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)10.0.81.0/24

network10.0.81.0/24

broadcast10.0.81.255

first host10.0.81.1

last host10.0.81.254

subnet mask255.255.255.0

wildcard0.0.0.255

addresses256

usable hosts254

classA

ipcalc 10.0.81.0/24

address00001010.00000000.01010001.00000000

subnet mask11111111.11111111.11111111.00000000

network00001010.00000000.01010001.00000000

broadcast00001010.00000000.01010001.11111111

green = network part, grey = host part

hex0x0a005100

decimal167792896

reverse dns0.81.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:5100

/24 split into /31 · 128 subnets

close ×

#	network	host range	broadcast
1	10.0.81.0/31	10.0.81.0 – 10.0.81.1	10.0.81.1
2	10.0.81.2/31	10.0.81.2 – 10.0.81.3	10.0.81.3
3	10.0.81.4/31	10.0.81.4 – 10.0.81.5	10.0.81.5
4	10.0.81.6/31	10.0.81.6 – 10.0.81.7	10.0.81.7
5	10.0.81.8/31	10.0.81.8 – 10.0.81.9	10.0.81.9
6	10.0.81.10/31	10.0.81.10 – 10.0.81.11	10.0.81.11
7	10.0.81.12/31	10.0.81.12 – 10.0.81.13	10.0.81.13
8	10.0.81.14/31	10.0.81.14 – 10.0.81.15	10.0.81.15
9	10.0.81.16/31	10.0.81.16 – 10.0.81.17	10.0.81.17
10	10.0.81.18/31	10.0.81.18 – 10.0.81.19	10.0.81.19
11	10.0.81.20/31	10.0.81.20 – 10.0.81.21	10.0.81.21
12	10.0.81.22/31	10.0.81.22 – 10.0.81.23	10.0.81.23
13	10.0.81.24/31	10.0.81.24 – 10.0.81.25	10.0.81.25
14	10.0.81.26/31	10.0.81.26 – 10.0.81.27	10.0.81.27
15	10.0.81.28/31	10.0.81.28 – 10.0.81.29	10.0.81.29
16	10.0.81.30/31	10.0.81.30 – 10.0.81.31	10.0.81.31
17	10.0.81.32/31	10.0.81.32 – 10.0.81.33	10.0.81.33
18	10.0.81.34/31	10.0.81.34 – 10.0.81.35	10.0.81.35
19	10.0.81.36/31	10.0.81.36 – 10.0.81.37	10.0.81.37
20	10.0.81.38/31	10.0.81.38 – 10.0.81.39	10.0.81.39
21	10.0.81.40/31	10.0.81.40 – 10.0.81.41	10.0.81.41
22	10.0.81.42/31	10.0.81.42 – 10.0.81.43	10.0.81.43
23	10.0.81.44/31	10.0.81.44 – 10.0.81.45	10.0.81.45
24	10.0.81.46/31	10.0.81.46 – 10.0.81.47	10.0.81.47
25	10.0.81.48/31	10.0.81.48 – 10.0.81.49	10.0.81.49
26	10.0.81.50/31	10.0.81.50 – 10.0.81.51	10.0.81.51
27	10.0.81.52/31	10.0.81.52 – 10.0.81.53	10.0.81.53
28	10.0.81.54/31	10.0.81.54 – 10.0.81.55	10.0.81.55
29	10.0.81.56/31	10.0.81.56 – 10.0.81.57	10.0.81.57
30	10.0.81.58/31	10.0.81.58 – 10.0.81.59	10.0.81.59
31	10.0.81.60/31	10.0.81.60 – 10.0.81.61	10.0.81.61
32	10.0.81.62/31	10.0.81.62 – 10.0.81.63	10.0.81.63
33	10.0.81.64/31	10.0.81.64 – 10.0.81.65	10.0.81.65
34	10.0.81.66/31	10.0.81.66 – 10.0.81.67	10.0.81.67
35	10.0.81.68/31	10.0.81.68 – 10.0.81.69	10.0.81.69
36	10.0.81.70/31	10.0.81.70 – 10.0.81.71	10.0.81.71
37	10.0.81.72/31	10.0.81.72 – 10.0.81.73	10.0.81.73
