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)10.0.99.0/25

network10.0.99.0/25

broadcast10.0.99.127

first host10.0.99.1

last host10.0.99.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.0.99.0/25

address00001010.00000000.01100011.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000000.01100011.00000000

broadcast00001010.00000000.01100011.01111111

green = network part, grey = host part

hex0x0a006300

decimal167797504

reverse dns0.99.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:6300

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.0.99.0/31	10.0.99.0 – 10.0.99.1	10.0.99.1
2	10.0.99.2/31	10.0.99.2 – 10.0.99.3	10.0.99.3
3	10.0.99.4/31	10.0.99.4 – 10.0.99.5	10.0.99.5
4	10.0.99.6/31	10.0.99.6 – 10.0.99.7	10.0.99.7
5	10.0.99.8/31	10.0.99.8 – 10.0.99.9	10.0.99.9
6	10.0.99.10/31	10.0.99.10 – 10.0.99.11	10.0.99.11
7	10.0.99.12/31	10.0.99.12 – 10.0.99.13	10.0.99.13
8	10.0.99.14/31	10.0.99.14 – 10.0.99.15	10.0.99.15
9	10.0.99.16/31	10.0.99.16 – 10.0.99.17	10.0.99.17
10	10.0.99.18/31	10.0.99.18 – 10.0.99.19	10.0.99.19
11	10.0.99.20/31	10.0.99.20 – 10.0.99.21	10.0.99.21
12	10.0.99.22/31	10.0.99.22 – 10.0.99.23	10.0.99.23
13	10.0.99.24/31	10.0.99.24 – 10.0.99.25	10.0.99.25
14	10.0.99.26/31	10.0.99.26 – 10.0.99.27	10.0.99.27
15	10.0.99.28/31	10.0.99.28 – 10.0.99.29	10.0.99.29
16	10.0.99.30/31	10.0.99.30 – 10.0.99.31	10.0.99.31
17	10.0.99.32/31	10.0.99.32 – 10.0.99.33	10.0.99.33
18	10.0.99.34/31	10.0.99.34 – 10.0.99.35	10.0.99.35
19	10.0.99.36/31	10.0.99.36 – 10.0.99.37	10.0.99.37
20	10.0.99.38/31	10.0.99.38 – 10.0.99.39	10.0.99.39
21	10.0.99.40/31	10.0.99.40 – 10.0.99.41	10.0.99.41
22	10.0.99.42/31	10.0.99.42 – 10.0.99.43	10.0.99.43
23	10.0.99.44/31	10.0.99.44 – 10.0.99.45	10.0.99.45
24	10.0.99.46/31	10.0.99.46 – 10.0.99.47	10.0.99.47
25	10.0.99.48/31	10.0.99.48 – 10.0.99.49	10.0.99.49
26	10.0.99.50/31	10.0.99.50 – 10.0.99.51	10.0.99.51
27	10.0.99.52/31	10.0.99.52 – 10.0.99.53	10.0.99.53
28	10.0.99.54/31	10.0.99.54 – 10.0.99.55	10.0.99.55
29	10.0.99.56/31	10.0.99.56 – 10.0.99.57	10.0.99.57
30	10.0.99.58/31	10.0.99.58 – 10.0.99.59	10.0.99.59
31	10.0.99.60/31	10.0.99.60 – 10.0.99.61	10.0.99.61
32	10.0.99.62/31	10.0.99.62 – 10.0.99.63	10.0.99.63
33	10.0.99.64/31	10.0.99.64 – 10.0.99.65	10.0.99.65
34	10.0.99.66/31	10.0.99.66 – 10.0.99.67	10.0.99.67
35	10.0.99.68/31	10.0.99.68 – 10.0.99.69	10.0.99.69
36	10.0.99.70/31	10.0.99.70 – 10.0.99.71	10.0.99.71
37	10.0.99.72/31	10.0.99.72 – 10.0.99.73	10.0.99.73
38	10.0.99.74/31	10.0.99.74 – 10.0.99.75	10.0.99.75
39	10.0.99.76/31	10.0.99.76 – 10.0.99.77	10.0.99.77
40	10.0.99.78/31	10.0.99.78 – 10.0.99.79	10.0.99.79
41	10.0.99.80/31	10.0.99.80 – 10.0.99.81	10.0.99.81
42	10.0.99.82/31	10.0.99.82 – 10.0.99.83	10.0.99.83
43	10.0.99.84/31	10.0.99.84 – 10.0.99.85	10.0.99.85
44	10.0.99.86/31	10.0.99.86 – 10.0.99.87	10.0.99.87
45	10.0.99.88/31	10.0.99.88 – 10.0.99.89	10.0.99.89
46	10.0.99.90/31	10.0.99.90 – 10.0.99.91	10.0.99.91
47	10.0.99.92/31	10.0.99.92 – 10.0.99.93	10.0.99.93
48	10.0.99.94/31	10.0.99.94 – 10.0.99.95	10.0.99.95
49	10.0.99.96/31	10.0.99.96 – 10.0.99.97	10.0.99.97
50	10.0.99.98/31	10.0.99.98 – 10.0.99.99	10.0.99.99
51	10.0.99.100/31	10.0.99.100 – 10.0.99.101	10.0.99.101
52	10.0.99.102/31	10.0.99.102 – 10.0.99.103	10.0.99.103
53	10.0.99.104/31	10.0.99.104 – 10.0.99.105	10.0.99.105
54	10.0.99.106/31	10.0.99.106 – 10.0.99.107	10.0.99.107
55	10.0.99.108/31	10.0.99.108 – 10.0.99.109	10.0.99.109
56	10.0.99.110/31	10.0.99.110 – 10.0.99.111	10.0.99.111
57	10.0.99.112/31	10.0.99.112 – 10.0.99.113	10.0.99.113
58	10.0.99.114/31	10.0.99.114 – 10.0.99.115	10.0.99.115
59	10.0.99.116/31	10.0.99.116 – 10.0.99.117	10.0.99.117
60	10.0.99.118/31	10.0.99.118 – 10.0.99.119	10.0.99.119
61	10.0.99.120/31	10.0.99.120 – 10.0.99.121	10.0.99.121
62	10.0.99.122/31	10.0.99.122 – 10.0.99.123	10.0.99.123
63	10.0.99.124/31	10.0.99.124 – 10.0.99.125	10.0.99.125
64	10.0.99.126/31	10.0.99.126 – 10.0.99.127	10.0.99.127

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 →