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)10.3.184.0/21

network10.3.184.0/21

broadcast10.3.191.255

first host10.3.184.1

last host10.3.191.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.3.184.0/21

address00001010.00000011.10111000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000011.10111000.00000000

broadcast00001010.00000011.10111111.11111111

green = network part, grey = host part

hex0x0a03b800

decimal168015872

reverse dns0.184.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:b800

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.3.184.0/28	10.3.184.1 – 10.3.184.14	10.3.184.15
2	10.3.184.16/28	10.3.184.17 – 10.3.184.30	10.3.184.31
3	10.3.184.32/28	10.3.184.33 – 10.3.184.46	10.3.184.47
4	10.3.184.48/28	10.3.184.49 – 10.3.184.62	10.3.184.63
5	10.3.184.64/28	10.3.184.65 – 10.3.184.78	10.3.184.79
6	10.3.184.80/28	10.3.184.81 – 10.3.184.94	10.3.184.95
7	10.3.184.96/28	10.3.184.97 – 10.3.184.110	10.3.184.111
8	10.3.184.112/28	10.3.184.113 – 10.3.184.126	10.3.184.127
9	10.3.184.128/28	10.3.184.129 – 10.3.184.142	10.3.184.143
10	10.3.184.144/28	10.3.184.145 – 10.3.184.158	10.3.184.159
11	10.3.184.160/28	10.3.184.161 – 10.3.184.174	10.3.184.175
12	10.3.184.176/28	10.3.184.177 – 10.3.184.190	10.3.184.191
13	10.3.184.192/28	10.3.184.193 – 10.3.184.206	10.3.184.207
14	10.3.184.208/28	10.3.184.209 – 10.3.184.222	10.3.184.223
15	10.3.184.224/28	10.3.184.225 – 10.3.184.238	10.3.184.239
16	10.3.184.240/28	10.3.184.241 – 10.3.184.254	10.3.184.255
17	10.3.185.0/28	10.3.185.1 – 10.3.185.14	10.3.185.15
18	10.3.185.16/28	10.3.185.17 – 10.3.185.30	10.3.185.31
19	10.3.185.32/28	10.3.185.33 – 10.3.185.46	10.3.185.47
20	10.3.185.48/28	10.3.185.49 – 10.3.185.62	10.3.185.63
21	10.3.185.64/28	10.3.185.65 – 10.3.185.78	10.3.185.79
22	10.3.185.80/28	10.3.185.81 – 10.3.185.94	10.3.185.95
23	10.3.185.96/28	10.3.185.97 – 10.3.185.110	10.3.185.111
24	10.3.185.112/28	10.3.185.113 – 10.3.185.126	10.3.185.127
25	10.3.185.128/28	10.3.185.129 – 10.3.185.142	10.3.185.143
26	10.3.185.144/28	10.3.185.145 – 10.3.185.158	10.3.185.159
27	10.3.185.160/28	10.3.185.161 – 10.3.185.174	10.3.185.175
28	10.3.185.176/28	10.3.185.177 – 10.3.185.190	10.3.185.191
29	10.3.185.192/28	10.3.185.193 – 10.3.185.206	10.3.185.207
30	10.3.185.208/28	10.3.185.209 – 10.3.185.222	10.3.185.223
31	10.3.185.224/28	10.3.185.225 – 10.3.185.238	10.3.185.239
32	10.3.185.240/28	10.3.185.241 – 10.3.185.254	10.3.185.255
33	10.3.186.0/28	10.3.186.1 – 10.3.186.14	10.3.186.15
34	10.3.186.16/28	10.3.186.17 – 10.3.186.30	10.3.186.31
35	10.3.186.32/28	10.3.186.33 – 10.3.186.46	10.3.186.47
36	10.3.186.48/28	10.3.186.49 – 10.3.186.62	10.3.186.63
37	10.3.186.64/28	10.3.186.65 – 10.3.186.78	10.3.186.79
38	10.3.186.80/28	10.3.186.81 – 10.3.186.94	10.3.186.95
39	10.3.186.96/28	10.3.186.97 – 10.3.186.110	10.3.186.111
40	10.3.186.112/28	10.3.186.113 – 10.3.186.126	10.3.186.127
