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)10.0.20.128/25

network10.0.20.128/25

broadcast10.0.20.255

first host10.0.20.129

last host10.0.20.254

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.0.20.128/25

address00001010.00000000.00010100.10000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000000.00010100.10000000

broadcast00001010.00000000.00010100.11111111

green = network part, grey = host part

hex0x0a001480

decimal167777408

reverse dns128.20.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:1480

/25 split into /32 · 128 subnets

close ×

#	network	host range	broadcast
1	10.0.20.128/32	10.0.20.128 – 10.0.20.128	10.0.20.128
2	10.0.20.129/32	10.0.20.129 – 10.0.20.129	10.0.20.129
3	10.0.20.130/32	10.0.20.130 – 10.0.20.130	10.0.20.130
4	10.0.20.131/32	10.0.20.131 – 10.0.20.131	10.0.20.131
5	10.0.20.132/32	10.0.20.132 – 10.0.20.132	10.0.20.132
6	10.0.20.133/32	10.0.20.133 – 10.0.20.133	10.0.20.133
7	10.0.20.134/32	10.0.20.134 – 10.0.20.134	10.0.20.134
8	10.0.20.135/32	10.0.20.135 – 10.0.20.135	10.0.20.135
9	10.0.20.136/32	10.0.20.136 – 10.0.20.136	10.0.20.136
10	10.0.20.137/32	10.0.20.137 – 10.0.20.137	10.0.20.137
11	10.0.20.138/32	10.0.20.138 – 10.0.20.138	10.0.20.138
12	10.0.20.139/32	10.0.20.139 – 10.0.20.139	10.0.20.139
13	10.0.20.140/32	10.0.20.140 – 10.0.20.140	10.0.20.140
14	10.0.20.141/32	10.0.20.141 – 10.0.20.141	10.0.20.141
15	10.0.20.142/32	10.0.20.142 – 10.0.20.142	10.0.20.142
16	10.0.20.143/32	10.0.20.143 – 10.0.20.143	10.0.20.143
17	10.0.20.144/32	10.0.20.144 – 10.0.20.144	10.0.20.144
18	10.0.20.145/32	10.0.20.145 – 10.0.20.145	10.0.20.145
19	10.0.20.146/32	10.0.20.146 – 10.0.20.146	10.0.20.146
20	10.0.20.147/32	10.0.20.147 – 10.0.20.147	10.0.20.147
21	10.0.20.148/32	10.0.20.148 – 10.0.20.148	10.0.20.148
22	10.0.20.149/32	10.0.20.149 – 10.0.20.149	10.0.20.149
23	10.0.20.150/32	10.0.20.150 – 10.0.20.150	10.0.20.150
24	10.0.20.151/32	10.0.20.151 – 10.0.20.151	10.0.20.151
25	10.0.20.152/32	10.0.20.152 – 10.0.20.152	10.0.20.152
26	10.0.20.153/32	10.0.20.153 – 10.0.20.153	10.0.20.153
27	10.0.20.154/32	10.0.20.154 – 10.0.20.154	10.0.20.154
28	10.0.20.155/32	10.0.20.155 – 10.0.20.155	10.0.20.155
29	10.0.20.156/32	10.0.20.156 – 10.0.20.156	10.0.20.156
30	10.0.20.157/32	10.0.20.157 – 10.0.20.157	10.0.20.157
31	10.0.20.158/32	10.0.20.158 – 10.0.20.158	10.0.20.158
32	10.0.20.159/32	10.0.20.159 – 10.0.20.159	10.0.20.159
33	10.0.20.160/32	10.0.20.160 – 10.0.20.160	10.0.20.160
34	10.0.20.161/32	10.0.20.161 – 10.0.20.161	10.0.20.161
35	10.0.20.162/32	10.0.20.162 – 10.0.20.162	10.0.20.162
36	10.0.20.163/32	10.0.20.163 – 10.0.20.163	10.0.20.163
