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)10.3.124.0/25

network10.3.124.0/25

broadcast10.3.124.127

first host10.3.124.1

last host10.3.124.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.3.124.0/25

address00001010.00000011.01111100.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000011.01111100.00000000

broadcast00001010.00000011.01111100.01111111

green = network part, grey = host part

hex0x0a037c00

decimal168000512

reverse dns0.124.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:7c00

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.3.124.0/31	10.3.124.0 – 10.3.124.1	10.3.124.1
2	10.3.124.2/31	10.3.124.2 – 10.3.124.3	10.3.124.3
3	10.3.124.4/31	10.3.124.4 – 10.3.124.5	10.3.124.5
4	10.3.124.6/31	10.3.124.6 – 10.3.124.7	10.3.124.7
5	10.3.124.8/31	10.3.124.8 – 10.3.124.9	10.3.124.9
6	10.3.124.10/31	10.3.124.10 – 10.3.124.11	10.3.124.11
7	10.3.124.12/31	10.3.124.12 – 10.3.124.13	10.3.124.13
8	10.3.124.14/31	10.3.124.14 – 10.3.124.15	10.3.124.15
9	10.3.124.16/31	10.3.124.16 – 10.3.124.17	10.3.124.17
10	10.3.124.18/31	10.3.124.18 – 10.3.124.19	10.3.124.19
11	10.3.124.20/31	10.3.124.20 – 10.3.124.21	10.3.124.21
12	10.3.124.22/31	10.3.124.22 – 10.3.124.23	10.3.124.23
13	10.3.124.24/31	10.3.124.24 – 10.3.124.25	10.3.124.25
14	10.3.124.26/31	10.3.124.26 – 10.3.124.27	10.3.124.27
15	10.3.124.28/31	10.3.124.28 – 10.3.124.29	10.3.124.29
16	10.3.124.30/31	10.3.124.30 – 10.3.124.31	10.3.124.31
17	10.3.124.32/31	10.3.124.32 – 10.3.124.33	10.3.124.33
18	10.3.124.34/31	10.3.124.34 – 10.3.124.35	10.3.124.35
19	10.3.124.36/31	10.3.124.36 – 10.3.124.37	10.3.124.37
20	10.3.124.38/31	10.3.124.38 – 10.3.124.39	10.3.124.39
21	10.3.124.40/31	10.3.124.40 – 10.3.124.41	10.3.124.41
22	10.3.124.42/31	10.3.124.42 – 10.3.124.43	10.3.124.43
23	10.3.124.44/31	10.3.124.44 – 10.3.124.45	10.3.124.45
24	10.3.124.46/31	10.3.124.46 – 10.3.124.47	10.3.124.47
25	10.3.124.48/31	10.3.124.48 – 10.3.124.49	10.3.124.49
26	10.3.124.50/31	10.3.124.50 – 10.3.124.51	10.3.124.51
27	10.3.124.52/31	10.3.124.52 – 10.3.124.53	10.3.124.53
28	10.3.124.54/31	10.3.124.54 – 10.3.124.55	10.3.124.55
29	10.3.124.56/31	10.3.124.56 – 10.3.124.57	10.3.124.57
30	10.3.124.58/31	10.3.124.58 – 10.3.124.59	10.3.124.59
31	10.3.124.60/31	10.3.124.60 – 10.3.124.61	10.3.124.61
32	10.3.124.62/31	10.3.124.62 – 10.3.124.63	10.3.124.63
33	10.3.124.64/31	10.3.124.64 – 10.3.124.65	10.3.124.65
34	10.3.124.66/31	10.3.124.66 – 10.3.124.67	10.3.124.67
35	10.3.124.68/31	10.3.124.68 – 10.3.124.69	10.3.124.69
36	10.3.124.70/31	10.3.124.70 – 10.3.124.71	10.3.124.71
37	10.3.124.72/31	10.3.124.72 – 10.3.124.73	10.3.124.73
38	10.3.124.74/31	10.3.124.74 – 10.3.124.75	10.3.124.75
39	10.3.124.76/31	10.3.124.76 – 10.3.124.77	10.3.124.77
40	10.3.124.78/31	10.3.124.78 – 10.3.124.79	10.3.124.79
41	10.3.124.80/31	10.3.124.80 – 10.3.124.81	10.3.124.81
42	10.3.124.82/31	10.3.124.82 – 10.3.124.83	10.3.124.83
43	10.3.124.84/31	10.3.124.84 – 10.3.124.85	10.3.124.85
44	10.3.124.86/31	10.3.124.86 – 10.3.124.87	10.3.124.87
45	10.3.124.88/31	10.3.124.88 – 10.3.124.89	10.3.124.89
46	10.3.124.90/31	10.3.124.90 – 10.3.124.91	10.3.124.91
47	10.3.124.92/31	10.3.124.92 – 10.3.124.93	10.3.124.93
48	10.3.124.94/31	10.3.124.94 – 10.3.124.95	10.3.124.95
49	10.3.124.96/31	10.3.124.96 – 10.3.124.97	10.3.124.97
50	10.3.124.98/31	10.3.124.98 – 10.3.124.99	10.3.124.99
51	10.3.124.100/31	10.3.124.100 – 10.3.124.101	10.3.124.101
52	10.3.124.102/31	10.3.124.102 – 10.3.124.103	10.3.124.103
53	10.3.124.104/31	10.3.124.104 – 10.3.124.105	10.3.124.105
54	10.3.124.106/31	10.3.124.106 – 10.3.124.107	10.3.124.107
55	10.3.124.108/31	10.3.124.108 – 10.3.124.109	10.3.124.109
56	10.3.124.110/31	10.3.124.110 – 10.3.124.111	10.3.124.111
57	10.3.124.112/31	10.3.124.112 – 10.3.124.113	10.3.124.113
58	10.3.124.114/31	10.3.124.114 – 10.3.124.115	10.3.124.115
59	10.3.124.116/31	10.3.124.116 – 10.3.124.117	10.3.124.117
60	10.3.124.118/31	10.3.124.118 – 10.3.124.119	10.3.124.119
61	10.3.124.120/31	10.3.124.120 – 10.3.124.121	10.3.124.121
62	10.3.124.122/31	10.3.124.122 – 10.3.124.123	10.3.124.123
63	10.3.124.124/31	10.3.124.124 – 10.3.124.125	10.3.124.125
64	10.3.124.126/31	10.3.124.126 – 10.3.124.127	10.3.124.127

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 →