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)10.2.66.0/23

network10.2.66.0/23

broadcast10.2.67.255

first host10.2.66.1

last host10.2.67.254

subnet mask255.255.254.0

wildcard0.0.1.255

addresses512

usable hosts510

classA

ipcalc 10.2.66.0/23

address00001010.00000010.01000010.00000000

subnet mask11111111.11111111.11111110.00000000

network00001010.00000010.01000010.00000000

broadcast00001010.00000010.01000011.11111111

green = network part, grey = host part

hex0x0a024200

decimal167920128

reverse dns0.66.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:4200

/23 split into /30 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.66.0/30	10.2.66.1 – 10.2.66.2	10.2.66.3
2	10.2.66.4/30	10.2.66.5 – 10.2.66.6	10.2.66.7
3	10.2.66.8/30	10.2.66.9 – 10.2.66.10	10.2.66.11
4	10.2.66.12/30	10.2.66.13 – 10.2.66.14	10.2.66.15
5	10.2.66.16/30	10.2.66.17 – 10.2.66.18	10.2.66.19
6	10.2.66.20/30	10.2.66.21 – 10.2.66.22	10.2.66.23
7	10.2.66.24/30	10.2.66.25 – 10.2.66.26	10.2.66.27
8	10.2.66.28/30	10.2.66.29 – 10.2.66.30	10.2.66.31
9	10.2.66.32/30	10.2.66.33 – 10.2.66.34	10.2.66.35
10	10.2.66.36/30	10.2.66.37 – 10.2.66.38	10.2.66.39
11	10.2.66.40/30	10.2.66.41 – 10.2.66.42	10.2.66.43
12	10.2.66.44/30	10.2.66.45 – 10.2.66.46	10.2.66.47
13	10.2.66.48/30	10.2.66.49 – 10.2.66.50	10.2.66.51
14	10.2.66.52/30	10.2.66.53 – 10.2.66.54	10.2.66.55
15	10.2.66.56/30	10.2.66.57 – 10.2.66.58	10.2.66.59
16	10.2.66.60/30	10.2.66.61 – 10.2.66.62	10.2.66.63
17	10.2.66.64/30	10.2.66.65 – 10.2.66.66	10.2.66.67
18	10.2.66.68/30	10.2.66.69 – 10.2.66.70	10.2.66.71
19	10.2.66.72/30	10.2.66.73 – 10.2.66.74	10.2.66.75
20	10.2.66.76/30	10.2.66.77 – 10.2.66.78	10.2.66.79
21	10.2.66.80/30	10.2.66.81 – 10.2.66.82	10.2.66.83
22	10.2.66.84/30	10.2.66.85 – 10.2.66.86	10.2.66.87
23	10.2.66.88/30	10.2.66.89 – 10.2.66.90	10.2.66.91
24	10.2.66.92/30	10.2.66.93 – 10.2.66.94	10.2.66.95
25	10.2.66.96/30	10.2.66.97 – 10.2.66.98	10.2.66.99
26	10.2.66.100/30	10.2.66.101 – 10.2.66.102	10.2.66.103
27	10.2.66.104/30	10.2.66.105 – 10.2.66.106	10.2.66.107
28	10.2.66.108/30	10.2.66.109 – 10.2.66.110	10.2.66.111
29	10.2.66.112/30	10.2.66.113 – 10.2.66.114	10.2.66.115
30	10.2.66.116/30	10.2.66.117 – 10.2.66.118	10.2.66.119
31	10.2.66.120/30	10.2.66.121 – 10.2.66.122	10.2.66.123
32	10.2.66.124/30	10.2.66.125 – 10.2.66.126	10.2.66.127
33	10.2.66.128/30	10.2.66.129 – 10.2.66.130	10.2.66.131
34	10.2.66.132/30	10.2.66.133 – 10.2.66.134	10.2.66.135
35	10.2.66.136/30	10.2.66.137 – 10.2.66.138	10.2.66.139
36	10.2.66.140/30	10.2.66.141 – 10.2.66.142	10.2.66.143
37	10.2.66.144/30	10.2.66.145 – 10.2.66.146	10.2.66.147
38	10.2.66.148/30	10.2.66.149 – 10.2.66.150	10.2.66.151
39	10.2.66.152/30	10.2.66.153 – 10.2.66.154	10.2.66.155
