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)10.2.216.0/21

network10.2.216.0/21

broadcast10.2.223.255

first host10.2.216.1

last host10.2.223.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.2.216.0/21

address00001010.00000010.11011000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000010.11011000.00000000

broadcast00001010.00000010.11011111.11111111

green = network part, grey = host part

hex0x0a02d800

decimal167958528

reverse dns0.216.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:d800

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.216.0/28	10.2.216.1 – 10.2.216.14	10.2.216.15
2	10.2.216.16/28	10.2.216.17 – 10.2.216.30	10.2.216.31
3	10.2.216.32/28	10.2.216.33 – 10.2.216.46	10.2.216.47
4	10.2.216.48/28	10.2.216.49 – 10.2.216.62	10.2.216.63
5	10.2.216.64/28	10.2.216.65 – 10.2.216.78	10.2.216.79
6	10.2.216.80/28	10.2.216.81 – 10.2.216.94	10.2.216.95
7	10.2.216.96/28	10.2.216.97 – 10.2.216.110	10.2.216.111
8	10.2.216.112/28	10.2.216.113 – 10.2.216.126	10.2.216.127
9	10.2.216.128/28	10.2.216.129 – 10.2.216.142	10.2.216.143
10	10.2.216.144/28	10.2.216.145 – 10.2.216.158	10.2.216.159
11	10.2.216.160/28	10.2.216.161 – 10.2.216.174	10.2.216.175
12	10.2.216.176/28	10.2.216.177 – 10.2.216.190	10.2.216.191
13	10.2.216.192/28	10.2.216.193 – 10.2.216.206	10.2.216.207
14	10.2.216.208/28	10.2.216.209 – 10.2.216.222	10.2.216.223
15	10.2.216.224/28	10.2.216.225 – 10.2.216.238	10.2.216.239
16	10.2.216.240/28	10.2.216.241 – 10.2.216.254	10.2.216.255
17	10.2.217.0/28	10.2.217.1 – 10.2.217.14	10.2.217.15
18	10.2.217.16/28	10.2.217.17 – 10.2.217.30	10.2.217.31
19	10.2.217.32/28	10.2.217.33 – 10.2.217.46	10.2.217.47
20	10.2.217.48/28	10.2.217.49 – 10.2.217.62	10.2.217.63
21	10.2.217.64/28	10.2.217.65 – 10.2.217.78	10.2.217.79
22	10.2.217.80/28	10.2.217.81 – 10.2.217.94	10.2.217.95
23	10.2.217.96/28	10.2.217.97 – 10.2.217.110	10.2.217.111
24	10.2.217.112/28	10.2.217.113 – 10.2.217.126	10.2.217.127
25	10.2.217.128/28	10.2.217.129 – 10.2.217.142	10.2.217.143
26	10.2.217.144/28	10.2.217.145 – 10.2.217.158	10.2.217.159
27	10.2.217.160/28	10.2.217.161 – 10.2.217.174	10.2.217.175
28	10.2.217.176/28	10.2.217.177 – 10.2.217.190	10.2.217.191
29	10.2.217.192/28	10.2.217.193 – 10.2.217.206	10.2.217.207
30	10.2.217.208/28	10.2.217.209 – 10.2.217.222	10.2.217.223
31	10.2.217.224/28	10.2.217.225 – 10.2.217.238	10.2.217.239
32	10.2.217.240/28	10.2.217.241 – 10.2.217.254	10.2.217.255
33	10.2.218.0/28	10.2.218.1 – 10.2.218.14	10.2.218.15
34	10.2.218.16/28	10.2.218.17 – 10.2.218.30	10.2.218.31
35	10.2.218.32/28	10.2.218.33 – 10.2.218.46	10.2.218.47
36	10.2.218.48/28	10.2.218.49 – 10.2.218.62	10.2.218.63
37	10.2.218.64/28	10.2.218.65 – 10.2.218.78	10.2.218.79
