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)10.0.80.0/21

network10.0.80.0/21

broadcast10.0.87.255

first host10.0.80.1

last host10.0.87.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.0.80.0/21

address00001010.00000000.01010000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000000.01010000.00000000

broadcast00001010.00000000.01010111.11111111

green = network part, grey = host part

hex0x0a005000

decimal167792640

reverse dns0.80.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:5000

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.0.80.0/28	10.0.80.1 – 10.0.80.14	10.0.80.15
2	10.0.80.16/28	10.0.80.17 – 10.0.80.30	10.0.80.31
3	10.0.80.32/28	10.0.80.33 – 10.0.80.46	10.0.80.47
4	10.0.80.48/28	10.0.80.49 – 10.0.80.62	10.0.80.63
5	10.0.80.64/28	10.0.80.65 – 10.0.80.78	10.0.80.79
6	10.0.80.80/28	10.0.80.81 – 10.0.80.94	10.0.80.95
7	10.0.80.96/28	10.0.80.97 – 10.0.80.110	10.0.80.111
8	10.0.80.112/28	10.0.80.113 – 10.0.80.126	10.0.80.127
9	10.0.80.128/28	10.0.80.129 – 10.0.80.142	10.0.80.143
10	10.0.80.144/28	10.0.80.145 – 10.0.80.158	10.0.80.159
11	10.0.80.160/28	10.0.80.161 – 10.0.80.174	10.0.80.175
12	10.0.80.176/28	10.0.80.177 – 10.0.80.190	10.0.80.191
13	10.0.80.192/28	10.0.80.193 – 10.0.80.206	10.0.80.207
14	10.0.80.208/28	10.0.80.209 – 10.0.80.222	10.0.80.223
15	10.0.80.224/28	10.0.80.225 – 10.0.80.238	10.0.80.239
16	10.0.80.240/28	10.0.80.241 – 10.0.80.254	10.0.80.255
17	10.0.81.0/28	10.0.81.1 – 10.0.81.14	10.0.81.15
18	10.0.81.16/28	10.0.81.17 – 10.0.81.30	10.0.81.31
19	10.0.81.32/28	10.0.81.33 – 10.0.81.46	10.0.81.47
20	10.0.81.48/28	10.0.81.49 – 10.0.81.62	10.0.81.63
21	10.0.81.64/28	10.0.81.65 – 10.0.81.78	10.0.81.79
22	10.0.81.80/28	10.0.81.81 – 10.0.81.94	10.0.81.95
23	10.0.81.96/28	10.0.81.97 – 10.0.81.110	10.0.81.111
24	10.0.81.112/28	10.0.81.113 – 10.0.81.126	10.0.81.127
25	10.0.81.128/28	10.0.81.129 – 10.0.81.142	10.0.81.143
26	10.0.81.144/28	10.0.81.145 – 10.0.81.158	10.0.81.159
27	10.0.81.160/28	10.0.81.161 – 10.0.81.174	10.0.81.175
28	10.0.81.176/28	10.0.81.177 – 10.0.81.190	10.0.81.191
29	10.0.81.192/28	10.0.81.193 – 10.0.81.206	10.0.81.207
30	10.0.81.208/28	10.0.81.209 – 10.0.81.222	10.0.81.223
31	10.0.81.224/28	10.0.81.225 – 10.0.81.238	10.0.81.239
32	10.0.81.240/28	10.0.81.241 – 10.0.81.254	10.0.81.255
33	10.0.82.0/28	10.0.82.1 – 10.0.82.14	10.0.82.15
34	10.0.82.16/28	10.0.82.17 – 10.0.82.30	10.0.82.31
35	10.0.82.32/28	10.0.82.33 – 10.0.82.46	10.0.82.47
36	10.0.82.48/28	10.0.82.49 – 10.0.82.62	10.0.82.63
37	10.0.82.64/28	10.0.82.65 – 10.0.82.78	10.0.82.79
