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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.

Network32.128.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
32.128.0.0
Broadcast address
32.255.255.255
First usable
32.128.0.1
Last usable
32.255.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
Type
Public public
Old class
A (default /8)
As numbers
Hex 20800000 · Integer 545259520 to 553648127
Reverse DNS zones
128.32.in-addr.arpa
129.32.in-addr.arpa
130.32.in-addr.arpa
131.32.in-addr.arpa
132.32.in-addr.arpa
133.32.in-addr.arpa
134.32.in-addr.arpa
135.32.in-addr.arpa
136.32.in-addr.arpa
137.32.in-addr.arpa
138.32.in-addr.arpa
139.32.in-addr.arpa
140.32.in-addr.arpa
141.32.in-addr.arpa
142.32.in-addr.arpa
143.32.in-addr.arpa
and 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address00100000.10000000.00000000.0000000032.128.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network00100000.10000000.00000000.0000000032.128.0.0
Broadcast00100000.11111111.11111111.1111111132.255.255.255
Split into smaller subnets/18
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

32.128.0.0/9 makes 512 subnets of /18; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
132.128.0.0/1832.128.0.1 to 32.128.63.25432.128.63.25516,382
232.128.64.0/1832.128.64.1 to 32.128.127.25432.128.127.25516,382
332.128.128.0/1832.128.128.1 to 32.128.191.25432.128.191.25516,382
432.128.192.0/1832.128.192.1 to 32.128.255.25432.128.255.25516,382
532.129.0.0/1832.129.0.1 to 32.129.63.25432.129.63.25516,382
632.129.64.0/1832.129.64.1 to 32.129.127.25432.129.127.25516,382
732.129.128.0/1832.129.128.1 to 32.129.191.25432.129.191.25516,382
832.129.192.0/1832.129.192.1 to 32.129.255.25432.129.255.25516,382
932.130.0.0/1832.130.0.1 to 32.130.63.25432.130.63.25516,382
1032.130.64.0/1832.130.64.1 to 32.130.127.25432.130.127.25516,382
1132.130.128.0/1832.130.128.1 to 32.130.191.25432.130.191.25516,382
1232.130.192.0/1832.130.192.1 to 32.130.255.25432.130.255.25516,382
1332.131.0.0/1832.131.0.1 to 32.131.63.25432.131.63.25516,382
1432.131.64.0/1832.131.64.1 to 32.131.127.25432.131.127.25516,382
1532.131.128.0/1832.131.128.1 to 32.131.191.25432.131.191.25516,382
1632.131.192.0/1832.131.192.1 to 32.131.255.25432.131.255.25516,382
1732.132.0.0/1832.132.0.1 to 32.132.63.25432.132.63.25516,382
1832.132.64.0/1832.132.64.1 to 32.132.127.25432.132.127.25516,382
1932.132.128.0/1832.132.128.1 to 32.132.191.25432.132.191.25516,382
2032.132.192.0/1832.132.192.1 to 32.132.255.25432.132.255.25516,382
2132.133.0.0/1832.133.0.1 to 32.133.63.25432.133.63.25516,382
2232.133.64.0/1832.133.64.1 to 32.133.127.25432.133.127.25516,382
2332.133.128.0/1832.133.128.1 to 32.133.191.25432.133.191.25516,382
2432.133.192.0/1832.133.192.1 to 32.133.255.25432.133.255.25516,382
2532.134.0.0/1832.134.0.1 to 32.134.63.25432.134.63.25516,382
2632.134.64.0/1832.134.64.1 to 32.134.127.25432.134.127.25516,382
2732.134.128.0/1832.134.128.1 to 32.134.191.25432.134.191.25516,382
2832.134.192.0/1832.134.192.1 to 32.134.255.25432.134.255.25516,382
