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)10.2.20.0/24

network10.2.20.0/24

broadcast10.2.20.255

first host10.2.20.1

last host10.2.20.254

subnet mask255.255.255.0

wildcard0.0.0.255

addresses256

usable hosts254

classA

ipcalc 10.2.20.0/24

address00001010.00000010.00010100.00000000

subnet mask11111111.11111111.11111111.00000000

network00001010.00000010.00010100.00000000

broadcast00001010.00000010.00010100.11111111

green = network part, grey = host part

hex0x0a021400

decimal167908352

reverse dns0.20.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:1400

/24 split into /31 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.20.0/31	10.2.20.0 – 10.2.20.1	10.2.20.1
2	10.2.20.2/31	10.2.20.2 – 10.2.20.3	10.2.20.3
3	10.2.20.4/31	10.2.20.4 – 10.2.20.5	10.2.20.5
4	10.2.20.6/31	10.2.20.6 – 10.2.20.7	10.2.20.7
5	10.2.20.8/31	10.2.20.8 – 10.2.20.9	10.2.20.9
6	10.2.20.10/31	10.2.20.10 – 10.2.20.11	10.2.20.11
7	10.2.20.12/31	10.2.20.12 – 10.2.20.13	10.2.20.13
8	10.2.20.14/31	10.2.20.14 – 10.2.20.15	10.2.20.15
9	10.2.20.16/31	10.2.20.16 – 10.2.20.17	10.2.20.17
10	10.2.20.18/31	10.2.20.18 – 10.2.20.19	10.2.20.19
11	10.2.20.20/31	10.2.20.20 – 10.2.20.21	10.2.20.21
12	10.2.20.22/31	10.2.20.22 – 10.2.20.23	10.2.20.23
13	10.2.20.24/31	10.2.20.24 – 10.2.20.25	10.2.20.25
14	10.2.20.26/31	10.2.20.26 – 10.2.20.27	10.2.20.27
15	10.2.20.28/31	10.2.20.28 – 10.2.20.29	10.2.20.29
16	10.2.20.30/31	10.2.20.30 – 10.2.20.31	10.2.20.31
17	10.2.20.32/31	10.2.20.32 – 10.2.20.33	10.2.20.33
18	10.2.20.34/31	10.2.20.34 – 10.2.20.35	10.2.20.35
19	10.2.20.36/31	10.2.20.36 – 10.2.20.37	10.2.20.37
20	10.2.20.38/31	10.2.20.38 – 10.2.20.39	10.2.20.39
21	10.2.20.40/31	10.2.20.40 – 10.2.20.41	10.2.20.41
22	10.2.20.42/31	10.2.20.42 – 10.2.20.43	10.2.20.43
23	10.2.20.44/31	10.2.20.44 – 10.2.20.45	10.2.20.45
24	10.2.20.46/31	10.2.20.46 – 10.2.20.47	10.2.20.47
25	10.2.20.48/31	10.2.20.48 – 10.2.20.49	10.2.20.49
26	10.2.20.50/31	10.2.20.50 – 10.2.20.51	10.2.20.51
27	10.2.20.52/31	10.2.20.52 – 10.2.20.53	10.2.20.53
28	10.2.20.54/31	10.2.20.54 – 10.2.20.55	10.2.20.55
29	10.2.20.56/31	10.2.20.56 – 10.2.20.57	10.2.20.57
30	10.2.20.58/31	10.2.20.58 – 10.2.20.59	10.2.20.59
31	10.2.20.60/31	10.2.20.60 – 10.2.20.61	10.2.20.61
32	10.2.20.62/31	10.2.20.62 – 10.2.20.63	10.2.20.63
33	10.2.20.64/31	10.2.20.64 – 10.2.20.65	10.2.20.65
34	10.2.20.66/31	10.2.20.66 – 10.2.20.67	10.2.20.67
35	10.2.20.68/31	10.2.20.68 – 10.2.20.69	10.2.20.69
36	10.2.20.70/31	10.2.20.70 – 10.2.20.71	10.2.20.71
37	10.2.20.72/31	10.2.20.72 – 10.2.20.73	10.2.20.73
38	10.2.20.74/31	10.2.20.74 – 10.2.20.75	10.2.20.75
39	10.2.20.76/31	10.2.20.76 – 10.2.20.77	10.2.20.77
40	10.2.20.78/31	10.2.20.78 – 10.2.20.79	10.2.20.79
