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)10.0.18.128/25

network10.0.18.128/25

broadcast10.0.18.255

first host10.0.18.129

last host10.0.18.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.0.18.128/25

address00001010.00000000.00010010.10000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000000.00010010.10000000

broadcast00001010.00000000.00010010.11111111

green = network part, grey = host part

hex0x0a001280

decimal167776896

reverse dns128.18.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:1280

/25 split into /32 · 128 subnets

close ×

#	network	host range	broadcast
1	10.0.18.128/32	10.0.18.128 – 10.0.18.128	10.0.18.128
2	10.0.18.129/32	10.0.18.129 – 10.0.18.129	10.0.18.129
3	10.0.18.130/32	10.0.18.130 – 10.0.18.130	10.0.18.130
4	10.0.18.131/32	10.0.18.131 – 10.0.18.131	10.0.18.131
5	10.0.18.132/32	10.0.18.132 – 10.0.18.132	10.0.18.132
6	10.0.18.133/32	10.0.18.133 – 10.0.18.133	10.0.18.133
7	10.0.18.134/32	10.0.18.134 – 10.0.18.134	10.0.18.134
8	10.0.18.135/32	10.0.18.135 – 10.0.18.135	10.0.18.135
9	10.0.18.136/32	10.0.18.136 – 10.0.18.136	10.0.18.136
10	10.0.18.137/32	10.0.18.137 – 10.0.18.137	10.0.18.137
11	10.0.18.138/32	10.0.18.138 – 10.0.18.138	10.0.18.138
12	10.0.18.139/32	10.0.18.139 – 10.0.18.139	10.0.18.139
13	10.0.18.140/32	10.0.18.140 – 10.0.18.140	10.0.18.140
14	10.0.18.141/32	10.0.18.141 – 10.0.18.141	10.0.18.141
15	10.0.18.142/32	10.0.18.142 – 10.0.18.142	10.0.18.142
16	10.0.18.143/32	10.0.18.143 – 10.0.18.143	10.0.18.143
17	10.0.18.144/32	10.0.18.144 – 10.0.18.144	10.0.18.144
18	10.0.18.145/32	10.0.18.145 – 10.0.18.145	10.0.18.145
19	10.0.18.146/32	10.0.18.146 – 10.0.18.146	10.0.18.146
20	10.0.18.147/32	10.0.18.147 – 10.0.18.147	10.0.18.147
21	10.0.18.148/32	10.0.18.148 – 10.0.18.148	10.0.18.148
22	10.0.18.149/32	10.0.18.149 – 10.0.18.149	10.0.18.149
23	10.0.18.150/32	10.0.18.150 – 10.0.18.150	10.0.18.150
24	10.0.18.151/32	10.0.18.151 – 10.0.18.151	10.0.18.151
25	10.0.18.152/32	10.0.18.152 – 10.0.18.152	10.0.18.152
26	10.0.18.153/32	10.0.18.153 – 10.0.18.153	10.0.18.153
27	10.0.18.154/32	10.0.18.154 – 10.0.18.154	10.0.18.154
28	10.0.18.155/32	10.0.18.155 – 10.0.18.155	10.0.18.155
29	10.0.18.156/32	10.0.18.156 – 10.0.18.156	10.0.18.156
30	10.0.18.157/32	10.0.18.157 – 10.0.18.157	10.0.18.157
31	10.0.18.158/32	10.0.18.158 – 10.0.18.158	10.0.18.158
32	10.0.18.159/32	10.0.18.159 – 10.0.18.159	10.0.18.159
33	10.0.18.160/32	10.0.18.160 – 10.0.18.160	10.0.18.160
34	10.0.18.161/32	10.0.18.161 – 10.0.18.161	10.0.18.161
35	10.0.18.162/32	10.0.18.162 – 10.0.18.162	10.0.18.162
36	10.0.18.163/32	10.0.18.163 – 10.0.18.163	10.0.18.163