37	10.0.20.164/32	10.0.20.164 – 10.0.20.164	10.0.20.164
38	10.0.20.165/32	10.0.20.165 – 10.0.20.165	10.0.20.165
39	10.0.20.166/32	10.0.20.166 – 10.0.20.166	10.0.20.166
40	10.0.20.167/32	10.0.20.167 – 10.0.20.167	10.0.20.167
41	10.0.20.168/32	10.0.20.168 – 10.0.20.168	10.0.20.168
42	10.0.20.169/32	10.0.20.169 – 10.0.20.169	10.0.20.169
43	10.0.20.170/32	10.0.20.170 – 10.0.20.170	10.0.20.170
44	10.0.20.171/32	10.0.20.171 – 10.0.20.171	10.0.20.171
45	10.0.20.172/32	10.0.20.172 – 10.0.20.172	10.0.20.172
46	10.0.20.173/32	10.0.20.173 – 10.0.20.173	10.0.20.173
47	10.0.20.174/32	10.0.20.174 – 10.0.20.174	10.0.20.174
48	10.0.20.175/32	10.0.20.175 – 10.0.20.175	10.0.20.175
49	10.0.20.176/32	10.0.20.176 – 10.0.20.176	10.0.20.176
50	10.0.20.177/32	10.0.20.177 – 10.0.20.177	10.0.20.177
51	10.0.20.178/32	10.0.20.178 – 10.0.20.178	10.0.20.178
52	10.0.20.179/32	10.0.20.179 – 10.0.20.179	10.0.20.179
53	10.0.20.180/32	10.0.20.180 – 10.0.20.180	10.0.20.180
54	10.0.20.181/32	10.0.20.181 – 10.0.20.181	10.0.20.181
55	10.0.20.182/32	10.0.20.182 – 10.0.20.182	10.0.20.182
56	10.0.20.183/32	10.0.20.183 – 10.0.20.183	10.0.20.183
57	10.0.20.184/32	10.0.20.184 – 10.0.20.184	10.0.20.184
58	10.0.20.185/32	10.0.20.185 – 10.0.20.185	10.0.20.185
59	10.0.20.186/32	10.0.20.186 – 10.0.20.186	10.0.20.186
60	10.0.20.187/32	10.0.20.187 – 10.0.20.187	10.0.20.187
61	10.0.20.188/32	10.0.20.188 – 10.0.20.188	10.0.20.188
62	10.0.20.189/32	10.0.20.189 – 10.0.20.189	10.0.20.189
63	10.0.20.190/32	10.0.20.190 – 10.0.20.190	10.0.20.190
64	10.0.20.191/32	10.0.20.191 – 10.0.20.191	10.0.20.191
65	10.0.20.192/32	10.0.20.192 – 10.0.20.192	10.0.20.192
66	10.0.20.193/32	10.0.20.193 – 10.0.20.193	10.0.20.193
67	10.0.20.194/32	10.0.20.194 – 10.0.20.194	10.0.20.194
68	10.0.20.195/32	10.0.20.195 – 10.0.20.195	10.0.20.195
69	10.0.20.196/32	10.0.20.196 – 10.0.20.196	10.0.20.196
70	10.0.20.197/32	10.0.20.197 – 10.0.20.197	10.0.20.197
71	10.0.20.198/32	10.0.20.198 – 10.0.20.198	10.0.20.198
72	10.0.20.199/32	10.0.20.199 – 10.0.20.199	10.0.20.199
73	10.0.20.200/32	10.0.20.200 – 10.0.20.200	10.0.20.200
74	10.0.20.201/32	10.0.20.201 – 10.0.20.201	10.0.20.201
75	10.0.20.202/32	10.0.20.202 – 10.0.20.202	10.0.20.202
76	10.0.20.203/32	10.0.20.203 – 10.0.20.203	10.0.20.203
77	10.0.20.204/32	10.0.20.204 – 10.0.20.204	10.0.20.204
78	10.0.20.205/32	10.0.20.205 – 10.0.20.205	10.0.20.205
79	10.0.20.206/32	10.0.20.206 – 10.0.20.206	10.0.20.206
80	10.0.20.207/32	10.0.20.207 – 10.0.20.207	10.0.20.207
81	10.0.20.208/32	10.0.20.208 – 10.0.20.208	10.0.20.208
82	10.0.20.209/32	10.0.20.209 – 10.0.20.209	10.0.20.209
83	10.0.20.210/32	10.0.20.210 – 10.0.20.210	10.0.20.210