41	10.2.20.80/31	10.2.20.80 – 10.2.20.81	10.2.20.81
42	10.2.20.82/31	10.2.20.82 – 10.2.20.83	10.2.20.83
43	10.2.20.84/31	10.2.20.84 – 10.2.20.85	10.2.20.85
44	10.2.20.86/31	10.2.20.86 – 10.2.20.87	10.2.20.87
45	10.2.20.88/31	10.2.20.88 – 10.2.20.89	10.2.20.89
46	10.2.20.90/31	10.2.20.90 – 10.2.20.91	10.2.20.91
47	10.2.20.92/31	10.2.20.92 – 10.2.20.93	10.2.20.93
48	10.2.20.94/31	10.2.20.94 – 10.2.20.95	10.2.20.95
49	10.2.20.96/31	10.2.20.96 – 10.2.20.97	10.2.20.97
50	10.2.20.98/31	10.2.20.98 – 10.2.20.99	10.2.20.99
51	10.2.20.100/31	10.2.20.100 – 10.2.20.101	10.2.20.101
52	10.2.20.102/31	10.2.20.102 – 10.2.20.103	10.2.20.103
53	10.2.20.104/31	10.2.20.104 – 10.2.20.105	10.2.20.105
54	10.2.20.106/31	10.2.20.106 – 10.2.20.107	10.2.20.107
55	10.2.20.108/31	10.2.20.108 – 10.2.20.109	10.2.20.109
56	10.2.20.110/31	10.2.20.110 – 10.2.20.111	10.2.20.111
57	10.2.20.112/31	10.2.20.112 – 10.2.20.113	10.2.20.113
58	10.2.20.114/31	10.2.20.114 – 10.2.20.115	10.2.20.115
59	10.2.20.116/31	10.2.20.116 – 10.2.20.117	10.2.20.117
60	10.2.20.118/31	10.2.20.118 – 10.2.20.119	10.2.20.119
61	10.2.20.120/31	10.2.20.120 – 10.2.20.121	10.2.20.121
62	10.2.20.122/31	10.2.20.122 – 10.2.20.123	10.2.20.123
63	10.2.20.124/31	10.2.20.124 – 10.2.20.125	10.2.20.125
64	10.2.20.126/31	10.2.20.126 – 10.2.20.127	10.2.20.127
65	10.2.20.128/31	10.2.20.128 – 10.2.20.129	10.2.20.129
66	10.2.20.130/31	10.2.20.130 – 10.2.20.131	10.2.20.131
67	10.2.20.132/31	10.2.20.132 – 10.2.20.133	10.2.20.133
68	10.2.20.134/31	10.2.20.134 – 10.2.20.135	10.2.20.135
69	10.2.20.136/31	10.2.20.136 – 10.2.20.137	10.2.20.137
70	10.2.20.138/31	10.2.20.138 – 10.2.20.139	10.2.20.139
71	10.2.20.140/31	10.2.20.140 – 10.2.20.141	10.2.20.141
72	10.2.20.142/31	10.2.20.142 – 10.2.20.143	10.2.20.143
73	10.2.20.144/31	10.2.20.144 – 10.2.20.145	10.2.20.145
74	10.2.20.146/31	10.2.20.146 – 10.2.20.147	10.2.20.147
75	10.2.20.148/31	10.2.20.148 – 10.2.20.149	10.2.20.149
76	10.2.20.150/31	10.2.20.150 – 10.2.20.151	10.2.20.151
77	10.2.20.152/31	10.2.20.152 – 10.2.20.153	10.2.20.153
78	10.2.20.154/31	10.2.20.154 – 10.2.20.155	10.2.20.155
79	10.2.20.156/31	10.2.20.156 – 10.2.20.157	10.2.20.157
80	10.2.20.158/31	10.2.20.158 – 10.2.20.159	10.2.20.159
81	10.2.20.160/31	10.2.20.160 – 10.2.20.161	10.2.20.161
82	10.2.20.162/31	10.2.20.162 – 10.2.20.163	10.2.20.163
83	10.2.20.164/31	10.2.20.164 – 10.2.20.165	10.2.20.165
84	10.2.20.166/31	10.2.20.166 – 10.2.20.167	10.2.20.167
85	10.2.20.168/31	10.2.20.168 – 10.2.20.169	10.2.20.169
86	10.2.20.170/31	10.2.20.170 – 10.2.20.171	10.2.20.171
87	10.2.20.172/31	10.2.20.172 – 10.2.20.173	10.2.20.173
88	10.2.20.174/31	10.2.20.174 – 10.2.20.175	10.2.20.175
89	10.2.20.176/31	10.2.20.176 – 10.2.20.177	10.2.20.177