41	10.3.186.128/28	10.3.186.129 – 10.3.186.142	10.3.186.143
42	10.3.186.144/28	10.3.186.145 – 10.3.186.158	10.3.186.159
43	10.3.186.160/28	10.3.186.161 – 10.3.186.174	10.3.186.175
44	10.3.186.176/28	10.3.186.177 – 10.3.186.190	10.3.186.191
45	10.3.186.192/28	10.3.186.193 – 10.3.186.206	10.3.186.207
46	10.3.186.208/28	10.3.186.209 – 10.3.186.222	10.3.186.223
47	10.3.186.224/28	10.3.186.225 – 10.3.186.238	10.3.186.239
48	10.3.186.240/28	10.3.186.241 – 10.3.186.254	10.3.186.255
49	10.3.187.0/28	10.3.187.1 – 10.3.187.14	10.3.187.15
50	10.3.187.16/28	10.3.187.17 – 10.3.187.30	10.3.187.31
51	10.3.187.32/28	10.3.187.33 – 10.3.187.46	10.3.187.47
52	10.3.187.48/28	10.3.187.49 – 10.3.187.62	10.3.187.63
53	10.3.187.64/28	10.3.187.65 – 10.3.187.78	10.3.187.79
54	10.3.187.80/28	10.3.187.81 – 10.3.187.94	10.3.187.95
55	10.3.187.96/28	10.3.187.97 – 10.3.187.110	10.3.187.111
56	10.3.187.112/28	10.3.187.113 – 10.3.187.126	10.3.187.127
57	10.3.187.128/28	10.3.187.129 – 10.3.187.142	10.3.187.143
58	10.3.187.144/28	10.3.187.145 – 10.3.187.158	10.3.187.159
59	10.3.187.160/28	10.3.187.161 – 10.3.187.174	10.3.187.175
60	10.3.187.176/28	10.3.187.177 – 10.3.187.190	10.3.187.191
61	10.3.187.192/28	10.3.187.193 – 10.3.187.206	10.3.187.207
62	10.3.187.208/28	10.3.187.209 – 10.3.187.222	10.3.187.223
63	10.3.187.224/28	10.3.187.225 – 10.3.187.238	10.3.187.239
64	10.3.187.240/28	10.3.187.241 – 10.3.187.254	10.3.187.255
65	10.3.188.0/28	10.3.188.1 – 10.3.188.14	10.3.188.15
66	10.3.188.16/28	10.3.188.17 – 10.3.188.30	10.3.188.31
67	10.3.188.32/28	10.3.188.33 – 10.3.188.46	10.3.188.47
68	10.3.188.48/28	10.3.188.49 – 10.3.188.62	10.3.188.63
69	10.3.188.64/28	10.3.188.65 – 10.3.188.78	10.3.188.79
70	10.3.188.80/28	10.3.188.81 – 10.3.188.94	10.3.188.95
71	10.3.188.96/28	10.3.188.97 – 10.3.188.110	10.3.188.111
72	10.3.188.112/28	10.3.188.113 – 10.3.188.126	10.3.188.127
73	10.3.188.128/28	10.3.188.129 – 10.3.188.142	10.3.188.143
74	10.3.188.144/28	10.3.188.145 – 10.3.188.158	10.3.188.159
75	10.3.188.160/28	10.3.188.161 – 10.3.188.174	10.3.188.175
76	10.3.188.176/28	10.3.188.177 – 10.3.188.190	10.3.188.191
77	10.3.188.192/28	10.3.188.193 – 10.3.188.206	10.3.188.207
78	10.3.188.208/28	10.3.188.209 – 10.3.188.222	10.3.188.223
79	10.3.188.224/28	10.3.188.225 – 10.3.188.238	10.3.188.239
80	10.3.188.240/28	10.3.188.241 – 10.3.188.254	10.3.188.255
81	10.3.189.0/28	10.3.189.1 – 10.3.189.14	10.3.189.15
82	10.3.189.16/28	10.3.189.17 – 10.3.189.30	10.3.189.31
83	10.3.189.32/28	10.3.189.33 – 10.3.189.46	10.3.189.47
84	10.3.189.48/28	10.3.189.49 – 10.3.189.62	10.3.189.63
85	10.3.189.64/28	10.3.189.65 – 10.3.189.78	10.3.189.79
86	10.3.189.80/28	10.3.189.81 – 10.3.189.94	10.3.189.95
87	10.3.189.96/28	10.3.189.97 – 10.3.189.110	10.3.189.111
88	10.3.189.112/28	10.3.189.113 – 10.3.189.126	10.3.189.127
89	10.3.189.128/28	10.3.189.129 – 10.3.189.142	10.3.189.143
