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)10.78.239.128/25

network10.78.239.128/25

broadcast10.78.239.255

first host10.78.239.129

last host10.78.239.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.78.239.128/25

address00001010.01001110.11101111.10000000

subnet mask11111111.11111111.11111111.10000000

network00001010.01001110.11101111.10000000

broadcast00001010.01001110.11101111.11111111

green = network part, grey = host part

hex0x0a4eef80

decimal172945280

reverse dns128.239.78.10.in-addr.arpa

ipv4-mapped::ffff:a4e:ef80

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.78.239.128/31	10.78.239.128 – 10.78.239.129	10.78.239.129
2	10.78.239.130/31	10.78.239.130 – 10.78.239.131	10.78.239.131
3	10.78.239.132/31	10.78.239.132 – 10.78.239.133	10.78.239.133
4	10.78.239.134/31	10.78.239.134 – 10.78.239.135	10.78.239.135
5	10.78.239.136/31	10.78.239.136 – 10.78.239.137	10.78.239.137
6	10.78.239.138/31	10.78.239.138 – 10.78.239.139	10.78.239.139
7	10.78.239.140/31	10.78.239.140 – 10.78.239.141	10.78.239.141
8	10.78.239.142/31	10.78.239.142 – 10.78.239.143	10.78.239.143
9	10.78.239.144/31	10.78.239.144 – 10.78.239.145	10.78.239.145
10	10.78.239.146/31	10.78.239.146 – 10.78.239.147	10.78.239.147
11	10.78.239.148/31	10.78.239.148 – 10.78.239.149	10.78.239.149
12	10.78.239.150/31	10.78.239.150 – 10.78.239.151	10.78.239.151
13	10.78.239.152/31	10.78.239.152 – 10.78.239.153	10.78.239.153
14	10.78.239.154/31	10.78.239.154 – 10.78.239.155	10.78.239.155
15	10.78.239.156/31	10.78.239.156 – 10.78.239.157	10.78.239.157
16	10.78.239.158/31	10.78.239.158 – 10.78.239.159	10.78.239.159
17	10.78.239.160/31	10.78.239.160 – 10.78.239.161	10.78.239.161
18	10.78.239.162/31	10.78.239.162 – 10.78.239.163	10.78.239.163
19	10.78.239.164/31	10.78.239.164 – 10.78.239.165	10.78.239.165
20	10.78.239.166/31	10.78.239.166 – 10.78.239.167	10.78.239.167
21	10.78.239.168/31	10.78.239.168 – 10.78.239.169	10.78.239.169
22	10.78.239.170/31	10.78.239.170 – 10.78.239.171	10.78.239.171
23	10.78.239.172/31	10.78.239.172 – 10.78.239.173	10.78.239.173
24	10.78.239.174/31	10.78.239.174 – 10.78.239.175	10.78.239.175
25	10.78.239.176/31	10.78.239.176 – 10.78.239.177	10.78.239.177
26	10.78.239.178/31	10.78.239.178 – 10.78.239.179	10.78.239.179
27	10.78.239.180/31	10.78.239.180 – 10.78.239.181	10.78.239.181
28	10.78.239.182/31	10.78.239.182 – 10.78.239.183	10.78.239.183
29	10.78.239.184/31	10.78.239.184 – 10.78.239.185	10.78.239.185
30	10.78.239.186/31	10.78.239.186 – 10.78.239.187	10.78.239.187
31	10.78.239.188/31	10.78.239.188 – 10.78.239.189	10.78.239.189
32	10.78.239.190/31	10.78.239.190 – 10.78.239.191	10.78.239.191
33	10.78.239.192/31	10.78.239.192 – 10.78.239.193	10.78.239.193
34	10.78.239.194/31	10.78.239.194 – 10.78.239.195	10.78.239.195
35	10.78.239.196/31	10.78.239.196 – 10.78.239.197	10.78.239.197
36	10.78.239.198/31	10.78.239.198 – 10.78.239.199	10.78.239.199
37	10.78.239.200/31	10.78.239.200 – 10.78.239.201	10.78.239.201
38	10.78.239.202/31	10.78.239.202 – 10.78.239.203	10.78.239.203
39	10.78.239.204/31	10.78.239.204 – 10.78.239.205	10.78.239.205
40	10.78.239.206/31	10.78.239.206 – 10.78.239.207	10.78.239.207
41	10.78.239.208/31	10.78.239.208 – 10.78.239.209	10.78.239.209
42	10.78.239.210/31	10.78.239.210 – 10.78.239.211	10.78.239.211
43	10.78.239.212/31	10.78.239.212 – 10.78.239.213	10.78.239.213
44	10.78.239.214/31	10.78.239.214 – 10.78.239.215	10.78.239.215
45	10.78.239.216/31	10.78.239.216 – 10.78.239.217	10.78.239.217
46	10.78.239.218/31	10.78.239.218 – 10.78.239.219	10.78.239.219
47	10.78.239.220/31	10.78.239.220 – 10.78.239.221	10.78.239.221
48	10.78.239.222/31	10.78.239.222 – 10.78.239.223	10.78.239.223
49	10.78.239.224/31	10.78.239.224 – 10.78.239.225	10.78.239.225
50	10.78.239.226/31	10.78.239.226 – 10.78.239.227	10.78.239.227
51	10.78.239.228/31	10.78.239.228 – 10.78.239.229	10.78.239.229
52	10.78.239.230/31	10.78.239.230 – 10.78.239.231	10.78.239.231
53	10.78.239.232/31	10.78.239.232 – 10.78.239.233	10.78.239.233
54	10.78.239.234/31	10.78.239.234 – 10.78.239.235	10.78.239.235
55	10.78.239.236/31	10.78.239.236 – 10.78.239.237	10.78.239.237
56	10.78.239.238/31	10.78.239.238 – 10.78.239.239	10.78.239.239
57	10.78.239.240/31	10.78.239.240 – 10.78.239.241	10.78.239.241
58	10.78.239.242/31	10.78.239.242 – 10.78.239.243	10.78.239.243
59	10.78.239.244/31	10.78.239.244 – 10.78.239.245	10.78.239.245
60	10.78.239.246/31	10.78.239.246 – 10.78.239.247	10.78.239.247
61	10.78.239.248/31	10.78.239.248 – 10.78.239.249	10.78.239.249
62	10.78.239.250/31	10.78.239.250 – 10.78.239.251	10.78.239.251
63	10.78.239.252/31	10.78.239.252 – 10.78.239.253	10.78.239.253
64	10.78.239.254/31	10.78.239.254 – 10.78.239.255	10.78.239.255

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 →