40	10.2.66.156/30	10.2.66.157 – 10.2.66.158	10.2.66.159
41	10.2.66.160/30	10.2.66.161 – 10.2.66.162	10.2.66.163
42	10.2.66.164/30	10.2.66.165 – 10.2.66.166	10.2.66.167
43	10.2.66.168/30	10.2.66.169 – 10.2.66.170	10.2.66.171
44	10.2.66.172/30	10.2.66.173 – 10.2.66.174	10.2.66.175
45	10.2.66.176/30	10.2.66.177 – 10.2.66.178	10.2.66.179
46	10.2.66.180/30	10.2.66.181 – 10.2.66.182	10.2.66.183
47	10.2.66.184/30	10.2.66.185 – 10.2.66.186	10.2.66.187
48	10.2.66.188/30	10.2.66.189 – 10.2.66.190	10.2.66.191
49	10.2.66.192/30	10.2.66.193 – 10.2.66.194	10.2.66.195
50	10.2.66.196/30	10.2.66.197 – 10.2.66.198	10.2.66.199
51	10.2.66.200/30	10.2.66.201 – 10.2.66.202	10.2.66.203
52	10.2.66.204/30	10.2.66.205 – 10.2.66.206	10.2.66.207
53	10.2.66.208/30	10.2.66.209 – 10.2.66.210	10.2.66.211
54	10.2.66.212/30	10.2.66.213 – 10.2.66.214	10.2.66.215
55	10.2.66.216/30	10.2.66.217 – 10.2.66.218	10.2.66.219
56	10.2.66.220/30	10.2.66.221 – 10.2.66.222	10.2.66.223
57	10.2.66.224/30	10.2.66.225 – 10.2.66.226	10.2.66.227
58	10.2.66.228/30	10.2.66.229 – 10.2.66.230	10.2.66.231
59	10.2.66.232/30	10.2.66.233 – 10.2.66.234	10.2.66.235
60	10.2.66.236/30	10.2.66.237 – 10.2.66.238	10.2.66.239
61	10.2.66.240/30	10.2.66.241 – 10.2.66.242	10.2.66.243
62	10.2.66.244/30	10.2.66.245 – 10.2.66.246	10.2.66.247
63	10.2.66.248/30	10.2.66.249 – 10.2.66.250	10.2.66.251
64	10.2.66.252/30	10.2.66.253 – 10.2.66.254	10.2.66.255
65	10.2.67.0/30	10.2.67.1 – 10.2.67.2	10.2.67.3
66	10.2.67.4/30	10.2.67.5 – 10.2.67.6	10.2.67.7
67	10.2.67.8/30	10.2.67.9 – 10.2.67.10	10.2.67.11
68	10.2.67.12/30	10.2.67.13 – 10.2.67.14	10.2.67.15
69	10.2.67.16/30	10.2.67.17 – 10.2.67.18	10.2.67.19
70	10.2.67.20/30	10.2.67.21 – 10.2.67.22	10.2.67.23
71	10.2.67.24/30	10.2.67.25 – 10.2.67.26	10.2.67.27
72	10.2.67.28/30	10.2.67.29 – 10.2.67.30	10.2.67.31
73	10.2.67.32/30	10.2.67.33 – 10.2.67.34	10.2.67.35
74	10.2.67.36/30	10.2.67.37 – 10.2.67.38	10.2.67.39
75	10.2.67.40/30	10.2.67.41 – 10.2.67.42	10.2.67.43
76	10.2.67.44/30	10.2.67.45 – 10.2.67.46	10.2.67.47
77	10.2.67.48/30	10.2.67.49 – 10.2.67.50	10.2.67.51
78	10.2.67.52/30	10.2.67.53 – 10.2.67.54	10.2.67.55
79	10.2.67.56/30	10.2.67.57 – 10.2.67.58	10.2.67.59
80	10.2.67.60/30	10.2.67.61 – 10.2.67.62	10.2.67.63
81	10.2.67.64/30	10.2.67.65 – 10.2.67.66	10.2.67.67
82	10.2.67.68/30	10.2.67.69 – 10.2.67.70	10.2.67.71
83	10.2.67.72/30	10.2.67.73 – 10.2.67.74	10.2.67.75
84	10.2.67.76/30	10.2.67.77 – 10.2.67.78	10.2.67.79
85	10.2.67.80/30	10.2.67.81 – 10.2.67.82	10.2.67.83
86	10.2.67.84/30	10.2.67.85 – 10.2.67.86	10.2.67.87
87	10.2.67.88/30	10.2.67.89 – 10.2.67.90	10.2.67.91
88	10.2.67.92/30	10.2.67.93 – 10.2.67.94	10.2.67.95
89	10.2.67.96/30	10.2.67.97 – 10.2.67.98	10.2.67.99
