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)10.3.18.0/23

network10.3.18.0/23

broadcast10.3.19.255

first host10.3.18.1

last host10.3.19.254

subnet mask255.255.254.0

wildcard0.0.1.255

addresses512

usable hosts510

classA

ipcalc 10.3.18.0/23

address00001010.00000011.00010010.00000000

subnet mask11111111.11111111.11111110.00000000

network00001010.00000011.00010010.00000000

broadcast00001010.00000011.00010011.11111111

green = network part, grey = host part

hex0x0a031200

decimal167973376

reverse dns0.18.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:1200

/23 split into /28 · 32 subnets

close ×

#	network	host range	broadcast
1	10.3.18.0/28	10.3.18.1 – 10.3.18.14	10.3.18.15
2	10.3.18.16/28	10.3.18.17 – 10.3.18.30	10.3.18.31
3	10.3.18.32/28	10.3.18.33 – 10.3.18.46	10.3.18.47
4	10.3.18.48/28	10.3.18.49 – 10.3.18.62	10.3.18.63
5	10.3.18.64/28	10.3.18.65 – 10.3.18.78	10.3.18.79
6	10.3.18.80/28	10.3.18.81 – 10.3.18.94	10.3.18.95
7	10.3.18.96/28	10.3.18.97 – 10.3.18.110	10.3.18.111
8	10.3.18.112/28	10.3.18.113 – 10.3.18.126	10.3.18.127
9	10.3.18.128/28	10.3.18.129 – 10.3.18.142	10.3.18.143
10	10.3.18.144/28	10.3.18.145 – 10.3.18.158	10.3.18.159
11	10.3.18.160/28	10.3.18.161 – 10.3.18.174	10.3.18.175
12	10.3.18.176/28	10.3.18.177 – 10.3.18.190	10.3.18.191
13	10.3.18.192/28	10.3.18.193 – 10.3.18.206	10.3.18.207
14	10.3.18.208/28	10.3.18.209 – 10.3.18.222	10.3.18.223
15	10.3.18.224/28	10.3.18.225 – 10.3.18.238	10.3.18.239
16	10.3.18.240/28	10.3.18.241 – 10.3.18.254	10.3.18.255
17	10.3.19.0/28	10.3.19.1 – 10.3.19.14	10.3.19.15
18	10.3.19.16/28	10.3.19.17 – 10.3.19.30	10.3.19.31
19	10.3.19.32/28	10.3.19.33 – 10.3.19.46	10.3.19.47
20	10.3.19.48/28	10.3.19.49 – 10.3.19.62	10.3.19.63
21	10.3.19.64/28	10.3.19.65 – 10.3.19.78	10.3.19.79
22	10.3.19.80/28	10.3.19.81 – 10.3.19.94	10.3.19.95
23	10.3.19.96/28	10.3.19.97 – 10.3.19.110	10.3.19.111
24	10.3.19.112/28	10.3.19.113 – 10.3.19.126	10.3.19.127
25	10.3.19.128/28	10.3.19.129 – 10.3.19.142	10.3.19.143
26	10.3.19.144/28	10.3.19.145 – 10.3.19.158	10.3.19.159
27	10.3.19.160/28	10.3.19.161 – 10.3.19.174	10.3.19.175
28	10.3.19.176/28	10.3.19.177 – 10.3.19.190	10.3.19.191
29	10.3.19.192/28	10.3.19.193 – 10.3.19.206	10.3.19.207
30	10.3.19.208/28	10.3.19.209 – 10.3.19.222	10.3.19.223
31	10.3.19.224/28	10.3.19.225 – 10.3.19.238	10.3.19.239
32	10.3.19.240/28	10.3.19.241 – 10.3.19.254	10.3.19.255

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 →