2932.135.0.0/1832.135.0.1 to 32.135.63.25432.135.63.25516,382
3032.135.64.0/1832.135.64.1 to 32.135.127.25432.135.127.25516,382
3132.135.128.0/1832.135.128.1 to 32.135.191.25432.135.191.25516,382
3232.135.192.0/1832.135.192.1 to 32.135.255.25432.135.255.25516,382
3332.136.0.0/1832.136.0.1 to 32.136.63.25432.136.63.25516,382
3432.136.64.0/1832.136.64.1 to 32.136.127.25432.136.127.25516,382
3532.136.128.0/1832.136.128.1 to 32.136.191.25432.136.191.25516,382
3632.136.192.0/1832.136.192.1 to 32.136.255.25432.136.255.25516,382
3732.137.0.0/1832.137.0.1 to 32.137.63.25432.137.63.25516,382
3832.137.64.0/1832.137.64.1 to 32.137.127.25432.137.127.25516,382
3932.137.128.0/1832.137.128.1 to 32.137.191.25432.137.191.25516,382
4032.137.192.0/1832.137.192.1 to 32.137.255.25432.137.255.25516,382
4132.138.0.0/1832.138.0.1 to 32.138.63.25432.138.63.25516,382
4232.138.64.0/1832.138.64.1 to 32.138.127.25432.138.127.25516,382
4332.138.128.0/1832.138.128.1 to 32.138.191.25432.138.191.25516,382
4432.138.192.0/1832.138.192.1 to 32.138.255.25432.138.255.25516,382
4532.139.0.0/1832.139.0.1 to 32.139.63.25432.139.63.25516,382
4632.139.64.0/1832.139.64.1 to 32.139.127.25432.139.127.25516,382
4732.139.128.0/1832.139.128.1 to 32.139.191.25432.139.191.25516,382
4832.139.192.0/1832.139.192.1 to 32.139.255.25432.139.255.25516,382
4932.140.0.0/1832.140.0.1 to 32.140.63.25432.140.63.25516,382
5032.140.64.0/1832.140.64.1 to 32.140.127.25432.140.127.25516,382
5132.140.128.0/1832.140.128.1 to 32.140.191.25432.140.191.25516,382
5232.140.192.0/1832.140.192.1 to 32.140.255.25432.140.255.25516,382
5332.141.0.0/1832.141.0.1 to 32.141.63.25432.141.63.25516,382
5432.141.64.0/1832.141.64.1 to 32.141.127.25432.141.127.25516,382
5532.141.128.0/1832.141.128.1 to 32.141.191.25432.141.191.25516,382
5632.141.192.0/1832.141.192.1 to 32.141.255.25432.141.255.25516,382
5732.142.0.0/1832.142.0.1 to 32.142.63.25432.142.63.25516,382
5832.142.64.0/1832.142.64.1 to 32.142.127.25432.142.127.25516,382
5932.142.128.0/1832.142.128.1 to 32.142.191.25432.142.191.25516,382
6032.142.192.0/1832.142.192.1 to 32.142.255.25432.142.255.25516,382
6132.143.0.0/1832.143.0.1 to 32.143.63.25432.143.63.25516,382
6232.143.64.0/1832.143.64.1 to 32.143.127.25432.143.127.25516,382
6332.143.128.0/1832.143.128.1 to 32.143.191.25432.143.191.25516,382
6432.143.192.0/1832.143.192.1 to 32.143.255.25432.143.255.25516,382
6532.144.0.0/1832.144.0.1 to 32.144.63.25432.144.63.25516,382
6632.144.64.0/1832.144.64.1 to 32.144.127.25432.144.127.25516,382
6732.144.128.0/1832.144.128.1 to 32.144.191.25432.144.191.25516,382
6832.144.192.0/1832.144.192.1 to 32.144.255.25432.144.255.25516,382
6932.145.0.0/1832.145.0.1 to 32.145.63.25432.145.63.25516,382
7032.145.64.0/1832.145.64.1 to 32.145.127.25432.145.127.25516,382
7132.145.128.0/1832.145.128.1 to 32.145.191.25432.145.191.25516,382
7232.145.192.0/1832.145.192.1 to 32.145.255.25432.145.255.25516,382
7332.146.0.0/1832.146.0.1 to 32.146.63.25432.146.63.25516,382
7432.146.64.0/1832.146.64.1 to 32.146.127.25432.146.127.25516,382
