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)10.71.187.0/24

network10.71.187.0/24

broadcast10.71.187.255

first host10.71.187.1

last host10.71.187.254

subnet mask255.255.255.0

wildcard0.0.0.255

addresses256

usable hosts254

classA

ipcalc 10.71.187.0/24

address00001010.01000111.10111011.00000000

subnet mask11111111.11111111.11111111.00000000

network00001010.01000111.10111011.00000000

broadcast00001010.01000111.10111011.11111111

green = network part, grey = host part

hex0x0a47bb00

decimal172473088

reverse dns0.187.71.10.in-addr.arpa

ipv4-mapped::ffff:a47:bb00

/24 split into /30 · 64 subnets

close ×

#	network	host range	broadcast
1	10.71.187.0/30	10.71.187.1 – 10.71.187.2	10.71.187.3
2	10.71.187.4/30	10.71.187.5 – 10.71.187.6	10.71.187.7
3	10.71.187.8/30	10.71.187.9 – 10.71.187.10	10.71.187.11
4	10.71.187.12/30	10.71.187.13 – 10.71.187.14	10.71.187.15
5	10.71.187.16/30	10.71.187.17 – 10.71.187.18	10.71.187.19
6	10.71.187.20/30	10.71.187.21 – 10.71.187.22	10.71.187.23
7	10.71.187.24/30	10.71.187.25 – 10.71.187.26	10.71.187.27
8	10.71.187.28/30	10.71.187.29 – 10.71.187.30	10.71.187.31
9	10.71.187.32/30	10.71.187.33 – 10.71.187.34	10.71.187.35
10	10.71.187.36/30	10.71.187.37 – 10.71.187.38	10.71.187.39
11	10.71.187.40/30	10.71.187.41 – 10.71.187.42	10.71.187.43
12	10.71.187.44/30	10.71.187.45 – 10.71.187.46	10.71.187.47
13	10.71.187.48/30	10.71.187.49 – 10.71.187.50	10.71.187.51
14	10.71.187.52/30	10.71.187.53 – 10.71.187.54	10.71.187.55
15	10.71.187.56/30	10.71.187.57 – 10.71.187.58	10.71.187.59
16	10.71.187.60/30	10.71.187.61 – 10.71.187.62	10.71.187.63
17	10.71.187.64/30	10.71.187.65 – 10.71.187.66	10.71.187.67
18	10.71.187.68/30	10.71.187.69 – 10.71.187.70	10.71.187.71
19	10.71.187.72/30	10.71.187.73 – 10.71.187.74	10.71.187.75
20	10.71.187.76/30	10.71.187.77 – 10.71.187.78	10.71.187.79
21	10.71.187.80/30	10.71.187.81 – 10.71.187.82	10.71.187.83
22	10.71.187.84/30	10.71.187.85 – 10.71.187.86	10.71.187.87
23	10.71.187.88/30	10.71.187.89 – 10.71.187.90	10.71.187.91
24	10.71.187.92/30	10.71.187.93 – 10.71.187.94	10.71.187.95
25	10.71.187.96/30	10.71.187.97 – 10.71.187.98	10.71.187.99
26	10.71.187.100/30	10.71.187.101 – 10.71.187.102	10.71.187.103
27	10.71.187.104/30	10.71.187.105 – 10.71.187.106	10.71.187.107
28	10.71.187.108/30	10.71.187.109 – 10.71.187.110	10.71.187.111
29	10.71.187.112/30	10.71.187.113 – 10.71.187.114	10.71.187.115
30	10.71.187.116/30	10.71.187.117 – 10.71.187.118	10.71.187.119
31	10.71.187.120/30	10.71.187.121 – 10.71.187.122	10.71.187.123
32	10.71.187.124/30	10.71.187.125 – 10.71.187.126	10.71.187.127
33	10.71.187.128/30	10.71.187.129 – 10.71.187.130	10.71.187.131
34	10.71.187.132/30	10.71.187.133 – 10.71.187.134	10.71.187.135
35	10.71.187.136/30	10.71.187.137 – 10.71.187.138	10.71.187.139
36	10.71.187.140/30	10.71.187.141 – 10.71.187.142	10.71.187.143
37	10.71.187.144/30	10.71.187.145 – 10.71.187.146	10.71.187.147
38	10.71.187.148/30	10.71.187.149 – 10.71.187.150	10.71.187.151
39	10.71.187.152/30	10.71.187.153 – 10.71.187.154	10.71.187.155
40	10.71.187.156/30	10.71.187.157 – 10.71.187.158	10.71.187.159
41	10.71.187.160/30	10.71.187.161 – 10.71.187.162	10.71.187.163
42	10.71.187.164/30	10.71.187.165 – 10.71.187.166	10.71.187.167
43	10.71.187.168/30	10.71.187.169 – 10.71.187.170	10.71.187.171
44	10.71.187.172/30	10.71.187.173 – 10.71.187.174	10.71.187.175
45	10.71.187.176/30	10.71.187.177 – 10.71.187.178	10.71.187.179
46	10.71.187.180/30	10.71.187.181 – 10.71.187.182	10.71.187.183
47	10.71.187.184/30	10.71.187.185 – 10.71.187.186	10.71.187.187
48	10.71.187.188/30	10.71.187.189 – 10.71.187.190	10.71.187.191
49	10.71.187.192/30	10.71.187.193 – 10.71.187.194	10.71.187.195
50	10.71.187.196/30	10.71.187.197 – 10.71.187.198	10.71.187.199
51	10.71.187.200/30	10.71.187.201 – 10.71.187.202	10.71.187.203
52	10.71.187.204/30	10.71.187.205 – 10.71.187.206	10.71.187.207
53	10.71.187.208/30	10.71.187.209 – 10.71.187.210	10.71.187.211
54	10.71.187.212/30	10.71.187.213 – 10.71.187.214	10.71.187.215
55	10.71.187.216/30	10.71.187.217 – 10.71.187.218	10.71.187.219
56	10.71.187.220/30	10.71.187.221 – 10.71.187.222	10.71.187.223
57	10.71.187.224/30	10.71.187.225 – 10.71.187.226	10.71.187.227
58	10.71.187.228/30	10.71.187.229 – 10.71.187.230	10.71.187.231
59	10.71.187.232/30	10.71.187.233 – 10.71.187.234	10.71.187.235
60	10.71.187.236/30	10.71.187.237 – 10.71.187.238	10.71.187.239
61	10.71.187.240/30	10.71.187.241 – 10.71.187.242	10.71.187.243
62	10.71.187.244/30	10.71.187.245 – 10.71.187.246	10.71.187.247
63	10.71.187.248/30	10.71.187.249 – 10.71.187.250	10.71.187.251
64	10.71.187.252/30	10.71.187.253 – 10.71.187.254	10.71.187.255

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 →