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IPv4 Subnet Calculator

Enter an IP with a CIDR prefix or a subnet mask to see its network, broadcast, host range, and host count. You can also split the network into smaller subnets.

$ ipcalc
private IP (RFC 1918)10.45.0.0/20
network10.45.0.0/20
broadcast10.45.15.255
first host10.45.0.1
last host10.45.15.254
subnet mask255.255.240.0
wildcard0.0.15.255
addresses4,096
usable hosts4,094
classA
ipcalc 10.45.0.0/20
address00001010.00101101.00000000.00000000
subnet mask11111111.11111111.11110000.00000000
network00001010.00101101.00000000.00000000
broadcast00001010.00101101.00001111.11111111
green = network part, grey = host part
hex0x0a2d0000
decimal170721280
reverse dns0.0.45.10.in-addr.arpa
ipv4-mapped::ffff:a2d:0

/20 split into /26 · 64 subnets

close ×
#networkhost rangebroadcast
110.45.0.0/2610.45.0.1 – 10.45.0.6210.45.0.63
210.45.0.64/2610.45.0.65 – 10.45.0.12610.45.0.127
310.45.0.128/2610.45.0.129 – 10.45.0.19010.45.0.191
410.45.0.192/2610.45.0.193 – 10.45.0.25410.45.0.255
510.45.1.0/2610.45.1.1 – 10.45.1.6210.45.1.63
610.45.1.64/2610.45.1.65 – 10.45.1.12610.45.1.127
710.45.1.128/2610.45.1.129 – 10.45.1.19010.45.1.191
810.45.1.192/2610.45.1.193 – 10.45.1.25410.45.1.255
910.45.2.0/2610.45.2.1 – 10.45.2.6210.45.2.63
1010.45.2.64/2610.45.2.65 – 10.45.2.12610.45.2.127
1110.45.2.128/2610.45.2.129 – 10.45.2.19010.45.2.191
1210.45.2.192/2610.45.2.193 – 10.45.2.25410.45.2.255
1310.45.3.0/2610.45.3.1 – 10.45.3.6210.45.3.63
1410.45.3.64/2610.45.3.65 – 10.45.3.12610.45.3.127
1510.45.3.128/2610.45.3.129 – 10.45.3.19010.45.3.191
1610.45.3.192/2610.45.3.193 – 10.45.3.25410.45.3.255
1710.45.4.0/2610.45.4.1 – 10.45.4.6210.45.4.63
1810.45.4.64/2610.45.4.65 – 10.45.4.12610.45.4.127
1910.45.4.128/2610.45.4.129 – 10.45.4.19010.45.4.191
2010.45.4.192/2610.45.4.193 – 10.45.4.25410.45.4.255
2110.45.5.0/2610.45.5.1 – 10.45.5.6210.45.5.63
2210.45.5.64/2610.45.5.65 – 10.45.5.12610.45.5.127
2310.45.5.128/2610.45.5.129 – 10.45.5.19010.45.5.191
2410.45.5.192/2610.45.5.193 – 10.45.5.25410.45.5.255
2510.45.6.0/2610.45.6.1 – 10.45.6.6210.45.6.63
2610.45.6.64/2610.45.6.65 – 10.45.6.12610.45.6.127
2710.45.6.128/2610.45.6.129 – 10.45.6.19010.45.6.191
2810.45.6.192/2610.45.6.193 – 10.45.6.25410.45.6.255
2910.45.7.0/2610.45.7.1 – 10.45.7.6210.45.7.63
3010.45.7.64/2610.45.7.65 – 10.45.7.12610.45.7.127
3110.45.7.128/2610.45.7.129 – 10.45.7.19010.45.7.191
3210.45.7.192/2610.45.7.193 – 10.45.7.25410.45.7.255
3310.45.8.0/2610.45.8.1 – 10.45.8.6210.45.8.63
3410.45.8.64/2610.45.8.65 – 10.45.8.12610.45.8.127
3510.45.8.128/2610.45.8.129 – 10.45.8.19010.45.8.191
3610.45.8.192/2610.45.8.193 – 10.45.8.25410.45.8.255
3710.45.9.0/2610.45.9.1 – 10.45.9.6210.45.9.63
3810.45.9.64/2610.45.9.65 – 10.45.9.12610.45.9.127
3910.45.9.128/2610.45.9.129 – 10.45.9.19010.45.9.191
4010.45.9.192/2610.45.9.193 – 10.45.9.25410.45.9.255
4110.45.10.0/2610.45.10.1 – 10.45.10.6210.45.10.63
4210.45.10.64/2610.45.10.65 – 10.45.10.12610.45.10.127
4310.45.10.128/2610.45.10.129 – 10.45.10.19010.45.10.191
4410.45.10.192/2610.45.10.193 – 10.45.10.25410.45.10.255
4510.45.11.0/2610.45.11.1 – 10.45.11.6210.45.11.63
4610.45.11.64/2610.45.11.65 – 10.45.11.12610.45.11.127
4710.45.11.128/2610.45.11.129 – 10.45.11.19010.45.11.191
4810.45.11.192/2610.45.11.193 – 10.45.11.25410.45.11.255
4910.45.12.0/2610.45.12.1 – 10.45.12.6210.45.12.63
5010.45.12.64/2610.45.12.65 – 10.45.12.12610.45.12.127
5110.45.12.128/2610.45.12.129 – 10.45.12.19010.45.12.191
5210.45.12.192/2610.45.12.193 – 10.45.12.25410.45.12.255
5310.45.13.0/2610.45.13.1 – 10.45.13.6210.45.13.63
5410.45.13.64/2610.45.13.65 – 10.45.13.12610.45.13.127
5510.45.13.128/2610.45.13.129 – 10.45.13.19010.45.13.191
5610.45.13.192/2610.45.13.193 – 10.45.13.25410.45.13.255
5710.45.14.0/2610.45.14.1 – 10.45.14.6210.45.14.63
5810.45.14.64/2610.45.14.65 – 10.45.14.12610.45.14.127
5910.45.14.128/2610.45.14.129 – 10.45.14.19010.45.14.191
6010.45.14.192/2610.45.14.193 – 10.45.14.25410.45.14.255
6110.45.15.0/2610.45.15.1 – 10.45.15.6210.45.15.63
6210.45.15.64/2610.45.15.65 – 10.45.15.12610.45.15.127
6310.45.15.128/2610.45.15.129 – 10.45.15.19010.45.15.191
6410.45.15.192/2610.45.15.193 – 10.45.15.25410.45.15.255
01 / table