37	10.0.18.164/32	10.0.18.164 – 10.0.18.164	10.0.18.164
38	10.0.18.165/32	10.0.18.165 – 10.0.18.165	10.0.18.165
39	10.0.18.166/32	10.0.18.166 – 10.0.18.166	10.0.18.166
40	10.0.18.167/32	10.0.18.167 – 10.0.18.167	10.0.18.167
41	10.0.18.168/32	10.0.18.168 – 10.0.18.168	10.0.18.168
42	10.0.18.169/32	10.0.18.169 – 10.0.18.169	10.0.18.169
43	10.0.18.170/32	10.0.18.170 – 10.0.18.170	10.0.18.170
44	10.0.18.171/32	10.0.18.171 – 10.0.18.171	10.0.18.171
45	10.0.18.172/32	10.0.18.172 – 10.0.18.172	10.0.18.172
46	10.0.18.173/32	10.0.18.173 – 10.0.18.173	10.0.18.173
47	10.0.18.174/32	10.0.18.174 – 10.0.18.174	10.0.18.174
48	10.0.18.175/32	10.0.18.175 – 10.0.18.175	10.0.18.175
49	10.0.18.176/32	10.0.18.176 – 10.0.18.176	10.0.18.176
50	10.0.18.177/32	10.0.18.177 – 10.0.18.177	10.0.18.177
51	10.0.18.178/32	10.0.18.178 – 10.0.18.178	10.0.18.178
52	10.0.18.179/32	10.0.18.179 – 10.0.18.179	10.0.18.179
53	10.0.18.180/32	10.0.18.180 – 10.0.18.180	10.0.18.180
54	10.0.18.181/32	10.0.18.181 – 10.0.18.181	10.0.18.181
55	10.0.18.182/32	10.0.18.182 – 10.0.18.182	10.0.18.182
56	10.0.18.183/32	10.0.18.183 – 10.0.18.183	10.0.18.183
57	10.0.18.184/32	10.0.18.184 – 10.0.18.184	10.0.18.184
58	10.0.18.185/32	10.0.18.185 – 10.0.18.185	10.0.18.185
59	10.0.18.186/32	10.0.18.186 – 10.0.18.186	10.0.18.186
60	10.0.18.187/32	10.0.18.187 – 10.0.18.187	10.0.18.187
61	10.0.18.188/32	10.0.18.188 – 10.0.18.188	10.0.18.188
62	10.0.18.189/32	10.0.18.189 – 10.0.18.189	10.0.18.189
63	10.0.18.190/32	10.0.18.190 – 10.0.18.190	10.0.18.190
64	10.0.18.191/32	10.0.18.191 – 10.0.18.191	10.0.18.191
65	10.0.18.192/32	10.0.18.192 – 10.0.18.192	10.0.18.192
66	10.0.18.193/32	10.0.18.193 – 10.0.18.193	10.0.18.193
67	10.0.18.194/32	10.0.18.194 – 10.0.18.194	10.0.18.194
68	10.0.18.195/32	10.0.18.195 – 10.0.18.195	10.0.18.195
69	10.0.18.196/32	10.0.18.196 – 10.0.18.196	10.0.18.196
70	10.0.18.197/32	10.0.18.197 – 10.0.18.197	10.0.18.197
71	10.0.18.198/32	10.0.18.198 – 10.0.18.198	10.0.18.198
72	10.0.18.199/32	10.0.18.199 – 10.0.18.199	10.0.18.199
73	10.0.18.200/32	10.0.18.200 – 10.0.18.200	10.0.18.200
74	10.0.18.201/32	10.0.18.201 – 10.0.18.201	10.0.18.201
75	10.0.18.202/32	10.0.18.202 – 10.0.18.202	10.0.18.202
76	10.0.18.203/32	10.0.18.203 – 10.0.18.203	10.0.18.203
77	10.0.18.204/32	10.0.18.204 – 10.0.18.204	10.0.18.204
78	10.0.18.205/32	10.0.18.205 – 10.0.18.205	10.0.18.205
79	10.0.18.206/32	10.0.18.206 – 10.0.18.206	10.0.18.206
80	10.0.18.207/32	10.0.18.207 – 10.0.18.207	10.0.18.207
81	10.0.18.208/32	10.0.18.208 – 10.0.18.208	10.0.18.208
82	10.0.18.209/32	10.0.18.209 – 10.0.18.209	10.0.18.209
83	10.0.18.210/32	10.0.18.210 – 10.0.18.210	10.0.18.210
