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 /31 · 64 subnets

close ×

#	network	host range	broadcast
1	172.16.5.0/31	172.16.5.0 – 172.16.5.1	172.16.5.1
2	172.16.5.2/31	172.16.5.2 – 172.16.5.3	172.16.5.3
3	172.16.5.4/31	172.16.5.4 – 172.16.5.5	172.16.5.5
4	172.16.5.6/31	172.16.5.6 – 172.16.5.7	172.16.5.7
5	172.16.5.8/31	172.16.5.8 – 172.16.5.9	172.16.5.9
6	172.16.5.10/31	172.16.5.10 – 172.16.5.11	172.16.5.11
7	172.16.5.12/31	172.16.5.12 – 172.16.5.13	172.16.5.13
8	172.16.5.14/31	172.16.5.14 – 172.16.5.15	172.16.5.15
9	172.16.5.16/31	172.16.5.16 – 172.16.5.17	172.16.5.17
10	172.16.5.18/31	172.16.5.18 – 172.16.5.19	172.16.5.19
11	172.16.5.20/31	172.16.5.20 – 172.16.5.21	172.16.5.21
12	172.16.5.22/31	172.16.5.22 – 172.16.5.23	172.16.5.23
13	172.16.5.24/31	172.16.5.24 – 172.16.5.25	172.16.5.25
14	172.16.5.26/31	172.16.5.26 – 172.16.5.27	172.16.5.27
15	172.16.5.28/31	172.16.5.28 – 172.16.5.29	172.16.5.29
16	172.16.5.30/31	172.16.5.30 – 172.16.5.31	172.16.5.31
17	172.16.5.32/31	172.16.5.32 – 172.16.5.33	172.16.5.33
18	172.16.5.34/31	172.16.5.34 – 172.16.5.35	172.16.5.35
19	172.16.5.36/31	172.16.5.36 – 172.16.5.37	172.16.5.37
20	172.16.5.38/31	172.16.5.38 – 172.16.5.39	172.16.5.39
21	172.16.5.40/31	172.16.5.40 – 172.16.5.41	172.16.5.41
22	172.16.5.42/31	172.16.5.42 – 172.16.5.43	172.16.5.43
23	172.16.5.44/31	172.16.5.44 – 172.16.5.45	172.16.5.45
24	172.16.5.46/31	172.16.5.46 – 172.16.5.47	172.16.5.47
25	172.16.5.48/31	172.16.5.48 – 172.16.5.49	172.16.5.49
26	172.16.5.50/31	172.16.5.50 – 172.16.5.51	172.16.5.51
27	172.16.5.52/31	172.16.5.52 – 172.16.5.53	172.16.5.53
28	172.16.5.54/31	172.16.5.54 – 172.16.5.55	172.16.5.55
29	172.16.5.56/31	172.16.5.56 – 172.16.5.57	172.16.5.57
30	172.16.5.58/31	172.16.5.58 – 172.16.5.59	172.16.5.59
31	172.16.5.60/31	172.16.5.60 – 172.16.5.61	172.16.5.61
32	172.16.5.62/31	172.16.5.62 – 172.16.5.63	172.16.5.63
33	172.16.5.64/31	172.16.5.64 – 172.16.5.65	172.16.5.65
34	172.16.5.66/31	172.16.5.66 – 172.16.5.67	172.16.5.67
35	172.16.5.68/31	172.16.5.68 – 172.16.5.69	172.16.5.69
36	172.16.5.70/31	172.16.5.70 – 172.16.5.71	172.16.5.71
37	172.16.5.72/31	172.16.5.72 – 172.16.5.73	172.16.5.73
38	172.16.5.74/31	172.16.5.74 – 172.16.5.75	172.16.5.75
39	172.16.5.76/31	172.16.5.76 – 172.16.5.77	172.16.5.77
40	172.16.5.78/31	172.16.5.78 – 172.16.5.79	172.16.5.79
41	172.16.5.80/31	172.16.5.80 – 172.16.5.81	172.16.5.81
42	172.16.5.82/31	172.16.5.82 – 172.16.5.83	172.16.5.83
43	172.16.5.84/31	172.16.5.84 – 172.16.5.85	172.16.5.85
44	172.16.5.86/31	172.16.5.86 – 172.16.5.87	172.16.5.87
45	172.16.5.88/31	172.16.5.88 – 172.16.5.89	172.16.5.89
46	172.16.5.90/31	172.16.5.90 – 172.16.5.91	172.16.5.91
47	172.16.5.92/31	172.16.5.92 – 172.16.5.93	172.16.5.93
48	172.16.5.94/31	172.16.5.94 – 172.16.5.95	172.16.5.95
49	172.16.5.96/31	172.16.5.96 – 172.16.5.97	172.16.5.97
50	172.16.5.98/31	172.16.5.98 – 172.16.5.99	172.16.5.99
51	172.16.5.100/31	172.16.5.100 – 172.16.5.101	172.16.5.101
52	172.16.5.102/31	172.16.5.102 – 172.16.5.103	172.16.5.103
53	172.16.5.104/31	172.16.5.104 – 172.16.5.105	172.16.5.105
54	172.16.5.106/31	172.16.5.106 – 172.16.5.107	172.16.5.107
55	172.16.5.108/31	172.16.5.108 – 172.16.5.109	172.16.5.109
56	172.16.5.110/31	172.16.5.110 – 172.16.5.111	172.16.5.111
57	172.16.5.112/31	172.16.5.112 – 172.16.5.113	172.16.5.113
58	172.16.5.114/31	172.16.5.114 – 172.16.5.115	172.16.5.115
59	172.16.5.116/31	172.16.5.116 – 172.16.5.117	172.16.5.117
60	172.16.5.118/31	172.16.5.118 – 172.16.5.119	172.16.5.119
61	172.16.5.120/31	172.16.5.120 – 172.16.5.121	172.16.5.121
62	172.16.5.122/31	172.16.5.122 – 172.16.5.123	172.16.5.123
63	172.16.5.124/31	172.16.5.124 – 172.16.5.125	172.16.5.125
64	172.16.5.126/31	172.16.5.126 – 172.16.5.127	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 →