38	10.0.82.80/28	10.0.82.81 – 10.0.82.94	10.0.82.95
39	10.0.82.96/28	10.0.82.97 – 10.0.82.110	10.0.82.111
40	10.0.82.112/28	10.0.82.113 – 10.0.82.126	10.0.82.127
41	10.0.82.128/28	10.0.82.129 – 10.0.82.142	10.0.82.143
42	10.0.82.144/28	10.0.82.145 – 10.0.82.158	10.0.82.159
43	10.0.82.160/28	10.0.82.161 – 10.0.82.174	10.0.82.175
44	10.0.82.176/28	10.0.82.177 – 10.0.82.190	10.0.82.191
45	10.0.82.192/28	10.0.82.193 – 10.0.82.206	10.0.82.207
46	10.0.82.208/28	10.0.82.209 – 10.0.82.222	10.0.82.223
47	10.0.82.224/28	10.0.82.225 – 10.0.82.238	10.0.82.239
48	10.0.82.240/28	10.0.82.241 – 10.0.82.254	10.0.82.255
49	10.0.83.0/28	10.0.83.1 – 10.0.83.14	10.0.83.15
50	10.0.83.16/28	10.0.83.17 – 10.0.83.30	10.0.83.31
51	10.0.83.32/28	10.0.83.33 – 10.0.83.46	10.0.83.47
52	10.0.83.48/28	10.0.83.49 – 10.0.83.62	10.0.83.63
53	10.0.83.64/28	10.0.83.65 – 10.0.83.78	10.0.83.79
54	10.0.83.80/28	10.0.83.81 – 10.0.83.94	10.0.83.95
55	10.0.83.96/28	10.0.83.97 – 10.0.83.110	10.0.83.111
56	10.0.83.112/28	10.0.83.113 – 10.0.83.126	10.0.83.127
57	10.0.83.128/28	10.0.83.129 – 10.0.83.142	10.0.83.143
58	10.0.83.144/28	10.0.83.145 – 10.0.83.158	10.0.83.159
59	10.0.83.160/28	10.0.83.161 – 10.0.83.174	10.0.83.175
60	10.0.83.176/28	10.0.83.177 – 10.0.83.190	10.0.83.191
61	10.0.83.192/28	10.0.83.193 – 10.0.83.206	10.0.83.207
62	10.0.83.208/28	10.0.83.209 – 10.0.83.222	10.0.83.223
63	10.0.83.224/28	10.0.83.225 – 10.0.83.238	10.0.83.239
64	10.0.83.240/28	10.0.83.241 – 10.0.83.254	10.0.83.255
65	10.0.84.0/28	10.0.84.1 – 10.0.84.14	10.0.84.15
66	10.0.84.16/28	10.0.84.17 – 10.0.84.30	10.0.84.31
67	10.0.84.32/28	10.0.84.33 – 10.0.84.46	10.0.84.47
68	10.0.84.48/28	10.0.84.49 – 10.0.84.62	10.0.84.63
69	10.0.84.64/28	10.0.84.65 – 10.0.84.78	10.0.84.79
70	10.0.84.80/28	10.0.84.81 – 10.0.84.94	10.0.84.95
71	10.0.84.96/28	10.0.84.97 – 10.0.84.110	10.0.84.111
72	10.0.84.112/28	10.0.84.113 – 10.0.84.126	10.0.84.127
73	10.0.84.128/28	10.0.84.129 – 10.0.84.142	10.0.84.143
74	10.0.84.144/28	10.0.84.145 – 10.0.84.158	10.0.84.159
75	10.0.84.160/28	10.0.84.161 – 10.0.84.174	10.0.84.175
76	10.0.84.176/28	10.0.84.177 – 10.0.84.190	10.0.84.191
77	10.0.84.192/28	10.0.84.193 – 10.0.84.206	10.0.84.207
78	10.0.84.208/28	10.0.84.209 – 10.0.84.222	10.0.84.223
79	10.0.84.224/28	10.0.84.225 – 10.0.84.238	10.0.84.239
80	10.0.84.240/28	10.0.84.241 – 10.0.84.254	10.0.84.255
81	10.0.85.0/28	10.0.85.1 – 10.0.85.14	10.0.85.15
82	10.0.85.16/28	10.0.85.17 – 10.0.85.30	10.0.85.31
83	10.0.85.32/28	10.0.85.33 – 10.0.85.46	10.0.85.47
