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)10.3.181.0/24

network10.3.181.0/24

broadcast10.3.181.255

first host10.3.181.1

last host10.3.181.254

subnet mask255.255.255.0

wildcard0.0.0.255

addresses256

usable hosts254

classA

ipcalc 10.3.181.0/24

address00001010.00000011.10110101.00000000

subnet mask11111111.11111111.11111111.00000000

network00001010.00000011.10110101.00000000

broadcast00001010.00000011.10110101.11111111

green = network part, grey = host part

hex0x0a03b500

decimal168015104

reverse dns0.181.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:b500

/24 split into /30 · 64 subnets

close ×

#	network	host range	broadcast
1	10.3.181.0/30	10.3.181.1 – 10.3.181.2	10.3.181.3
2	10.3.181.4/30	10.3.181.5 – 10.3.181.6	10.3.181.7
3	10.3.181.8/30	10.3.181.9 – 10.3.181.10	10.3.181.11
4	10.3.181.12/30	10.3.181.13 – 10.3.181.14	10.3.181.15
5	10.3.181.16/30	10.3.181.17 – 10.3.181.18	10.3.181.19
6	10.3.181.20/30	10.3.181.21 – 10.3.181.22	10.3.181.23
7	10.3.181.24/30	10.3.181.25 – 10.3.181.26	10.3.181.27
8	10.3.181.28/30	10.3.181.29 – 10.3.181.30	10.3.181.31
9	10.3.181.32/30	10.3.181.33 – 10.3.181.34	10.3.181.35
10	10.3.181.36/30	10.3.181.37 – 10.3.181.38	10.3.181.39
11	10.3.181.40/30	10.3.181.41 – 10.3.181.42	10.3.181.43
12	10.3.181.44/30	10.3.181.45 – 10.3.181.46	10.3.181.47
13	10.3.181.48/30	10.3.181.49 – 10.3.181.50	10.3.181.51
14	10.3.181.52/30	10.3.181.53 – 10.3.181.54	10.3.181.55
15	10.3.181.56/30	10.3.181.57 – 10.3.181.58	10.3.181.59
16	10.3.181.60/30	10.3.181.61 – 10.3.181.62	10.3.181.63
17	10.3.181.64/30	10.3.181.65 – 10.3.181.66	10.3.181.67
18	10.3.181.68/30	10.3.181.69 – 10.3.181.70	10.3.181.71
19	10.3.181.72/30	10.3.181.73 – 10.3.181.74	10.3.181.75
20	10.3.181.76/30	10.3.181.77 – 10.3.181.78	10.3.181.79
21	10.3.181.80/30	10.3.181.81 – 10.3.181.82	10.3.181.83
22	10.3.181.84/30	10.3.181.85 – 10.3.181.86	10.3.181.87
23	10.3.181.88/30	10.3.181.89 – 10.3.181.90	10.3.181.91
24	10.3.181.92/30	10.3.181.93 – 10.3.181.94	10.3.181.95
25	10.3.181.96/30	10.3.181.97 – 10.3.181.98	10.3.181.99
26	10.3.181.100/30	10.3.181.101 – 10.3.181.102	10.3.181.103
27	10.3.181.104/30	10.3.181.105 – 10.3.181.106	10.3.181.107
28	10.3.181.108/30	10.3.181.109 – 10.3.181.110	10.3.181.111
29	10.3.181.112/30	10.3.181.113 – 10.3.181.114	10.3.181.115
30	10.3.181.116/30	10.3.181.117 – 10.3.181.118	10.3.181.119
31	10.3.181.120/30	10.3.181.121 – 10.3.181.122	10.3.181.123
32	10.3.181.124/30	10.3.181.125 – 10.3.181.126	10.3.181.127
33	10.3.181.128/30	10.3.181.129 – 10.3.181.130	10.3.181.131
34	10.3.181.132/30	10.3.181.133 – 10.3.181.134	10.3.181.135
35	10.3.181.136/30	10.3.181.137 – 10.3.181.138	10.3.181.139
36	10.3.181.140/30	10.3.181.141 – 10.3.181.142	10.3.181.143
37	10.3.181.144/30	10.3.181.145 – 10.3.181.146	10.3.181.147
38	10.3.181.148/30	10.3.181.149 – 10.3.181.150	10.3.181.151
39	10.3.181.152/30	10.3.181.153 – 10.3.181.154	10.3.181.155
40	10.3.181.156/30	10.3.181.157 – 10.3.181.158	10.3.181.159
41	10.3.181.160/30	10.3.181.161 – 10.3.181.162	10.3.181.163
42	10.3.181.164/30	10.3.181.165 – 10.3.181.166	10.3.181.167
43	10.3.181.168/30	10.3.181.169 – 10.3.181.170	10.3.181.171
44	10.3.181.172/30	10.3.181.173 – 10.3.181.174	10.3.181.175
45	10.3.181.176/30	10.3.181.177 – 10.3.181.178	10.3.181.179
46	10.3.181.180/30	10.3.181.181 – 10.3.181.182	10.3.181.183
47	10.3.181.184/30	10.3.181.185 – 10.3.181.186	10.3.181.187
48	10.3.181.188/30	10.3.181.189 – 10.3.181.190	10.3.181.191
49	10.3.181.192/30	10.3.181.193 – 10.3.181.194	10.3.181.195
50	10.3.181.196/30	10.3.181.197 – 10.3.181.198	10.3.181.199
51	10.3.181.200/30	10.3.181.201 – 10.3.181.202	10.3.181.203
52	10.3.181.204/30	10.3.181.205 – 10.3.181.206	10.3.181.207
53	10.3.181.208/30	10.3.181.209 – 10.3.181.210	10.3.181.211
54	10.3.181.212/30	10.3.181.213 – 10.3.181.214	10.3.181.215
55	10.3.181.216/30	10.3.181.217 – 10.3.181.218	10.3.181.219
56	10.3.181.220/30	10.3.181.221 – 10.3.181.222	10.3.181.223
57	10.3.181.224/30	10.3.181.225 – 10.3.181.226	10.3.181.227
58	10.3.181.228/30	10.3.181.229 – 10.3.181.230	10.3.181.231
59	10.3.181.232/30	10.3.181.233 – 10.3.181.234	10.3.181.235
60	10.3.181.236/30	10.3.181.237 – 10.3.181.238	10.3.181.239
61	10.3.181.240/30	10.3.181.241 – 10.3.181.242	10.3.181.243
62	10.3.181.244/30	10.3.181.245 – 10.3.181.246	10.3.181.247
63	10.3.181.248/30	10.3.181.249 – 10.3.181.250	10.3.181.251
64	10.3.181.252/30	10.3.181.253 – 10.3.181.254	10.3.181.255

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 /24
/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	1
/25	255.255.255.128	128	126	2 split →
/26	255.255.255.192	64	62	4 split →
/27	255.255.255.224	32	30	8 split →
/28	255.255.255.240	16	14	16 split →
/29	255.255.255.248	8	6	32 split →
/30	255.255.255.252	4	2	64 split →
/31	255.255.255.254	2	2	128 split →
/32	255.255.255.255	1	1	256 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 →