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)10.2.17.0/25

network10.2.17.0/25

broadcast10.2.17.127

first host10.2.17.1

last host10.2.17.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.2.17.0/25

address00001010.00000010.00010001.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000010.00010001.00000000

broadcast00001010.00000010.00010001.01111111

green = network part, grey = host part

hex0x0a021100

decimal167907584

reverse dns0.17.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:1100

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.2.17.0/31	10.2.17.0 – 10.2.17.1	10.2.17.1
2	10.2.17.2/31	10.2.17.2 – 10.2.17.3	10.2.17.3
3	10.2.17.4/31	10.2.17.4 – 10.2.17.5	10.2.17.5
4	10.2.17.6/31	10.2.17.6 – 10.2.17.7	10.2.17.7
5	10.2.17.8/31	10.2.17.8 – 10.2.17.9	10.2.17.9
6	10.2.17.10/31	10.2.17.10 – 10.2.17.11	10.2.17.11
7	10.2.17.12/31	10.2.17.12 – 10.2.17.13	10.2.17.13
8	10.2.17.14/31	10.2.17.14 – 10.2.17.15	10.2.17.15
9	10.2.17.16/31	10.2.17.16 – 10.2.17.17	10.2.17.17
10	10.2.17.18/31	10.2.17.18 – 10.2.17.19	10.2.17.19
11	10.2.17.20/31	10.2.17.20 – 10.2.17.21	10.2.17.21
12	10.2.17.22/31	10.2.17.22 – 10.2.17.23	10.2.17.23
13	10.2.17.24/31	10.2.17.24 – 10.2.17.25	10.2.17.25
14	10.2.17.26/31	10.2.17.26 – 10.2.17.27	10.2.17.27
15	10.2.17.28/31	10.2.17.28 – 10.2.17.29	10.2.17.29
16	10.2.17.30/31	10.2.17.30 – 10.2.17.31	10.2.17.31
17	10.2.17.32/31	10.2.17.32 – 10.2.17.33	10.2.17.33
18	10.2.17.34/31	10.2.17.34 – 10.2.17.35	10.2.17.35
19	10.2.17.36/31	10.2.17.36 – 10.2.17.37	10.2.17.37
20	10.2.17.38/31	10.2.17.38 – 10.2.17.39	10.2.17.39
21	10.2.17.40/31	10.2.17.40 – 10.2.17.41	10.2.17.41
22	10.2.17.42/31	10.2.17.42 – 10.2.17.43	10.2.17.43
23	10.2.17.44/31	10.2.17.44 – 10.2.17.45	10.2.17.45
24	10.2.17.46/31	10.2.17.46 – 10.2.17.47	10.2.17.47
25	10.2.17.48/31	10.2.17.48 – 10.2.17.49	10.2.17.49
26	10.2.17.50/31	10.2.17.50 – 10.2.17.51	10.2.17.51
27	10.2.17.52/31	10.2.17.52 – 10.2.17.53	10.2.17.53
28	10.2.17.54/31	10.2.17.54 – 10.2.17.55	10.2.17.55
29	10.2.17.56/31	10.2.17.56 – 10.2.17.57	10.2.17.57
30	10.2.17.58/31	10.2.17.58 – 10.2.17.59	10.2.17.59
31	10.2.17.60/31	10.2.17.60 – 10.2.17.61	10.2.17.61
32	10.2.17.62/31	10.2.17.62 – 10.2.17.63	10.2.17.63
33	10.2.17.64/31	10.2.17.64 – 10.2.17.65	10.2.17.65
34	10.2.17.66/31	10.2.17.66 – 10.2.17.67	10.2.17.67
35	10.2.17.68/31	10.2.17.68 – 10.2.17.69	10.2.17.69
36	10.2.17.70/31	10.2.17.70 – 10.2.17.71	10.2.17.71
37	10.2.17.72/31	10.2.17.72 – 10.2.17.73	10.2.17.73
38	10.2.17.74/31	10.2.17.74 – 10.2.17.75	10.2.17.75
39	10.2.17.76/31	10.2.17.76 – 10.2.17.77	10.2.17.77
40	10.2.17.78/31	10.2.17.78 – 10.2.17.79	10.2.17.79
41	10.2.17.80/31	10.2.17.80 – 10.2.17.81	10.2.17.81
42	10.2.17.82/31	10.2.17.82 – 10.2.17.83	10.2.17.83
43	10.2.17.84/31	10.2.17.84 – 10.2.17.85	10.2.17.85
44	10.2.17.86/31	10.2.17.86 – 10.2.17.87	10.2.17.87
45	10.2.17.88/31	10.2.17.88 – 10.2.17.89	10.2.17.89
46	10.2.17.90/31	10.2.17.90 – 10.2.17.91	10.2.17.91
47	10.2.17.92/31	10.2.17.92 – 10.2.17.93	10.2.17.93
48	10.2.17.94/31	10.2.17.94 – 10.2.17.95	10.2.17.95
49	10.2.17.96/31	10.2.17.96 – 10.2.17.97	10.2.17.97
50	10.2.17.98/31	10.2.17.98 – 10.2.17.99	10.2.17.99
51	10.2.17.100/31	10.2.17.100 – 10.2.17.101	10.2.17.101
52	10.2.17.102/31	10.2.17.102 – 10.2.17.103	10.2.17.103
53	10.2.17.104/31	10.2.17.104 – 10.2.17.105	10.2.17.105
54	10.2.17.106/31	10.2.17.106 – 10.2.17.107	10.2.17.107
55	10.2.17.108/31	10.2.17.108 – 10.2.17.109	10.2.17.109
56	10.2.17.110/31	10.2.17.110 – 10.2.17.111	10.2.17.111
57	10.2.17.112/31	10.2.17.112 – 10.2.17.113	10.2.17.113
58	10.2.17.114/31	10.2.17.114 – 10.2.17.115	10.2.17.115
59	10.2.17.116/31	10.2.17.116 – 10.2.17.117	10.2.17.117
60	10.2.17.118/31	10.2.17.118 – 10.2.17.119	10.2.17.119
61	10.2.17.120/31	10.2.17.120 – 10.2.17.121	10.2.17.121
62	10.2.17.122/31	10.2.17.122 – 10.2.17.123	10.2.17.123
63	10.2.17.124/31	10.2.17.124 – 10.2.17.125	10.2.17.125
64	10.2.17.126/31	10.2.17.126 – 10.2.17.127	10.2.17.127

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 →