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)172.16.0.128/25

network172.16.0.128/25

broadcast172.16.0.255

first host172.16.0.129

last host172.16.0.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classB

ipcalc 172.16.0.128/25

address10101100.00010000.00000000.10000000

subnet mask11111111.11111111.11111111.10000000

network10101100.00010000.00000000.10000000

broadcast10101100.00010000.00000000.11111111

green = network part, grey = host part

hex0xac100080

decimal2886729856

reverse dns128.0.16.172.in-addr.arpa

ipv4-mapped::ffff:ac10:80

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	172.16.0.128/31	172.16.0.128 – 172.16.0.129	172.16.0.129
2	172.16.0.130/31	172.16.0.130 – 172.16.0.131	172.16.0.131
3	172.16.0.132/31	172.16.0.132 – 172.16.0.133	172.16.0.133
4	172.16.0.134/31	172.16.0.134 – 172.16.0.135	172.16.0.135
5	172.16.0.136/31	172.16.0.136 – 172.16.0.137	172.16.0.137
6	172.16.0.138/31	172.16.0.138 – 172.16.0.139	172.16.0.139
7	172.16.0.140/31	172.16.0.140 – 172.16.0.141	172.16.0.141
8	172.16.0.142/31	172.16.0.142 – 172.16.0.143	172.16.0.143
9	172.16.0.144/31	172.16.0.144 – 172.16.0.145	172.16.0.145
10	172.16.0.146/31	172.16.0.146 – 172.16.0.147	172.16.0.147
11	172.16.0.148/31	172.16.0.148 – 172.16.0.149	172.16.0.149
12	172.16.0.150/31	172.16.0.150 – 172.16.0.151	172.16.0.151
13	172.16.0.152/31	172.16.0.152 – 172.16.0.153	172.16.0.153
14	172.16.0.154/31	172.16.0.154 – 172.16.0.155	172.16.0.155
15	172.16.0.156/31	172.16.0.156 – 172.16.0.157	172.16.0.157
16	172.16.0.158/31	172.16.0.158 – 172.16.0.159	172.16.0.159
17	172.16.0.160/31	172.16.0.160 – 172.16.0.161	172.16.0.161
18	172.16.0.162/31	172.16.0.162 – 172.16.0.163	172.16.0.163
19	172.16.0.164/31	172.16.0.164 – 172.16.0.165	172.16.0.165
20	172.16.0.166/31	172.16.0.166 – 172.16.0.167	172.16.0.167
21	172.16.0.168/31	172.16.0.168 – 172.16.0.169	172.16.0.169
22	172.16.0.170/31	172.16.0.170 – 172.16.0.171	172.16.0.171
23	172.16.0.172/31	172.16.0.172 – 172.16.0.173	172.16.0.173
24	172.16.0.174/31	172.16.0.174 – 172.16.0.175	172.16.0.175
25	172.16.0.176/31	172.16.0.176 – 172.16.0.177	172.16.0.177
26	172.16.0.178/31	172.16.0.178 – 172.16.0.179	172.16.0.179
27	172.16.0.180/31	172.16.0.180 – 172.16.0.181	172.16.0.181
28	172.16.0.182/31	172.16.0.182 – 172.16.0.183	172.16.0.183
29	172.16.0.184/31	172.16.0.184 – 172.16.0.185	172.16.0.185
30	172.16.0.186/31	172.16.0.186 – 172.16.0.187	172.16.0.187
31	172.16.0.188/31	172.16.0.188 – 172.16.0.189	172.16.0.189
32	172.16.0.190/31	172.16.0.190 – 172.16.0.191	172.16.0.191
33	172.16.0.192/31	172.16.0.192 – 172.16.0.193	172.16.0.193
34	172.16.0.194/31	172.16.0.194 – 172.16.0.195	172.16.0.195
35	172.16.0.196/31	172.16.0.196 – 172.16.0.197	172.16.0.197
36	172.16.0.198/31	172.16.0.198 – 172.16.0.199	172.16.0.199
37	172.16.0.200/31	172.16.0.200 – 172.16.0.201	172.16.0.201
38	172.16.0.202/31	172.16.0.202 – 172.16.0.203	172.16.0.203
39	172.16.0.204/31	172.16.0.204 – 172.16.0.205	172.16.0.205
40	172.16.0.206/31	172.16.0.206 – 172.16.0.207	172.16.0.207
41	172.16.0.208/31	172.16.0.208 – 172.16.0.209	172.16.0.209
42	172.16.0.210/31	172.16.0.210 – 172.16.0.211	172.16.0.211
43	172.16.0.212/31	172.16.0.212 – 172.16.0.213	172.16.0.213
44	172.16.0.214/31	172.16.0.214 – 172.16.0.215	172.16.0.215
45	172.16.0.216/31	172.16.0.216 – 172.16.0.217	172.16.0.217
46	172.16.0.218/31	172.16.0.218 – 172.16.0.219	172.16.0.219
47	172.16.0.220/31	172.16.0.220 – 172.16.0.221	172.16.0.221
48	172.16.0.222/31	172.16.0.222 – 172.16.0.223	172.16.0.223
49	172.16.0.224/31	172.16.0.224 – 172.16.0.225	172.16.0.225
50	172.16.0.226/31	172.16.0.226 – 172.16.0.227	172.16.0.227
51	172.16.0.228/31	172.16.0.228 – 172.16.0.229	172.16.0.229
52	172.16.0.230/31	172.16.0.230 – 172.16.0.231	172.16.0.231
53	172.16.0.232/31	172.16.0.232 – 172.16.0.233	172.16.0.233
54	172.16.0.234/31	172.16.0.234 – 172.16.0.235	172.16.0.235
55	172.16.0.236/31	172.16.0.236 – 172.16.0.237	172.16.0.237
56	172.16.0.238/31	172.16.0.238 – 172.16.0.239	172.16.0.239
57	172.16.0.240/31	172.16.0.240 – 172.16.0.241	172.16.0.241
58	172.16.0.242/31	172.16.0.242 – 172.16.0.243	172.16.0.243
59	172.16.0.244/31	172.16.0.244 – 172.16.0.245	172.16.0.245
60	172.16.0.246/31	172.16.0.246 – 172.16.0.247	172.16.0.247
61	172.16.0.248/31	172.16.0.248 – 172.16.0.249	172.16.0.249
62	172.16.0.250/31	172.16.0.250 – 172.16.0.251	172.16.0.251
63	172.16.0.252/31	172.16.0.252 – 172.16.0.253	172.16.0.253
64	172.16.0.254/31	172.16.0.254 – 172.16.0.255	172.16.0.255

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 →