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)10.0.18.0/23

network10.0.18.0/23

broadcast10.0.19.255

first host10.0.18.1

last host10.0.19.254

subnet mask255.255.254.0

wildcard0.0.1.255

addresses512

usable hosts510

classA

ipcalc 10.0.18.0/23

address00001010.00000000.00010010.00000000

subnet mask11111111.11111111.11111110.00000000

network00001010.00000000.00010010.00000000

broadcast00001010.00000000.00010011.11111111

green = network part, grey = host part

hex0x0a001200

decimal167776768

reverse dns0.18.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:1200

/23 split into /29 · 64 subnets

close ×

#	network	host range	broadcast
1	10.0.18.0/29	10.0.18.1 – 10.0.18.6	10.0.18.7
2	10.0.18.8/29	10.0.18.9 – 10.0.18.14	10.0.18.15
3	10.0.18.16/29	10.0.18.17 – 10.0.18.22	10.0.18.23
4	10.0.18.24/29	10.0.18.25 – 10.0.18.30	10.0.18.31
5	10.0.18.32/29	10.0.18.33 – 10.0.18.38	10.0.18.39
6	10.0.18.40/29	10.0.18.41 – 10.0.18.46	10.0.18.47
7	10.0.18.48/29	10.0.18.49 – 10.0.18.54	10.0.18.55
8	10.0.18.56/29	10.0.18.57 – 10.0.18.62	10.0.18.63
9	10.0.18.64/29	10.0.18.65 – 10.0.18.70	10.0.18.71
10	10.0.18.72/29	10.0.18.73 – 10.0.18.78	10.0.18.79
11	10.0.18.80/29	10.0.18.81 – 10.0.18.86	10.0.18.87
12	10.0.18.88/29	10.0.18.89 – 10.0.18.94	10.0.18.95
13	10.0.18.96/29	10.0.18.97 – 10.0.18.102	10.0.18.103
14	10.0.18.104/29	10.0.18.105 – 10.0.18.110	10.0.18.111
15	10.0.18.112/29	10.0.18.113 – 10.0.18.118	10.0.18.119
16	10.0.18.120/29	10.0.18.121 – 10.0.18.126	10.0.18.127
17	10.0.18.128/29	10.0.18.129 – 10.0.18.134	10.0.18.135
18	10.0.18.136/29	10.0.18.137 – 10.0.18.142	10.0.18.143
19	10.0.18.144/29	10.0.18.145 – 10.0.18.150	10.0.18.151
20	10.0.18.152/29	10.0.18.153 – 10.0.18.158	10.0.18.159
21	10.0.18.160/29	10.0.18.161 – 10.0.18.166	10.0.18.167
22	10.0.18.168/29	10.0.18.169 – 10.0.18.174	10.0.18.175
23	10.0.18.176/29	10.0.18.177 – 10.0.18.182	10.0.18.183
24	10.0.18.184/29	10.0.18.185 – 10.0.18.190	10.0.18.191
25	10.0.18.192/29	10.0.18.193 – 10.0.18.198	10.0.18.199
26	10.0.18.200/29	10.0.18.201 – 10.0.18.206	10.0.18.207
27	10.0.18.208/29	10.0.18.209 – 10.0.18.214	10.0.18.215
28	10.0.18.216/29	10.0.18.217 – 10.0.18.222	10.0.18.223
29	10.0.18.224/29	10.0.18.225 – 10.0.18.230	10.0.18.231
30	10.0.18.232/29	10.0.18.233 – 10.0.18.238	10.0.18.239
31	10.0.18.240/29	10.0.18.241 – 10.0.18.246	10.0.18.247
32	10.0.18.248/29	10.0.18.249 – 10.0.18.254	10.0.18.255
33	10.0.19.0/29	10.0.19.1 – 10.0.19.6	10.0.19.7
34	10.0.19.8/29	10.0.19.9 – 10.0.19.14	10.0.19.15
35	10.0.19.16/29	10.0.19.17 – 10.0.19.22	10.0.19.23
36	10.0.19.24/29	10.0.19.25 – 10.0.19.30	10.0.19.31
37	10.0.19.32/29	10.0.19.33 – 10.0.19.38	10.0.19.39
38	10.0.19.40/29	10.0.19.41 – 10.0.19.46	10.0.19.47
39	10.0.19.48/29	10.0.19.49 – 10.0.19.54	10.0.19.55
40	10.0.19.56/29	10.0.19.57 – 10.0.19.62	10.0.19.63
41	10.0.19.64/29	10.0.19.65 – 10.0.19.70	10.0.19.71
42	10.0.19.72/29	10.0.19.73 – 10.0.19.78	10.0.19.79
43	10.0.19.80/29	10.0.19.81 – 10.0.19.86	10.0.19.87
44	10.0.19.88/29	10.0.19.89 – 10.0.19.94	10.0.19.95
45	10.0.19.96/29	10.0.19.97 – 10.0.19.102	10.0.19.103
46	10.0.19.104/29	10.0.19.105 – 10.0.19.110	10.0.19.111
47	10.0.19.112/29	10.0.19.113 – 10.0.19.118	10.0.19.119
48	10.0.19.120/29	10.0.19.121 – 10.0.19.126	10.0.19.127
49	10.0.19.128/29	10.0.19.129 – 10.0.19.134	10.0.19.135
50	10.0.19.136/29	10.0.19.137 – 10.0.19.142	10.0.19.143
51	10.0.19.144/29	10.0.19.145 – 10.0.19.150	10.0.19.151
52	10.0.19.152/29	10.0.19.153 – 10.0.19.158	10.0.19.159
53	10.0.19.160/29	10.0.19.161 – 10.0.19.166	10.0.19.167
54	10.0.19.168/29	10.0.19.169 – 10.0.19.174	10.0.19.175
55	10.0.19.176/29	10.0.19.177 – 10.0.19.182	10.0.19.183
56	10.0.19.184/29	10.0.19.185 – 10.0.19.190	10.0.19.191
57	10.0.19.192/29	10.0.19.193 – 10.0.19.198	10.0.19.199
58	10.0.19.200/29	10.0.19.201 – 10.0.19.206	10.0.19.207
59	10.0.19.208/29	10.0.19.209 – 10.0.19.214	10.0.19.215
60	10.0.19.216/29	10.0.19.217 – 10.0.19.222	10.0.19.223
61	10.0.19.224/29	10.0.19.225 – 10.0.19.230	10.0.19.231
62	10.0.19.232/29	10.0.19.233 – 10.0.19.238	10.0.19.239
63	10.0.19.240/29	10.0.19.241 – 10.0.19.246	10.0.19.247
64	10.0.19.248/29	10.0.19.249 – 10.0.19.254	10.0.19.255

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 /23
/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	1
/24	255.255.255.0	256	254	2 split →
/25	255.255.255.128	128	126	4 split →
/26	255.255.255.192	64	62	8 split →
/27	255.255.255.224	32	30	16 split →
/28	255.255.255.240	16	14	32 split →
/29	255.255.255.248	8	6	64 split →
/30	255.255.255.252	4	2	128 split →
/31	255.255.255.254	2	2	256 split →
/32	255.255.255.255	1	1	512 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 →