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)10.10.240.0/20

network10.10.240.0/20

broadcast10.10.255.255

first host10.10.240.1

last host10.10.255.254

subnet mask255.255.240.0

wildcard0.0.15.255

addresses4,096

usable hosts4,094

classA

ipcalc 10.10.240.0/20

address00001010.00001010.11110000.00000000

subnet mask11111111.11111111.11110000.00000000

network00001010.00001010.11110000.00000000

broadcast00001010.00001010.11111111.11111111

green = network part, grey = host part

hex0x0a0af000

decimal168488960

reverse dns0.240.10.10.in-addr.arpa

ipv4-mapped::ffff:a0a:f000

/20 split into /26 · 64 subnets

close ×

#	network	host range	broadcast
1	10.10.240.0/26	10.10.240.1 – 10.10.240.62	10.10.240.63
2	10.10.240.64/26	10.10.240.65 – 10.10.240.126	10.10.240.127
3	10.10.240.128/26	10.10.240.129 – 10.10.240.190	10.10.240.191
4	10.10.240.192/26	10.10.240.193 – 10.10.240.254	10.10.240.255
5	10.10.241.0/26	10.10.241.1 – 10.10.241.62	10.10.241.63
6	10.10.241.64/26	10.10.241.65 – 10.10.241.126	10.10.241.127
7	10.10.241.128/26	10.10.241.129 – 10.10.241.190	10.10.241.191
8	10.10.241.192/26	10.10.241.193 – 10.10.241.254	10.10.241.255
9	10.10.242.0/26	10.10.242.1 – 10.10.242.62	10.10.242.63
10	10.10.242.64/26	10.10.242.65 – 10.10.242.126	10.10.242.127
11	10.10.242.128/26	10.10.242.129 – 10.10.242.190	10.10.242.191
12	10.10.242.192/26	10.10.242.193 – 10.10.242.254	10.10.242.255
13	10.10.243.0/26	10.10.243.1 – 10.10.243.62	10.10.243.63
14	10.10.243.64/26	10.10.243.65 – 10.10.243.126	10.10.243.127
15	10.10.243.128/26	10.10.243.129 – 10.10.243.190	10.10.243.191
16	10.10.243.192/26	10.10.243.193 – 10.10.243.254	10.10.243.255
17	10.10.244.0/26	10.10.244.1 – 10.10.244.62	10.10.244.63
18	10.10.244.64/26	10.10.244.65 – 10.10.244.126	10.10.244.127
19	10.10.244.128/26	10.10.244.129 – 10.10.244.190	10.10.244.191
20	10.10.244.192/26	10.10.244.193 – 10.10.244.254	10.10.244.255
21	10.10.245.0/26	10.10.245.1 – 10.10.245.62	10.10.245.63
22	10.10.245.64/26	10.10.245.65 – 10.10.245.126	10.10.245.127
23	10.10.245.128/26	10.10.245.129 – 10.10.245.190	10.10.245.191
24	10.10.245.192/26	10.10.245.193 – 10.10.245.254	10.10.245.255
25	10.10.246.0/26	10.10.246.1 – 10.10.246.62	10.10.246.63
26	10.10.246.64/26	10.10.246.65 – 10.10.246.126	10.10.246.127
27	10.10.246.128/26	10.10.246.129 – 10.10.246.190	10.10.246.191
28	10.10.246.192/26	10.10.246.193 – 10.10.246.254	10.10.246.255
29	10.10.247.0/26	10.10.247.1 – 10.10.247.62	10.10.247.63
30	10.10.247.64/26	10.10.247.65 – 10.10.247.126	10.10.247.127
31	10.10.247.128/26	10.10.247.129 – 10.10.247.190	10.10.247.191
32	10.10.247.192/26	10.10.247.193 – 10.10.247.254	10.10.247.255
33	10.10.248.0/26	10.10.248.1 – 10.10.248.62	10.10.248.63
34	10.10.248.64/26	10.10.248.65 – 10.10.248.126	10.10.248.127
35	10.10.248.128/26	10.10.248.129 – 10.10.248.190	10.10.248.191
36	10.10.248.192/26	10.10.248.193 – 10.10.248.254	10.10.248.255
37	10.10.249.0/26	10.10.249.1 – 10.10.249.62	10.10.249.63
38	10.10.249.64/26	10.10.249.65 – 10.10.249.126	10.10.249.127
39	10.10.249.128/26	10.10.249.129 – 10.10.249.190	10.10.249.191
40	10.10.249.192/26	10.10.249.193 – 10.10.249.254	10.10.249.255
41	10.10.250.0/26	10.10.250.1 – 10.10.250.62	10.10.250.63
42	10.10.250.64/26	10.10.250.65 – 10.10.250.126	10.10.250.127
43	10.10.250.128/26	10.10.250.129 – 10.10.250.190	10.10.250.191
44	10.10.250.192/26	10.10.250.193 – 10.10.250.254	10.10.250.255
45	10.10.251.0/26	10.10.251.1 – 10.10.251.62	10.10.251.63
46	10.10.251.64/26	10.10.251.65 – 10.10.251.126	10.10.251.127
47	10.10.251.128/26	10.10.251.129 – 10.10.251.190	10.10.251.191
48	10.10.251.192/26	10.10.251.193 – 10.10.251.254	10.10.251.255
49	10.10.252.0/26	10.10.252.1 – 10.10.252.62	10.10.252.63
50	10.10.252.64/26	10.10.252.65 – 10.10.252.126	10.10.252.127
51	10.10.252.128/26	10.10.252.129 – 10.10.252.190	10.10.252.191
52	10.10.252.192/26	10.10.252.193 – 10.10.252.254	10.10.252.255
53	10.10.253.0/26	10.10.253.1 – 10.10.253.62	10.10.253.63
54	10.10.253.64/26	10.10.253.65 – 10.10.253.126	10.10.253.127
55	10.10.253.128/26	10.10.253.129 – 10.10.253.190	10.10.253.191
56	10.10.253.192/26	10.10.253.193 – 10.10.253.254	10.10.253.255
57	10.10.254.0/26	10.10.254.1 – 10.10.254.62	10.10.254.63
58	10.10.254.64/26	10.10.254.65 – 10.10.254.126	10.10.254.127
59	10.10.254.128/26	10.10.254.129 – 10.10.254.190	10.10.254.191
60	10.10.254.192/26	10.10.254.193 – 10.10.254.254	10.10.254.255
61	10.10.255.0/26	10.10.255.1 – 10.10.255.62	10.10.255.63
62	10.10.255.64/26	10.10.255.65 – 10.10.255.126	10.10.255.127
63	10.10.255.128/26	10.10.255.129 – 10.10.255.190	10.10.255.191
64	10.10.255.192/26	10.10.255.193 – 10.10.255.254	10.10.255.255

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 /20
/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	1
/21	255.255.248.0	2,048	2,046	2 split →
/22	255.255.252.0	1,024	1,022	4 split →
/23	255.255.254.0	512	510	8 split →
/24	255.255.255.0	256	254	16 split →
/25	255.255.255.128	128	126	32 split →
/26	255.255.255.192	64	62	64 split →
/27	255.255.255.224	32	30	128 split →
/28	255.255.255.240	16	14	256 split →
/29	255.255.255.248	8	6	512 split →
/30	255.255.255.252	4	2	1,024 split →
/31	255.255.255.254	2	2	2,048 split →
/32	255.255.255.255	1	1	4,096 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 →