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)172.16.12.0/25

network172.16.12.0/25

broadcast172.16.12.127

first host172.16.12.1

last host172.16.12.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classB

ipcalc 172.16.12.0/25

address10101100.00010000.00001100.00000000

subnet mask11111111.11111111.11111111.10000000

network10101100.00010000.00001100.00000000

broadcast10101100.00010000.00001100.01111111

green = network part, grey = host part

hex0xac100c00

decimal2886732800

reverse dns0.12.16.172.in-addr.arpa

ipv4-mapped::ffff:ac10:c00

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	172.16.12.0/31	172.16.12.0 – 172.16.12.1	172.16.12.1
2	172.16.12.2/31	172.16.12.2 – 172.16.12.3	172.16.12.3
3	172.16.12.4/31	172.16.12.4 – 172.16.12.5	172.16.12.5
4	172.16.12.6/31	172.16.12.6 – 172.16.12.7	172.16.12.7
5	172.16.12.8/31	172.16.12.8 – 172.16.12.9	172.16.12.9
6	172.16.12.10/31	172.16.12.10 – 172.16.12.11	172.16.12.11
7	172.16.12.12/31	172.16.12.12 – 172.16.12.13	172.16.12.13
8	172.16.12.14/31	172.16.12.14 – 172.16.12.15	172.16.12.15
9	172.16.12.16/31	172.16.12.16 – 172.16.12.17	172.16.12.17
10	172.16.12.18/31	172.16.12.18 – 172.16.12.19	172.16.12.19
11	172.16.12.20/31	172.16.12.20 – 172.16.12.21	172.16.12.21
12	172.16.12.22/31	172.16.12.22 – 172.16.12.23	172.16.12.23
13	172.16.12.24/31	172.16.12.24 – 172.16.12.25	172.16.12.25
14	172.16.12.26/31	172.16.12.26 – 172.16.12.27	172.16.12.27
15	172.16.12.28/31	172.16.12.28 – 172.16.12.29	172.16.12.29
16	172.16.12.30/31	172.16.12.30 – 172.16.12.31	172.16.12.31
17	172.16.12.32/31	172.16.12.32 – 172.16.12.33	172.16.12.33
18	172.16.12.34/31	172.16.12.34 – 172.16.12.35	172.16.12.35
19	172.16.12.36/31	172.16.12.36 – 172.16.12.37	172.16.12.37
20	172.16.12.38/31	172.16.12.38 – 172.16.12.39	172.16.12.39
21	172.16.12.40/31	172.16.12.40 – 172.16.12.41	172.16.12.41
22	172.16.12.42/31	172.16.12.42 – 172.16.12.43	172.16.12.43
23	172.16.12.44/31	172.16.12.44 – 172.16.12.45	172.16.12.45
24	172.16.12.46/31	172.16.12.46 – 172.16.12.47	172.16.12.47
25	172.16.12.48/31	172.16.12.48 – 172.16.12.49	172.16.12.49
26	172.16.12.50/31	172.16.12.50 – 172.16.12.51	172.16.12.51
27	172.16.12.52/31	172.16.12.52 – 172.16.12.53	172.16.12.53
28	172.16.12.54/31	172.16.12.54 – 172.16.12.55	172.16.12.55
29	172.16.12.56/31	172.16.12.56 – 172.16.12.57	172.16.12.57
30	172.16.12.58/31	172.16.12.58 – 172.16.12.59	172.16.12.59
31	172.16.12.60/31	172.16.12.60 – 172.16.12.61	172.16.12.61
32	172.16.12.62/31	172.16.12.62 – 172.16.12.63	172.16.12.63
33	172.16.12.64/31	172.16.12.64 – 172.16.12.65	172.16.12.65
34	172.16.12.66/31	172.16.12.66 – 172.16.12.67	172.16.12.67
35	172.16.12.68/31	172.16.12.68 – 172.16.12.69	172.16.12.69
36	172.16.12.70/31	172.16.12.70 – 172.16.12.71	172.16.12.71
37	172.16.12.72/31	172.16.12.72 – 172.16.12.73	172.16.12.73
38	172.16.12.74/31	172.16.12.74 – 172.16.12.75	172.16.12.75
39	172.16.12.76/31	172.16.12.76 – 172.16.12.77	172.16.12.77
40	172.16.12.78/31	172.16.12.78 – 172.16.12.79	172.16.12.79
41	172.16.12.80/31	172.16.12.80 – 172.16.12.81	172.16.12.81
42	172.16.12.82/31	172.16.12.82 – 172.16.12.83	172.16.12.83
43	172.16.12.84/31	172.16.12.84 – 172.16.12.85	172.16.12.85
44	172.16.12.86/31	172.16.12.86 – 172.16.12.87	172.16.12.87
45	172.16.12.88/31	172.16.12.88 – 172.16.12.89	172.16.12.89
46	172.16.12.90/31	172.16.12.90 – 172.16.12.91	172.16.12.91
47	172.16.12.92/31	172.16.12.92 – 172.16.12.93	172.16.12.93
48	172.16.12.94/31	172.16.12.94 – 172.16.12.95	172.16.12.95
49	172.16.12.96/31	172.16.12.96 – 172.16.12.97	172.16.12.97
50	172.16.12.98/31	172.16.12.98 – 172.16.12.99	172.16.12.99
51	172.16.12.100/31	172.16.12.100 – 172.16.12.101	172.16.12.101
52	172.16.12.102/31	172.16.12.102 – 172.16.12.103	172.16.12.103
53	172.16.12.104/31	172.16.12.104 – 172.16.12.105	172.16.12.105
54	172.16.12.106/31	172.16.12.106 – 172.16.12.107	172.16.12.107
55	172.16.12.108/31	172.16.12.108 – 172.16.12.109	172.16.12.109
56	172.16.12.110/31	172.16.12.110 – 172.16.12.111	172.16.12.111
57	172.16.12.112/31	172.16.12.112 – 172.16.12.113	172.16.12.113
58	172.16.12.114/31	172.16.12.114 – 172.16.12.115	172.16.12.115
59	172.16.12.116/31	172.16.12.116 – 172.16.12.117	172.16.12.117
60	172.16.12.118/31	172.16.12.118 – 172.16.12.119	172.16.12.119
61	172.16.12.120/31	172.16.12.120 – 172.16.12.121	172.16.12.121
62	172.16.12.122/31	172.16.12.122 – 172.16.12.123	172.16.12.123
63	172.16.12.124/31	172.16.12.124 – 172.16.12.125	172.16.12.125
64	172.16.12.126/31	172.16.12.126 – 172.16.12.127	172.16.12.127

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 →