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)10.0.18.0/24

network10.0.18.0/24

broadcast10.0.18.255

first host10.0.18.1

last host10.0.18.254

subnet mask255.255.255.0

wildcard0.0.0.255

addresses256

usable hosts254

classA

ipcalc 10.0.18.0/24

address00001010.00000000.00010010.00000000

subnet mask11111111.11111111.11111111.00000000

network00001010.00000000.00010010.00000000

broadcast00001010.00000000.00010010.11111111

green = network part, grey = host part

hex0x0a001200

decimal167776768

reverse dns0.18.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:1200

/24 split into /30 · 64 subnets

close ×

#	network	host range	broadcast
1	10.0.18.0/30	10.0.18.1 – 10.0.18.2	10.0.18.3
2	10.0.18.4/30	10.0.18.5 – 10.0.18.6	10.0.18.7
3	10.0.18.8/30	10.0.18.9 – 10.0.18.10	10.0.18.11
4	10.0.18.12/30	10.0.18.13 – 10.0.18.14	10.0.18.15
5	10.0.18.16/30	10.0.18.17 – 10.0.18.18	10.0.18.19
6	10.0.18.20/30	10.0.18.21 – 10.0.18.22	10.0.18.23
7	10.0.18.24/30	10.0.18.25 – 10.0.18.26	10.0.18.27
8	10.0.18.28/30	10.0.18.29 – 10.0.18.30	10.0.18.31
9	10.0.18.32/30	10.0.18.33 – 10.0.18.34	10.0.18.35
10	10.0.18.36/30	10.0.18.37 – 10.0.18.38	10.0.18.39
11	10.0.18.40/30	10.0.18.41 – 10.0.18.42	10.0.18.43
12	10.0.18.44/30	10.0.18.45 – 10.0.18.46	10.0.18.47
13	10.0.18.48/30	10.0.18.49 – 10.0.18.50	10.0.18.51
14	10.0.18.52/30	10.0.18.53 – 10.0.18.54	10.0.18.55
15	10.0.18.56/30	10.0.18.57 – 10.0.18.58	10.0.18.59
16	10.0.18.60/30	10.0.18.61 – 10.0.18.62	10.0.18.63
17	10.0.18.64/30	10.0.18.65 – 10.0.18.66	10.0.18.67
18	10.0.18.68/30	10.0.18.69 – 10.0.18.70	10.0.18.71
19	10.0.18.72/30	10.0.18.73 – 10.0.18.74	10.0.18.75
20	10.0.18.76/30	10.0.18.77 – 10.0.18.78	10.0.18.79
21	10.0.18.80/30	10.0.18.81 – 10.0.18.82	10.0.18.83
22	10.0.18.84/30	10.0.18.85 – 10.0.18.86	10.0.18.87
23	10.0.18.88/30	10.0.18.89 – 10.0.18.90	10.0.18.91
24	10.0.18.92/30	10.0.18.93 – 10.0.18.94	10.0.18.95
25	10.0.18.96/30	10.0.18.97 – 10.0.18.98	10.0.18.99
26	10.0.18.100/30	10.0.18.101 – 10.0.18.102	10.0.18.103
27	10.0.18.104/30	10.0.18.105 – 10.0.18.106	10.0.18.107
28	10.0.18.108/30	10.0.18.109 – 10.0.18.110	10.0.18.111
29	10.0.18.112/30	10.0.18.113 – 10.0.18.114	10.0.18.115
30	10.0.18.116/30	10.0.18.117 – 10.0.18.118	10.0.18.119
31	10.0.18.120/30	10.0.18.121 – 10.0.18.122	10.0.18.123
32	10.0.18.124/30	10.0.18.125 – 10.0.18.126	10.0.18.127
33	10.0.18.128/30	10.0.18.129 – 10.0.18.130	10.0.18.131
34	10.0.18.132/30	10.0.18.133 – 10.0.18.134	10.0.18.135
35	10.0.18.136/30	10.0.18.137 – 10.0.18.138	10.0.18.139
36	10.0.18.140/30	10.0.18.141 – 10.0.18.142	10.0.18.143
37	10.0.18.144/30	10.0.18.145 – 10.0.18.146	10.0.18.147
38	10.0.18.148/30	10.0.18.149 – 10.0.18.150	10.0.18.151
39	10.0.18.152/30	10.0.18.153 – 10.0.18.154	10.0.18.155
40	10.0.18.156/30	10.0.18.157 – 10.0.18.158	10.0.18.159
41	10.0.18.160/30	10.0.18.161 – 10.0.18.162	10.0.18.163
42	10.0.18.164/30	10.0.18.165 – 10.0.18.166	10.0.18.167
43	10.0.18.168/30	10.0.18.169 – 10.0.18.170	10.0.18.171
44	10.0.18.172/30	10.0.18.173 – 10.0.18.174	10.0.18.175
45	10.0.18.176/30	10.0.18.177 – 10.0.18.178	10.0.18.179
46	10.0.18.180/30	10.0.18.181 – 10.0.18.182	10.0.18.183
47	10.0.18.184/30	10.0.18.185 – 10.0.18.186	10.0.18.187
48	10.0.18.188/30	10.0.18.189 – 10.0.18.190	10.0.18.191
49	10.0.18.192/30	10.0.18.193 – 10.0.18.194	10.0.18.195
50	10.0.18.196/30	10.0.18.197 – 10.0.18.198	10.0.18.199
51	10.0.18.200/30	10.0.18.201 – 10.0.18.202	10.0.18.203
52	10.0.18.204/30	10.0.18.205 – 10.0.18.206	10.0.18.207
53	10.0.18.208/30	10.0.18.209 – 10.0.18.210	10.0.18.211
54	10.0.18.212/30	10.0.18.213 – 10.0.18.214	10.0.18.215
55	10.0.18.216/30	10.0.18.217 – 10.0.18.218	10.0.18.219
56	10.0.18.220/30	10.0.18.221 – 10.0.18.222	10.0.18.223
57	10.0.18.224/30	10.0.18.225 – 10.0.18.226	10.0.18.227
58	10.0.18.228/30	10.0.18.229 – 10.0.18.230	10.0.18.231
59	10.0.18.232/30	10.0.18.233 – 10.0.18.234	10.0.18.235
60	10.0.18.236/30	10.0.18.237 – 10.0.18.238	10.0.18.239
61	10.0.18.240/30	10.0.18.241 – 10.0.18.242	10.0.18.243
62	10.0.18.244/30	10.0.18.245 – 10.0.18.246	10.0.18.247
63	10.0.18.248/30	10.0.18.249 – 10.0.18.250	10.0.18.251
64	10.0.18.252/30	10.0.18.253 – 10.0.18.254	10.0.18.255

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 →