38	10.2.218.80/28	10.2.218.81 – 10.2.218.94	10.2.218.95
39	10.2.218.96/28	10.2.218.97 – 10.2.218.110	10.2.218.111
40	10.2.218.112/28	10.2.218.113 – 10.2.218.126	10.2.218.127
41	10.2.218.128/28	10.2.218.129 – 10.2.218.142	10.2.218.143
42	10.2.218.144/28	10.2.218.145 – 10.2.218.158	10.2.218.159
43	10.2.218.160/28	10.2.218.161 – 10.2.218.174	10.2.218.175
44	10.2.218.176/28	10.2.218.177 – 10.2.218.190	10.2.218.191
45	10.2.218.192/28	10.2.218.193 – 10.2.218.206	10.2.218.207
46	10.2.218.208/28	10.2.218.209 – 10.2.218.222	10.2.218.223
47	10.2.218.224/28	10.2.218.225 – 10.2.218.238	10.2.218.239
48	10.2.218.240/28	10.2.218.241 – 10.2.218.254	10.2.218.255
49	10.2.219.0/28	10.2.219.1 – 10.2.219.14	10.2.219.15
50	10.2.219.16/28	10.2.219.17 – 10.2.219.30	10.2.219.31
51	10.2.219.32/28	10.2.219.33 – 10.2.219.46	10.2.219.47
52	10.2.219.48/28	10.2.219.49 – 10.2.219.62	10.2.219.63
53	10.2.219.64/28	10.2.219.65 – 10.2.219.78	10.2.219.79
54	10.2.219.80/28	10.2.219.81 – 10.2.219.94	10.2.219.95
55	10.2.219.96/28	10.2.219.97 – 10.2.219.110	10.2.219.111
56	10.2.219.112/28	10.2.219.113 – 10.2.219.126	10.2.219.127
57	10.2.219.128/28	10.2.219.129 – 10.2.219.142	10.2.219.143
58	10.2.219.144/28	10.2.219.145 – 10.2.219.158	10.2.219.159
59	10.2.219.160/28	10.2.219.161 – 10.2.219.174	10.2.219.175
60	10.2.219.176/28	10.2.219.177 – 10.2.219.190	10.2.219.191
61	10.2.219.192/28	10.2.219.193 – 10.2.219.206	10.2.219.207
62	10.2.219.208/28	10.2.219.209 – 10.2.219.222	10.2.219.223
63	10.2.219.224/28	10.2.219.225 – 10.2.219.238	10.2.219.239
64	10.2.219.240/28	10.2.219.241 – 10.2.219.254	10.2.219.255
65	10.2.220.0/28	10.2.220.1 – 10.2.220.14	10.2.220.15
66	10.2.220.16/28	10.2.220.17 – 10.2.220.30	10.2.220.31
67	10.2.220.32/28	10.2.220.33 – 10.2.220.46	10.2.220.47
68	10.2.220.48/28	10.2.220.49 – 10.2.220.62	10.2.220.63
69	10.2.220.64/28	10.2.220.65 – 10.2.220.78	10.2.220.79
70	10.2.220.80/28	10.2.220.81 – 10.2.220.94	10.2.220.95
71	10.2.220.96/28	10.2.220.97 – 10.2.220.110	10.2.220.111
72	10.2.220.112/28	10.2.220.113 – 10.2.220.126	10.2.220.127
73	10.2.220.128/28	10.2.220.129 – 10.2.220.142	10.2.220.143
74	10.2.220.144/28	10.2.220.145 – 10.2.220.158	10.2.220.159
75	10.2.220.160/28	10.2.220.161 – 10.2.220.174	10.2.220.175
76	10.2.220.176/28	10.2.220.177 – 10.2.220.190	10.2.220.191
77	10.2.220.192/28	10.2.220.193 – 10.2.220.206	10.2.220.207
78	10.2.220.208/28	10.2.220.209 – 10.2.220.222	10.2.220.223
79	10.2.220.224/28	10.2.220.225 – 10.2.220.238	10.2.220.239
80	10.2.220.240/28	10.2.220.241 – 10.2.220.254	10.2.220.255
81	10.2.221.0/28	10.2.221.1 – 10.2.221.14	10.2.221.15
82	10.2.221.16/28	10.2.221.17 – 10.2.221.30	10.2.221.31
83	10.2.221.32/28	10.2.221.33 – 10.2.221.46	10.2.221.47