84	10.0.85.48/28	10.0.85.49 – 10.0.85.62	10.0.85.63
85	10.0.85.64/28	10.0.85.65 – 10.0.85.78	10.0.85.79
86	10.0.85.80/28	10.0.85.81 – 10.0.85.94	10.0.85.95
87	10.0.85.96/28	10.0.85.97 – 10.0.85.110	10.0.85.111
88	10.0.85.112/28	10.0.85.113 – 10.0.85.126	10.0.85.127
89	10.0.85.128/28	10.0.85.129 – 10.0.85.142	10.0.85.143
90	10.0.85.144/28	10.0.85.145 – 10.0.85.158	10.0.85.159
91	10.0.85.160/28	10.0.85.161 – 10.0.85.174	10.0.85.175
92	10.0.85.176/28	10.0.85.177 – 10.0.85.190	10.0.85.191
93	10.0.85.192/28	10.0.85.193 – 10.0.85.206	10.0.85.207
94	10.0.85.208/28	10.0.85.209 – 10.0.85.222	10.0.85.223
95	10.0.85.224/28	10.0.85.225 – 10.0.85.238	10.0.85.239
96	10.0.85.240/28	10.0.85.241 – 10.0.85.254	10.0.85.255
97	10.0.86.0/28	10.0.86.1 – 10.0.86.14	10.0.86.15
98	10.0.86.16/28	10.0.86.17 – 10.0.86.30	10.0.86.31
99	10.0.86.32/28	10.0.86.33 – 10.0.86.46	10.0.86.47
100	10.0.86.48/28	10.0.86.49 – 10.0.86.62	10.0.86.63
101	10.0.86.64/28	10.0.86.65 – 10.0.86.78	10.0.86.79
102	10.0.86.80/28	10.0.86.81 – 10.0.86.94	10.0.86.95
103	10.0.86.96/28	10.0.86.97 – 10.0.86.110	10.0.86.111
104	10.0.86.112/28	10.0.86.113 – 10.0.86.126	10.0.86.127
105	10.0.86.128/28	10.0.86.129 – 10.0.86.142	10.0.86.143
106	10.0.86.144/28	10.0.86.145 – 10.0.86.158	10.0.86.159
107	10.0.86.160/28	10.0.86.161 – 10.0.86.174	10.0.86.175
108	10.0.86.176/28	10.0.86.177 – 10.0.86.190	10.0.86.191
109	10.0.86.192/28	10.0.86.193 – 10.0.86.206	10.0.86.207
110	10.0.86.208/28	10.0.86.209 – 10.0.86.222	10.0.86.223
111	10.0.86.224/28	10.0.86.225 – 10.0.86.238	10.0.86.239
112	10.0.86.240/28	10.0.86.241 – 10.0.86.254	10.0.86.255
113	10.0.87.0/28	10.0.87.1 – 10.0.87.14	10.0.87.15
114	10.0.87.16/28	10.0.87.17 – 10.0.87.30	10.0.87.31
115	10.0.87.32/28	10.0.87.33 – 10.0.87.46	10.0.87.47
116	10.0.87.48/28	10.0.87.49 – 10.0.87.62	10.0.87.63
117	10.0.87.64/28	10.0.87.65 – 10.0.87.78	10.0.87.79
118	10.0.87.80/28	10.0.87.81 – 10.0.87.94	10.0.87.95
119	10.0.87.96/28	10.0.87.97 – 10.0.87.110	10.0.87.111
120	10.0.87.112/28	10.0.87.113 – 10.0.87.126	10.0.87.127
121	10.0.87.128/28	10.0.87.129 – 10.0.87.142	10.0.87.143
122	10.0.87.144/28	10.0.87.145 – 10.0.87.158	10.0.87.159
123	10.0.87.160/28	10.0.87.161 – 10.0.87.174	10.0.87.175
124	10.0.87.176/28	10.0.87.177 – 10.0.87.190	10.0.87.191
125	10.0.87.192/28	10.0.87.193 – 10.0.87.206	10.0.87.207
126	10.0.87.208/28	10.0.87.209 – 10.0.87.222	10.0.87.223
127	10.0.87.224/28	10.0.87.225 – 10.0.87.238	10.0.87.239
128	10.0.87.240/28	10.0.87.241 – 10.0.87.254	10.0.87.255

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 →