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)10.2.8.128/25

network10.2.8.128/25

broadcast10.2.8.255

first host10.2.8.129

last host10.2.8.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.2.8.128/25

address00001010.00000010.00001000.10000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000010.00001000.10000000

broadcast00001010.00000010.00001000.11111111

green = network part, grey = host part

hex0x0a020880

decimal167905408

reverse dns128.8.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:880

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.2.8.128/31	10.2.8.128 – 10.2.8.129	10.2.8.129
2	10.2.8.130/31	10.2.8.130 – 10.2.8.131	10.2.8.131
3	10.2.8.132/31	10.2.8.132 – 10.2.8.133	10.2.8.133
4	10.2.8.134/31	10.2.8.134 – 10.2.8.135	10.2.8.135
5	10.2.8.136/31	10.2.8.136 – 10.2.8.137	10.2.8.137
6	10.2.8.138/31	10.2.8.138 – 10.2.8.139	10.2.8.139
7	10.2.8.140/31	10.2.8.140 – 10.2.8.141	10.2.8.141
8	10.2.8.142/31	10.2.8.142 – 10.2.8.143	10.2.8.143
9	10.2.8.144/31	10.2.8.144 – 10.2.8.145	10.2.8.145
10	10.2.8.146/31	10.2.8.146 – 10.2.8.147	10.2.8.147
11	10.2.8.148/31	10.2.8.148 – 10.2.8.149	10.2.8.149
12	10.2.8.150/31	10.2.8.150 – 10.2.8.151	10.2.8.151
13	10.2.8.152/31	10.2.8.152 – 10.2.8.153	10.2.8.153
14	10.2.8.154/31	10.2.8.154 – 10.2.8.155	10.2.8.155
15	10.2.8.156/31	10.2.8.156 – 10.2.8.157	10.2.8.157
16	10.2.8.158/31	10.2.8.158 – 10.2.8.159	10.2.8.159
17	10.2.8.160/31	10.2.8.160 – 10.2.8.161	10.2.8.161
18	10.2.8.162/31	10.2.8.162 – 10.2.8.163	10.2.8.163
19	10.2.8.164/31	10.2.8.164 – 10.2.8.165	10.2.8.165
20	10.2.8.166/31	10.2.8.166 – 10.2.8.167	10.2.8.167
21	10.2.8.168/31	10.2.8.168 – 10.2.8.169	10.2.8.169
22	10.2.8.170/31	10.2.8.170 – 10.2.8.171	10.2.8.171
23	10.2.8.172/31	10.2.8.172 – 10.2.8.173	10.2.8.173
24	10.2.8.174/31	10.2.8.174 – 10.2.8.175	10.2.8.175
25	10.2.8.176/31	10.2.8.176 – 10.2.8.177	10.2.8.177
26	10.2.8.178/31	10.2.8.178 – 10.2.8.179	10.2.8.179
27	10.2.8.180/31	10.2.8.180 – 10.2.8.181	10.2.8.181
28	10.2.8.182/31	10.2.8.182 – 10.2.8.183	10.2.8.183
29	10.2.8.184/31	10.2.8.184 – 10.2.8.185	10.2.8.185
30	10.2.8.186/31	10.2.8.186 – 10.2.8.187	10.2.8.187
31	10.2.8.188/31	10.2.8.188 – 10.2.8.189	10.2.8.189
32	10.2.8.190/31	10.2.8.190 – 10.2.8.191	10.2.8.191
33	10.2.8.192/31	10.2.8.192 – 10.2.8.193	10.2.8.193
34	10.2.8.194/31	10.2.8.194 – 10.2.8.195	10.2.8.195
35	10.2.8.196/31	10.2.8.196 – 10.2.8.197	10.2.8.197
36	10.2.8.198/31	10.2.8.198 – 10.2.8.199	10.2.8.199
37	10.2.8.200/31	10.2.8.200 – 10.2.8.201	10.2.8.201
38	10.2.8.202/31	10.2.8.202 – 10.2.8.203	10.2.8.203
39	10.2.8.204/31	10.2.8.204 – 10.2.8.205	10.2.8.205
40	10.2.8.206/31	10.2.8.206 – 10.2.8.207	10.2.8.207
41	10.2.8.208/31	10.2.8.208 – 10.2.8.209	10.2.8.209
42	10.2.8.210/31	10.2.8.210 – 10.2.8.211	10.2.8.211
43	10.2.8.212/31	10.2.8.212 – 10.2.8.213	10.2.8.213
44	10.2.8.214/31	10.2.8.214 – 10.2.8.215	10.2.8.215
45	10.2.8.216/31	10.2.8.216 – 10.2.8.217	10.2.8.217
46	10.2.8.218/31	10.2.8.218 – 10.2.8.219	10.2.8.219
47	10.2.8.220/31	10.2.8.220 – 10.2.8.221	10.2.8.221
48	10.2.8.222/31	10.2.8.222 – 10.2.8.223	10.2.8.223
49	10.2.8.224/31	10.2.8.224 – 10.2.8.225	10.2.8.225
50	10.2.8.226/31	10.2.8.226 – 10.2.8.227	10.2.8.227
51	10.2.8.228/31	10.2.8.228 – 10.2.8.229	10.2.8.229
52	10.2.8.230/31	10.2.8.230 – 10.2.8.231	10.2.8.231
53	10.2.8.232/31	10.2.8.232 – 10.2.8.233	10.2.8.233
54	10.2.8.234/31	10.2.8.234 – 10.2.8.235	10.2.8.235
55	10.2.8.236/31	10.2.8.236 – 10.2.8.237	10.2.8.237
56	10.2.8.238/31	10.2.8.238 – 10.2.8.239	10.2.8.239
57	10.2.8.240/31	10.2.8.240 – 10.2.8.241	10.2.8.241
58	10.2.8.242/31	10.2.8.242 – 10.2.8.243	10.2.8.243
59	10.2.8.244/31	10.2.8.244 – 10.2.8.245	10.2.8.245
60	10.2.8.246/31	10.2.8.246 – 10.2.8.247	10.2.8.247
61	10.2.8.248/31	10.2.8.248 – 10.2.8.249	10.2.8.249
62	10.2.8.250/31	10.2.8.250 – 10.2.8.251	10.2.8.251
63	10.2.8.252/31	10.2.8.252 – 10.2.8.253	10.2.8.253
64	10.2.8.254/31	10.2.8.254 – 10.2.8.255	10.2.8.255

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 →