84	10.2.221.48/28	10.2.221.49 – 10.2.221.62	10.2.221.63
85	10.2.221.64/28	10.2.221.65 – 10.2.221.78	10.2.221.79
86	10.2.221.80/28	10.2.221.81 – 10.2.221.94	10.2.221.95
87	10.2.221.96/28	10.2.221.97 – 10.2.221.110	10.2.221.111
88	10.2.221.112/28	10.2.221.113 – 10.2.221.126	10.2.221.127
89	10.2.221.128/28	10.2.221.129 – 10.2.221.142	10.2.221.143
90	10.2.221.144/28	10.2.221.145 – 10.2.221.158	10.2.221.159
91	10.2.221.160/28	10.2.221.161 – 10.2.221.174	10.2.221.175
92	10.2.221.176/28	10.2.221.177 – 10.2.221.190	10.2.221.191
93	10.2.221.192/28	10.2.221.193 – 10.2.221.206	10.2.221.207
94	10.2.221.208/28	10.2.221.209 – 10.2.221.222	10.2.221.223
95	10.2.221.224/28	10.2.221.225 – 10.2.221.238	10.2.221.239
96	10.2.221.240/28	10.2.221.241 – 10.2.221.254	10.2.221.255
97	10.2.222.0/28	10.2.222.1 – 10.2.222.14	10.2.222.15
98	10.2.222.16/28	10.2.222.17 – 10.2.222.30	10.2.222.31
99	10.2.222.32/28	10.2.222.33 – 10.2.222.46	10.2.222.47
100	10.2.222.48/28	10.2.222.49 – 10.2.222.62	10.2.222.63
101	10.2.222.64/28	10.2.222.65 – 10.2.222.78	10.2.222.79
102	10.2.222.80/28	10.2.222.81 – 10.2.222.94	10.2.222.95
103	10.2.222.96/28	10.2.222.97 – 10.2.222.110	10.2.222.111
104	10.2.222.112/28	10.2.222.113 – 10.2.222.126	10.2.222.127
105	10.2.222.128/28	10.2.222.129 – 10.2.222.142	10.2.222.143
106	10.2.222.144/28	10.2.222.145 – 10.2.222.158	10.2.222.159
107	10.2.222.160/28	10.2.222.161 – 10.2.222.174	10.2.222.175
108	10.2.222.176/28	10.2.222.177 – 10.2.222.190	10.2.222.191
109	10.2.222.192/28	10.2.222.193 – 10.2.222.206	10.2.222.207
110	10.2.222.208/28	10.2.222.209 – 10.2.222.222	10.2.222.223
111	10.2.222.224/28	10.2.222.225 – 10.2.222.238	10.2.222.239
112	10.2.222.240/28	10.2.222.241 – 10.2.222.254	10.2.222.255
113	10.2.223.0/28	10.2.223.1 – 10.2.223.14	10.2.223.15
114	10.2.223.16/28	10.2.223.17 – 10.2.223.30	10.2.223.31
115	10.2.223.32/28	10.2.223.33 – 10.2.223.46	10.2.223.47
116	10.2.223.48/28	10.2.223.49 – 10.2.223.62	10.2.223.63
117	10.2.223.64/28	10.2.223.65 – 10.2.223.78	10.2.223.79
118	10.2.223.80/28	10.2.223.81 – 10.2.223.94	10.2.223.95
119	10.2.223.96/28	10.2.223.97 – 10.2.223.110	10.2.223.111
120	10.2.223.112/28	10.2.223.113 – 10.2.223.126	10.2.223.127
121	10.2.223.128/28	10.2.223.129 – 10.2.223.142	10.2.223.143
122	10.2.223.144/28	10.2.223.145 – 10.2.223.158	10.2.223.159
123	10.2.223.160/28	10.2.223.161 – 10.2.223.174	10.2.223.175
124	10.2.223.176/28	10.2.223.177 – 10.2.223.190	10.2.223.191
125	10.2.223.192/28	10.2.223.193 – 10.2.223.206	10.2.223.207
126	10.2.223.208/28	10.2.223.209 – 10.2.223.222	10.2.223.223
127	10.2.223.224/28	10.2.223.225 – 10.2.223.238	10.2.223.239
128	10.2.223.240/28	10.2.223.241 – 10.2.223.254	10.2.223.255

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 →