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)10.28.2.128/25

network10.28.2.128/25

broadcast10.28.2.255

first host10.28.2.129

last host10.28.2.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.28.2.128/25

address00001010.00011100.00000010.10000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00011100.00000010.10000000

broadcast00001010.00011100.00000010.11111111

green = network part, grey = host part

hex0x0a1c0280

decimal169607808

reverse dns128.2.28.10.in-addr.arpa

ipv4-mapped::ffff:a1c:280

/25 split into /30 · 32 subnets

close ×

#	network	host range	broadcast
1	10.28.2.128/30	10.28.2.129 – 10.28.2.130	10.28.2.131
2	10.28.2.132/30	10.28.2.133 – 10.28.2.134	10.28.2.135
3	10.28.2.136/30	10.28.2.137 – 10.28.2.138	10.28.2.139
4	10.28.2.140/30	10.28.2.141 – 10.28.2.142	10.28.2.143
5	10.28.2.144/30	10.28.2.145 – 10.28.2.146	10.28.2.147
6	10.28.2.148/30	10.28.2.149 – 10.28.2.150	10.28.2.151
7	10.28.2.152/30	10.28.2.153 – 10.28.2.154	10.28.2.155
8	10.28.2.156/30	10.28.2.157 – 10.28.2.158	10.28.2.159
9	10.28.2.160/30	10.28.2.161 – 10.28.2.162	10.28.2.163
10	10.28.2.164/30	10.28.2.165 – 10.28.2.166	10.28.2.167
11	10.28.2.168/30	10.28.2.169 – 10.28.2.170	10.28.2.171
12	10.28.2.172/30	10.28.2.173 – 10.28.2.174	10.28.2.175
13	10.28.2.176/30	10.28.2.177 – 10.28.2.178	10.28.2.179
14	10.28.2.180/30	10.28.2.181 – 10.28.2.182	10.28.2.183
15	10.28.2.184/30	10.28.2.185 – 10.28.2.186	10.28.2.187
16	10.28.2.188/30	10.28.2.189 – 10.28.2.190	10.28.2.191
17	10.28.2.192/30	10.28.2.193 – 10.28.2.194	10.28.2.195
18	10.28.2.196/30	10.28.2.197 – 10.28.2.198	10.28.2.199
19	10.28.2.200/30	10.28.2.201 – 10.28.2.202	10.28.2.203
20	10.28.2.204/30	10.28.2.205 – 10.28.2.206	10.28.2.207
21	10.28.2.208/30	10.28.2.209 – 10.28.2.210	10.28.2.211
22	10.28.2.212/30	10.28.2.213 – 10.28.2.214	10.28.2.215
23	10.28.2.216/30	10.28.2.217 – 10.28.2.218	10.28.2.219
24	10.28.2.220/30	10.28.2.221 – 10.28.2.222	10.28.2.223
25	10.28.2.224/30	10.28.2.225 – 10.28.2.226	10.28.2.227
26	10.28.2.228/30	10.28.2.229 – 10.28.2.230	10.28.2.231
27	10.28.2.232/30	10.28.2.233 – 10.28.2.234	10.28.2.235
28	10.28.2.236/30	10.28.2.237 – 10.28.2.238	10.28.2.239
29	10.28.2.240/30	10.28.2.241 – 10.28.2.242	10.28.2.243
30	10.28.2.244/30	10.28.2.245 – 10.28.2.246	10.28.2.247
31	10.28.2.248/30	10.28.2.249 – 10.28.2.250	10.28.2.251
32	10.28.2.252/30	10.28.2.253 – 10.28.2.254	10.28.2.255

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 /25
/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	-
/24	255.255.255.0	256	254	-
/25	255.255.255.128	128	126	1
/26	255.255.255.192	64	62	2 split →
/27	255.255.255.224	32	30	4 split →
/28	255.255.255.240	16	14	8 split →
/29	255.255.255.248	8	6	16 split →
/30	255.255.255.252	4	2	32 split →
/31	255.255.255.254	2	2	64 split →
/32	255.255.255.255	1	1	128 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 →