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)10.0.205.0/24

network10.0.205.0/24

broadcast10.0.205.255

first host10.0.205.1

last host10.0.205.254

subnet mask255.255.255.0

wildcard0.0.0.255

addresses256

usable hosts254

classA

ipcalc 10.0.205.0/24

address00001010.00000000.11001101.00000000

subnet mask11111111.11111111.11111111.00000000

network00001010.00000000.11001101.00000000

broadcast00001010.00000000.11001101.11111111

green = network part, grey = host part

hex0x0a00cd00

decimal167824640

reverse dns0.205.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:cd00

/24 split into /31 · 128 subnets

close ×

#	network	host range	broadcast
1	10.0.205.0/31	10.0.205.0 – 10.0.205.1	10.0.205.1
2	10.0.205.2/31	10.0.205.2 – 10.0.205.3	10.0.205.3
3	10.0.205.4/31	10.0.205.4 – 10.0.205.5	10.0.205.5
4	10.0.205.6/31	10.0.205.6 – 10.0.205.7	10.0.205.7
5	10.0.205.8/31	10.0.205.8 – 10.0.205.9	10.0.205.9
6	10.0.205.10/31	10.0.205.10 – 10.0.205.11	10.0.205.11
7	10.0.205.12/31	10.0.205.12 – 10.0.205.13	10.0.205.13
8	10.0.205.14/31	10.0.205.14 – 10.0.205.15	10.0.205.15
9	10.0.205.16/31	10.0.205.16 – 10.0.205.17	10.0.205.17
10	10.0.205.18/31	10.0.205.18 – 10.0.205.19	10.0.205.19
11	10.0.205.20/31	10.0.205.20 – 10.0.205.21	10.0.205.21
12	10.0.205.22/31	10.0.205.22 – 10.0.205.23	10.0.205.23
13	10.0.205.24/31	10.0.205.24 – 10.0.205.25	10.0.205.25
14	10.0.205.26/31	10.0.205.26 – 10.0.205.27	10.0.205.27
15	10.0.205.28/31	10.0.205.28 – 10.0.205.29	10.0.205.29
16	10.0.205.30/31	10.0.205.30 – 10.0.205.31	10.0.205.31
17	10.0.205.32/31	10.0.205.32 – 10.0.205.33	10.0.205.33
18	10.0.205.34/31	10.0.205.34 – 10.0.205.35	10.0.205.35
19	10.0.205.36/31	10.0.205.36 – 10.0.205.37	10.0.205.37
20	10.0.205.38/31	10.0.205.38 – 10.0.205.39	10.0.205.39
21	10.0.205.40/31	10.0.205.40 – 10.0.205.41	10.0.205.41
22	10.0.205.42/31	10.0.205.42 – 10.0.205.43	10.0.205.43
23	10.0.205.44/31	10.0.205.44 – 10.0.205.45	10.0.205.45
24	10.0.205.46/31	10.0.205.46 – 10.0.205.47	10.0.205.47
25	10.0.205.48/31	10.0.205.48 – 10.0.205.49	10.0.205.49
26	10.0.205.50/31	10.0.205.50 – 10.0.205.51	10.0.205.51
27	10.0.205.52/31	10.0.205.52 – 10.0.205.53	10.0.205.53
28	10.0.205.54/31	10.0.205.54 – 10.0.205.55	10.0.205.55
29	10.0.205.56/31	10.0.205.56 – 10.0.205.57	10.0.205.57
30	10.0.205.58/31	10.0.205.58 – 10.0.205.59	10.0.205.59
31	10.0.205.60/31	10.0.205.60 – 10.0.205.61	10.0.205.61
32	10.0.205.62/31	10.0.205.62 – 10.0.205.63	10.0.205.63
33	10.0.205.64/31	10.0.205.64 – 10.0.205.65	10.0.205.65
34	10.0.205.66/31	10.0.205.66 – 10.0.205.67	10.0.205.67
35	10.0.205.68/31	10.0.205.68 – 10.0.205.69	10.0.205.69
36	10.0.205.70/31	10.0.205.70 – 10.0.205.71	10.0.205.71
37	10.0.205.72/31	10.0.205.72 – 10.0.205.73	10.0.205.73