90	10.2.20.178/31	10.2.20.178 – 10.2.20.179	10.2.20.179
91	10.2.20.180/31	10.2.20.180 – 10.2.20.181	10.2.20.181
92	10.2.20.182/31	10.2.20.182 – 10.2.20.183	10.2.20.183
93	10.2.20.184/31	10.2.20.184 – 10.2.20.185	10.2.20.185
94	10.2.20.186/31	10.2.20.186 – 10.2.20.187	10.2.20.187
95	10.2.20.188/31	10.2.20.188 – 10.2.20.189	10.2.20.189
96	10.2.20.190/31	10.2.20.190 – 10.2.20.191	10.2.20.191
97	10.2.20.192/31	10.2.20.192 – 10.2.20.193	10.2.20.193
98	10.2.20.194/31	10.2.20.194 – 10.2.20.195	10.2.20.195
99	10.2.20.196/31	10.2.20.196 – 10.2.20.197	10.2.20.197
100	10.2.20.198/31	10.2.20.198 – 10.2.20.199	10.2.20.199
101	10.2.20.200/31	10.2.20.200 – 10.2.20.201	10.2.20.201
102	10.2.20.202/31	10.2.20.202 – 10.2.20.203	10.2.20.203
103	10.2.20.204/31	10.2.20.204 – 10.2.20.205	10.2.20.205
104	10.2.20.206/31	10.2.20.206 – 10.2.20.207	10.2.20.207
105	10.2.20.208/31	10.2.20.208 – 10.2.20.209	10.2.20.209
106	10.2.20.210/31	10.2.20.210 – 10.2.20.211	10.2.20.211
107	10.2.20.212/31	10.2.20.212 – 10.2.20.213	10.2.20.213
108	10.2.20.214/31	10.2.20.214 – 10.2.20.215	10.2.20.215
109	10.2.20.216/31	10.2.20.216 – 10.2.20.217	10.2.20.217
110	10.2.20.218/31	10.2.20.218 – 10.2.20.219	10.2.20.219
111	10.2.20.220/31	10.2.20.220 – 10.2.20.221	10.2.20.221
112	10.2.20.222/31	10.2.20.222 – 10.2.20.223	10.2.20.223
113	10.2.20.224/31	10.2.20.224 – 10.2.20.225	10.2.20.225
114	10.2.20.226/31	10.2.20.226 – 10.2.20.227	10.2.20.227
115	10.2.20.228/31	10.2.20.228 – 10.2.20.229	10.2.20.229
116	10.2.20.230/31	10.2.20.230 – 10.2.20.231	10.2.20.231
117	10.2.20.232/31	10.2.20.232 – 10.2.20.233	10.2.20.233
118	10.2.20.234/31	10.2.20.234 – 10.2.20.235	10.2.20.235
119	10.2.20.236/31	10.2.20.236 – 10.2.20.237	10.2.20.237
120	10.2.20.238/31	10.2.20.238 – 10.2.20.239	10.2.20.239
121	10.2.20.240/31	10.2.20.240 – 10.2.20.241	10.2.20.241
122	10.2.20.242/31	10.2.20.242 – 10.2.20.243	10.2.20.243
123	10.2.20.244/31	10.2.20.244 – 10.2.20.245	10.2.20.245
124	10.2.20.246/31	10.2.20.246 – 10.2.20.247	10.2.20.247
125	10.2.20.248/31	10.2.20.248 – 10.2.20.249	10.2.20.249
126	10.2.20.250/31	10.2.20.250 – 10.2.20.251	10.2.20.251
127	10.2.20.252/31	10.2.20.252 – 10.2.20.253	10.2.20.253
128	10.2.20.254/31	10.2.20.254 – 10.2.20.255	10.2.20.255

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 /24
/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	1
/25	255.255.255.128	128	126	2 split →
/26	255.255.255.192	64	62	4 split →
/27	255.255.255.224	32	30	8 split →
/28	255.255.255.240	16	14	16 split →
/29	255.255.255.248	8	6	32 split →
/30	255.255.255.252	4	2	64 split →
/31	255.255.255.254	2	2	128 split →
/32	255.255.255.255	1	1	256 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 →