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)10.3.151.0/25

network10.3.151.0/25

broadcast10.3.151.127

first host10.3.151.1

last host10.3.151.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.3.151.0/25

address00001010.00000011.10010111.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000011.10010111.00000000

broadcast00001010.00000011.10010111.01111111

green = network part, grey = host part

hex0x0a039700

decimal168007424

reverse dns0.151.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:9700

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.3.151.0/31	10.3.151.0 – 10.3.151.1	10.3.151.1
2	10.3.151.2/31	10.3.151.2 – 10.3.151.3	10.3.151.3
3	10.3.151.4/31	10.3.151.4 – 10.3.151.5	10.3.151.5
4	10.3.151.6/31	10.3.151.6 – 10.3.151.7	10.3.151.7
5	10.3.151.8/31	10.3.151.8 – 10.3.151.9	10.3.151.9
6	10.3.151.10/31	10.3.151.10 – 10.3.151.11	10.3.151.11
7	10.3.151.12/31	10.3.151.12 – 10.3.151.13	10.3.151.13
8	10.3.151.14/31	10.3.151.14 – 10.3.151.15	10.3.151.15
9	10.3.151.16/31	10.3.151.16 – 10.3.151.17	10.3.151.17
10	10.3.151.18/31	10.3.151.18 – 10.3.151.19	10.3.151.19
11	10.3.151.20/31	10.3.151.20 – 10.3.151.21	10.3.151.21
12	10.3.151.22/31	10.3.151.22 – 10.3.151.23	10.3.151.23
13	10.3.151.24/31	10.3.151.24 – 10.3.151.25	10.3.151.25
14	10.3.151.26/31	10.3.151.26 – 10.3.151.27	10.3.151.27
15	10.3.151.28/31	10.3.151.28 – 10.3.151.29	10.3.151.29
16	10.3.151.30/31	10.3.151.30 – 10.3.151.31	10.3.151.31
17	10.3.151.32/31	10.3.151.32 – 10.3.151.33	10.3.151.33
18	10.3.151.34/31	10.3.151.34 – 10.3.151.35	10.3.151.35
19	10.3.151.36/31	10.3.151.36 – 10.3.151.37	10.3.151.37
20	10.3.151.38/31	10.3.151.38 – 10.3.151.39	10.3.151.39
21	10.3.151.40/31	10.3.151.40 – 10.3.151.41	10.3.151.41
22	10.3.151.42/31	10.3.151.42 – 10.3.151.43	10.3.151.43
23	10.3.151.44/31	10.3.151.44 – 10.3.151.45	10.3.151.45
24	10.3.151.46/31	10.3.151.46 – 10.3.151.47	10.3.151.47
25	10.3.151.48/31	10.3.151.48 – 10.3.151.49	10.3.151.49
26	10.3.151.50/31	10.3.151.50 – 10.3.151.51	10.3.151.51
27	10.3.151.52/31	10.3.151.52 – 10.3.151.53	10.3.151.53
28	10.3.151.54/31	10.3.151.54 – 10.3.151.55	10.3.151.55
29	10.3.151.56/31	10.3.151.56 – 10.3.151.57	10.3.151.57
30	10.3.151.58/31	10.3.151.58 – 10.3.151.59	10.3.151.59
31	10.3.151.60/31	10.3.151.60 – 10.3.151.61	10.3.151.61
32	10.3.151.62/31	10.3.151.62 – 10.3.151.63	10.3.151.63
33	10.3.151.64/31	10.3.151.64 – 10.3.151.65	10.3.151.65
34	10.3.151.66/31	10.3.151.66 – 10.3.151.67	10.3.151.67
35	10.3.151.68/31	10.3.151.68 – 10.3.151.69	10.3.151.69
36	10.3.151.70/31	10.3.151.70 – 10.3.151.71	10.3.151.71
37	10.3.151.72/31	10.3.151.72 – 10.3.151.73	10.3.151.73
38	10.3.151.74/31	10.3.151.74 – 10.3.151.75	10.3.151.75
39	10.3.151.76/31	10.3.151.76 – 10.3.151.77	10.3.151.77
40	10.3.151.78/31	10.3.151.78 – 10.3.151.79	10.3.151.79
41	10.3.151.80/31	10.3.151.80 – 10.3.151.81	10.3.151.81
42	10.3.151.82/31	10.3.151.82 – 10.3.151.83	10.3.151.83
43	10.3.151.84/31	10.3.151.84 – 10.3.151.85	10.3.151.85
44	10.3.151.86/31	10.3.151.86 – 10.3.151.87	10.3.151.87
45	10.3.151.88/31	10.3.151.88 – 10.3.151.89	10.3.151.89
46	10.3.151.90/31	10.3.151.90 – 10.3.151.91	10.3.151.91
47	10.3.151.92/31	10.3.151.92 – 10.3.151.93	10.3.151.93
48	10.3.151.94/31	10.3.151.94 – 10.3.151.95	10.3.151.95
49	10.3.151.96/31	10.3.151.96 – 10.3.151.97	10.3.151.97
50	10.3.151.98/31	10.3.151.98 – 10.3.151.99	10.3.151.99
51	10.3.151.100/31	10.3.151.100 – 10.3.151.101	10.3.151.101
52	10.3.151.102/31	10.3.151.102 – 10.3.151.103	10.3.151.103
53	10.3.151.104/31	10.3.151.104 – 10.3.151.105	10.3.151.105
54	10.3.151.106/31	10.3.151.106 – 10.3.151.107	10.3.151.107
55	10.3.151.108/31	10.3.151.108 – 10.3.151.109	10.3.151.109
56	10.3.151.110/31	10.3.151.110 – 10.3.151.111	10.3.151.111
57	10.3.151.112/31	10.3.151.112 – 10.3.151.113	10.3.151.113
58	10.3.151.114/31	10.3.151.114 – 10.3.151.115	10.3.151.115
59	10.3.151.116/31	10.3.151.116 – 10.3.151.117	10.3.151.117
60	10.3.151.118/31	10.3.151.118 – 10.3.151.119	10.3.151.119
61	10.3.151.120/31	10.3.151.120 – 10.3.151.121	10.3.151.121
62	10.3.151.122/31	10.3.151.122 – 10.3.151.123	10.3.151.123
63	10.3.151.124/31	10.3.151.124 – 10.3.151.125	10.3.151.125
64	10.3.151.126/31	10.3.151.126 – 10.3.151.127	10.3.151.127

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 →