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)10.2.32.0/21

network10.2.32.0/21

broadcast10.2.39.255

first host10.2.32.1

last host10.2.39.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.2.32.0/21

address00001010.00000010.00100000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000010.00100000.00000000

broadcast00001010.00000010.00100111.11111111

green = network part, grey = host part

hex0x0a022000

decimal167911424

reverse dns0.32.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:2000

/21 split into /27 · 64 subnets

close ×

#	network	host range	broadcast
1	10.2.32.0/27	10.2.32.1 – 10.2.32.30	10.2.32.31
2	10.2.32.32/27	10.2.32.33 – 10.2.32.62	10.2.32.63
3	10.2.32.64/27	10.2.32.65 – 10.2.32.94	10.2.32.95
4	10.2.32.96/27	10.2.32.97 – 10.2.32.126	10.2.32.127
5	10.2.32.128/27	10.2.32.129 – 10.2.32.158	10.2.32.159
6	10.2.32.160/27	10.2.32.161 – 10.2.32.190	10.2.32.191
7	10.2.32.192/27	10.2.32.193 – 10.2.32.222	10.2.32.223
8	10.2.32.224/27	10.2.32.225 – 10.2.32.254	10.2.32.255
9	10.2.33.0/27	10.2.33.1 – 10.2.33.30	10.2.33.31
10	10.2.33.32/27	10.2.33.33 – 10.2.33.62	10.2.33.63
11	10.2.33.64/27	10.2.33.65 – 10.2.33.94	10.2.33.95
12	10.2.33.96/27	10.2.33.97 – 10.2.33.126	10.2.33.127
13	10.2.33.128/27	10.2.33.129 – 10.2.33.158	10.2.33.159
14	10.2.33.160/27	10.2.33.161 – 10.2.33.190	10.2.33.191
15	10.2.33.192/27	10.2.33.193 – 10.2.33.222	10.2.33.223
16	10.2.33.224/27	10.2.33.225 – 10.2.33.254	10.2.33.255
17	10.2.34.0/27	10.2.34.1 – 10.2.34.30	10.2.34.31
18	10.2.34.32/27	10.2.34.33 – 10.2.34.62	10.2.34.63
19	10.2.34.64/27	10.2.34.65 – 10.2.34.94	10.2.34.95
20	10.2.34.96/27	10.2.34.97 – 10.2.34.126	10.2.34.127
21	10.2.34.128/27	10.2.34.129 – 10.2.34.158	10.2.34.159
22	10.2.34.160/27	10.2.34.161 – 10.2.34.190	10.2.34.191
23	10.2.34.192/27	10.2.34.193 – 10.2.34.222	10.2.34.223
24	10.2.34.224/27	10.2.34.225 – 10.2.34.254	10.2.34.255
25	10.2.35.0/27	10.2.35.1 – 10.2.35.30	10.2.35.31
26	10.2.35.32/27	10.2.35.33 – 10.2.35.62	10.2.35.63
27	10.2.35.64/27	10.2.35.65 – 10.2.35.94	10.2.35.95
28	10.2.35.96/27	10.2.35.97 – 10.2.35.126	10.2.35.127
29	10.2.35.128/27	10.2.35.129 – 10.2.35.158	10.2.35.159
30	10.2.35.160/27	10.2.35.161 – 10.2.35.190	10.2.35.191
31	10.2.35.192/27	10.2.35.193 – 10.2.35.222	10.2.35.223
32	10.2.35.224/27	10.2.35.225 – 10.2.35.254	10.2.35.255
33	10.2.36.0/27	10.2.36.1 – 10.2.36.30	10.2.36.31
34	10.2.36.32/27	10.2.36.33 – 10.2.36.62	10.2.36.63
35	10.2.36.64/27	10.2.36.65 – 10.2.36.94	10.2.36.95
36	10.2.36.96/27	10.2.36.97 – 10.2.36.126	10.2.36.127
37	10.2.36.128/27	10.2.36.129 – 10.2.36.158	10.2.36.159
38	10.2.36.160/27	10.2.36.161 – 10.2.36.190	10.2.36.191
39	10.2.36.192/27	10.2.36.193 – 10.2.36.222	10.2.36.223
40	10.2.36.224/27	10.2.36.225 – 10.2.36.254	10.2.36.255
41	10.2.37.0/27	10.2.37.1 – 10.2.37.30	10.2.37.31
42	10.2.37.32/27	10.2.37.33 – 10.2.37.62	10.2.37.63
43	10.2.37.64/27	10.2.37.65 – 10.2.37.94	10.2.37.95
44	10.2.37.96/27	10.2.37.97 – 10.2.37.126	10.2.37.127
45	10.2.37.128/27	10.2.37.129 – 10.2.37.158	10.2.37.159
46	10.2.37.160/27	10.2.37.161 – 10.2.37.190	10.2.37.191
47	10.2.37.192/27	10.2.37.193 – 10.2.37.222	10.2.37.223
48	10.2.37.224/27	10.2.37.225 – 10.2.37.254	10.2.37.255
49	10.2.38.0/27	10.2.38.1 – 10.2.38.30	10.2.38.31
50	10.2.38.32/27	10.2.38.33 – 10.2.38.62	10.2.38.63
51	10.2.38.64/27	10.2.38.65 – 10.2.38.94	10.2.38.95
52	10.2.38.96/27	10.2.38.97 – 10.2.38.126	10.2.38.127
53	10.2.38.128/27	10.2.38.129 – 10.2.38.158	10.2.38.159
54	10.2.38.160/27	10.2.38.161 – 10.2.38.190	10.2.38.191
55	10.2.38.192/27	10.2.38.193 – 10.2.38.222	10.2.38.223
56	10.2.38.224/27	10.2.38.225 – 10.2.38.254	10.2.38.255
57	10.2.39.0/27	10.2.39.1 – 10.2.39.30	10.2.39.31
58	10.2.39.32/27	10.2.39.33 – 10.2.39.62	10.2.39.63
59	10.2.39.64/27	10.2.39.65 – 10.2.39.94	10.2.39.95
60	10.2.39.96/27	10.2.39.97 – 10.2.39.126	10.2.39.127
61	10.2.39.128/27	10.2.39.129 – 10.2.39.158	10.2.39.159
62	10.2.39.160/27	10.2.39.161 – 10.2.39.190	10.2.39.191
63	10.2.39.192/27	10.2.39.193 – 10.2.39.222	10.2.39.223
64	10.2.39.224/27	10.2.39.225 – 10.2.39.254	10.2.39.255

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 →