38	10.0.81.74/31	10.0.81.74 – 10.0.81.75	10.0.81.75
39	10.0.81.76/31	10.0.81.76 – 10.0.81.77	10.0.81.77
40	10.0.81.78/31	10.0.81.78 – 10.0.81.79	10.0.81.79
41	10.0.81.80/31	10.0.81.80 – 10.0.81.81	10.0.81.81
42	10.0.81.82/31	10.0.81.82 – 10.0.81.83	10.0.81.83
43	10.0.81.84/31	10.0.81.84 – 10.0.81.85	10.0.81.85
44	10.0.81.86/31	10.0.81.86 – 10.0.81.87	10.0.81.87
45	10.0.81.88/31	10.0.81.88 – 10.0.81.89	10.0.81.89
46	10.0.81.90/31	10.0.81.90 – 10.0.81.91	10.0.81.91
47	10.0.81.92/31	10.0.81.92 – 10.0.81.93	10.0.81.93
48	10.0.81.94/31	10.0.81.94 – 10.0.81.95	10.0.81.95
49	10.0.81.96/31	10.0.81.96 – 10.0.81.97	10.0.81.97
50	10.0.81.98/31	10.0.81.98 – 10.0.81.99	10.0.81.99
51	10.0.81.100/31	10.0.81.100 – 10.0.81.101	10.0.81.101
52	10.0.81.102/31	10.0.81.102 – 10.0.81.103	10.0.81.103
53	10.0.81.104/31	10.0.81.104 – 10.0.81.105	10.0.81.105
54	10.0.81.106/31	10.0.81.106 – 10.0.81.107	10.0.81.107
55	10.0.81.108/31	10.0.81.108 – 10.0.81.109	10.0.81.109
56	10.0.81.110/31	10.0.81.110 – 10.0.81.111	10.0.81.111
57	10.0.81.112/31	10.0.81.112 – 10.0.81.113	10.0.81.113
58	10.0.81.114/31	10.0.81.114 – 10.0.81.115	10.0.81.115
59	10.0.81.116/31	10.0.81.116 – 10.0.81.117	10.0.81.117
60	10.0.81.118/31	10.0.81.118 – 10.0.81.119	10.0.81.119
61	10.0.81.120/31	10.0.81.120 – 10.0.81.121	10.0.81.121
62	10.0.81.122/31	10.0.81.122 – 10.0.81.123	10.0.81.123
63	10.0.81.124/31	10.0.81.124 – 10.0.81.125	10.0.81.125
64	10.0.81.126/31	10.0.81.126 – 10.0.81.127	10.0.81.127
65	10.0.81.128/31	10.0.81.128 – 10.0.81.129	10.0.81.129
66	10.0.81.130/31	10.0.81.130 – 10.0.81.131	10.0.81.131
67	10.0.81.132/31	10.0.81.132 – 10.0.81.133	10.0.81.133
68	10.0.81.134/31	10.0.81.134 – 10.0.81.135	10.0.81.135
69	10.0.81.136/31	10.0.81.136 – 10.0.81.137	10.0.81.137
70	10.0.81.138/31	10.0.81.138 – 10.0.81.139	10.0.81.139
71	10.0.81.140/31	10.0.81.140 – 10.0.81.141	10.0.81.141
72	10.0.81.142/31	10.0.81.142 – 10.0.81.143	10.0.81.143
73	10.0.81.144/31	10.0.81.144 – 10.0.81.145	10.0.81.145
74	10.0.81.146/31	10.0.81.146 – 10.0.81.147	10.0.81.147
75	10.0.81.148/31	10.0.81.148 – 10.0.81.149	10.0.81.149
76	10.0.81.150/31	10.0.81.150 – 10.0.81.151	10.0.81.151
77	10.0.81.152/31	10.0.81.152 – 10.0.81.153	10.0.81.153
78	10.0.81.154/31	10.0.81.154 – 10.0.81.155	10.0.81.155
79	10.0.81.156/31	10.0.81.156 – 10.0.81.157	10.0.81.157
80	10.0.81.158/31	10.0.81.158 – 10.0.81.159	10.0.81.159
81	10.0.81.160/31	10.0.81.160 – 10.0.81.161	10.0.81.161
82	10.0.81.162/31	10.0.81.162 – 10.0.81.163	10.0.81.163
83	10.0.81.164/31	10.0.81.164 – 10.0.81.165	10.0.81.165
84	10.0.81.166/31	10.0.81.166 – 10.0.81.167	10.0.81.167
