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)10.2.20.0/23

network10.2.20.0/23

broadcast10.2.21.255

first host10.2.20.1

last host10.2.21.254

subnet mask255.255.254.0

wildcard0.0.1.255

addresses512

usable hosts510

classA

ipcalc 10.2.20.0/23

address00001010.00000010.00010100.00000000

subnet mask11111111.11111111.11111110.00000000

network00001010.00000010.00010100.00000000

broadcast00001010.00000010.00010101.11111111

green = network part, grey = host part

hex0x0a021400

decimal167908352

reverse dns0.20.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:1400

/23 split into /29 · 64 subnets

close ×

#	network	host range	broadcast
1	10.2.20.0/29	10.2.20.1 – 10.2.20.6	10.2.20.7
2	10.2.20.8/29	10.2.20.9 – 10.2.20.14	10.2.20.15
3	10.2.20.16/29	10.2.20.17 – 10.2.20.22	10.2.20.23
4	10.2.20.24/29	10.2.20.25 – 10.2.20.30	10.2.20.31
5	10.2.20.32/29	10.2.20.33 – 10.2.20.38	10.2.20.39
6	10.2.20.40/29	10.2.20.41 – 10.2.20.46	10.2.20.47
7	10.2.20.48/29	10.2.20.49 – 10.2.20.54	10.2.20.55
8	10.2.20.56/29	10.2.20.57 – 10.2.20.62	10.2.20.63
9	10.2.20.64/29	10.2.20.65 – 10.2.20.70	10.2.20.71
10	10.2.20.72/29	10.2.20.73 – 10.2.20.78	10.2.20.79
11	10.2.20.80/29	10.2.20.81 – 10.2.20.86	10.2.20.87
12	10.2.20.88/29	10.2.20.89 – 10.2.20.94	10.2.20.95
13	10.2.20.96/29	10.2.20.97 – 10.2.20.102	10.2.20.103
14	10.2.20.104/29	10.2.20.105 – 10.2.20.110	10.2.20.111
15	10.2.20.112/29	10.2.20.113 – 10.2.20.118	10.2.20.119
16	10.2.20.120/29	10.2.20.121 – 10.2.20.126	10.2.20.127
17	10.2.20.128/29	10.2.20.129 – 10.2.20.134	10.2.20.135
18	10.2.20.136/29	10.2.20.137 – 10.2.20.142	10.2.20.143
19	10.2.20.144/29	10.2.20.145 – 10.2.20.150	10.2.20.151
20	10.2.20.152/29	10.2.20.153 – 10.2.20.158	10.2.20.159
21	10.2.20.160/29	10.2.20.161 – 10.2.20.166	10.2.20.167
22	10.2.20.168/29	10.2.20.169 – 10.2.20.174	10.2.20.175
23	10.2.20.176/29	10.2.20.177 – 10.2.20.182	10.2.20.183
24	10.2.20.184/29	10.2.20.185 – 10.2.20.190	10.2.20.191
25	10.2.20.192/29	10.2.20.193 – 10.2.20.198	10.2.20.199
26	10.2.20.200/29	10.2.20.201 – 10.2.20.206	10.2.20.207
27	10.2.20.208/29	10.2.20.209 – 10.2.20.214	10.2.20.215
28	10.2.20.216/29	10.2.20.217 – 10.2.20.222	10.2.20.223
29	10.2.20.224/29	10.2.20.225 – 10.2.20.230	10.2.20.231
30	10.2.20.232/29	10.2.20.233 – 10.2.20.238	10.2.20.239
31	10.2.20.240/29	10.2.20.241 – 10.2.20.246	10.2.20.247
32	10.2.20.248/29	10.2.20.249 – 10.2.20.254	10.2.20.255
33	10.2.21.0/29	10.2.21.1 – 10.2.21.6	10.2.21.7
34	10.2.21.8/29	10.2.21.9 – 10.2.21.14	10.2.21.15
35	10.2.21.16/29	10.2.21.17 – 10.2.21.22	10.2.21.23
36	10.2.21.24/29	10.2.21.25 – 10.2.21.30	10.2.21.31
37	10.2.21.32/29	10.2.21.33 – 10.2.21.38	10.2.21.39
38	10.2.21.40/29	10.2.21.41 – 10.2.21.46	10.2.21.47
39	10.2.21.48/29	10.2.21.49 – 10.2.21.54	10.2.21.55
40	10.2.21.56/29	10.2.21.57 – 10.2.21.62	10.2.21.63
41	10.2.21.64/29	10.2.21.65 – 10.2.21.70	10.2.21.71
42	10.2.21.72/29	10.2.21.73 – 10.2.21.78	10.2.21.79
43	10.2.21.80/29	10.2.21.81 – 10.2.21.86	10.2.21.87
44	10.2.21.88/29	10.2.21.89 – 10.2.21.94	10.2.21.95
45	10.2.21.96/29	10.2.21.97 – 10.2.21.102	10.2.21.103
46	10.2.21.104/29	10.2.21.105 – 10.2.21.110	10.2.21.111
47	10.2.21.112/29	10.2.21.113 – 10.2.21.118	10.2.21.119
48	10.2.21.120/29	10.2.21.121 – 10.2.21.126	10.2.21.127
49	10.2.21.128/29	10.2.21.129 – 10.2.21.134	10.2.21.135
50	10.2.21.136/29	10.2.21.137 – 10.2.21.142	10.2.21.143
51	10.2.21.144/29	10.2.21.145 – 10.2.21.150	10.2.21.151
52	10.2.21.152/29	10.2.21.153 – 10.2.21.158	10.2.21.159
53	10.2.21.160/29	10.2.21.161 – 10.2.21.166	10.2.21.167
54	10.2.21.168/29	10.2.21.169 – 10.2.21.174	10.2.21.175
55	10.2.21.176/29	10.2.21.177 – 10.2.21.182	10.2.21.183
56	10.2.21.184/29	10.2.21.185 – 10.2.21.190	10.2.21.191
57	10.2.21.192/29	10.2.21.193 – 10.2.21.198	10.2.21.199
58	10.2.21.200/29	10.2.21.201 – 10.2.21.206	10.2.21.207
59	10.2.21.208/29	10.2.21.209 – 10.2.21.214	10.2.21.215
60	10.2.21.216/29	10.2.21.217 – 10.2.21.222	10.2.21.223
61	10.2.21.224/29	10.2.21.225 – 10.2.21.230	10.2.21.231
62	10.2.21.232/29	10.2.21.233 – 10.2.21.238	10.2.21.239
63	10.2.21.240/29	10.2.21.241 – 10.2.21.246	10.2.21.247
64	10.2.21.248/29	10.2.21.249 – 10.2.21.254	10.2.21.255

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