ip
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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
Try:192.168.1.10/2410.0.0.0/8172.16.5.4/20203.0.113.9/29
IPv6 calculator →
private IP (RFC 1918)10.0.81.0/25
network10.0.81.0/25
broadcast10.0.81.127
first host10.0.81.1
last host10.0.81.126
subnet mask255.255.255.128
wildcard0.0.0.127
addresses128
usable hosts126
classA
ipcalc 10.0.81.0/25
address00001010.00000000.01010001.00000000
subnet mask11111111.11111111.11111111.10000000
network00001010.00000000.01010001.00000000
broadcast00001010.00000000.01010001.01111111
green = network part, grey = host part
hex0x0a005100
decimal167792896
reverse dns0.81.0.10.in-addr.arpa
ipv4-mapped::ffff:a00:5100

/25 split into /31 · 64 subnets

close ×
#networkhost rangebroadcast
110.0.81.0/3110.0.81.0 – 10.0.81.110.0.81.1
210.0.81.2/3110.0.81.2 – 10.0.81.310.0.81.3
310.0.81.4/3110.0.81.4 – 10.0.81.510.0.81.5
410.0.81.6/3110.0.81.6 – 10.0.81.710.0.81.7
510.0.81.8/3110.0.81.8 – 10.0.81.910.0.81.9
610.0.81.10/3110.0.81.10 – 10.0.81.1110.0.81.11
710.0.81.12/3110.0.81.12 – 10.0.81.1310.0.81.13
810.0.81.14/3110.0.81.14 – 10.0.81.1510.0.81.15
910.0.81.16/3110.0.81.16 – 10.0.81.1710.0.81.17
1010.0.81.18/3110.0.81.18 – 10.0.81.1910.0.81.19
1110.0.81.20/3110.0.81.20 – 10.0.81.2110.0.81.21
1210.0.81.22/3110.0.81.22 – 10.0.81.2310.0.81.23
1310.0.81.24/3110.0.81.24 – 10.0.81.2510.0.81.25
1410.0.81.26/3110.0.81.26 – 10.0.81.2710.0.81.27
1510.0.81.28/3110.0.81.28 – 10.0.81.2910.0.81.29
1610.0.81.30/3110.0.81.30 – 10.0.81.3110.0.81.31
1710.0.81.32/3110.0.81.32 – 10.0.81.3310.0.81.33
1810.0.81.34/3110.0.81.34 – 10.0.81.3510.0.81.35
1910.0.81.36/3110.0.81.36 – 10.0.81.3710.0.81.37
2010.0.81.38/3110.0.81.38 – 10.0.81.3910.0.81.39
2110.0.81.40/3110.0.81.40 – 10.0.81.4110.0.81.41
2210.0.81.42/3110.0.81.42 – 10.0.81.4310.0.81.43
2310.0.81.44/3110.0.81.44 – 10.0.81.4510.0.81.45
2410.0.81.46/3110.0.81.46 – 10.0.81.4710.0.81.47
2510.0.81.48/3110.0.81.48 – 10.0.81.4910.0.81.49
2610.0.81.50/3110.0.81.50 – 10.0.81.5110.0.81.51
2710.0.81.52/3110.0.81.52 – 10.0.81.5310.0.81.53
2810.0.81.54/3110.0.81.54 – 10.0.81.5510.0.81.55
2910.0.81.56/3110.0.81.56 – 10.0.81.5710.0.81.57
3010.0.81.58/3110.0.81.58 – 10.0.81.5910.0.81.59
3110.0.81.60/3110.0.81.60 – 10.0.81.6110.0.81.61
3210.0.81.62/3110.0.81.62 – 10.0.81.6310.0.81.63
3310.0.81.64/3110.0.81.64 – 10.0.81.6510.0.81.65
3410.0.81.66/3110.0.81.66 – 10.0.81.6710.0.81.67
3510.0.81.68/3110.0.81.68 – 10.0.81.6910.0.81.69
3610.0.81.70/3110.0.81.70 – 10.0.81.7110.0.81.71
3710.0.81.72/3110.0.81.72 – 10.0.81.7310.0.81.73
3810.0.81.74/3110.0.81.74 – 10.0.81.7510.0.81.75
3910.0.81.76/3110.0.81.76 – 10.0.81.7710.0.81.77
4010.0.81.78/3110.0.81.78 – 10.0.81.7910.0.81.79
4110.0.81.80/3110.0.81.80 – 10.0.81.8110.0.81.81
4210.0.81.82/3110.0.81.82 – 10.0.81.8310.0.81.83
4310.0.81.84/3110.0.81.84 – 10.0.81.8510.0.81.85
4410.0.81.86/3110.0.81.86 – 10.0.81.8710.0.81.87
4510.0.81.88/3110.0.81.88 – 10.0.81.8910.0.81.89
4610.0.81.90/3110.0.81.90 – 10.0.81.9110.0.81.91
4710.0.81.92/3110.0.81.92 – 10.0.81.9310.0.81.93
4810.0.81.94/3110.0.81.94 – 10.0.81.9510.0.81.95
4910.0.81.96/3110.0.81.96 – 10.0.81.9710.0.81.97
5010.0.81.98/3110.0.81.98 – 10.0.81.9910.0.81.99
5110.0.81.100/3110.0.81.100 – 10.0.81.10110.0.81.101
5210.0.81.102/3110.0.81.102 – 10.0.81.10310.0.81.103
5310.0.81.104/3110.0.81.104 – 10.0.81.10510.0.81.105
5410.0.81.106/3110.0.81.106 – 10.0.81.10710.0.81.107
5510.0.81.108/3110.0.81.108 – 10.0.81.10910.0.81.109
5610.0.81.110/3110.0.81.110 – 10.0.81.11110.0.81.111
5710.0.81.112/3110.0.81.112 – 10.0.81.11310.0.81.113
5810.0.81.114/3110.0.81.114 – 10.0.81.11510.0.81.115
5910.0.81.116/3110.0.81.116 – 10.0.81.11710.0.81.117
6010.0.81.118/3110.0.81.118 – 10.0.81.11910.0.81.119
6110.0.81.120/3110.0.81.120 – 10.0.81.12110.0.81.121
6210.0.81.122/3110.0.81.122 – 10.0.81.12310.0.81.123
6310.0.81.124/3110.0.81.124 – 10.0.81.12510.0.81.125
6410.0.81.126/3110.0.81.126 – 10.0.81.12710.0.81.127
01 / table

IPv4 CIDR prefix table.

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

prefixsubnet maskaddresseshostsin your /25
/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-
/21255.255.248.02,0482,046-
/22255.255.252.01,0241,022-
/23255.255.254.0512510-
/24255.255.255.0256254-
/25255.255.255.1281281261
/26255.255.255.19264622 split →
/27255.255.255.22432304 split →
/28255.255.255.24016148 split →
/29255.255.255.2488616 split →
/30255.255.255.2524232 split →
/31255.255.255.2542264 split →
/32255.255.255.25511128 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 →