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)10.166.72.0/23

network10.166.72.0/23

broadcast10.166.73.255

first host10.166.72.1

last host10.166.73.254

subnet mask255.255.254.0

wildcard0.0.1.255

addresses512

usable hosts510

classA

ipcalc 10.166.72.0/23

address00001010.10100110.01001000.00000000

subnet mask11111111.11111111.11111110.00000000

network00001010.10100110.01001000.00000000

broadcast00001010.10100110.01001001.11111111

green = network part, grey = host part

hex0x0aa64800

decimal178669568

reverse dns0.72.166.10.in-addr.arpa

ipv4-mapped::ffff:aa6:4800

/23 split into /29 · 64 subnets

close ×

#	network	host range	broadcast
1	10.166.72.0/29	10.166.72.1 – 10.166.72.6	10.166.72.7
2	10.166.72.8/29	10.166.72.9 – 10.166.72.14	10.166.72.15
3	10.166.72.16/29	10.166.72.17 – 10.166.72.22	10.166.72.23
4	10.166.72.24/29	10.166.72.25 – 10.166.72.30	10.166.72.31
5	10.166.72.32/29	10.166.72.33 – 10.166.72.38	10.166.72.39
6	10.166.72.40/29	10.166.72.41 – 10.166.72.46	10.166.72.47
7	10.166.72.48/29	10.166.72.49 – 10.166.72.54	10.166.72.55
8	10.166.72.56/29	10.166.72.57 – 10.166.72.62	10.166.72.63
9	10.166.72.64/29	10.166.72.65 – 10.166.72.70	10.166.72.71
10	10.166.72.72/29	10.166.72.73 – 10.166.72.78	10.166.72.79
11	10.166.72.80/29	10.166.72.81 – 10.166.72.86	10.166.72.87
12	10.166.72.88/29	10.166.72.89 – 10.166.72.94	10.166.72.95
13	10.166.72.96/29	10.166.72.97 – 10.166.72.102	10.166.72.103
14	10.166.72.104/29	10.166.72.105 – 10.166.72.110	10.166.72.111
15	10.166.72.112/29	10.166.72.113 – 10.166.72.118	10.166.72.119
16	10.166.72.120/29	10.166.72.121 – 10.166.72.126	10.166.72.127
17	10.166.72.128/29	10.166.72.129 – 10.166.72.134	10.166.72.135
18	10.166.72.136/29	10.166.72.137 – 10.166.72.142	10.166.72.143
19	10.166.72.144/29	10.166.72.145 – 10.166.72.150	10.166.72.151
20	10.166.72.152/29	10.166.72.153 – 10.166.72.158	10.166.72.159
21	10.166.72.160/29	10.166.72.161 – 10.166.72.166	10.166.72.167
22	10.166.72.168/29	10.166.72.169 – 10.166.72.174	10.166.72.175
23	10.166.72.176/29	10.166.72.177 – 10.166.72.182	10.166.72.183
24	10.166.72.184/29	10.166.72.185 – 10.166.72.190	10.166.72.191
25	10.166.72.192/29	10.166.72.193 – 10.166.72.198	10.166.72.199
26	10.166.72.200/29	10.166.72.201 – 10.166.72.206	10.166.72.207
27	10.166.72.208/29	10.166.72.209 – 10.166.72.214	10.166.72.215
28	10.166.72.216/29	10.166.72.217 – 10.166.72.222	10.166.72.223
29	10.166.72.224/29	10.166.72.225 – 10.166.72.230	10.166.72.231
30	10.166.72.232/29	10.166.72.233 – 10.166.72.238	10.166.72.239
31	10.166.72.240/29	10.166.72.241 – 10.166.72.246	10.166.72.247
32	10.166.72.248/29	10.166.72.249 – 10.166.72.254	10.166.72.255
33	10.166.73.0/29	10.166.73.1 – 10.166.73.6	10.166.73.7
34	10.166.73.8/29	10.166.73.9 – 10.166.73.14	10.166.73.15
35	10.166.73.16/29	10.166.73.17 – 10.166.73.22	10.166.73.23
36	10.166.73.24/29	10.166.73.25 – 10.166.73.30	10.166.73.31
37	10.166.73.32/29	10.166.73.33 – 10.166.73.38	10.166.73.39
38	10.166.73.40/29	10.166.73.41 – 10.166.73.46	10.166.73.47
39	10.166.73.48/29	10.166.73.49 – 10.166.73.54	10.166.73.55
40	10.166.73.56/29	10.166.73.57 – 10.166.73.62	10.166.73.63
41	10.166.73.64/29	10.166.73.65 – 10.166.73.70	10.166.73.71
42	10.166.73.72/29	10.166.73.73 – 10.166.73.78	10.166.73.79
43	10.166.73.80/29	10.166.73.81 – 10.166.73.86	10.166.73.87
44	10.166.73.88/29	10.166.73.89 – 10.166.73.94	10.166.73.95
45	10.166.73.96/29	10.166.73.97 – 10.166.73.102	10.166.73.103
46	10.166.73.104/29	10.166.73.105 – 10.166.73.110	10.166.73.111
47	10.166.73.112/29	10.166.73.113 – 10.166.73.118	10.166.73.119
48	10.166.73.120/29	10.166.73.121 – 10.166.73.126	10.166.73.127
49	10.166.73.128/29	10.166.73.129 – 10.166.73.134	10.166.73.135
50	10.166.73.136/29	10.166.73.137 – 10.166.73.142	10.166.73.143
51	10.166.73.144/29	10.166.73.145 – 10.166.73.150	10.166.73.151
52	10.166.73.152/29	10.166.73.153 – 10.166.73.158	10.166.73.159
53	10.166.73.160/29	10.166.73.161 – 10.166.73.166	10.166.73.167
54	10.166.73.168/29	10.166.73.169 – 10.166.73.174	10.166.73.175
55	10.166.73.176/29	10.166.73.177 – 10.166.73.182	10.166.73.183
56	10.166.73.184/29	10.166.73.185 – 10.166.73.190	10.166.73.191
57	10.166.73.192/29	10.166.73.193 – 10.166.73.198	10.166.73.199
58	10.166.73.200/29	10.166.73.201 – 10.166.73.206	10.166.73.207
59	10.166.73.208/29	10.166.73.209 – 10.166.73.214	10.166.73.215
60	10.166.73.216/29	10.166.73.217 – 10.166.73.222	10.166.73.223
61	10.166.73.224/29	10.166.73.225 – 10.166.73.230	10.166.73.231
62	10.166.73.232/29	10.166.73.233 – 10.166.73.238	10.166.73.239
63	10.166.73.240/29	10.166.73.241 – 10.166.73.246	10.166.73.247
64	10.166.73.248/29	10.166.73.249 – 10.166.73.254	10.166.73.255

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 →