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)10.71.239.0/25

network10.71.239.0/25

broadcast10.71.239.127

first host10.71.239.1

last host10.71.239.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.71.239.0/25

address00001010.01000111.11101111.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.01000111.11101111.00000000

broadcast00001010.01000111.11101111.01111111

green = network part, grey = host part

hex0x0a47ef00

decimal172486400

reverse dns0.239.71.10.in-addr.arpa

ipv4-mapped::ffff:a47:ef00

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.71.239.0/31	10.71.239.0 – 10.71.239.1	10.71.239.1
2	10.71.239.2/31	10.71.239.2 – 10.71.239.3	10.71.239.3
3	10.71.239.4/31	10.71.239.4 – 10.71.239.5	10.71.239.5
4	10.71.239.6/31	10.71.239.6 – 10.71.239.7	10.71.239.7
5	10.71.239.8/31	10.71.239.8 – 10.71.239.9	10.71.239.9
6	10.71.239.10/31	10.71.239.10 – 10.71.239.11	10.71.239.11
7	10.71.239.12/31	10.71.239.12 – 10.71.239.13	10.71.239.13
8	10.71.239.14/31	10.71.239.14 – 10.71.239.15	10.71.239.15
9	10.71.239.16/31	10.71.239.16 – 10.71.239.17	10.71.239.17
10	10.71.239.18/31	10.71.239.18 – 10.71.239.19	10.71.239.19
11	10.71.239.20/31	10.71.239.20 – 10.71.239.21	10.71.239.21
12	10.71.239.22/31	10.71.239.22 – 10.71.239.23	10.71.239.23
13	10.71.239.24/31	10.71.239.24 – 10.71.239.25	10.71.239.25
14	10.71.239.26/31	10.71.239.26 – 10.71.239.27	10.71.239.27
15	10.71.239.28/31	10.71.239.28 – 10.71.239.29	10.71.239.29
16	10.71.239.30/31	10.71.239.30 – 10.71.239.31	10.71.239.31
17	10.71.239.32/31	10.71.239.32 – 10.71.239.33	10.71.239.33
18	10.71.239.34/31	10.71.239.34 – 10.71.239.35	10.71.239.35
19	10.71.239.36/31	10.71.239.36 – 10.71.239.37	10.71.239.37
20	10.71.239.38/31	10.71.239.38 – 10.71.239.39	10.71.239.39
21	10.71.239.40/31	10.71.239.40 – 10.71.239.41	10.71.239.41
22	10.71.239.42/31	10.71.239.42 – 10.71.239.43	10.71.239.43
23	10.71.239.44/31	10.71.239.44 – 10.71.239.45	10.71.239.45
24	10.71.239.46/31	10.71.239.46 – 10.71.239.47	10.71.239.47
25	10.71.239.48/31	10.71.239.48 – 10.71.239.49	10.71.239.49
26	10.71.239.50/31	10.71.239.50 – 10.71.239.51	10.71.239.51
27	10.71.239.52/31	10.71.239.52 – 10.71.239.53	10.71.239.53
28	10.71.239.54/31	10.71.239.54 – 10.71.239.55	10.71.239.55
29	10.71.239.56/31	10.71.239.56 – 10.71.239.57	10.71.239.57
30	10.71.239.58/31	10.71.239.58 – 10.71.239.59	10.71.239.59
31	10.71.239.60/31	10.71.239.60 – 10.71.239.61	10.71.239.61
32	10.71.239.62/31	10.71.239.62 – 10.71.239.63	10.71.239.63
33	10.71.239.64/31	10.71.239.64 – 10.71.239.65	10.71.239.65
34	10.71.239.66/31	10.71.239.66 – 10.71.239.67	10.71.239.67
35	10.71.239.68/31	10.71.239.68 – 10.71.239.69	10.71.239.69
36	10.71.239.70/31	10.71.239.70 – 10.71.239.71	10.71.239.71
37	10.71.239.72/31	10.71.239.72 – 10.71.239.73	10.71.239.73
38	10.71.239.74/31	10.71.239.74 – 10.71.239.75	10.71.239.75
39	10.71.239.76/31	10.71.239.76 – 10.71.239.77	10.71.239.77
40	10.71.239.78/31	10.71.239.78 – 10.71.239.79	10.71.239.79
41	10.71.239.80/31	10.71.239.80 – 10.71.239.81	10.71.239.81
42	10.71.239.82/31	10.71.239.82 – 10.71.239.83	10.71.239.83
43	10.71.239.84/31	10.71.239.84 – 10.71.239.85	10.71.239.85
44	10.71.239.86/31	10.71.239.86 – 10.71.239.87	10.71.239.87
45	10.71.239.88/31	10.71.239.88 – 10.71.239.89	10.71.239.89
46	10.71.239.90/31	10.71.239.90 – 10.71.239.91	10.71.239.91
47	10.71.239.92/31	10.71.239.92 – 10.71.239.93	10.71.239.93
48	10.71.239.94/31	10.71.239.94 – 10.71.239.95	10.71.239.95
49	10.71.239.96/31	10.71.239.96 – 10.71.239.97	10.71.239.97
50	10.71.239.98/31	10.71.239.98 – 10.71.239.99	10.71.239.99
51	10.71.239.100/31	10.71.239.100 – 10.71.239.101	10.71.239.101
52	10.71.239.102/31	10.71.239.102 – 10.71.239.103	10.71.239.103
53	10.71.239.104/31	10.71.239.104 – 10.71.239.105	10.71.239.105
54	10.71.239.106/31	10.71.239.106 – 10.71.239.107	10.71.239.107
55	10.71.239.108/31	10.71.239.108 – 10.71.239.109	10.71.239.109
56	10.71.239.110/31	10.71.239.110 – 10.71.239.111	10.71.239.111
57	10.71.239.112/31	10.71.239.112 – 10.71.239.113	10.71.239.113
58	10.71.239.114/31	10.71.239.114 – 10.71.239.115	10.71.239.115
59	10.71.239.116/31	10.71.239.116 – 10.71.239.117	10.71.239.117
60	10.71.239.118/31	10.71.239.118 – 10.71.239.119	10.71.239.119
61	10.71.239.120/31	10.71.239.120 – 10.71.239.121	10.71.239.121
62	10.71.239.122/31	10.71.239.122 – 10.71.239.123	10.71.239.123
63	10.71.239.124/31	10.71.239.124 – 10.71.239.125	10.71.239.125
64	10.71.239.126/31	10.71.239.126 – 10.71.239.127	10.71.239.127

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 →