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)10.167.216.0/21

network10.167.216.0/21

broadcast10.167.223.255

first host10.167.216.1

last host10.167.223.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.167.216.0/21

address00001010.10100111.11011000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.10100111.11011000.00000000

broadcast00001010.10100111.11011111.11111111

green = network part, grey = host part

hex0x0aa7d800

decimal178771968

reverse dns0.216.167.10.in-addr.arpa

ipv4-mapped::ffff:aa7:d800

/21 split into /27 · 64 subnets

close ×

#	network	host range	broadcast
1	10.167.216.0/27	10.167.216.1 – 10.167.216.30	10.167.216.31
2	10.167.216.32/27	10.167.216.33 – 10.167.216.62	10.167.216.63
3	10.167.216.64/27	10.167.216.65 – 10.167.216.94	10.167.216.95
4	10.167.216.96/27	10.167.216.97 – 10.167.216.126	10.167.216.127
5	10.167.216.128/27	10.167.216.129 – 10.167.216.158	10.167.216.159
6	10.167.216.160/27	10.167.216.161 – 10.167.216.190	10.167.216.191
7	10.167.216.192/27	10.167.216.193 – 10.167.216.222	10.167.216.223
8	10.167.216.224/27	10.167.216.225 – 10.167.216.254	10.167.216.255
9	10.167.217.0/27	10.167.217.1 – 10.167.217.30	10.167.217.31
10	10.167.217.32/27	10.167.217.33 – 10.167.217.62	10.167.217.63
11	10.167.217.64/27	10.167.217.65 – 10.167.217.94	10.167.217.95
12	10.167.217.96/27	10.167.217.97 – 10.167.217.126	10.167.217.127
13	10.167.217.128/27	10.167.217.129 – 10.167.217.158	10.167.217.159
14	10.167.217.160/27	10.167.217.161 – 10.167.217.190	10.167.217.191
15	10.167.217.192/27	10.167.217.193 – 10.167.217.222	10.167.217.223
16	10.167.217.224/27	10.167.217.225 – 10.167.217.254	10.167.217.255
17	10.167.218.0/27	10.167.218.1 – 10.167.218.30	10.167.218.31
18	10.167.218.32/27	10.167.218.33 – 10.167.218.62	10.167.218.63
19	10.167.218.64/27	10.167.218.65 – 10.167.218.94	10.167.218.95
20	10.167.218.96/27	10.167.218.97 – 10.167.218.126	10.167.218.127
21	10.167.218.128/27	10.167.218.129 – 10.167.218.158	10.167.218.159
22	10.167.218.160/27	10.167.218.161 – 10.167.218.190	10.167.218.191
23	10.167.218.192/27	10.167.218.193 – 10.167.218.222	10.167.218.223
24	10.167.218.224/27	10.167.218.225 – 10.167.218.254	10.167.218.255
25	10.167.219.0/27	10.167.219.1 – 10.167.219.30	10.167.219.31
26	10.167.219.32/27	10.167.219.33 – 10.167.219.62	10.167.219.63
27	10.167.219.64/27	10.167.219.65 – 10.167.219.94	10.167.219.95
28	10.167.219.96/27	10.167.219.97 – 10.167.219.126	10.167.219.127
29	10.167.219.128/27	10.167.219.129 – 10.167.219.158	10.167.219.159
30	10.167.219.160/27	10.167.219.161 – 10.167.219.190	10.167.219.191
31	10.167.219.192/27	10.167.219.193 – 10.167.219.222	10.167.219.223
32	10.167.219.224/27	10.167.219.225 – 10.167.219.254	10.167.219.255
33	10.167.220.0/27	10.167.220.1 – 10.167.220.30	10.167.220.31
34	10.167.220.32/27	10.167.220.33 – 10.167.220.62	10.167.220.63
35	10.167.220.64/27	10.167.220.65 – 10.167.220.94	10.167.220.95
36	10.167.220.96/27	10.167.220.97 – 10.167.220.126	10.167.220.127
37	10.167.220.128/27	10.167.220.129 – 10.167.220.158	10.167.220.159
38	10.167.220.160/27	10.167.220.161 – 10.167.220.190	10.167.220.191
39	10.167.220.192/27	10.167.220.193 – 10.167.220.222	10.167.220.223
40	10.167.220.224/27	10.167.220.225 – 10.167.220.254	10.167.220.255
41	10.167.221.0/27	10.167.221.1 – 10.167.221.30	10.167.221.31
42	10.167.221.32/27	10.167.221.33 – 10.167.221.62	10.167.221.63
43	10.167.221.64/27	10.167.221.65 – 10.167.221.94	10.167.221.95
44	10.167.221.96/27	10.167.221.97 – 10.167.221.126	10.167.221.127
45	10.167.221.128/27	10.167.221.129 – 10.167.221.158	10.167.221.159
46	10.167.221.160/27	10.167.221.161 – 10.167.221.190	10.167.221.191
47	10.167.221.192/27	10.167.221.193 – 10.167.221.222	10.167.221.223
48	10.167.221.224/27	10.167.221.225 – 10.167.221.254	10.167.221.255
49	10.167.222.0/27	10.167.222.1 – 10.167.222.30	10.167.222.31
50	10.167.222.32/27	10.167.222.33 – 10.167.222.62	10.167.222.63
51	10.167.222.64/27	10.167.222.65 – 10.167.222.94	10.167.222.95
52	10.167.222.96/27	10.167.222.97 – 10.167.222.126	10.167.222.127
53	10.167.222.128/27	10.167.222.129 – 10.167.222.158	10.167.222.159
54	10.167.222.160/27	10.167.222.161 – 10.167.222.190	10.167.222.191
55	10.167.222.192/27	10.167.222.193 – 10.167.222.222	10.167.222.223
56	10.167.222.224/27	10.167.222.225 – 10.167.222.254	10.167.222.255
57	10.167.223.0/27	10.167.223.1 – 10.167.223.30	10.167.223.31
58	10.167.223.32/27	10.167.223.33 – 10.167.223.62	10.167.223.63
59	10.167.223.64/27	10.167.223.65 – 10.167.223.94	10.167.223.95
60	10.167.223.96/27	10.167.223.97 – 10.167.223.126	10.167.223.127
61	10.167.223.128/27	10.167.223.129 – 10.167.223.158	10.167.223.159
62	10.167.223.160/27	10.167.223.161 – 10.167.223.190	10.167.223.191
63	10.167.223.192/27	10.167.223.193 – 10.167.223.222	10.167.223.223
64	10.167.223.224/27	10.167.223.225 – 10.167.223.254	10.167.223.255

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 →