7532.146.128.0/1832.146.128.1 to 32.146.191.25432.146.191.25516,382
7632.146.192.0/1832.146.192.1 to 32.146.255.25432.146.255.25516,382
7732.147.0.0/1832.147.0.1 to 32.147.63.25432.147.63.25516,382
7832.147.64.0/1832.147.64.1 to 32.147.127.25432.147.127.25516,382
7932.147.128.0/1832.147.128.1 to 32.147.191.25432.147.191.25516,382
8032.147.192.0/1832.147.192.1 to 32.147.255.25432.147.255.25516,382
8132.148.0.0/1832.148.0.1 to 32.148.63.25432.148.63.25516,382
8232.148.64.0/1832.148.64.1 to 32.148.127.25432.148.127.25516,382
8332.148.128.0/1832.148.128.1 to 32.148.191.25432.148.191.25516,382
8432.148.192.0/1832.148.192.1 to 32.148.255.25432.148.255.25516,382
8532.149.0.0/1832.149.0.1 to 32.149.63.25432.149.63.25516,382
8632.149.64.0/1832.149.64.1 to 32.149.127.25432.149.127.25516,382
8732.149.128.0/1832.149.128.1 to 32.149.191.25432.149.191.25516,382
8832.149.192.0/1832.149.192.1 to 32.149.255.25432.149.255.25516,382
8932.150.0.0/1832.150.0.1 to 32.150.63.25432.150.63.25516,382
9032.150.64.0/1832.150.64.1 to 32.150.127.25432.150.127.25516,382
9132.150.128.0/1832.150.128.1 to 32.150.191.25432.150.191.25516,382
9232.150.192.0/1832.150.192.1 to 32.150.255.25432.150.255.25516,382
9332.151.0.0/1832.151.0.1 to 32.151.63.25432.151.63.25516,382
9432.151.64.0/1832.151.64.1 to 32.151.127.25432.151.127.25516,382
9532.151.128.0/1832.151.128.1 to 32.151.191.25432.151.191.25516,382
9632.151.192.0/1832.151.192.1 to 32.151.255.25432.151.255.25516,382
9732.152.0.0/1832.152.0.1 to 32.152.63.25432.152.63.25516,382
9832.152.64.0/1832.152.64.1 to 32.152.127.25432.152.127.25516,382
9932.152.128.0/1832.152.128.1 to 32.152.191.25432.152.191.25516,382
10032.152.192.0/1832.152.192.1 to 32.152.255.25432.152.255.25516,382
10132.153.0.0/1832.153.0.1 to 32.153.63.25432.153.63.25516,382
10232.153.64.0/1832.153.64.1 to 32.153.127.25432.153.127.25516,382
10332.153.128.0/1832.153.128.1 to 32.153.191.25432.153.191.25516,382
10432.153.192.0/1832.153.192.1 to 32.153.255.25432.153.255.25516,382
10532.154.0.0/1832.154.0.1 to 32.154.63.25432.154.63.25516,382
10632.154.64.0/1832.154.64.1 to 32.154.127.25432.154.127.25516,382
10732.154.128.0/1832.154.128.1 to 32.154.191.25432.154.191.25516,382
10832.154.192.0/1832.154.192.1 to 32.154.255.25432.154.255.25516,382
10932.155.0.0/1832.155.0.1 to 32.155.63.25432.155.63.25516,382
11032.155.64.0/1832.155.64.1 to 32.155.127.25432.155.127.25516,382
11132.155.128.0/1832.155.128.1 to 32.155.191.25432.155.191.25516,382
11232.155.192.0/1832.155.192.1 to 32.155.255.25432.155.255.25516,382
11332.156.0.0/1832.156.0.1 to 32.156.63.25432.156.63.25516,382
11432.156.64.0/1832.156.64.1 to 32.156.127.25432.156.127.25516,382
11532.156.128.0/1832.156.128.1 to 32.156.191.25432.156.191.25516,382
11632.156.192.0/1832.156.192.1 to 32.156.255.25432.156.255.25516,382
11732.157.0.0/1832.157.0.1 to 32.157.63.25432.157.63.25516,382
11832.157.64.0/1832.157.64.1 to 32.157.127.25432.157.127.25516,382
11932.157.128.0/1832.157.128.1 to 32.157.191.25432.157.191.25516,382
12032.157.192.0/1832.157.192.1 to 32.157.255.25432.157.255.25516,382
