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)10.2.128.0/23

network10.2.128.0/23

broadcast10.2.129.255

first host10.2.128.1

last host10.2.129.254

subnet mask255.255.254.0

wildcard0.0.1.255

addresses512

usable hosts510

classA

ipcalc 10.2.128.0/23

address00001010.00000010.10000000.00000000

subnet mask11111111.11111111.11111110.00000000

network00001010.00000010.10000000.00000000

broadcast00001010.00000010.10000001.11111111

green = network part, grey = host part

hex0x0a028000

decimal167936000

reverse dns0.128.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:8000

/23 split into /30 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.128.0/30	10.2.128.1 – 10.2.128.2	10.2.128.3
2	10.2.128.4/30	10.2.128.5 – 10.2.128.6	10.2.128.7
3	10.2.128.8/30	10.2.128.9 – 10.2.128.10	10.2.128.11
4	10.2.128.12/30	10.2.128.13 – 10.2.128.14	10.2.128.15
5	10.2.128.16/30	10.2.128.17 – 10.2.128.18	10.2.128.19
6	10.2.128.20/30	10.2.128.21 – 10.2.128.22	10.2.128.23
7	10.2.128.24/30	10.2.128.25 – 10.2.128.26	10.2.128.27
8	10.2.128.28/30	10.2.128.29 – 10.2.128.30	10.2.128.31
9	10.2.128.32/30	10.2.128.33 – 10.2.128.34	10.2.128.35
10	10.2.128.36/30	10.2.128.37 – 10.2.128.38	10.2.128.39
11	10.2.128.40/30	10.2.128.41 – 10.2.128.42	10.2.128.43
12	10.2.128.44/30	10.2.128.45 – 10.2.128.46	10.2.128.47
13	10.2.128.48/30	10.2.128.49 – 10.2.128.50	10.2.128.51
14	10.2.128.52/30	10.2.128.53 – 10.2.128.54	10.2.128.55
15	10.2.128.56/30	10.2.128.57 – 10.2.128.58	10.2.128.59
16	10.2.128.60/30	10.2.128.61 – 10.2.128.62	10.2.128.63
17	10.2.128.64/30	10.2.128.65 – 10.2.128.66	10.2.128.67
18	10.2.128.68/30	10.2.128.69 – 10.2.128.70	10.2.128.71
19	10.2.128.72/30	10.2.128.73 – 10.2.128.74	10.2.128.75
20	10.2.128.76/30	10.2.128.77 – 10.2.128.78	10.2.128.79
21	10.2.128.80/30	10.2.128.81 – 10.2.128.82	10.2.128.83
22	10.2.128.84/30	10.2.128.85 – 10.2.128.86	10.2.128.87
23	10.2.128.88/30	10.2.128.89 – 10.2.128.90	10.2.128.91
24	10.2.128.92/30	10.2.128.93 – 10.2.128.94	10.2.128.95
25	10.2.128.96/30	10.2.128.97 – 10.2.128.98	10.2.128.99
26	10.2.128.100/30	10.2.128.101 – 10.2.128.102	10.2.128.103
27	10.2.128.104/30	10.2.128.105 – 10.2.128.106	10.2.128.107
28	10.2.128.108/30	10.2.128.109 – 10.2.128.110	10.2.128.111
29	10.2.128.112/30	10.2.128.113 – 10.2.128.114	10.2.128.115
30	10.2.128.116/30	10.2.128.117 – 10.2.128.118	10.2.128.119
31	10.2.128.120/30	10.2.128.121 – 10.2.128.122	10.2.128.123
32	10.2.128.124/30	10.2.128.125 – 10.2.128.126	10.2.128.127
33	10.2.128.128/30	10.2.128.129 – 10.2.128.130	10.2.128.131
34	10.2.128.132/30	10.2.128.133 – 10.2.128.134	10.2.128.135
35	10.2.128.136/30	10.2.128.137 – 10.2.128.138	10.2.128.139
36	10.2.128.140/30	10.2.128.141 – 10.2.128.142	10.2.128.143