84	10.0.20.211/32	10.0.20.211 – 10.0.20.211	10.0.20.211
85	10.0.20.212/32	10.0.20.212 – 10.0.20.212	10.0.20.212
86	10.0.20.213/32	10.0.20.213 – 10.0.20.213	10.0.20.213
87	10.0.20.214/32	10.0.20.214 – 10.0.20.214	10.0.20.214
88	10.0.20.215/32	10.0.20.215 – 10.0.20.215	10.0.20.215
89	10.0.20.216/32	10.0.20.216 – 10.0.20.216	10.0.20.216
90	10.0.20.217/32	10.0.20.217 – 10.0.20.217	10.0.20.217
91	10.0.20.218/32	10.0.20.218 – 10.0.20.218	10.0.20.218
92	10.0.20.219/32	10.0.20.219 – 10.0.20.219	10.0.20.219
93	10.0.20.220/32	10.0.20.220 – 10.0.20.220	10.0.20.220
94	10.0.20.221/32	10.0.20.221 – 10.0.20.221	10.0.20.221
95	10.0.20.222/32	10.0.20.222 – 10.0.20.222	10.0.20.222
96	10.0.20.223/32	10.0.20.223 – 10.0.20.223	10.0.20.223
97	10.0.20.224/32	10.0.20.224 – 10.0.20.224	10.0.20.224
98	10.0.20.225/32	10.0.20.225 – 10.0.20.225	10.0.20.225
99	10.0.20.226/32	10.0.20.226 – 10.0.20.226	10.0.20.226
100	10.0.20.227/32	10.0.20.227 – 10.0.20.227	10.0.20.227
101	10.0.20.228/32	10.0.20.228 – 10.0.20.228	10.0.20.228
102	10.0.20.229/32	10.0.20.229 – 10.0.20.229	10.0.20.229
103	10.0.20.230/32	10.0.20.230 – 10.0.20.230	10.0.20.230
104	10.0.20.231/32	10.0.20.231 – 10.0.20.231	10.0.20.231
105	10.0.20.232/32	10.0.20.232 – 10.0.20.232	10.0.20.232
106	10.0.20.233/32	10.0.20.233 – 10.0.20.233	10.0.20.233
107	10.0.20.234/32	10.0.20.234 – 10.0.20.234	10.0.20.234
108	10.0.20.235/32	10.0.20.235 – 10.0.20.235	10.0.20.235
109	10.0.20.236/32	10.0.20.236 – 10.0.20.236	10.0.20.236
110	10.0.20.237/32	10.0.20.237 – 10.0.20.237	10.0.20.237
111	10.0.20.238/32	10.0.20.238 – 10.0.20.238	10.0.20.238
112	10.0.20.239/32	10.0.20.239 – 10.0.20.239	10.0.20.239
113	10.0.20.240/32	10.0.20.240 – 10.0.20.240	10.0.20.240
114	10.0.20.241/32	10.0.20.241 – 10.0.20.241	10.0.20.241
115	10.0.20.242/32	10.0.20.242 – 10.0.20.242	10.0.20.242
116	10.0.20.243/32	10.0.20.243 – 10.0.20.243	10.0.20.243
117	10.0.20.244/32	10.0.20.244 – 10.0.20.244	10.0.20.244
118	10.0.20.245/32	10.0.20.245 – 10.0.20.245	10.0.20.245
119	10.0.20.246/32	10.0.20.246 – 10.0.20.246	10.0.20.246
120	10.0.20.247/32	10.0.20.247 – 10.0.20.247	10.0.20.247
121	10.0.20.248/32	10.0.20.248 – 10.0.20.248	10.0.20.248
122	10.0.20.249/32	10.0.20.249 – 10.0.20.249	10.0.20.249
123	10.0.20.250/32	10.0.20.250 – 10.0.20.250	10.0.20.250
124	10.0.20.251/32	10.0.20.251 – 10.0.20.251	10.0.20.251
125	10.0.20.252/32	10.0.20.252 – 10.0.20.252	10.0.20.252
126	10.0.20.253/32	10.0.20.253 – 10.0.20.253	10.0.20.253
127	10.0.20.254/32	10.0.20.254 – 10.0.20.254	10.0.20.254
128	10.0.20.255/32	10.0.20.255 – 10.0.20.255	10.0.20.255

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 →