38	10.0.205.74/31	10.0.205.74 – 10.0.205.75	10.0.205.75
39	10.0.205.76/31	10.0.205.76 – 10.0.205.77	10.0.205.77
40	10.0.205.78/31	10.0.205.78 – 10.0.205.79	10.0.205.79
41	10.0.205.80/31	10.0.205.80 – 10.0.205.81	10.0.205.81
42	10.0.205.82/31	10.0.205.82 – 10.0.205.83	10.0.205.83
43	10.0.205.84/31	10.0.205.84 – 10.0.205.85	10.0.205.85
44	10.0.205.86/31	10.0.205.86 – 10.0.205.87	10.0.205.87
45	10.0.205.88/31	10.0.205.88 – 10.0.205.89	10.0.205.89
46	10.0.205.90/31	10.0.205.90 – 10.0.205.91	10.0.205.91
47	10.0.205.92/31	10.0.205.92 – 10.0.205.93	10.0.205.93
48	10.0.205.94/31	10.0.205.94 – 10.0.205.95	10.0.205.95
49	10.0.205.96/31	10.0.205.96 – 10.0.205.97	10.0.205.97
50	10.0.205.98/31	10.0.205.98 – 10.0.205.99	10.0.205.99
51	10.0.205.100/31	10.0.205.100 – 10.0.205.101	10.0.205.101
52	10.0.205.102/31	10.0.205.102 – 10.0.205.103	10.0.205.103
53	10.0.205.104/31	10.0.205.104 – 10.0.205.105	10.0.205.105
54	10.0.205.106/31	10.0.205.106 – 10.0.205.107	10.0.205.107
55	10.0.205.108/31	10.0.205.108 – 10.0.205.109	10.0.205.109
56	10.0.205.110/31	10.0.205.110 – 10.0.205.111	10.0.205.111
57	10.0.205.112/31	10.0.205.112 – 10.0.205.113	10.0.205.113
58	10.0.205.114/31	10.0.205.114 – 10.0.205.115	10.0.205.115
59	10.0.205.116/31	10.0.205.116 – 10.0.205.117	10.0.205.117
60	10.0.205.118/31	10.0.205.118 – 10.0.205.119	10.0.205.119
61	10.0.205.120/31	10.0.205.120 – 10.0.205.121	10.0.205.121
62	10.0.205.122/31	10.0.205.122 – 10.0.205.123	10.0.205.123
63	10.0.205.124/31	10.0.205.124 – 10.0.205.125	10.0.205.125
64	10.0.205.126/31	10.0.205.126 – 10.0.205.127	10.0.205.127
65	10.0.205.128/31	10.0.205.128 – 10.0.205.129	10.0.205.129
66	10.0.205.130/31	10.0.205.130 – 10.0.205.131	10.0.205.131
67	10.0.205.132/31	10.0.205.132 – 10.0.205.133	10.0.205.133
68	10.0.205.134/31	10.0.205.134 – 10.0.205.135	10.0.205.135
69	10.0.205.136/31	10.0.205.136 – 10.0.205.137	10.0.205.137
70	10.0.205.138/31	10.0.205.138 – 10.0.205.139	10.0.205.139
71	10.0.205.140/31	10.0.205.140 – 10.0.205.141	10.0.205.141
72	10.0.205.142/31	10.0.205.142 – 10.0.205.143	10.0.205.143
73	10.0.205.144/31	10.0.205.144 – 10.0.205.145	10.0.205.145
74	10.0.205.146/31	10.0.205.146 – 10.0.205.147	10.0.205.147
75	10.0.205.148/31	10.0.205.148 – 10.0.205.149	10.0.205.149
76	10.0.205.150/31	10.0.205.150 – 10.0.205.151	10.0.205.151
77	10.0.205.152/31	10.0.205.152 – 10.0.205.153	10.0.205.153
78	10.0.205.154/31	10.0.205.154 – 10.0.205.155	10.0.205.155
79	10.0.205.156/31	10.0.205.156 – 10.0.205.157	10.0.205.157
80	10.0.205.158/31	10.0.205.158 – 10.0.205.159	10.0.205.159
81	10.0.205.160/31	10.0.205.160 – 10.0.205.161	10.0.205.161
82	10.0.205.162/31	10.0.205.162 – 10.0.205.163	10.0.205.163
83	10.0.205.164/31	10.0.205.164 – 10.0.205.165	10.0.205.165
84	10.0.205.166/31	10.0.205.166 – 10.0.205.167	10.0.205.167
