ip
ipku.in

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
Try:192.168.1.10/2410.0.0.0/8172.16.5.4/20203.0.113.9/29
IPv6 calculator →
private IP (RFC 1918)10.76.32.0/21
network10.76.32.0/21
broadcast10.76.39.255
first host10.76.32.1
last host10.76.39.254
subnet mask255.255.248.0
wildcard0.0.7.255
addresses2,048
usable hosts2,046
classA
ipcalc 10.76.32.0/21
address00001010.01001100.00100000.00000000
subnet mask11111111.11111111.11111000.00000000
network00001010.01001100.00100000.00000000
broadcast00001010.01001100.00100111.11111111
green = network part, grey = host part
hex0x0a4c2000
decimal172761088
reverse dns0.32.76.10.in-addr.arpa
ipv4-mapped::ffff:a4c:2000

/21 split into /26 · 32 subnets

close ×
#networkhost rangebroadcast
110.76.32.0/2610.76.32.1 – 10.76.32.6210.76.32.63
210.76.32.64/2610.76.32.65 – 10.76.32.12610.76.32.127
310.76.32.128/2610.76.32.129 – 10.76.32.19010.76.32.191
410.76.32.192/2610.76.32.193 – 10.76.32.25410.76.32.255
510.76.33.0/2610.76.33.1 – 10.76.33.6210.76.33.63
610.76.33.64/2610.76.33.65 – 10.76.33.12610.76.33.127
710.76.33.128/2610.76.33.129 – 10.76.33.19010.76.33.191
810.76.33.192/2610.76.33.193 – 10.76.33.25410.76.33.255
910.76.34.0/2610.76.34.1 – 10.76.34.6210.76.34.63
1010.76.34.64/2610.76.34.65 – 10.76.34.12610.76.34.127
1110.76.34.128/2610.76.34.129 – 10.76.34.19010.76.34.191
1210.76.34.192/2610.76.34.193 – 10.76.34.25410.76.34.255
1310.76.35.0/2610.76.35.1 – 10.76.35.6210.76.35.63
1410.76.35.64/2610.76.35.65 – 10.76.35.12610.76.35.127
1510.76.35.128/2610.76.35.129 – 10.76.35.19010.76.35.191
1610.76.35.192/2610.76.35.193 – 10.76.35.25410.76.35.255
1710.76.36.0/2610.76.36.1 – 10.76.36.6210.76.36.63
1810.76.36.64/2610.76.36.65 – 10.76.36.12610.76.36.127
1910.76.36.128/2610.76.36.129 – 10.76.36.19010.76.36.191
2010.76.36.192/2610.76.36.193 – 10.76.36.25410.76.36.255
2110.76.37.0/2610.76.37.1 – 10.76.37.6210.76.37.63
2210.76.37.64/2610.76.37.65 – 10.76.37.12610.76.37.127
2310.76.37.128/2610.76.37.129 – 10.76.37.19010.76.37.191
2410.76.37.192/2610.76.37.193 – 10.76.37.25410.76.37.255
2510.76.38.0/2610.76.38.1 – 10.76.38.6210.76.38.63
2610.76.38.64/2610.76.38.65 – 10.76.38.12610.76.38.127
2710.76.38.128/2610.76.38.129 – 10.76.38.19010.76.38.191
2810.76.38.192/2610.76.38.193 – 10.76.38.25410.76.38.255
2910.76.39.0/2610.76.39.1 – 10.76.39.6210.76.39.63
3010.76.39.64/2610.76.39.65 – 10.76.39.12610.76.39.127
3110.76.39.128/2610.76.39.129 – 10.76.39.19010.76.39.191
3210.76.39.192/2610.76.39.193 – 10.76.39.25410.76.39.255
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /21
/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-
/20255.255.240.04,0964,094-
/21255.255.248.02,0482,0461
/22255.255.252.01,0241,0222 split →
/23255.255.254.05125104 split →
/24255.255.255.02562548 split →
/25255.255.255.12812812616 split →
/26255.255.255.192646232 split →
/27255.255.255.224323064 split →
/28255.255.255.2401614128 split →
/29255.255.255.24886256 split →
/30255.255.255.25242512 split →
/31255.255.255.254221,024 split →
/32255.255.255.255112,048 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 →