144.1 to 13.121.159.25413.121.159.2554,094
15513.121.160.0/2013.121.160.1 to 13.121.175.25413.121.175.2554,094
15613.121.176.0/2013.121.176.1 to 13.121.191.25413.121.191.2554,094
15713.121.192.0/2013.121.192.1 to 13.121.207.25413.121.207.2554,094
15813.121.208.0/2013.121.208.1 to 13.121.223.25413.121.223.2554,094
15913.121.224.0/2013.121.224.1 to 13.121.239.25413.121.239.2554,094
16013.121.240.0/2013.121.240.1 to 13.121.255.25413.121.255.2554,094
16113.122.0.0/2013.122.0.1 to 13.122.15.25413.122.15.2554,094
16213.122.16.0/2013.122.16.1 to 13.122.31.25413.122.31.2554,094
16313.122.32.0/2013.122.32.1 to 13.122.47.25413.122.47.2554,094
16413.122.48.0/2013.122.48.1 to 13.122.63.25413.122.63.2554,094
16513.122.64.0/2013.122.64.1 to 13.122.79.25413.122.79.2554,094
16613.122.80.0/2013.122.80.1 to 13.122.95.25413.122.95.2554,094
16713.122.96.0/2013.122.96.1 to 13.122.111.25413.122.111.2554,094
16813.122.112.0/2013.122.112.1 to 13.122.127.25413.122.127.2554,094
16913.122.128.0/2013.122.128.1 to 13.122.143.25413.122.143.2554,094
17013.122.144.0/2013.122.144.1 to 13.122.159.25413.122.159.2554,094
17113.122.160.0/2013.122.160.1 to 13.122.175.25413.122.175.2554,094
17213.122.176.0/2013.122.176.1 to 13.122.191.25413.122.191.2554,094
17313.122.192.0/2013.122.192.1 to 13.122.207.25413.122.207.2554,094
17413.122.208.0/2013.122.208.1 to 13.122.223.25413.122.223.2554,094
17513.122.224.0/2013.122.224.1 to 13.122.239.25413.122.239.2554,094
17613.122.240.0/2013.122.240.1 to 13.122.255.25413.122.255.2554,094
17713.123.0.0/2013.123.0.1 to 13.123.15.25413.123.15.2554,094
17813.123.16.0/2013.123.16.1 to 13.123.31.25413.123.31.2554,094
17913.123.32.0/2013.123.32.1 to 13.123.47.25413.123.47.2554,094
18013.123.48.0/2013.123.48.1 to 13.123.63.25413.123.63.2554,094
18113.123.64.0/2013.123.64.1 to 13.123.79.25413.123.79.2554,094
18213.123.80.0/2013.123.80.1 to 13.123.95.25413.123.95.2554,094
18313.123.96.0/2013.123.96.1 to 13.123.111.25413.123.111.2554,094
18413.123.112.0/2013.123.112.1 to 13.123.127.25413.123.127.2554,094
18513.123.128.0/2013.123.128.1 to 13.123.143.25413.123.143.2554,094
18613.123.144.0/2013.123.144.1 to 13.123.159.25413.123.159.2554,094
18713.123.160.0/2013.123.160.1 to 13.123.175.25413.123.175.2554,094
18813.123.176.0/2013.123.176.1 to 13.123.191.25413.123.191.2554,094
18913.123.192.0/2013.123.192.1 to 13.123.207.25413.123.207.2554,094
19013.123.208.0/2013.123.208.1 to 13.123.223.25413.123.223.2554,094
19113.123.224.0/2013.123.224.1 to 13.123.239.25413.123.239.2554,094
19213.123.240.0/2013.123.240.1 to 13.123.255.25413.123.255.2554,094
19313.124.0.0/2013.124.0.1 to 13.124.15.25413.124.15.2554,094
19413.124.16.0/2013.124.16.1 to 13.124.31.25413.124.31.2554,094
19513.124.32.0/2013.124.32.1 to 13.124.47.25413.124.47.2554,094
19613.124.48.0/2013.124.48.1 to 13.124.63.25413.124.63.2554,094
19713.124.64.0/2013.124.64.1 to 13.124.79.25413.124.79.2554,094
19813.124.80.0/2013.124.80.1 to 13.124.95.25413.124.95.2554,094
19913.124.96.0/2013.124.96.1 to 13.124.111.25413.124.111.2554,094
20013.124.112.0/2013.124.112.1 to 13.124.127.25413.124.127.2554,094
20113.124.128.0/2013.124.128.1 to 13.124.143.25413.124.143.2554,094
20213.124.144.0/2013.124.144.1 to 13.124.159.25413.124.159.2554,094
20313.124.160.0/2013.124.160.1 to 13.124.175.25413.124.175.2554,094
20413.124.176.0/2013.124.176.1 to 13.124.191.25413.124.191.2554,094
20513.124.192.0/2013.124.192.1 to 13.124.207.25413.124.207.2554,094
