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)10.15.16.0/20

network10.15.16.0/20

broadcast10.15.31.255

first host10.15.16.1

last host10.15.31.254

subnet mask255.255.240.0

wildcard0.0.15.255

addresses4,096

usable hosts4,094

classA

ipcalc 10.15.16.0/20

address00001010.00001111.00010000.00000000

subnet mask11111111.11111111.11110000.00000000

network00001010.00001111.00010000.00000000

broadcast00001010.00001111.00011111.11111111

green = network part, grey = host part

hex0x0a0f1000

decimal168759296

reverse dns0.16.15.10.in-addr.arpa

ipv4-mapped::ffff:a0f:1000

/20 split into /26 · 64 subnets

close ×

#	network	host range	broadcast
1	10.15.16.0/26	10.15.16.1 – 10.15.16.62	10.15.16.63
2	10.15.16.64/26	10.15.16.65 – 10.15.16.126	10.15.16.127
3	10.15.16.128/26	10.15.16.129 – 10.15.16.190	10.15.16.191
4	10.15.16.192/26	10.15.16.193 – 10.15.16.254	10.15.16.255
5	10.15.17.0/26	10.15.17.1 – 10.15.17.62	10.15.17.63
6	10.15.17.64/26	10.15.17.65 – 10.15.17.126	10.15.17.127
7	10.15.17.128/26	10.15.17.129 – 10.15.17.190	10.15.17.191
8	10.15.17.192/26	10.15.17.193 – 10.15.17.254	10.15.17.255
9	10.15.18.0/26	10.15.18.1 – 10.15.18.62	10.15.18.63
10	10.15.18.64/26	10.15.18.65 – 10.15.18.126	10.15.18.127
11	10.15.18.128/26	10.15.18.129 – 10.15.18.190	10.15.18.191
12	10.15.18.192/26	10.15.18.193 – 10.15.18.254	10.15.18.255
13	10.15.19.0/26	10.15.19.1 – 10.15.19.62	10.15.19.63
14	10.15.19.64/26	10.15.19.65 – 10.15.19.126	10.15.19.127
15	10.15.19.128/26	10.15.19.129 – 10.15.19.190	10.15.19.191
16	10.15.19.192/26	10.15.19.193 – 10.15.19.254	10.15.19.255
17	10.15.20.0/26	10.15.20.1 – 10.15.20.62	10.15.20.63
18	10.15.20.64/26	10.15.20.65 – 10.15.20.126	10.15.20.127
19	10.15.20.128/26	10.15.20.129 – 10.15.20.190	10.15.20.191
20	10.15.20.192/26	10.15.20.193 – 10.15.20.254	10.15.20.255
21	10.15.21.0/26	10.15.21.1 – 10.15.21.62	10.15.21.63
22	10.15.21.64/26	10.15.21.65 – 10.15.21.126	10.15.21.127
23	10.15.21.128/26	10.15.21.129 – 10.15.21.190	10.15.21.191
24	10.15.21.192/26	10.15.21.193 – 10.15.21.254	10.15.21.255
25	10.15.22.0/26	10.15.22.1 – 10.15.22.62	10.15.22.63
26	10.15.22.64/26	10.15.22.65 – 10.15.22.126	10.15.22.127
27	10.15.22.128/26	10.15.22.129 – 10.15.22.190	10.15.22.191
28	10.15.22.192/26	10.15.22.193 – 10.15.22.254	10.15.22.255
29	10.15.23.0/26	10.15.23.1 – 10.15.23.62	10.15.23.63
30	10.15.23.64/26	10.15.23.65 – 10.15.23.126	10.15.23.127
31	10.15.23.128/26	10.15.23.129 – 10.15.23.190	10.15.23.191
32	10.15.23.192/26	10.15.23.193 – 10.15.23.254	10.15.23.255
33	10.15.24.0/26	10.15.24.1 – 10.15.24.62	10.15.24.63
34	10.15.24.64/26	10.15.24.65 – 10.15.24.126	10.15.24.127
35	10.15.24.128/26	10.15.24.129 – 10.15.24.190	10.15.24.191
36	10.15.24.192/26	10.15.24.193 – 10.15.24.254	10.15.24.255
37	10.15.25.0/26	10.15.25.1 – 10.15.25.62	10.15.25.63
38	10.15.25.64/26	10.15.25.65 – 10.15.25.126	10.15.25.127
39	10.15.25.128/26	10.15.25.129 – 10.15.25.190	10.15.25.191
40	10.15.25.192/26	10.15.25.193 – 10.15.25.254	10.15.25.255
41	10.15.26.0/26	10.15.26.1 – 10.15.26.62	10.15.26.63
42	10.15.26.64/26	10.15.26.65 – 10.15.26.126	10.15.26.127
43	10.15.26.128/26	10.15.26.129 – 10.15.26.190	10.15.26.191
44	10.15.26.192/26	10.15.26.193 – 10.15.26.254	10.15.26.255
45	10.15.27.0/26	10.15.27.1 – 10.15.27.62	10.15.27.63
46	10.15.27.64/26	10.15.27.65 – 10.15.27.126	10.15.27.127
47	10.15.27.128/26	10.15.27.129 – 10.15.27.190	10.15.27.191
48	10.15.27.192/26	10.15.27.193 – 10.15.27.254	10.15.27.255
49	10.15.28.0/26	10.15.28.1 – 10.15.28.62	10.15.28.63
50	10.15.28.64/26	10.15.28.65 – 10.15.28.126	10.15.28.127
51	10.15.28.128/26	10.15.28.129 – 10.15.28.190	10.15.28.191
52	10.15.28.192/26	10.15.28.193 – 10.15.28.254	10.15.28.255
53	10.15.29.0/26	10.15.29.1 – 10.15.29.62	10.15.29.63
54	10.15.29.64/26	10.15.29.65 – 10.15.29.126	10.15.29.127
55	10.15.29.128/26	10.15.29.129 – 10.15.29.190	10.15.29.191
56	10.15.29.192/26	10.15.29.193 – 10.15.29.254	10.15.29.255
57	10.15.30.0/26	10.15.30.1 – 10.15.30.62	10.15.30.63
58	10.15.30.64/26	10.15.30.65 – 10.15.30.126	10.15.30.127
59	10.15.30.128/26	10.15.30.129 – 10.15.30.190	10.15.30.191
60	10.15.30.192/26	10.15.30.193 – 10.15.30.254	10.15.30.255
61	10.15.31.0/26	10.15.31.1 – 10.15.31.62	10.15.31.63
62	10.15.31.64/26	10.15.31.65 – 10.15.31.126	10.15.31.127
63	10.15.31.128/26	10.15.31.129 – 10.15.31.190	10.15.31.191
64	10.15.31.192/26	10.15.31.193 – 10.15.31.254	10.15.31.255

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 /20
/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	1
/21	255.255.248.0	2,048	2,046	2 split →
/22	255.255.252.0	1,024	1,022	4 split →
/23	255.255.254.0	512	510	8 split →
/24	255.255.255.0	256	254	16 split →
/25	255.255.255.128	128	126	32 split →
/26	255.255.255.192	64	62	64 split →
/27	255.255.255.224	32	30	128 split →
/28	255.255.255.240	16	14	256 split →
/29	255.255.255.248	8	6	512 split →
/30	255.255.255.252	4	2	1,024 split →
/31	255.255.255.254	2	2	2,048 split →
/32	255.255.255.255	1	1	4,096 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 →