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)10.78.232.0/21

network10.78.232.0/21

broadcast10.78.239.255

first host10.78.232.1

last host10.78.239.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.78.232.0/21

address00001010.01001110.11101000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.01001110.11101000.00000000

broadcast00001010.01001110.11101111.11111111

green = network part, grey = host part

hex0x0a4ee800

decimal172943360

reverse dns0.232.78.10.in-addr.arpa

ipv4-mapped::ffff:a4e:e800

/21 split into /27 · 64 subnets

close ×

#	network	host range	broadcast
1	10.78.232.0/27	10.78.232.1 – 10.78.232.30	10.78.232.31
2	10.78.232.32/27	10.78.232.33 – 10.78.232.62	10.78.232.63
3	10.78.232.64/27	10.78.232.65 – 10.78.232.94	10.78.232.95
4	10.78.232.96/27	10.78.232.97 – 10.78.232.126	10.78.232.127
5	10.78.232.128/27	10.78.232.129 – 10.78.232.158	10.78.232.159
6	10.78.232.160/27	10.78.232.161 – 10.78.232.190	10.78.232.191
7	10.78.232.192/27	10.78.232.193 – 10.78.232.222	10.78.232.223
8	10.78.232.224/27	10.78.232.225 – 10.78.232.254	10.78.232.255
9	10.78.233.0/27	10.78.233.1 – 10.78.233.30	10.78.233.31
10	10.78.233.32/27	10.78.233.33 – 10.78.233.62	10.78.233.63
11	10.78.233.64/27	10.78.233.65 – 10.78.233.94	10.78.233.95
12	10.78.233.96/27	10.78.233.97 – 10.78.233.126	10.78.233.127
13	10.78.233.128/27	10.78.233.129 – 10.78.233.158	10.78.233.159
14	10.78.233.160/27	10.78.233.161 – 10.78.233.190	10.78.233.191
15	10.78.233.192/27	10.78.233.193 – 10.78.233.222	10.78.233.223
16	10.78.233.224/27	10.78.233.225 – 10.78.233.254	10.78.233.255
17	10.78.234.0/27	10.78.234.1 – 10.78.234.30	10.78.234.31
18	10.78.234.32/27	10.78.234.33 – 10.78.234.62	10.78.234.63
19	10.78.234.64/27	10.78.234.65 – 10.78.234.94	10.78.234.95
20	10.78.234.96/27	10.78.234.97 – 10.78.234.126	10.78.234.127
21	10.78.234.128/27	10.78.234.129 – 10.78.234.158	10.78.234.159
22	10.78.234.160/27	10.78.234.161 – 10.78.234.190	10.78.234.191
23	10.78.234.192/27	10.78.234.193 – 10.78.234.222	10.78.234.223
24	10.78.234.224/27	10.78.234.225 – 10.78.234.254	10.78.234.255
25	10.78.235.0/27	10.78.235.1 – 10.78.235.30	10.78.235.31
26	10.78.235.32/27	10.78.235.33 – 10.78.235.62	10.78.235.63
27	10.78.235.64/27	10.78.235.65 – 10.78.235.94	10.78.235.95
28	10.78.235.96/27	10.78.235.97 – 10.78.235.126	10.78.235.127
29	10.78.235.128/27	10.78.235.129 – 10.78.235.158	10.78.235.159
30	10.78.235.160/27	10.78.235.161 – 10.78.235.190	10.78.235.191
31	10.78.235.192/27	10.78.235.193 – 10.78.235.222	10.78.235.223
32	10.78.235.224/27	10.78.235.225 – 10.78.235.254	10.78.235.255
33	10.78.236.0/27	10.78.236.1 – 10.78.236.30	10.78.236.31
34	10.78.236.32/27	10.78.236.33 – 10.78.236.62	10.78.236.63
35	10.78.236.64/27	10.78.236.65 – 10.78.236.94	10.78.236.95
36	10.78.236.96/27	10.78.236.97 – 10.78.236.126	10.78.236.127
37	10.78.236.128/27	10.78.236.129 – 10.78.236.158	10.78.236.159
38	10.78.236.160/27	10.78.236.161 – 10.78.236.190	10.78.236.191
39	10.78.236.192/27	10.78.236.193 – 10.78.236.222	10.78.236.223
40	10.78.236.224/27	10.78.236.225 – 10.78.236.254	10.78.236.255
41	10.78.237.0/27	10.78.237.1 – 10.78.237.30	10.78.237.31
42	10.78.237.32/27	10.78.237.33 – 10.78.237.62	10.78.237.63
43	10.78.237.64/27	10.78.237.65 – 10.78.237.94	10.78.237.95
44	10.78.237.96/27	10.78.237.97 – 10.78.237.126	10.78.237.127
45	10.78.237.128/27	10.78.237.129 – 10.78.237.158	10.78.237.159
46	10.78.237.160/27	10.78.237.161 – 10.78.237.190	10.78.237.191
47	10.78.237.192/27	10.78.237.193 – 10.78.237.222	10.78.237.223
48	10.78.237.224/27	10.78.237.225 – 10.78.237.254	10.78.237.255
49	10.78.238.0/27	10.78.238.1 – 10.78.238.30	10.78.238.31
50	10.78.238.32/27	10.78.238.33 – 10.78.238.62	10.78.238.63
51	10.78.238.64/27	10.78.238.65 – 10.78.238.94	10.78.238.95
52	10.78.238.96/27	10.78.238.97 – 10.78.238.126	10.78.238.127
53	10.78.238.128/27	10.78.238.129 – 10.78.238.158	10.78.238.159
54	10.78.238.160/27	10.78.238.161 – 10.78.238.190	10.78.238.191
55	10.78.238.192/27	10.78.238.193 – 10.78.238.222	10.78.238.223
56	10.78.238.224/27	10.78.238.225 – 10.78.238.254	10.78.238.255
57	10.78.239.0/27	10.78.239.1 – 10.78.239.30	10.78.239.31
58	10.78.239.32/27	10.78.239.33 – 10.78.239.62	10.78.239.63
59	10.78.239.64/27	10.78.239.65 – 10.78.239.94	10.78.239.95
60	10.78.239.96/27	10.78.239.97 – 10.78.239.126	10.78.239.127
61	10.78.239.128/27	10.78.239.129 – 10.78.239.158	10.78.239.159
62	10.78.239.160/27	10.78.239.161 – 10.78.239.190	10.78.239.191
63	10.78.239.192/27	10.78.239.193 – 10.78.239.222	10.78.239.223
64	10.78.239.224/27	10.78.239.225 – 10.78.239.254	10.78.239.255

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