20613.124.208.0/2013.124.208.1 to 13.124.223.25413.124.223.2554,094
20713.124.224.0/2013.124.224.1 to 13.124.239.25413.124.239.2554,094
20813.124.240.0/2013.124.240.1 to 13.124.255.25413.124.255.2554,094
20913.125.0.0/2013.125.0.1 to 13.125.15.25413.125.15.2554,094
21013.125.16.0/2013.125.16.1 to 13.125.31.25413.125.31.2554,094
21113.125.32.0/2013.125.32.1 to 13.125.47.25413.125.47.2554,094
21213.125.48.0/2013.125.48.1 to 13.125.63.25413.125.63.2554,094
21313.125.64.0/2013.125.64.1 to 13.125.79.25413.125.79.2554,094
21413.125.80.0/2013.125.80.1 to 13.125.95.25413.125.95.2554,094
21513.125.96.0/2013.125.96.1 to 13.125.111.25413.125.111.2554,094
21613.125.112.0/2013.125.112.1 to 13.125.127.25413.125.127.2554,094
21713.125.128.0/2013.125.128.1 to 13.125.143.25413.125.143.2554,094
21813.125.144.0/2013.125.144.1 to 13.125.159.25413.125.159.2554,094
21913.125.160.0/2013.125.160.1 to 13.125.175.25413.125.175.2554,094
22013.125.176.0/2013.125.176.1 to 13.125.191.25413.125.191.2554,094
22113.125.192.0/2013.125.192.1 to 13.125.207.25413.125.207.2554,094
22213.125.208.0/2013.125.208.1 to 13.125.223.25413.125.223.2554,094
22313.125.224.0/2013.125.224.1 to 13.125.239.25413.125.239.2554,094
22413.125.240.0/2013.125.240.1 to 13.125.255.25413.125.255.2554,094
22513.126.0.0/2013.126.0.1 to 13.126.15.25413.126.15.2554,094
22613.126.16.0/2013.126.16.1 to 13.126.31.25413.126.31.2554,094
22713.126.32.0/2013.126.32.1 to 13.126.47.25413.126.47.2554,094
22813.126.48.0/2013.126.48.1 to 13.126.63.25413.126.63.2554,094
22913.126.64.0/2013.126.64.1 to 13.126.79.25413.126.79.2554,094
23013.126.80.0/2013.126.80.1 to 13.126.95.25413.126.95.2554,094
23113.126.96.0/2013.126.96.1 to 13.126.111.25413.126.111.2554,094
23213.126.112.0/2013.126.112.1 to 13.126.127.25413.126.127.2554,094
23313.126.128.0/2013.126.128.1 to 13.126.143.25413.126.143.2554,094
23413.126.144.0/2013.126.144.1 to 13.126.159.25413.126.159.2554,094
23513.126.160.0/2013.126.160.1 to 13.126.175.25413.126.175.2554,094
23613.126.176.0/2013.126.176.1 to 13.126.191.25413.126.191.2554,094
23713.126.192.0/2013.126.192.1 to 13.126.207.25413.126.207.2554,094
23813.126.208.0/2013.126.208.1 to 13.126.223.25413.126.223.2554,094
23913.126.224.0/2013.126.224.1 to 13.126.239.25413.126.239.2554,094
24013.126.240.0/2013.126.240.1 to 13.126.255.25413.126.255.2554,094
24113.127.0.0/2013.127.0.1 to 13.127.15.25413.127.15.2554,094
24213.127.16.0/2013.127.16.1 to 13.127.31.25413.127.31.2554,094
24313.127.32.0/2013.127.32.1 to 13.127.47.25413.127.47.2554,094
24413.127.48.0/2013.127.48.1 to 13.127.63.25413.127.63.2554,094
24513.127.64.0/2013.127.64.1 to 13.127.79.25413.127.79.2554,094
24613.127.80.0/2013.127.80.1 to 13.127.95.25413.127.95.2554,094
24713.127.96.0/2013.127.96.1 to 13.127.111.25413.127.111.2554,094
24813.127.112.0/2013.127.112.1 to 13.127.127.25413.127.127.2554,094
24913.127.128.0/2013.127.128.1 to 13.127.143.25413.127.143.2554,094
25013.127.144.0/2013.127.144.1 to 13.127.159.25413.127.159.2554,094
25113.127.160.0/2013.127.160.1 to 13.127.175.25413.127.175.2554,094
25213.127.176.0/2013.127.176.1 to 13.127.191.25413.127.191.2554,094
25313.127.192.0/2013.127.192.1 to 13.127.207.25413.127.207.2554,094
25413.127.208.0/2013.127.208.1 to 13.127.223.25413.127.223.2554,094
25513.127.224.0/2013.127.224.1 to 13.127.239.25413.127.239.2554,094
25613.127.240.0/2013.127.240.1 to 13.127.255.25413.127.255.2554,094

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.