12132.158.0.0/1832.158.0.1 to 32.158.63.25432.158.63.25516,382
12232.158.64.0/1832.158.64.1 to 32.158.127.25432.158.127.25516,382
12332.158.128.0/1832.158.128.1 to 32.158.191.25432.158.191.25516,382
12432.158.192.0/1832.158.192.1 to 32.158.255.25432.158.255.25516,382
12532.159.0.0/1832.159.0.1 to 32.159.63.25432.159.63.25516,382
12632.159.64.0/1832.159.64.1 to 32.159.127.25432.159.127.25516,382
12732.159.128.0/1832.159.128.1 to 32.159.191.25432.159.191.25516,382
12832.159.192.0/1832.159.192.1 to 32.159.255.25432.159.255.25516,382
12932.160.0.0/1832.160.0.1 to 32.160.63.25432.160.63.25516,382
13032.160.64.0/1832.160.64.1 to 32.160.127.25432.160.127.25516,382
13132.160.128.0/1832.160.128.1 to 32.160.191.25432.160.191.25516,382
13232.160.192.0/1832.160.192.1 to 32.160.255.25432.160.255.25516,382
13332.161.0.0/1832.161.0.1 to 32.161.63.25432.161.63.25516,382
13432.161.64.0/1832.161.64.1 to 32.161.127.25432.161.127.25516,382
13532.161.128.0/1832.161.128.1 to 32.161.191.25432.161.191.25516,382
13632.161.192.0/1832.161.192.1 to 32.161.255.25432.161.255.25516,382
13732.162.0.0/1832.162.0.1 to 32.162.63.25432.162.63.25516,382
13832.162.64.0/1832.162.64.1 to 32.162.127.25432.162.127.25516,382
13932.162.128.0/1832.162.128.1 to 32.162.191.25432.162.191.25516,382
14032.162.192.0/1832.162.192.1 to 32.162.255.25432.162.255.25516,382
14132.163.0.0/1832.163.0.1 to 32.163.63.25432.163.63.25516,382
14232.163.64.0/1832.163.64.1 to 32.163.127.25432.163.127.25516,382
14332.163.128.0/1832.163.128.1 to 32.163.191.25432.163.191.25516,382
14432.163.192.0/1832.163.192.1 to 32.163.255.25432.163.255.25516,382
14532.164.0.0/1832.164.0.1 to 32.164.63.25432.164.63.25516,382
14632.164.64.0/1832.164.64.1 to 32.164.127.25432.164.127.25516,382
14732.164.128.0/1832.164.128.1 to 32.164.191.25432.164.191.25516,382
14832.164.192.0/1832.164.192.1 to 32.164.255.25432.164.255.25516,382
14932.165.0.0/1832.165.0.1 to 32.165.63.25432.165.63.25516,382
15032.165.64.0/1832.165.64.1 to 32.165.127.25432.165.127.25516,382
15132.165.128.0/1832.165.128.1 to 32.165.191.25432.165.191.25516,382
15232.165.192.0/1832.165.192.1 to 32.165.255.25432.165.255.25516,382
15332.166.0.0/1832.166.0.1 to 32.166.63.25432.166.63.25516,382
15432.166.64.0/1832.166.64.1 to 32.166.127.25432.166.127.25516,382
15532.166.128.0/1832.166.128.1 to 32.166.191.25432.166.191.25516,382
15632.166.192.0/1832.166.192.1 to 32.166.255.25432.166.255.25516,382
15732.167.0.0/1832.167.0.1 to 32.167.63.25432.167.63.25516,382
15832.167.64.0/1832.167.64.1 to 32.167.127.25432.167.127.25516,382
15932.167.128.0/1832.167.128.1 to 32.167.191.25432.167.191.25516,382
16032.167.192.0/1832.167.192.1 to 32.167.255.25432.167.255.25516,382
16132.168.0.0/1832.168.0.1 to 32.168.63.25432.168.63.25516,382
16232.168.64.0/1832.168.64.1 to 32.168.127.25432.168.127.25516,382
16332.168.128.0/1832.168.128.1 to 32.168.191.25432.168.191.25516,382
16432.168.192.0/1832.168.192.1 to 32.168.255.25432.168.255.25516,382
16532.169.0.0/1832.169.0.1 to 32.169.63.25432.169.63.25516,382
16632.169.64.0/1832.169.64.1 to 32.169.127.25432.169.127.25516,382
