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)10.0.17.128/25

network10.0.17.128/25

broadcast10.0.17.255

first host10.0.17.129

last host10.0.17.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.0.17.128/25

address00001010.00000000.00010001.10000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000000.00010001.10000000

broadcast00001010.00000000.00010001.11111111

green = network part, grey = host part

hex0x0a001180

decimal167776640

reverse dns128.17.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:1180

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.0.17.128/31	10.0.17.128 – 10.0.17.129	10.0.17.129
2	10.0.17.130/31	10.0.17.130 – 10.0.17.131	10.0.17.131
3	10.0.17.132/31	10.0.17.132 – 10.0.17.133	10.0.17.133
4	10.0.17.134/31	10.0.17.134 – 10.0.17.135	10.0.17.135
5	10.0.17.136/31	10.0.17.136 – 10.0.17.137	10.0.17.137
6	10.0.17.138/31	10.0.17.138 – 10.0.17.139	10.0.17.139
7	10.0.17.140/31	10.0.17.140 – 10.0.17.141	10.0.17.141
8	10.0.17.142/31	10.0.17.142 – 10.0.17.143	10.0.17.143
9	10.0.17.144/31	10.0.17.144 – 10.0.17.145	10.0.17.145
10	10.0.17.146/31	10.0.17.146 – 10.0.17.147	10.0.17.147
11	10.0.17.148/31	10.0.17.148 – 10.0.17.149	10.0.17.149
12	10.0.17.150/31	10.0.17.150 – 10.0.17.151	10.0.17.151
13	10.0.17.152/31	10.0.17.152 – 10.0.17.153	10.0.17.153
14	10.0.17.154/31	10.0.17.154 – 10.0.17.155	10.0.17.155
15	10.0.17.156/31	10.0.17.156 – 10.0.17.157	10.0.17.157
16	10.0.17.158/31	10.0.17.158 – 10.0.17.159	10.0.17.159
17	10.0.17.160/31	10.0.17.160 – 10.0.17.161	10.0.17.161
18	10.0.17.162/31	10.0.17.162 – 10.0.17.163	10.0.17.163
19	10.0.17.164/31	10.0.17.164 – 10.0.17.165	10.0.17.165
20	10.0.17.166/31	10.0.17.166 – 10.0.17.167	10.0.17.167
21	10.0.17.168/31	10.0.17.168 – 10.0.17.169	10.0.17.169
22	10.0.17.170/31	10.0.17.170 – 10.0.17.171	10.0.17.171
23	10.0.17.172/31	10.0.17.172 – 10.0.17.173	10.0.17.173
24	10.0.17.174/31	10.0.17.174 – 10.0.17.175	10.0.17.175
25	10.0.17.176/31	10.0.17.176 – 10.0.17.177	10.0.17.177
26	10.0.17.178/31	10.0.17.178 – 10.0.17.179	10.0.17.179
27	10.0.17.180/31	10.0.17.180 – 10.0.17.181	10.0.17.181
28	10.0.17.182/31	10.0.17.182 – 10.0.17.183	10.0.17.183
29	10.0.17.184/31	10.0.17.184 – 10.0.17.185	10.0.17.185
30	10.0.17.186/31	10.0.17.186 – 10.0.17.187	10.0.17.187
31	10.0.17.188/31	10.0.17.188 – 10.0.17.189	10.0.17.189
32	10.0.17.190/31	10.0.17.190 – 10.0.17.191	10.0.17.191
33	10.0.17.192/31	10.0.17.192 – 10.0.17.193	10.0.17.193
34	10.0.17.194/31	10.0.17.194 – 10.0.17.195	10.0.17.195
35	10.0.17.196/31	10.0.17.196 – 10.0.17.197	10.0.17.197
36	10.0.17.198/31	10.0.17.198 – 10.0.17.199	10.0.17.199
37	10.0.17.200/31	10.0.17.200 – 10.0.17.201	10.0.17.201
38	10.0.17.202/31	10.0.17.202 – 10.0.17.203	10.0.17.203
39	10.0.17.204/31	10.0.17.204 – 10.0.17.205	10.0.17.205
40	10.0.17.206/31	10.0.17.206 – 10.0.17.207	10.0.17.207
41	10.0.17.208/31	10.0.17.208 – 10.0.17.209	10.0.17.209
42	10.0.17.210/31	10.0.17.210 – 10.0.17.211	10.0.17.211
43	10.0.17.212/31	10.0.17.212 – 10.0.17.213	10.0.17.213
44	10.0.17.214/31	10.0.17.214 – 10.0.17.215	10.0.17.215
45	10.0.17.216/31	10.0.17.216 – 10.0.17.217	10.0.17.217
46	10.0.17.218/31	10.0.17.218 – 10.0.17.219	10.0.17.219
47	10.0.17.220/31	10.0.17.220 – 10.0.17.221	10.0.17.221
48	10.0.17.222/31	10.0.17.222 – 10.0.17.223	10.0.17.223
49	10.0.17.224/31	10.0.17.224 – 10.0.17.225	10.0.17.225
50	10.0.17.226/31	10.0.17.226 – 10.0.17.227	10.0.17.227
51	10.0.17.228/31	10.0.17.228 – 10.0.17.229	10.0.17.229
52	10.0.17.230/31	10.0.17.230 – 10.0.17.231	10.0.17.231
53	10.0.17.232/31	10.0.17.232 – 10.0.17.233	10.0.17.233
54	10.0.17.234/31	10.0.17.234 – 10.0.17.235	10.0.17.235
55	10.0.17.236/31	10.0.17.236 – 10.0.17.237	10.0.17.237
56	10.0.17.238/31	10.0.17.238 – 10.0.17.239	10.0.17.239
57	10.0.17.240/31	10.0.17.240 – 10.0.17.241	10.0.17.241
58	10.0.17.242/31	10.0.17.242 – 10.0.17.243	10.0.17.243
59	10.0.17.244/31	10.0.17.244 – 10.0.17.245	10.0.17.245
60	10.0.17.246/31	10.0.17.246 – 10.0.17.247	10.0.17.247
61	10.0.17.248/31	10.0.17.248 – 10.0.17.249	10.0.17.249
62	10.0.17.250/31	10.0.17.250 – 10.0.17.251	10.0.17.251
63	10.0.17.252/31	10.0.17.252 – 10.0.17.253	10.0.17.253
64	10.0.17.254/31	10.0.17.254 – 10.0.17.255	10.0.17.255

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 →