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.

Try:192.168.1.10/24 10.0.0.0/8 172.16.5.4/20 203.0.113.9/29

IPv6 calculator →

private IP (RFC 1918)172.16.5.0/25

network172.16.5.0/25

broadcast172.16.5.127

first host172.16.5.1

last host172.16.5.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classB

ipcalc 172.16.5.0/25

address10101100.00010000.00000101.00000000

subnet mask11111111.11111111.11111111.10000000

network10101100.00010000.00000101.00000000

broadcast10101100.00010000.00000101.01111111

green = network part, grey = host part

hex0xac100500

decimal2886731008

reverse dns0.5.16.172.in-addr.arpa

ipv4-mapped::ffff:ac10:500

/25 split into /30 · 32 subnets

close ×

#	network	host range	broadcast
1	172.16.5.0/30	172.16.5.1 – 172.16.5.2	172.16.5.3
2	172.16.5.4/30	172.16.5.5 – 172.16.5.6	172.16.5.7
3	172.16.5.8/30	172.16.5.9 – 172.16.5.10	172.16.5.11
4	172.16.5.12/30	172.16.5.13 – 172.16.5.14	172.16.5.15
5	172.16.5.16/30	172.16.5.17 – 172.16.5.18	172.16.5.19
6	172.16.5.20/30	172.16.5.21 – 172.16.5.22	172.16.5.23
7	172.16.5.24/30	172.16.5.25 – 172.16.5.26	172.16.5.27
8	172.16.5.28/30	172.16.5.29 – 172.16.5.30	172.16.5.31
9	172.16.5.32/30	172.16.5.33 – 172.16.5.34	172.16.5.35
10	172.16.5.36/30	172.16.5.37 – 172.16.5.38	172.16.5.39
11	172.16.5.40/30	172.16.5.41 – 172.16.5.42	172.16.5.43
12	172.16.5.44/30	172.16.5.45 – 172.16.5.46	172.16.5.47
13	172.16.5.48/30	172.16.5.49 – 172.16.5.50	172.16.5.51
14	172.16.5.52/30	172.16.5.53 – 172.16.5.54	172.16.5.55
15	172.16.5.56/30	172.16.5.57 – 172.16.5.58	172.16.5.59
16	172.16.5.60/30	172.16.5.61 – 172.16.5.62	172.16.5.63
17	172.16.5.64/30	172.16.5.65 – 172.16.5.66	172.16.5.67
18	172.16.5.68/30	172.16.5.69 – 172.16.5.70	172.16.5.71
19	172.16.5.72/30	172.16.5.73 – 172.16.5.74	172.16.5.75
20	172.16.5.76/30	172.16.5.77 – 172.16.5.78	172.16.5.79
21	172.16.5.80/30	172.16.5.81 – 172.16.5.82	172.16.5.83
22	172.16.5.84/30	172.16.5.85 – 172.16.5.86	172.16.5.87
23	172.16.5.88/30	172.16.5.89 – 172.16.5.90	172.16.5.91
24	172.16.5.92/30	172.16.5.93 – 172.16.5.94	172.16.5.95
25	172.16.5.96/30	172.16.5.97 – 172.16.5.98	172.16.5.99
26	172.16.5.100/30	172.16.5.101 – 172.16.5.102	172.16.5.103
27	172.16.5.104/30	172.16.5.105 – 172.16.5.106	172.16.5.107
28	172.16.5.108/30	172.16.5.109 – 172.16.5.110	172.16.5.111
29	172.16.5.112/30	172.16.5.113 – 172.16.5.114	172.16.5.115
30	172.16.5.116/30	172.16.5.117 – 172.16.5.118	172.16.5.119
31	172.16.5.120/30	172.16.5.121 – 172.16.5.122	172.16.5.123
32	172.16.5.124/30	172.16.5.125 – 172.16.5.126	172.16.5.127

01 / table

IPv4 CIDR prefix table.

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

prefix	subnet mask	addresses	hosts	in your /25
/0	0.0.0.0	4,294,967,296	4,294,967,294	-
/1	128.0.0.0	2,147,483,648	2,147,483,646	-
/2	192.0.0.0	1,073,741,824	1,073,741,822	-
/3	224.0.0.0	536,870,912	536,870,910	-
/4	240.0.0.0	268,435,456	268,435,454	-
/5	248.0.0.0	134,217,728	134,217,726	-
/6	252.0.0.0	67,108,864	67,108,862	-
/7	254.0.0.0	33,554,432	33,554,430	-
/8	255.0.0.0	16,777,216	16,777,214	-
/9	255.128.0.0	8,388,608	8,388,606	-
/10	255.192.0.0	4,194,304	4,194,302	-
/11	255.224.0.0	2,097,152	2,097,150	-
/12	255.240.0.0	1,048,576	1,048,574	-
/13	255.248.0.0	524,288	524,286	-
/14	255.252.0.0	262,144	262,142	-
/15	255.254.0.0	131,072	131,070	-
/16	255.255.0.0	65,536	65,534	-
/17	255.255.128.0	32,768	32,766	-
/18	255.255.192.0	16,384	16,382	-
/19	255.255.224.0	8,192	8,190	-
/20	255.255.240.0	4,096	4,094	-
/21	255.255.248.0	2,048	2,046	-
/22	255.255.252.0	1,024	1,022	-
/23	255.255.254.0	512	510	-
/24	255.255.255.0	256	254	-
/25	255.255.255.128	128	126	1
/26	255.255.255.192	64	62	2 split →
/27	255.255.255.224	32	30	4 split →
/28	255.255.255.240	16	14	8 split →
/29	255.255.255.248	8	6	16 split →
/30	255.255.255.252	4	2	32 split →
/31	255.255.255.254	2	2	64 split →
/32	255.255.255.255	1	1	128 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 →