16732.169.128.0/1832.169.128.1 to 32.169.191.25432.169.191.25516,382
16832.169.192.0/1832.169.192.1 to 32.169.255.25432.169.255.25516,382
16932.170.0.0/1832.170.0.1 to 32.170.63.25432.170.63.25516,382
17032.170.64.0/1832.170.64.1 to 32.170.127.25432.170.127.25516,382
17132.170.128.0/1832.170.128.1 to 32.170.191.25432.170.191.25516,382
17232.170.192.0/1832.170.192.1 to 32.170.255.25432.170.255.25516,382
17332.171.0.0/1832.171.0.1 to 32.171.63.25432.171.63.25516,382
17432.171.64.0/1832.171.64.1 to 32.171.127.25432.171.127.25516,382
17532.171.128.0/1832.171.128.1 to 32.171.191.25432.171.191.25516,382
17632.171.192.0/1832.171.192.1 to 32.171.255.25432.171.255.25516,382
17732.172.0.0/1832.172.0.1 to 32.172.63.25432.172.63.25516,382
17832.172.64.0/1832.172.64.1 to 32.172.127.25432.172.127.25516,382
17932.172.128.0/1832.172.128.1 to 32.172.191.25432.172.191.25516,382
18032.172.192.0/1832.172.192.1 to 32.172.255.25432.172.255.25516,382
18132.173.0.0/1832.173.0.1 to 32.173.63.25432.173.63.25516,382
18232.173.64.0/1832.173.64.1 to 32.173.127.25432.173.127.25516,382
18332.173.128.0/1832.173.128.1 to 32.173.191.25432.173.191.25516,382
18432.173.192.0/1832.173.192.1 to 32.173.255.25432.173.255.25516,382
18532.174.0.0/1832.174.0.1 to 32.174.63.25432.174.63.25516,382
18632.174.64.0/1832.174.64.1 to 32.174.127.25432.174.127.25516,382
18732.174.128.0/1832.174.128.1 to 32.174.191.25432.174.191.25516,382
18832.174.192.0/1832.174.192.1 to 32.174.255.25432.174.255.25516,382
18932.175.0.0/1832.175.0.1 to 32.175.63.25432.175.63.25516,382
19032.175.64.0/1832.175.64.1 to 32.175.127.25432.175.127.25516,382
19132.175.128.0/1832.175.128.1 to 32.175.191.25432.175.191.25516,382
19232.175.192.0/1832.175.192.1 to 32.175.255.25432.175.255.25516,382
19332.176.0.0/1832.176.0.1 to 32.176.63.25432.176.63.25516,382
19432.176.64.0/1832.176.64.1 to 32.176.127.25432.176.127.25516,382
19532.176.128.0/1832.176.128.1 to 32.176.191.25432.176.191.25516,382
19632.176.192.0/1832.176.192.1 to 32.176.255.25432.176.255.25516,382
19732.177.0.0/1832.177.0.1 to 32.177.63.25432.177.63.25516,382
19832.177.64.0/1832.177.64.1 to 32.177.127.25432.177.127.25516,382
19932.177.128.0/1832.177.128.1 to 32.177.191.25432.177.191.25516,382
20032.177.192.0/1832.177.192.1 to 32.177.255.25432.177.255.25516,382
20132.178.0.0/1832.178.0.1 to 32.178.63.25432.178.63.25516,382
20232.178.64.0/1832.178.64.1 to 32.178.127.25432.178.127.25516,382
20332.178.128.0/1832.178.128.1 to 32.178.191.25432.178.191.25516,382
20432.178.192.0/1832.178.192.1 to 32.178.255.25432.178.255.25516,382
20532.179.0.0/1832.179.0.1 to 32.179.63.25432.179.63.25516,382
20632.179.64.0/1832.179.64.1 to 32.179.127.25432.179.127.25516,382
20732.179.128.0/1832.179.128.1 to 32.179.191.25432.179.191.25516,382
20832.179.192.0/1832.179.192.1 to 32.179.255.25432.179.255.25516,382
20932.180.0.0/1832.180.0.1 to 32.180.63.25432.180.63.25516,382
21032.180.64.0/1832.180.64.1 to 32.180.127.25432.180.127.25516,382
21132.180.128.0/1832.180.128.1 to 32.180.191.25432.180.191.25516,382