84	10.0.18.211/32	10.0.18.211 – 10.0.18.211	10.0.18.211
85	10.0.18.212/32	10.0.18.212 – 10.0.18.212	10.0.18.212
86	10.0.18.213/32	10.0.18.213 – 10.0.18.213	10.0.18.213
87	10.0.18.214/32	10.0.18.214 – 10.0.18.214	10.0.18.214
88	10.0.18.215/32	10.0.18.215 – 10.0.18.215	10.0.18.215
89	10.0.18.216/32	10.0.18.216 – 10.0.18.216	10.0.18.216
90	10.0.18.217/32	10.0.18.217 – 10.0.18.217	10.0.18.217
91	10.0.18.218/32	10.0.18.218 – 10.0.18.218	10.0.18.218
92	10.0.18.219/32	10.0.18.219 – 10.0.18.219	10.0.18.219
93	10.0.18.220/32	10.0.18.220 – 10.0.18.220	10.0.18.220
94	10.0.18.221/32	10.0.18.221 – 10.0.18.221	10.0.18.221
95	10.0.18.222/32	10.0.18.222 – 10.0.18.222	10.0.18.222
96	10.0.18.223/32	10.0.18.223 – 10.0.18.223	10.0.18.223
97	10.0.18.224/32	10.0.18.224 – 10.0.18.224	10.0.18.224
98	10.0.18.225/32	10.0.18.225 – 10.0.18.225	10.0.18.225
99	10.0.18.226/32	10.0.18.226 – 10.0.18.226	10.0.18.226
100	10.0.18.227/32	10.0.18.227 – 10.0.18.227	10.0.18.227
101	10.0.18.228/32	10.0.18.228 – 10.0.18.228	10.0.18.228
102	10.0.18.229/32	10.0.18.229 – 10.0.18.229	10.0.18.229
103	10.0.18.230/32	10.0.18.230 – 10.0.18.230	10.0.18.230
104	10.0.18.231/32	10.0.18.231 – 10.0.18.231	10.0.18.231
105	10.0.18.232/32	10.0.18.232 – 10.0.18.232	10.0.18.232
106	10.0.18.233/32	10.0.18.233 – 10.0.18.233	10.0.18.233
107	10.0.18.234/32	10.0.18.234 – 10.0.18.234	10.0.18.234
108	10.0.18.235/32	10.0.18.235 – 10.0.18.235	10.0.18.235
109	10.0.18.236/32	10.0.18.236 – 10.0.18.236	10.0.18.236
110	10.0.18.237/32	10.0.18.237 – 10.0.18.237	10.0.18.237
111	10.0.18.238/32	10.0.18.238 – 10.0.18.238	10.0.18.238
112	10.0.18.239/32	10.0.18.239 – 10.0.18.239	10.0.18.239
113	10.0.18.240/32	10.0.18.240 – 10.0.18.240	10.0.18.240
114	10.0.18.241/32	10.0.18.241 – 10.0.18.241	10.0.18.241
115	10.0.18.242/32	10.0.18.242 – 10.0.18.242	10.0.18.242
116	10.0.18.243/32	10.0.18.243 – 10.0.18.243	10.0.18.243
117	10.0.18.244/32	10.0.18.244 – 10.0.18.244	10.0.18.244
118	10.0.18.245/32	10.0.18.245 – 10.0.18.245	10.0.18.245
119	10.0.18.246/32	10.0.18.246 – 10.0.18.246	10.0.18.246
120	10.0.18.247/32	10.0.18.247 – 10.0.18.247	10.0.18.247
121	10.0.18.248/32	10.0.18.248 – 10.0.18.248	10.0.18.248
122	10.0.18.249/32	10.0.18.249 – 10.0.18.249	10.0.18.249
123	10.0.18.250/32	10.0.18.250 – 10.0.18.250	10.0.18.250
124	10.0.18.251/32	10.0.18.251 – 10.0.18.251	10.0.18.251
125	10.0.18.252/32	10.0.18.252 – 10.0.18.252	10.0.18.252
126	10.0.18.253/32	10.0.18.253 – 10.0.18.253	10.0.18.253
127	10.0.18.254/32	10.0.18.254 – 10.0.18.254	10.0.18.254
128	10.0.18.255/32	10.0.18.255 – 10.0.18.255	10.0.18.255

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 →