37	10.2.128.144/30	10.2.128.145 – 10.2.128.146	10.2.128.147
38	10.2.128.148/30	10.2.128.149 – 10.2.128.150	10.2.128.151
39	10.2.128.152/30	10.2.128.153 – 10.2.128.154	10.2.128.155
40	10.2.128.156/30	10.2.128.157 – 10.2.128.158	10.2.128.159
41	10.2.128.160/30	10.2.128.161 – 10.2.128.162	10.2.128.163
42	10.2.128.164/30	10.2.128.165 – 10.2.128.166	10.2.128.167
43	10.2.128.168/30	10.2.128.169 – 10.2.128.170	10.2.128.171
44	10.2.128.172/30	10.2.128.173 – 10.2.128.174	10.2.128.175
45	10.2.128.176/30	10.2.128.177 – 10.2.128.178	10.2.128.179
46	10.2.128.180/30	10.2.128.181 – 10.2.128.182	10.2.128.183
47	10.2.128.184/30	10.2.128.185 – 10.2.128.186	10.2.128.187
48	10.2.128.188/30	10.2.128.189 – 10.2.128.190	10.2.128.191
49	10.2.128.192/30	10.2.128.193 – 10.2.128.194	10.2.128.195
50	10.2.128.196/30	10.2.128.197 – 10.2.128.198	10.2.128.199
51	10.2.128.200/30	10.2.128.201 – 10.2.128.202	10.2.128.203
52	10.2.128.204/30	10.2.128.205 – 10.2.128.206	10.2.128.207
53	10.2.128.208/30	10.2.128.209 – 10.2.128.210	10.2.128.211
54	10.2.128.212/30	10.2.128.213 – 10.2.128.214	10.2.128.215
55	10.2.128.216/30	10.2.128.217 – 10.2.128.218	10.2.128.219
56	10.2.128.220/30	10.2.128.221 – 10.2.128.222	10.2.128.223
57	10.2.128.224/30	10.2.128.225 – 10.2.128.226	10.2.128.227
58	10.2.128.228/30	10.2.128.229 – 10.2.128.230	10.2.128.231
59	10.2.128.232/30	10.2.128.233 – 10.2.128.234	10.2.128.235
60	10.2.128.236/30	10.2.128.237 – 10.2.128.238	10.2.128.239
61	10.2.128.240/30	10.2.128.241 – 10.2.128.242	10.2.128.243
62	10.2.128.244/30	10.2.128.245 – 10.2.128.246	10.2.128.247
63	10.2.128.248/30	10.2.128.249 – 10.2.128.250	10.2.128.251
64	10.2.128.252/30	10.2.128.253 – 10.2.128.254	10.2.128.255
65	10.2.129.0/30	10.2.129.1 – 10.2.129.2	10.2.129.3
66	10.2.129.4/30	10.2.129.5 – 10.2.129.6	10.2.129.7
67	10.2.129.8/30	10.2.129.9 – 10.2.129.10	10.2.129.11
68	10.2.129.12/30	10.2.129.13 – 10.2.129.14	10.2.129.15
69	10.2.129.16/30	10.2.129.17 – 10.2.129.18	10.2.129.19
70	10.2.129.20/30	10.2.129.21 – 10.2.129.22	10.2.129.23
71	10.2.129.24/30	10.2.129.25 – 10.2.129.26	10.2.129.27
72	10.2.129.28/30	10.2.129.29 – 10.2.129.30	10.2.129.31
73	10.2.129.32/30	10.2.129.33 – 10.2.129.34	10.2.129.35
74	10.2.129.36/30	10.2.129.37 – 10.2.129.38	10.2.129.39
75	10.2.129.40/30	10.2.129.41 – 10.2.129.42	10.2.129.43
76	10.2.129.44/30	10.2.129.45 – 10.2.129.46	10.2.129.47
77	10.2.129.48/30	10.2.129.49 – 10.2.129.50	10.2.129.51
78	10.2.129.52/30	10.2.129.53 – 10.2.129.54	10.2.129.55
79	10.2.129.56/30	10.2.129.57 – 10.2.129.58	10.2.129.59
80	10.2.129.60/30	10.2.129.61 – 10.2.129.62	10.2.129.63
81	10.2.129.64/30	10.2.129.65 – 10.2.129.66	10.2.129.67
82	10.2.129.68/30	10.2.129.69 – 10.2.129.70	10.2.129.71
83	10.2.129.72/30	10.2.129.73 – 10.2.129.74	10.2.129.75