85	10.0.205.168/31	10.0.205.168 – 10.0.205.169	10.0.205.169
86	10.0.205.170/31	10.0.205.170 – 10.0.205.171	10.0.205.171
87	10.0.205.172/31	10.0.205.172 – 10.0.205.173	10.0.205.173
88	10.0.205.174/31	10.0.205.174 – 10.0.205.175	10.0.205.175
89	10.0.205.176/31	10.0.205.176 – 10.0.205.177	10.0.205.177
90	10.0.205.178/31	10.0.205.178 – 10.0.205.179	10.0.205.179
91	10.0.205.180/31	10.0.205.180 – 10.0.205.181	10.0.205.181
92	10.0.205.182/31	10.0.205.182 – 10.0.205.183	10.0.205.183
93	10.0.205.184/31	10.0.205.184 – 10.0.205.185	10.0.205.185
94	10.0.205.186/31	10.0.205.186 – 10.0.205.187	10.0.205.187
95	10.0.205.188/31	10.0.205.188 – 10.0.205.189	10.0.205.189
96	10.0.205.190/31	10.0.205.190 – 10.0.205.191	10.0.205.191
97	10.0.205.192/31	10.0.205.192 – 10.0.205.193	10.0.205.193
98	10.0.205.194/31	10.0.205.194 – 10.0.205.195	10.0.205.195
99	10.0.205.196/31	10.0.205.196 – 10.0.205.197	10.0.205.197
100	10.0.205.198/31	10.0.205.198 – 10.0.205.199	10.0.205.199
101	10.0.205.200/31	10.0.205.200 – 10.0.205.201	10.0.205.201
102	10.0.205.202/31	10.0.205.202 – 10.0.205.203	10.0.205.203
103	10.0.205.204/31	10.0.205.204 – 10.0.205.205	10.0.205.205
104	10.0.205.206/31	10.0.205.206 – 10.0.205.207	10.0.205.207
105	10.0.205.208/31	10.0.205.208 – 10.0.205.209	10.0.205.209
106	10.0.205.210/31	10.0.205.210 – 10.0.205.211	10.0.205.211
107	10.0.205.212/31	10.0.205.212 – 10.0.205.213	10.0.205.213
108	10.0.205.214/31	10.0.205.214 – 10.0.205.215	10.0.205.215
109	10.0.205.216/31	10.0.205.216 – 10.0.205.217	10.0.205.217
110	10.0.205.218/31	10.0.205.218 – 10.0.205.219	10.0.205.219
111	10.0.205.220/31	10.0.205.220 – 10.0.205.221	10.0.205.221
112	10.0.205.222/31	10.0.205.222 – 10.0.205.223	10.0.205.223
113	10.0.205.224/31	10.0.205.224 – 10.0.205.225	10.0.205.225
114	10.0.205.226/31	10.0.205.226 – 10.0.205.227	10.0.205.227
115	10.0.205.228/31	10.0.205.228 – 10.0.205.229	10.0.205.229
116	10.0.205.230/31	10.0.205.230 – 10.0.205.231	10.0.205.231
117	10.0.205.232/31	10.0.205.232 – 10.0.205.233	10.0.205.233
118	10.0.205.234/31	10.0.205.234 – 10.0.205.235	10.0.205.235
119	10.0.205.236/31	10.0.205.236 – 10.0.205.237	10.0.205.237
120	10.0.205.238/31	10.0.205.238 – 10.0.205.239	10.0.205.239
121	10.0.205.240/31	10.0.205.240 – 10.0.205.241	10.0.205.241
122	10.0.205.242/31	10.0.205.242 – 10.0.205.243	10.0.205.243
123	10.0.205.244/31	10.0.205.244 – 10.0.205.245	10.0.205.245
124	10.0.205.246/31	10.0.205.246 – 10.0.205.247	10.0.205.247
125	10.0.205.248/31	10.0.205.248 – 10.0.205.249	10.0.205.249
126	10.0.205.250/31	10.0.205.250 – 10.0.205.251	10.0.205.251
127	10.0.205.252/31	10.0.205.252 – 10.0.205.253	10.0.205.253
128	10.0.205.254/31	10.0.205.254 – 10.0.205.255	10.0.205.255

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 →