IPv4 CIDR prefix table.

Click a prefix longer than your network to split it into subnets.

prefixsubnet maskaddresseshostsin your /20
/00.0.0.04,294,967,2964,294,967,294-
/1128.0.0.02,147,483,6482,147,483,646-
/2192.0.0.01,073,741,8241,073,741,822-
/3224.0.0.0536,870,912536,870,910-
/4240.0.0.0268,435,456268,435,454-
/5248.0.0.0134,217,728134,217,726-
/6252.0.0.067,108,86467,108,862-
/7254.0.0.033,554,43233,554,430-
/8255.0.0.016,777,21616,777,214-
/9255.128.0.08,388,6088,388,606-
/10255.192.0.04,194,3044,194,302-
/11255.224.0.02,097,1522,097,150-
/12255.240.0.01,048,5761,048,574-
/13255.248.0.0524,288524,286-
/14255.252.0.0262,144262,142-
/15255.254.0.0131,072131,070-
/16255.255.0.065,53665,534-
/17255.255.128.032,76832,766-
/18255.255.192.016,38416,382-
/19255.255.224.08,1928,190-
/20255.255.240.04,0964,0941
/21255.255.248.02,0482,0462 split →
/22255.255.252.01,0241,0224 split →
/23255.255.254.05125108 split →
/24255.255.255.025625416 split →
/25255.255.255.12812812632 split →
/26255.255.255.192646264 split →
/27255.255.255.2243230128 split →
/28255.255.255.2401614256 split →
/29255.255.255.24886512 split →
/30255.255.255.252421,024 split →
/31255.255.255.254222,048 split →
/32255.255.255.255114,096 split →
02 / faq

About this calculator.

How do I use this subnet calculator?

▼

Type an IP address followed by a prefix, like 192.168.1.10/24, or by a subnet mask, like 192.168.1.10 255.255.255.0. Without a prefix it uses /24. Click a row in the table to split the network into smaller subnets.

Why are usable hosts always 2 fewer?

▼

The first address in a subnet is the network address and the last is the broadcast address, so neither can go to a device. The exceptions are /31 (point-to-point links, RFC 3021) and /32 (a single address), which use every address.

Can I use it from a terminal?

▼

Yes. curl 'ipku.in/en/tools/ipv4-subnet-calculator?q=192.168.1.10/24' returns the result as plain text.

Learn how to work it out →