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)10.2.19.128/25

network10.2.19.128/25

broadcast10.2.19.255

first host10.2.19.129

last host10.2.19.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.2.19.128/25

address00001010.00000010.00010011.10000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000010.00010011.10000000

broadcast00001010.00000010.00010011.11111111

green = network part, grey = host part

hex0x0a021380

decimal167908224

reverse dns128.19.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:1380

/25 split into /31 · 64 subnets

close ×

#	network	host range	broadcast
1	10.2.19.128/31	10.2.19.128 – 10.2.19.129	10.2.19.129
2	10.2.19.130/31	10.2.19.130 – 10.2.19.131	10.2.19.131
3	10.2.19.132/31	10.2.19.132 – 10.2.19.133	10.2.19.133
4	10.2.19.134/31	10.2.19.134 – 10.2.19.135	10.2.19.135
5	10.2.19.136/31	10.2.19.136 – 10.2.19.137	10.2.19.137
6	10.2.19.138/31	10.2.19.138 – 10.2.19.139	10.2.19.139
7	10.2.19.140/31	10.2.19.140 – 10.2.19.141	10.2.19.141
8	10.2.19.142/31	10.2.19.142 – 10.2.19.143	10.2.19.143
9	10.2.19.144/31	10.2.19.144 – 10.2.19.145	10.2.19.145
10	10.2.19.146/31	10.2.19.146 – 10.2.19.147	10.2.19.147
11	10.2.19.148/31	10.2.19.148 – 10.2.19.149	10.2.19.149
12	10.2.19.150/31	10.2.19.150 – 10.2.19.151	10.2.19.151
13	10.2.19.152/31	10.2.19.152 – 10.2.19.153	10.2.19.153
14	10.2.19.154/31	10.2.19.154 – 10.2.19.155	10.2.19.155
15	10.2.19.156/31	10.2.19.156 – 10.2.19.157	10.2.19.157
16	10.2.19.158/31	10.2.19.158 – 10.2.19.159	10.2.19.159
17	10.2.19.160/31	10.2.19.160 – 10.2.19.161	10.2.19.161
18	10.2.19.162/31	10.2.19.162 – 10.2.19.163	10.2.19.163
19	10.2.19.164/31	10.2.19.164 – 10.2.19.165	10.2.19.165
20	10.2.19.166/31	10.2.19.166 – 10.2.19.167	10.2.19.167
21	10.2.19.168/31	10.2.19.168 – 10.2.19.169	10.2.19.169
22	10.2.19.170/31	10.2.19.170 – 10.2.19.171	10.2.19.171
23	10.2.19.172/31	10.2.19.172 – 10.2.19.173	10.2.19.173
24	10.2.19.174/31	10.2.19.174 – 10.2.19.175	10.2.19.175
25	10.2.19.176/31	10.2.19.176 – 10.2.19.177	10.2.19.177
26	10.2.19.178/31	10.2.19.178 – 10.2.19.179	10.2.19.179
27	10.2.19.180/31	10.2.19.180 – 10.2.19.181	10.2.19.181
28	10.2.19.182/31	10.2.19.182 – 10.2.19.183	10.2.19.183
29	10.2.19.184/31	10.2.19.184 – 10.2.19.185	10.2.19.185
30	10.2.19.186/31	10.2.19.186 – 10.2.19.187	10.2.19.187
31	10.2.19.188/31	10.2.19.188 – 10.2.19.189	10.2.19.189
32	10.2.19.190/31	10.2.19.190 – 10.2.19.191	10.2.19.191
33	10.2.19.192/31	10.2.19.192 – 10.2.19.193	10.2.19.193
34	10.2.19.194/31	10.2.19.194 – 10.2.19.195	10.2.19.195
35	10.2.19.196/31	10.2.19.196 – 10.2.19.197	10.2.19.197
36	10.2.19.198/31	10.2.19.198 – 10.2.19.199	10.2.19.199
37	10.2.19.200/31	10.2.19.200 – 10.2.19.201	10.2.19.201
38	10.2.19.202/31	10.2.19.202 – 10.2.19.203	10.2.19.203
39	10.2.19.204/31	10.2.19.204 – 10.2.19.205	10.2.19.205
40	10.2.19.206/31	10.2.19.206 – 10.2.19.207	10.2.19.207
41	10.2.19.208/31	10.2.19.208 – 10.2.19.209	10.2.19.209
42	10.2.19.210/31	10.2.19.210 – 10.2.19.211	10.2.19.211
43	10.2.19.212/31	10.2.19.212 – 10.2.19.213	10.2.19.213
44	10.2.19.214/31	10.2.19.214 – 10.2.19.215	10.2.19.215
45	10.2.19.216/31	10.2.19.216 – 10.2.19.217	10.2.19.217
46	10.2.19.218/31	10.2.19.218 – 10.2.19.219	10.2.19.219
47	10.2.19.220/31	10.2.19.220 – 10.2.19.221	10.2.19.221
48	10.2.19.222/31	10.2.19.222 – 10.2.19.223	10.2.19.223
49	10.2.19.224/31	10.2.19.224 – 10.2.19.225	10.2.19.225
50	10.2.19.226/31	10.2.19.226 – 10.2.19.227	10.2.19.227
51	10.2.19.228/31	10.2.19.228 – 10.2.19.229	10.2.19.229
52	10.2.19.230/31	10.2.19.230 – 10.2.19.231	10.2.19.231
53	10.2.19.232/31	10.2.19.232 – 10.2.19.233	10.2.19.233
54	10.2.19.234/31	10.2.19.234 – 10.2.19.235	10.2.19.235
55	10.2.19.236/31	10.2.19.236 – 10.2.19.237	10.2.19.237
56	10.2.19.238/31	10.2.19.238 – 10.2.19.239	10.2.19.239
57	10.2.19.240/31	10.2.19.240 – 10.2.19.241	10.2.19.241
58	10.2.19.242/31	10.2.19.242 – 10.2.19.243	10.2.19.243
59	10.2.19.244/31	10.2.19.244 – 10.2.19.245	10.2.19.245
60	10.2.19.246/31	10.2.19.246 – 10.2.19.247	10.2.19.247
61	10.2.19.248/31	10.2.19.248 – 10.2.19.249	10.2.19.249
62	10.2.19.250/31	10.2.19.250 – 10.2.19.251	10.2.19.251
63	10.2.19.252/31	10.2.19.252 – 10.2.19.253	10.2.19.253
64	10.2.19.254/31	10.2.19.254 – 10.2.19.255	10.2.19.255

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 →