21232.180.192.0/1832.180.192.1 to 32.180.255.25432.180.255.25516,382
21332.181.0.0/1832.181.0.1 to 32.181.63.25432.181.63.25516,382
21432.181.64.0/1832.181.64.1 to 32.181.127.25432.181.127.25516,382
21532.181.128.0/1832.181.128.1 to 32.181.191.25432.181.191.25516,382
21632.181.192.0/1832.181.192.1 to 32.181.255.25432.181.255.25516,382
21732.182.0.0/1832.182.0.1 to 32.182.63.25432.182.63.25516,382
21832.182.64.0/1832.182.64.1 to 32.182.127.25432.182.127.25516,382
21932.182.128.0/1832.182.128.1 to 32.182.191.25432.182.191.25516,382
22032.182.192.0/1832.182.192.1 to 32.182.255.25432.182.255.25516,382
22132.183.0.0/1832.183.0.1 to 32.183.63.25432.183.63.25516,382
22232.183.64.0/1832.183.64.1 to 32.183.127.25432.183.127.25516,382
22332.183.128.0/1832.183.128.1 to 32.183.191.25432.183.191.25516,382
22432.183.192.0/1832.183.192.1 to 32.183.255.25432.183.255.25516,382
22532.184.0.0/1832.184.0.1 to 32.184.63.25432.184.63.25516,382
22632.184.64.0/1832.184.64.1 to 32.184.127.25432.184.127.25516,382
22732.184.128.0/1832.184.128.1 to 32.184.191.25432.184.191.25516,382
22832.184.192.0/1832.184.192.1 to 32.184.255.25432.184.255.25516,382
22932.185.0.0/1832.185.0.1 to 32.185.63.25432.185.63.25516,382
23032.185.64.0/1832.185.64.1 to 32.185.127.25432.185.127.25516,382
23132.185.128.0/1832.185.128.1 to 32.185.191.25432.185.191.25516,382
23232.185.192.0/1832.185.192.1 to 32.185.255.25432.185.255.25516,382
23332.186.0.0/1832.186.0.1 to 32.186.63.25432.186.63.25516,382
23432.186.64.0/1832.186.64.1 to 32.186.127.25432.186.127.25516,382
23532.186.128.0/1832.186.128.1 to 32.186.191.25432.186.191.25516,382
23632.186.192.0/1832.186.192.1 to 32.186.255.25432.186.255.25516,382
23732.187.0.0/1832.187.0.1 to 32.187.63.25432.187.63.25516,382
23832.187.64.0/1832.187.64.1 to 32.187.127.25432.187.127.25516,382
23932.187.128.0/1832.187.128.1 to 32.187.191.25432.187.191.25516,382
24032.187.192.0/1832.187.192.1 to 32.187.255.25432.187.255.25516,382
24132.188.0.0/1832.188.0.1 to 32.188.63.25432.188.63.25516,382
24232.188.64.0/1832.188.64.1 to 32.188.127.25432.188.127.25516,382
24332.188.128.0/1832.188.128.1 to 32.188.191.25432.188.191.25516,382
24432.188.192.0/1832.188.192.1 to 32.188.255.25432.188.255.25516,382
24532.189.0.0/1832.189.0.1 to 32.189.63.25432.189.63.25516,382
24632.189.64.0/1832.189.64.1 to 32.189.127.25432.189.127.25516,382
24732.189.128.0/1832.189.128.1 to 32.189.191.25432.189.191.25516,382
24832.189.192.0/1832.189.192.1 to 32.189.255.25432.189.255.25516,382
24932.190.0.0/1832.190.0.1 to 32.190.63.25432.190.63.25516,382
25032.190.64.0/1832.190.64.1 to 32.190.127.25432.190.127.25516,382
25132.190.128.0/1832.190.128.1 to 32.190.191.25432.190.191.25516,382
25232.190.192.0/1832.190.192.1 to 32.190.255.25432.190.255.25516,382
25332.191.0.0/1832.191.0.1 to 32.191.63.25432.191.63.25516,382
25432.191.64.0/1832.191.64.1 to 32.191.127.25432.191.127.25516,382
25532.191.128.0/1832.191.128.1 to 32.191.191.25432.191.191.25516,382
25632.191.192.0/1832.191.192.1 to 32.191.255.25432.191.255.25516,382

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.