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)10.5.88.0/21

network10.5.88.0/21

broadcast10.5.95.255

first host10.5.88.1

last host10.5.95.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.5.88.0/21

address00001010.00000101.01011000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000101.01011000.00000000

broadcast00001010.00000101.01011111.11111111

green = network part, grey = host part

hex0x0a055800

decimal168122368

reverse dns0.88.5.10.in-addr.arpa

ipv4-mapped::ffff:a05:5800

/21 split into /27 · 64 subnets

close ×

#	network	host range	broadcast
1	10.5.88.0/27	10.5.88.1 – 10.5.88.30	10.5.88.31
2	10.5.88.32/27	10.5.88.33 – 10.5.88.62	10.5.88.63
3	10.5.88.64/27	10.5.88.65 – 10.5.88.94	10.5.88.95
4	10.5.88.96/27	10.5.88.97 – 10.5.88.126	10.5.88.127
5	10.5.88.128/27	10.5.88.129 – 10.5.88.158	10.5.88.159
6	10.5.88.160/27	10.5.88.161 – 10.5.88.190	10.5.88.191
7	10.5.88.192/27	10.5.88.193 – 10.5.88.222	10.5.88.223
8	10.5.88.224/27	10.5.88.225 – 10.5.88.254	10.5.88.255
9	10.5.89.0/27	10.5.89.1 – 10.5.89.30	10.5.89.31
10	10.5.89.32/27	10.5.89.33 – 10.5.89.62	10.5.89.63
11	10.5.89.64/27	10.5.89.65 – 10.5.89.94	10.5.89.95
12	10.5.89.96/27	10.5.89.97 – 10.5.89.126	10.5.89.127
13	10.5.89.128/27	10.5.89.129 – 10.5.89.158	10.5.89.159
14	10.5.89.160/27	10.5.89.161 – 10.5.89.190	10.5.89.191
15	10.5.89.192/27	10.5.89.193 – 10.5.89.222	10.5.89.223
16	10.5.89.224/27	10.5.89.225 – 10.5.89.254	10.5.89.255
17	10.5.90.0/27	10.5.90.1 – 10.5.90.30	10.5.90.31
18	10.5.90.32/27	10.5.90.33 – 10.5.90.62	10.5.90.63
19	10.5.90.64/27	10.5.90.65 – 10.5.90.94	10.5.90.95
20	10.5.90.96/27	10.5.90.97 – 10.5.90.126	10.5.90.127
21	10.5.90.128/27	10.5.90.129 – 10.5.90.158	10.5.90.159
22	10.5.90.160/27	10.5.90.161 – 10.5.90.190	10.5.90.191
23	10.5.90.192/27	10.5.90.193 – 10.5.90.222	10.5.90.223
24	10.5.90.224/27	10.5.90.225 – 10.5.90.254	10.5.90.255
25	10.5.91.0/27	10.5.91.1 – 10.5.91.30	10.5.91.31
26	10.5.91.32/27	10.5.91.33 – 10.5.91.62	10.5.91.63
27	10.5.91.64/27	10.5.91.65 – 10.5.91.94	10.5.91.95
28	10.5.91.96/27	10.5.91.97 – 10.5.91.126	10.5.91.127
29	10.5.91.128/27	10.5.91.129 – 10.5.91.158	10.5.91.159
30	10.5.91.160/27	10.5.91.161 – 10.5.91.190	10.5.91.191
31	10.5.91.192/27	10.5.91.193 – 10.5.91.222	10.5.91.223
32	10.5.91.224/27	10.5.91.225 – 10.5.91.254	10.5.91.255
33	10.5.92.0/27	10.5.92.1 – 10.5.92.30	10.5.92.31
34	10.5.92.32/27	10.5.92.33 – 10.5.92.62	10.5.92.63
35	10.5.92.64/27	10.5.92.65 – 10.5.92.94	10.5.92.95
36	10.5.92.96/27	10.5.92.97 – 10.5.92.126	10.5.92.127
37	10.5.92.128/27	10.5.92.129 – 10.5.92.158	10.5.92.159
38	10.5.92.160/27	10.5.92.161 – 10.5.92.190	10.5.92.191
39	10.5.92.192/27	10.5.92.193 – 10.5.92.222	10.5.92.223
40	10.5.92.224/27	10.5.92.225 – 10.5.92.254	10.5.92.255
41	10.5.93.0/27	10.5.93.1 – 10.5.93.30	10.5.93.31
42	10.5.93.32/27	10.5.93.33 – 10.5.93.62	10.5.93.63
43	10.5.93.64/27	10.5.93.65 – 10.5.93.94	10.5.93.95
44	10.5.93.96/27	10.5.93.97 – 10.5.93.126	10.5.93.127
45	10.5.93.128/27	10.5.93.129 – 10.5.93.158	10.5.93.159
46	10.5.93.160/27	10.5.93.161 – 10.5.93.190	10.5.93.191
47	10.5.93.192/27	10.5.93.193 – 10.5.93.222	10.5.93.223
48	10.5.93.224/27	10.5.93.225 – 10.5.93.254	10.5.93.255
49	10.5.94.0/27	10.5.94.1 – 10.5.94.30	10.5.94.31
50	10.5.94.32/27	10.5.94.33 – 10.5.94.62	10.5.94.63
51	10.5.94.64/27	10.5.94.65 – 10.5.94.94	10.5.94.95
52	10.5.94.96/27	10.5.94.97 – 10.5.94.126	10.5.94.127
53	10.5.94.128/27	10.5.94.129 – 10.5.94.158	10.5.94.159
54	10.5.94.160/27	10.5.94.161 – 10.5.94.190	10.5.94.191
55	10.5.94.192/27	10.5.94.193 – 10.5.94.222	10.5.94.223
56	10.5.94.224/27	10.5.94.225 – 10.5.94.254	10.5.94.255
57	10.5.95.0/27	10.5.95.1 – 10.5.95.30	10.5.95.31
58	10.5.95.32/27	10.5.95.33 – 10.5.95.62	10.5.95.63
59	10.5.95.64/27	10.5.95.65 – 10.5.95.94	10.5.95.95
60	10.5.95.96/27	10.5.95.97 – 10.5.95.126	10.5.95.127
61	10.5.95.128/27	10.5.95.129 – 10.5.95.158	10.5.95.159
62	10.5.95.160/27	10.5.95.161 – 10.5.95.190	10.5.95.191
63	10.5.95.192/27	10.5.95.193 – 10.5.95.222	10.5.95.223
64	10.5.95.224/27	10.5.95.225 – 10.5.95.254	10.5.95.255

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 →