90	10.2.67.100/30	10.2.67.101 – 10.2.67.102	10.2.67.103
91	10.2.67.104/30	10.2.67.105 – 10.2.67.106	10.2.67.107
92	10.2.67.108/30	10.2.67.109 – 10.2.67.110	10.2.67.111
93	10.2.67.112/30	10.2.67.113 – 10.2.67.114	10.2.67.115
94	10.2.67.116/30	10.2.67.117 – 10.2.67.118	10.2.67.119
95	10.2.67.120/30	10.2.67.121 – 10.2.67.122	10.2.67.123
96	10.2.67.124/30	10.2.67.125 – 10.2.67.126	10.2.67.127
97	10.2.67.128/30	10.2.67.129 – 10.2.67.130	10.2.67.131
98	10.2.67.132/30	10.2.67.133 – 10.2.67.134	10.2.67.135
99	10.2.67.136/30	10.2.67.137 – 10.2.67.138	10.2.67.139
100	10.2.67.140/30	10.2.67.141 – 10.2.67.142	10.2.67.143
101	10.2.67.144/30	10.2.67.145 – 10.2.67.146	10.2.67.147
102	10.2.67.148/30	10.2.67.149 – 10.2.67.150	10.2.67.151
103	10.2.67.152/30	10.2.67.153 – 10.2.67.154	10.2.67.155
104	10.2.67.156/30	10.2.67.157 – 10.2.67.158	10.2.67.159
105	10.2.67.160/30	10.2.67.161 – 10.2.67.162	10.2.67.163
106	10.2.67.164/30	10.2.67.165 – 10.2.67.166	10.2.67.167
107	10.2.67.168/30	10.2.67.169 – 10.2.67.170	10.2.67.171
108	10.2.67.172/30	10.2.67.173 – 10.2.67.174	10.2.67.175
109	10.2.67.176/30	10.2.67.177 – 10.2.67.178	10.2.67.179
110	10.2.67.180/30	10.2.67.181 – 10.2.67.182	10.2.67.183
111	10.2.67.184/30	10.2.67.185 – 10.2.67.186	10.2.67.187
112	10.2.67.188/30	10.2.67.189 – 10.2.67.190	10.2.67.191
113	10.2.67.192/30	10.2.67.193 – 10.2.67.194	10.2.67.195
114	10.2.67.196/30	10.2.67.197 – 10.2.67.198	10.2.67.199
115	10.2.67.200/30	10.2.67.201 – 10.2.67.202	10.2.67.203
116	10.2.67.204/30	10.2.67.205 – 10.2.67.206	10.2.67.207
117	10.2.67.208/30	10.2.67.209 – 10.2.67.210	10.2.67.211
118	10.2.67.212/30	10.2.67.213 – 10.2.67.214	10.2.67.215
119	10.2.67.216/30	10.2.67.217 – 10.2.67.218	10.2.67.219
120	10.2.67.220/30	10.2.67.221 – 10.2.67.222	10.2.67.223
121	10.2.67.224/30	10.2.67.225 – 10.2.67.226	10.2.67.227
122	10.2.67.228/30	10.2.67.229 – 10.2.67.230	10.2.67.231
123	10.2.67.232/30	10.2.67.233 – 10.2.67.234	10.2.67.235
124	10.2.67.236/30	10.2.67.237 – 10.2.67.238	10.2.67.239
125	10.2.67.240/30	10.2.67.241 – 10.2.67.242	10.2.67.243
126	10.2.67.244/30	10.2.67.245 – 10.2.67.246	10.2.67.247
127	10.2.67.248/30	10.2.67.249 – 10.2.67.250	10.2.67.251
128	10.2.67.252/30	10.2.67.253 – 10.2.67.254	10.2.67.255

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 /23
/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	1
/24	255.255.255.0	256	254	2 split →
/25	255.255.255.128	128	126	4 split →
/26	255.255.255.192	64	62	8 split →
/27	255.255.255.224	32	30	16 split →
/28	255.255.255.240	16	14	32 split →
/29	255.255.255.248	8	6	64 split →
/30	255.255.255.252	4	2	128 split →
/31	255.255.255.254	2	2	256 split →
/32	255.255.255.255	1	1	512 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 →