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)10.167.104.0/21

network10.167.104.0/21

broadcast10.167.111.255

first host10.167.104.1

last host10.167.111.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.167.104.0/21

address00001010.10100111.01101000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.10100111.01101000.00000000

broadcast00001010.10100111.01101111.11111111

green = network part, grey = host part

hex0x0aa76800

decimal178743296

reverse dns0.104.167.10.in-addr.arpa

ipv4-mapped::ffff:aa7:6800

/21 split into /27 · 64 subnets

close ×

#	network	host range	broadcast
1	10.167.104.0/27	10.167.104.1 – 10.167.104.30	10.167.104.31
2	10.167.104.32/27	10.167.104.33 – 10.167.104.62	10.167.104.63
3	10.167.104.64/27	10.167.104.65 – 10.167.104.94	10.167.104.95
4	10.167.104.96/27	10.167.104.97 – 10.167.104.126	10.167.104.127
5	10.167.104.128/27	10.167.104.129 – 10.167.104.158	10.167.104.159
6	10.167.104.160/27	10.167.104.161 – 10.167.104.190	10.167.104.191
7	10.167.104.192/27	10.167.104.193 – 10.167.104.222	10.167.104.223
8	10.167.104.224/27	10.167.104.225 – 10.167.104.254	10.167.104.255
9	10.167.105.0/27	10.167.105.1 – 10.167.105.30	10.167.105.31
10	10.167.105.32/27	10.167.105.33 – 10.167.105.62	10.167.105.63
11	10.167.105.64/27	10.167.105.65 – 10.167.105.94	10.167.105.95
12	10.167.105.96/27	10.167.105.97 – 10.167.105.126	10.167.105.127
13	10.167.105.128/27	10.167.105.129 – 10.167.105.158	10.167.105.159
14	10.167.105.160/27	10.167.105.161 – 10.167.105.190	10.167.105.191
15	10.167.105.192/27	10.167.105.193 – 10.167.105.222	10.167.105.223
16	10.167.105.224/27	10.167.105.225 – 10.167.105.254	10.167.105.255
17	10.167.106.0/27	10.167.106.1 – 10.167.106.30	10.167.106.31
18	10.167.106.32/27	10.167.106.33 – 10.167.106.62	10.167.106.63
19	10.167.106.64/27	10.167.106.65 – 10.167.106.94	10.167.106.95
20	10.167.106.96/27	10.167.106.97 – 10.167.106.126	10.167.106.127
21	10.167.106.128/27	10.167.106.129 – 10.167.106.158	10.167.106.159
22	10.167.106.160/27	10.167.106.161 – 10.167.106.190	10.167.106.191
23	10.167.106.192/27	10.167.106.193 – 10.167.106.222	10.167.106.223
24	10.167.106.224/27	10.167.106.225 – 10.167.106.254	10.167.106.255
25	10.167.107.0/27	10.167.107.1 – 10.167.107.30	10.167.107.31
26	10.167.107.32/27	10.167.107.33 – 10.167.107.62	10.167.107.63
27	10.167.107.64/27	10.167.107.65 – 10.167.107.94	10.167.107.95
28	10.167.107.96/27	10.167.107.97 – 10.167.107.126	10.167.107.127
29	10.167.107.128/27	10.167.107.129 – 10.167.107.158	10.167.107.159
30	10.167.107.160/27	10.167.107.161 – 10.167.107.190	10.167.107.191
31	10.167.107.192/27	10.167.107.193 – 10.167.107.222	10.167.107.223
32	10.167.107.224/27	10.167.107.225 – 10.167.107.254	10.167.107.255
33	10.167.108.0/27	10.167.108.1 – 10.167.108.30	10.167.108.31
34	10.167.108.32/27	10.167.108.33 – 10.167.108.62	10.167.108.63
35	10.167.108.64/27	10.167.108.65 – 10.167.108.94	10.167.108.95
36	10.167.108.96/27	10.167.108.97 – 10.167.108.126	10.167.108.127
37	10.167.108.128/27	10.167.108.129 – 10.167.108.158	10.167.108.159
38	10.167.108.160/27	10.167.108.161 – 10.167.108.190	10.167.108.191
39	10.167.108.192/27	10.167.108.193 – 10.167.108.222	10.167.108.223
40	10.167.108.224/27	10.167.108.225 – 10.167.108.254	10.167.108.255
41	10.167.109.0/27	10.167.109.1 – 10.167.109.30	10.167.109.31
42	10.167.109.32/27	10.167.109.33 – 10.167.109.62	10.167.109.63
43	10.167.109.64/27	10.167.109.65 – 10.167.109.94	10.167.109.95
44	10.167.109.96/27	10.167.109.97 – 10.167.109.126	10.167.109.127
45	10.167.109.128/27	10.167.109.129 – 10.167.109.158	10.167.109.159
46	10.167.109.160/27	10.167.109.161 – 10.167.109.190	10.167.109.191
47	10.167.109.192/27	10.167.109.193 – 10.167.109.222	10.167.109.223
48	10.167.109.224/27	10.167.109.225 – 10.167.109.254	10.167.109.255
49	10.167.110.0/27	10.167.110.1 – 10.167.110.30	10.167.110.31
50	10.167.110.32/27	10.167.110.33 – 10.167.110.62	10.167.110.63
51	10.167.110.64/27	10.167.110.65 – 10.167.110.94	10.167.110.95
52	10.167.110.96/27	10.167.110.97 – 10.167.110.126	10.167.110.127
53	10.167.110.128/27	10.167.110.129 – 10.167.110.158	10.167.110.159
54	10.167.110.160/27	10.167.110.161 – 10.167.110.190	10.167.110.191
55	10.167.110.192/27	10.167.110.193 – 10.167.110.222	10.167.110.223
56	10.167.110.224/27	10.167.110.225 – 10.167.110.254	10.167.110.255
57	10.167.111.0/27	10.167.111.1 – 10.167.111.30	10.167.111.31
58	10.167.111.32/27	10.167.111.33 – 10.167.111.62	10.167.111.63
59	10.167.111.64/27	10.167.111.65 – 10.167.111.94	10.167.111.95
60	10.167.111.96/27	10.167.111.97 – 10.167.111.126	10.167.111.127
61	10.167.111.128/27	10.167.111.129 – 10.167.111.158	10.167.111.159
62	10.167.111.160/27	10.167.111.161 – 10.167.111.190	10.167.111.191
63	10.167.111.192/27	10.167.111.193 – 10.167.111.222	10.167.111.223
64	10.167.111.224/27	10.167.111.225 – 10.167.111.254	10.167.111.255

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 →