84	10.2.129.76/30	10.2.129.77 – 10.2.129.78	10.2.129.79
85	10.2.129.80/30	10.2.129.81 – 10.2.129.82	10.2.129.83
86	10.2.129.84/30	10.2.129.85 – 10.2.129.86	10.2.129.87
87	10.2.129.88/30	10.2.129.89 – 10.2.129.90	10.2.129.91
88	10.2.129.92/30	10.2.129.93 – 10.2.129.94	10.2.129.95
89	10.2.129.96/30	10.2.129.97 – 10.2.129.98	10.2.129.99
90	10.2.129.100/30	10.2.129.101 – 10.2.129.102	10.2.129.103
91	10.2.129.104/30	10.2.129.105 – 10.2.129.106	10.2.129.107
92	10.2.129.108/30	10.2.129.109 – 10.2.129.110	10.2.129.111
93	10.2.129.112/30	10.2.129.113 – 10.2.129.114	10.2.129.115
94	10.2.129.116/30	10.2.129.117 – 10.2.129.118	10.2.129.119
95	10.2.129.120/30	10.2.129.121 – 10.2.129.122	10.2.129.123
96	10.2.129.124/30	10.2.129.125 – 10.2.129.126	10.2.129.127
97	10.2.129.128/30	10.2.129.129 – 10.2.129.130	10.2.129.131
98	10.2.129.132/30	10.2.129.133 – 10.2.129.134	10.2.129.135
99	10.2.129.136/30	10.2.129.137 – 10.2.129.138	10.2.129.139
100	10.2.129.140/30	10.2.129.141 – 10.2.129.142	10.2.129.143
101	10.2.129.144/30	10.2.129.145 – 10.2.129.146	10.2.129.147
102	10.2.129.148/30	10.2.129.149 – 10.2.129.150	10.2.129.151
103	10.2.129.152/30	10.2.129.153 – 10.2.129.154	10.2.129.155
104	10.2.129.156/30	10.2.129.157 – 10.2.129.158	10.2.129.159
105	10.2.129.160/30	10.2.129.161 – 10.2.129.162	10.2.129.163
106	10.2.129.164/30	10.2.129.165 – 10.2.129.166	10.2.129.167
107	10.2.129.168/30	10.2.129.169 – 10.2.129.170	10.2.129.171
108	10.2.129.172/30	10.2.129.173 – 10.2.129.174	10.2.129.175
109	10.2.129.176/30	10.2.129.177 – 10.2.129.178	10.2.129.179
110	10.2.129.180/30	10.2.129.181 – 10.2.129.182	10.2.129.183
111	10.2.129.184/30	10.2.129.185 – 10.2.129.186	10.2.129.187
112	10.2.129.188/30	10.2.129.189 – 10.2.129.190	10.2.129.191
113	10.2.129.192/30	10.2.129.193 – 10.2.129.194	10.2.129.195
114	10.2.129.196/30	10.2.129.197 – 10.2.129.198	10.2.129.199
115	10.2.129.200/30	10.2.129.201 – 10.2.129.202	10.2.129.203
116	10.2.129.204/30	10.2.129.205 – 10.2.129.206	10.2.129.207
117	10.2.129.208/30	10.2.129.209 – 10.2.129.210	10.2.129.211
118	10.2.129.212/30	10.2.129.213 – 10.2.129.214	10.2.129.215
119	10.2.129.216/30	10.2.129.217 – 10.2.129.218	10.2.129.219
120	10.2.129.220/30	10.2.129.221 – 10.2.129.222	10.2.129.223
121	10.2.129.224/30	10.2.129.225 – 10.2.129.226	10.2.129.227
122	10.2.129.228/30	10.2.129.229 – 10.2.129.230	10.2.129.231
123	10.2.129.232/30	10.2.129.233 – 10.2.129.234	10.2.129.235
124	10.2.129.236/30	10.2.129.237 – 10.2.129.238	10.2.129.239
125	10.2.129.240/30	10.2.129.241 – 10.2.129.242	10.2.129.243
126	10.2.129.244/30	10.2.129.245 – 10.2.129.246	10.2.129.247
127	10.2.129.248/30	10.2.129.249 – 10.2.129.250	10.2.129.251
128	10.2.129.252/30	10.2.129.253 – 10.2.129.254	10.2.129.255

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 →