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)10.166.71.0/25

network10.166.71.0/25

broadcast10.166.71.127

first host10.166.71.1

last host10.166.71.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.166.71.0/25

address00001010.10100110.01000111.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.10100110.01000111.00000000

broadcast00001010.10100110.01000111.01111111

green = network part, grey = host part

hex0x0aa64700

decimal178669312

reverse dns0.71.166.10.in-addr.arpa

ipv4-mapped::ffff:aa6:4700

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.166.71.0/31	10.166.71.0 – 10.166.71.1	10.166.71.1
2	10.166.71.2/31	10.166.71.2 – 10.166.71.3	10.166.71.3
3	10.166.71.4/31	10.166.71.4 – 10.166.71.5	10.166.71.5
4	10.166.71.6/31	10.166.71.6 – 10.166.71.7	10.166.71.7
5	10.166.71.8/31	10.166.71.8 – 10.166.71.9	10.166.71.9
6	10.166.71.10/31	10.166.71.10 – 10.166.71.11	10.166.71.11
7	10.166.71.12/31	10.166.71.12 – 10.166.71.13	10.166.71.13
8	10.166.71.14/31	10.166.71.14 – 10.166.71.15	10.166.71.15
9	10.166.71.16/31	10.166.71.16 – 10.166.71.17	10.166.71.17
10	10.166.71.18/31	10.166.71.18 – 10.166.71.19	10.166.71.19
11	10.166.71.20/31	10.166.71.20 – 10.166.71.21	10.166.71.21
12	10.166.71.22/31	10.166.71.22 – 10.166.71.23	10.166.71.23
13	10.166.71.24/31	10.166.71.24 – 10.166.71.25	10.166.71.25
14	10.166.71.26/31	10.166.71.26 – 10.166.71.27	10.166.71.27
15	10.166.71.28/31	10.166.71.28 – 10.166.71.29	10.166.71.29
16	10.166.71.30/31	10.166.71.30 – 10.166.71.31	10.166.71.31
17	10.166.71.32/31	10.166.71.32 – 10.166.71.33	10.166.71.33
18	10.166.71.34/31	10.166.71.34 – 10.166.71.35	10.166.71.35
19	10.166.71.36/31	10.166.71.36 – 10.166.71.37	10.166.71.37
20	10.166.71.38/31	10.166.71.38 – 10.166.71.39	10.166.71.39
21	10.166.71.40/31	10.166.71.40 – 10.166.71.41	10.166.71.41
22	10.166.71.42/31	10.166.71.42 – 10.166.71.43	10.166.71.43
23	10.166.71.44/31	10.166.71.44 – 10.166.71.45	10.166.71.45
24	10.166.71.46/31	10.166.71.46 – 10.166.71.47	10.166.71.47
25	10.166.71.48/31	10.166.71.48 – 10.166.71.49	10.166.71.49
26	10.166.71.50/31	10.166.71.50 – 10.166.71.51	10.166.71.51
27	10.166.71.52/31	10.166.71.52 – 10.166.71.53	10.166.71.53
28	10.166.71.54/31	10.166.71.54 – 10.166.71.55	10.166.71.55
29	10.166.71.56/31	10.166.71.56 – 10.166.71.57	10.166.71.57
30	10.166.71.58/31	10.166.71.58 – 10.166.71.59	10.166.71.59
31	10.166.71.60/31	10.166.71.60 – 10.166.71.61	10.166.71.61
32	10.166.71.62/31	10.166.71.62 – 10.166.71.63	10.166.71.63
33	10.166.71.64/31	10.166.71.64 – 10.166.71.65	10.166.71.65
34	10.166.71.66/31	10.166.71.66 – 10.166.71.67	10.166.71.67
35	10.166.71.68/31	10.166.71.68 – 10.166.71.69	10.166.71.69
36	10.166.71.70/31	10.166.71.70 – 10.166.71.71	10.166.71.71
37	10.166.71.72/31	10.166.71.72 – 10.166.71.73	10.166.71.73
38	10.166.71.74/31	10.166.71.74 – 10.166.71.75	10.166.71.75
39	10.166.71.76/31	10.166.71.76 – 10.166.71.77	10.166.71.77
40	10.166.71.78/31	10.166.71.78 – 10.166.71.79	10.166.71.79
41	10.166.71.80/31	10.166.71.80 – 10.166.71.81	10.166.71.81
42	10.166.71.82/31	10.166.71.82 – 10.166.71.83	10.166.71.83
43	10.166.71.84/31	10.166.71.84 – 10.166.71.85	10.166.71.85
44	10.166.71.86/31	10.166.71.86 – 10.166.71.87	10.166.71.87
45	10.166.71.88/31	10.166.71.88 – 10.166.71.89	10.166.71.89
46	10.166.71.90/31	10.166.71.90 – 10.166.71.91	10.166.71.91
47	10.166.71.92/31	10.166.71.92 – 10.166.71.93	10.166.71.93
48	10.166.71.94/31	10.166.71.94 – 10.166.71.95	10.166.71.95
49	10.166.71.96/31	10.166.71.96 – 10.166.71.97	10.166.71.97
50	10.166.71.98/31	10.166.71.98 – 10.166.71.99	10.166.71.99
51	10.166.71.100/31	10.166.71.100 – 10.166.71.101	10.166.71.101
52	10.166.71.102/31	10.166.71.102 – 10.166.71.103	10.166.71.103
53	10.166.71.104/31	10.166.71.104 – 10.166.71.105	10.166.71.105
54	10.166.71.106/31	10.166.71.106 – 10.166.71.107	10.166.71.107
55	10.166.71.108/31	10.166.71.108 – 10.166.71.109	10.166.71.109
56	10.166.71.110/31	10.166.71.110 – 10.166.71.111	10.166.71.111
57	10.166.71.112/31	10.166.71.112 – 10.166.71.113	10.166.71.113
58	10.166.71.114/31	10.166.71.114 – 10.166.71.115	10.166.71.115
59	10.166.71.116/31	10.166.71.116 – 10.166.71.117	10.166.71.117
60	10.166.71.118/31	10.166.71.118 – 10.166.71.119	10.166.71.119
61	10.166.71.120/31	10.166.71.120 – 10.166.71.121	10.166.71.121
62	10.166.71.122/31	10.166.71.122 – 10.166.71.123	10.166.71.123
63	10.166.71.124/31	10.166.71.124 – 10.166.71.125	10.166.71.125
64	10.166.71.126/31	10.166.71.126 – 10.166.71.127	10.166.71.127

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 →