90	10.3.189.144/28	10.3.189.145 – 10.3.189.158	10.3.189.159
91	10.3.189.160/28	10.3.189.161 – 10.3.189.174	10.3.189.175
92	10.3.189.176/28	10.3.189.177 – 10.3.189.190	10.3.189.191
93	10.3.189.192/28	10.3.189.193 – 10.3.189.206	10.3.189.207
94	10.3.189.208/28	10.3.189.209 – 10.3.189.222	10.3.189.223
95	10.3.189.224/28	10.3.189.225 – 10.3.189.238	10.3.189.239
96	10.3.189.240/28	10.3.189.241 – 10.3.189.254	10.3.189.255
97	10.3.190.0/28	10.3.190.1 – 10.3.190.14	10.3.190.15
98	10.3.190.16/28	10.3.190.17 – 10.3.190.30	10.3.190.31
99	10.3.190.32/28	10.3.190.33 – 10.3.190.46	10.3.190.47
100	10.3.190.48/28	10.3.190.49 – 10.3.190.62	10.3.190.63
101	10.3.190.64/28	10.3.190.65 – 10.3.190.78	10.3.190.79
102	10.3.190.80/28	10.3.190.81 – 10.3.190.94	10.3.190.95
103	10.3.190.96/28	10.3.190.97 – 10.3.190.110	10.3.190.111
104	10.3.190.112/28	10.3.190.113 – 10.3.190.126	10.3.190.127
105	10.3.190.128/28	10.3.190.129 – 10.3.190.142	10.3.190.143
106	10.3.190.144/28	10.3.190.145 – 10.3.190.158	10.3.190.159
107	10.3.190.160/28	10.3.190.161 – 10.3.190.174	10.3.190.175
108	10.3.190.176/28	10.3.190.177 – 10.3.190.190	10.3.190.191
109	10.3.190.192/28	10.3.190.193 – 10.3.190.206	10.3.190.207
110	10.3.190.208/28	10.3.190.209 – 10.3.190.222	10.3.190.223
111	10.3.190.224/28	10.3.190.225 – 10.3.190.238	10.3.190.239
112	10.3.190.240/28	10.3.190.241 – 10.3.190.254	10.3.190.255
113	10.3.191.0/28	10.3.191.1 – 10.3.191.14	10.3.191.15
114	10.3.191.16/28	10.3.191.17 – 10.3.191.30	10.3.191.31
115	10.3.191.32/28	10.3.191.33 – 10.3.191.46	10.3.191.47
116	10.3.191.48/28	10.3.191.49 – 10.3.191.62	10.3.191.63
117	10.3.191.64/28	10.3.191.65 – 10.3.191.78	10.3.191.79
118	10.3.191.80/28	10.3.191.81 – 10.3.191.94	10.3.191.95
119	10.3.191.96/28	10.3.191.97 – 10.3.191.110	10.3.191.111
120	10.3.191.112/28	10.3.191.113 – 10.3.191.126	10.3.191.127
121	10.3.191.128/28	10.3.191.129 – 10.3.191.142	10.3.191.143
122	10.3.191.144/28	10.3.191.145 – 10.3.191.158	10.3.191.159
123	10.3.191.160/28	10.3.191.161 – 10.3.191.174	10.3.191.175
124	10.3.191.176/28	10.3.191.177 – 10.3.191.190	10.3.191.191
125	10.3.191.192/28	10.3.191.193 – 10.3.191.206	10.3.191.207
126	10.3.191.208/28	10.3.191.209 – 10.3.191.222	10.3.191.223
127	10.3.191.224/28	10.3.191.225 – 10.3.191.238	10.3.191.239
128	10.3.191.240/28	10.3.191.241 – 10.3.191.254	10.3.191.255

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 /21
/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	1
/22	255.255.252.0	1,024	1,022	2 split →
/23	255.255.254.0	512	510	4 split →
/24	255.255.255.0	256	254	8 split →
/25	255.255.255.128	128	126	16 split →
/26	255.255.255.192	64	62	32 split →
/27	255.255.255.224	32	30	64 split →
/28	255.255.255.240	16	14	128 split →
/29	255.255.255.248	8	6	256 split →
/30	255.255.255.252	4	2	512 split →
/31	255.255.255.254	2	2	1,024 split →
/32	255.255.255.255	1	1	2,048 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 →