85	10.0.81.168/31	10.0.81.168 – 10.0.81.169	10.0.81.169
86	10.0.81.170/31	10.0.81.170 – 10.0.81.171	10.0.81.171
87	10.0.81.172/31	10.0.81.172 – 10.0.81.173	10.0.81.173
88	10.0.81.174/31	10.0.81.174 – 10.0.81.175	10.0.81.175
89	10.0.81.176/31	10.0.81.176 – 10.0.81.177	10.0.81.177
90	10.0.81.178/31	10.0.81.178 – 10.0.81.179	10.0.81.179
91	10.0.81.180/31	10.0.81.180 – 10.0.81.181	10.0.81.181
92	10.0.81.182/31	10.0.81.182 – 10.0.81.183	10.0.81.183
93	10.0.81.184/31	10.0.81.184 – 10.0.81.185	10.0.81.185
94	10.0.81.186/31	10.0.81.186 – 10.0.81.187	10.0.81.187
95	10.0.81.188/31	10.0.81.188 – 10.0.81.189	10.0.81.189
96	10.0.81.190/31	10.0.81.190 – 10.0.81.191	10.0.81.191
97	10.0.81.192/31	10.0.81.192 – 10.0.81.193	10.0.81.193
98	10.0.81.194/31	10.0.81.194 – 10.0.81.195	10.0.81.195
99	10.0.81.196/31	10.0.81.196 – 10.0.81.197	10.0.81.197
100	10.0.81.198/31	10.0.81.198 – 10.0.81.199	10.0.81.199
101	10.0.81.200/31	10.0.81.200 – 10.0.81.201	10.0.81.201
102	10.0.81.202/31	10.0.81.202 – 10.0.81.203	10.0.81.203
103	10.0.81.204/31	10.0.81.204 – 10.0.81.205	10.0.81.205
104	10.0.81.206/31	10.0.81.206 – 10.0.81.207	10.0.81.207
105	10.0.81.208/31	10.0.81.208 – 10.0.81.209	10.0.81.209
106	10.0.81.210/31	10.0.81.210 – 10.0.81.211	10.0.81.211
107	10.0.81.212/31	10.0.81.212 – 10.0.81.213	10.0.81.213
108	10.0.81.214/31	10.0.81.214 – 10.0.81.215	10.0.81.215
109	10.0.81.216/31	10.0.81.216 – 10.0.81.217	10.0.81.217
110	10.0.81.218/31	10.0.81.218 – 10.0.81.219	10.0.81.219
111	10.0.81.220/31	10.0.81.220 – 10.0.81.221	10.0.81.221
112	10.0.81.222/31	10.0.81.222 – 10.0.81.223	10.0.81.223
113	10.0.81.224/31	10.0.81.224 – 10.0.81.225	10.0.81.225
114	10.0.81.226/31	10.0.81.226 – 10.0.81.227	10.0.81.227
115	10.0.81.228/31	10.0.81.228 – 10.0.81.229	10.0.81.229
116	10.0.81.230/31	10.0.81.230 – 10.0.81.231	10.0.81.231
117	10.0.81.232/31	10.0.81.232 – 10.0.81.233	10.0.81.233
118	10.0.81.234/31	10.0.81.234 – 10.0.81.235	10.0.81.235
119	10.0.81.236/31	10.0.81.236 – 10.0.81.237	10.0.81.237
120	10.0.81.238/31	10.0.81.238 – 10.0.81.239	10.0.81.239
121	10.0.81.240/31	10.0.81.240 – 10.0.81.241	10.0.81.241
122	10.0.81.242/31	10.0.81.242 – 10.0.81.243	10.0.81.243
123	10.0.81.244/31	10.0.81.244 – 10.0.81.245	10.0.81.245
124	10.0.81.246/31	10.0.81.246 – 10.0.81.247	10.0.81.247
125	10.0.81.248/31	10.0.81.248 – 10.0.81.249	10.0.81.249
126	10.0.81.250/31	10.0.81.250 – 10.0.81.251	10.0.81.251
127	10.0.81.252/31	10.0.81.252 – 10.0.81.253	10.0.81.253
128	10.0.81.254/31	10.0.81.254 – 10.0.81.255	10.0.81.255

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 →