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)172.16.4.0/25

network172.16.4.0/25

broadcast172.16.4.127

first host172.16.4.1

last host172.16.4.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classB

ipcalc 172.16.4.0/25

address10101100.00010000.00000100.00000000

subnet mask11111111.11111111.11111111.10000000

network10101100.00010000.00000100.00000000

broadcast10101100.00010000.00000100.01111111

green = network part, grey = host part

hex0xac100400

decimal2886730752

reverse dns0.4.16.172.in-addr.arpa

ipv4-mapped::ffff:ac10:400

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	172.16.4.0/31	172.16.4.0 – 172.16.4.1	172.16.4.1
2	172.16.4.2/31	172.16.4.2 – 172.16.4.3	172.16.4.3
3	172.16.4.4/31	172.16.4.4 – 172.16.4.5	172.16.4.5
4	172.16.4.6/31	172.16.4.6 – 172.16.4.7	172.16.4.7
5	172.16.4.8/31	172.16.4.8 – 172.16.4.9	172.16.4.9
6	172.16.4.10/31	172.16.4.10 – 172.16.4.11	172.16.4.11
7	172.16.4.12/31	172.16.4.12 – 172.16.4.13	172.16.4.13
8	172.16.4.14/31	172.16.4.14 – 172.16.4.15	172.16.4.15
9	172.16.4.16/31	172.16.4.16 – 172.16.4.17	172.16.4.17
10	172.16.4.18/31	172.16.4.18 – 172.16.4.19	172.16.4.19
11	172.16.4.20/31	172.16.4.20 – 172.16.4.21	172.16.4.21
12	172.16.4.22/31	172.16.4.22 – 172.16.4.23	172.16.4.23
13	172.16.4.24/31	172.16.4.24 – 172.16.4.25	172.16.4.25
14	172.16.4.26/31	172.16.4.26 – 172.16.4.27	172.16.4.27
15	172.16.4.28/31	172.16.4.28 – 172.16.4.29	172.16.4.29
16	172.16.4.30/31	172.16.4.30 – 172.16.4.31	172.16.4.31
17	172.16.4.32/31	172.16.4.32 – 172.16.4.33	172.16.4.33
18	172.16.4.34/31	172.16.4.34 – 172.16.4.35	172.16.4.35
19	172.16.4.36/31	172.16.4.36 – 172.16.4.37	172.16.4.37
20	172.16.4.38/31	172.16.4.38 – 172.16.4.39	172.16.4.39
21	172.16.4.40/31	172.16.4.40 – 172.16.4.41	172.16.4.41
22	172.16.4.42/31	172.16.4.42 – 172.16.4.43	172.16.4.43
23	172.16.4.44/31	172.16.4.44 – 172.16.4.45	172.16.4.45
24	172.16.4.46/31	172.16.4.46 – 172.16.4.47	172.16.4.47
25	172.16.4.48/31	172.16.4.48 – 172.16.4.49	172.16.4.49
26	172.16.4.50/31	172.16.4.50 – 172.16.4.51	172.16.4.51
27	172.16.4.52/31	172.16.4.52 – 172.16.4.53	172.16.4.53
28	172.16.4.54/31	172.16.4.54 – 172.16.4.55	172.16.4.55
29	172.16.4.56/31	172.16.4.56 – 172.16.4.57	172.16.4.57
30	172.16.4.58/31	172.16.4.58 – 172.16.4.59	172.16.4.59
31	172.16.4.60/31	172.16.4.60 – 172.16.4.61	172.16.4.61
32	172.16.4.62/31	172.16.4.62 – 172.16.4.63	172.16.4.63
33	172.16.4.64/31	172.16.4.64 – 172.16.4.65	172.16.4.65
34	172.16.4.66/31	172.16.4.66 – 172.16.4.67	172.16.4.67
35	172.16.4.68/31	172.16.4.68 – 172.16.4.69	172.16.4.69
36	172.16.4.70/31	172.16.4.70 – 172.16.4.71	172.16.4.71
37	172.16.4.72/31	172.16.4.72 – 172.16.4.73	172.16.4.73
38	172.16.4.74/31	172.16.4.74 – 172.16.4.75	172.16.4.75
39	172.16.4.76/31	172.16.4.76 – 172.16.4.77	172.16.4.77
40	172.16.4.78/31	172.16.4.78 – 172.16.4.79	172.16.4.79
41	172.16.4.80/31	172.16.4.80 – 172.16.4.81	172.16.4.81
42	172.16.4.82/31	172.16.4.82 – 172.16.4.83	172.16.4.83
43	172.16.4.84/31	172.16.4.84 – 172.16.4.85	172.16.4.85
44	172.16.4.86/31	172.16.4.86 – 172.16.4.87	172.16.4.87
45	172.16.4.88/31	172.16.4.88 – 172.16.4.89	172.16.4.89
46	172.16.4.90/31	172.16.4.90 – 172.16.4.91	172.16.4.91
47	172.16.4.92/31	172.16.4.92 – 172.16.4.93	172.16.4.93
48	172.16.4.94/31	172.16.4.94 – 172.16.4.95	172.16.4.95
49	172.16.4.96/31	172.16.4.96 – 172.16.4.97	172.16.4.97
50	172.16.4.98/31	172.16.4.98 – 172.16.4.99	172.16.4.99
51	172.16.4.100/31	172.16.4.100 – 172.16.4.101	172.16.4.101
52	172.16.4.102/31	172.16.4.102 – 172.16.4.103	172.16.4.103
53	172.16.4.104/31	172.16.4.104 – 172.16.4.105	172.16.4.105
54	172.16.4.106/31	172.16.4.106 – 172.16.4.107	172.16.4.107
55	172.16.4.108/31	172.16.4.108 – 172.16.4.109	172.16.4.109
56	172.16.4.110/31	172.16.4.110 – 172.16.4.111	172.16.4.111
57	172.16.4.112/31	172.16.4.112 – 172.16.4.113	172.16.4.113
58	172.16.4.114/31	172.16.4.114 – 172.16.4.115	172.16.4.115
59	172.16.4.116/31	172.16.4.116 – 172.16.4.117	172.16.4.117
60	172.16.4.118/31	172.16.4.118 – 172.16.4.119	172.16.4.119
61	172.16.4.120/31	172.16.4.120 – 172.16.4.121	172.16.4.121
62	172.16.4.122/31	172.16.4.122 – 172.16.4.123	172.16.4.123
63	172.16.4.124/31	172.16.4.124 – 172.16.4.125	172.16.4.125
64	172.16.4.126/31	172.16.4.126 – 172.16.4.127	172.16.4.127

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 →