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)10.2.80.0/21

network10.2.80.0/21

broadcast10.2.87.255

first host10.2.80.1

last host10.2.87.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.2.80.0/21

address00001010.00000010.01010000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000010.01010000.00000000

broadcast00001010.00000010.01010111.11111111

green = network part, grey = host part

hex0x0a025000

decimal167923712

reverse dns0.80.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:5000

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.80.0/28	10.2.80.1 – 10.2.80.14	10.2.80.15
2	10.2.80.16/28	10.2.80.17 – 10.2.80.30	10.2.80.31
3	10.2.80.32/28	10.2.80.33 – 10.2.80.46	10.2.80.47
4	10.2.80.48/28	10.2.80.49 – 10.2.80.62	10.2.80.63
5	10.2.80.64/28	10.2.80.65 – 10.2.80.78	10.2.80.79
6	10.2.80.80/28	10.2.80.81 – 10.2.80.94	10.2.80.95
7	10.2.80.96/28	10.2.80.97 – 10.2.80.110	10.2.80.111
8	10.2.80.112/28	10.2.80.113 – 10.2.80.126	10.2.80.127
9	10.2.80.128/28	10.2.80.129 – 10.2.80.142	10.2.80.143
10	10.2.80.144/28	10.2.80.145 – 10.2.80.158	10.2.80.159
11	10.2.80.160/28	10.2.80.161 – 10.2.80.174	10.2.80.175
12	10.2.80.176/28	10.2.80.177 – 10.2.80.190	10.2.80.191
13	10.2.80.192/28	10.2.80.193 – 10.2.80.206	10.2.80.207
14	10.2.80.208/28	10.2.80.209 – 10.2.80.222	10.2.80.223
15	10.2.80.224/28	10.2.80.225 – 10.2.80.238	10.2.80.239
16	10.2.80.240/28	10.2.80.241 – 10.2.80.254	10.2.80.255
17	10.2.81.0/28	10.2.81.1 – 10.2.81.14	10.2.81.15
18	10.2.81.16/28	10.2.81.17 – 10.2.81.30	10.2.81.31
19	10.2.81.32/28	10.2.81.33 – 10.2.81.46	10.2.81.47
20	10.2.81.48/28	10.2.81.49 – 10.2.81.62	10.2.81.63
21	10.2.81.64/28	10.2.81.65 – 10.2.81.78	10.2.81.79
22	10.2.81.80/28	10.2.81.81 – 10.2.81.94	10.2.81.95
23	10.2.81.96/28	10.2.81.97 – 10.2.81.110	10.2.81.111
24	10.2.81.112/28	10.2.81.113 – 10.2.81.126	10.2.81.127
25	10.2.81.128/28	10.2.81.129 – 10.2.81.142	10.2.81.143
26	10.2.81.144/28	10.2.81.145 – 10.2.81.158	10.2.81.159
27	10.2.81.160/28	10.2.81.161 – 10.2.81.174	10.2.81.175
28	10.2.81.176/28	10.2.81.177 – 10.2.81.190	10.2.81.191
29	10.2.81.192/28	10.2.81.193 – 10.2.81.206	10.2.81.207
30	10.2.81.208/28	10.2.81.209 – 10.2.81.222	10.2.81.223
31	10.2.81.224/28	10.2.81.225 – 10.2.81.238	10.2.81.239
32	10.2.81.240/28	10.2.81.241 – 10.2.81.254	10.2.81.255
33	10.2.82.0/28	10.2.82.1 – 10.2.82.14	10.2.82.15
34	10.2.82.16/28	10.2.82.17 – 10.2.82.30	10.2.82.31
35	10.2.82.32/28	10.2.82.33 – 10.2.82.46	10.2.82.47
36	10.2.82.48/28	10.2.82.49 – 10.2.82.62	10.2.82.63
37	10.2.82.64/28	10.2.82.65 – 10.2.82.78	10.2.82.79
38	10.2.82.80/28	10.2.82.81 – 10.2.82.94	10.2.82.95
39	10.2.82.96/28	10.2.82.97 – 10.2.82.110	10.2.82.111
40	10.2.82.112/28	10.2.82.113 – 10.2.82.126	10.2.82.127
41	10.2.82.128/28	10.2.82.129 – 10.2.82.142	10.2.82.143
42	10.2.82.144/28	10.2.82.145 – 10.2.82.158	10.2.82.159
43	10.2.82.160/28	10.2.82.161 – 10.2.82.174	10.2.82.175
44	10.2.82.176/28	10.2.82.177 – 10.2.82.190	10.2.82.191
45	10.2.82.192/28	10.2.82.193 – 10.2.82.206	10.2.82.207
46	10.2.82.208/28	10.2.82.209 – 10.2.82.222	10.2.82.223
47	10.2.82.224/28	10.2.82.225 – 10.2.82.238	10.2.82.239
48	10.2.82.240/28	10.2.82.241 – 10.2.82.254	10.2.82.255
49	10.2.83.0/28	10.2.83.1 – 10.2.83.14	10.2.83.15
50	10.2.83.16/28	10.2.83.17 – 10.2.83.30	10.2.83.31
51	10.2.83.32/28	10.2.83.33 – 10.2.83.46	10.2.83.47
52	10.2.83.48/28	10.2.83.49 – 10.2.83.62	10.2.83.63
53	10.2.83.64/28	10.2.83.65 – 10.2.83.78	10.2.83.79
54	10.2.83.80/28	10.2.83.81 – 10.2.83.94	10.2.83.95
55	10.2.83.96/28	10.2.83.97 – 10.2.83.110	10.2.83.111
56	10.2.83.112/28	10.2.83.113 – 10.2.83.126	10.2.83.127
57	10.2.83.128/28	10.2.83.129 – 10.2.83.142	10.2.83.143
58	10.2.83.144/28	10.2.83.145 – 10.2.83.158	10.2.83.159
59	10.2.83.160/28	10.2.83.161 – 10.2.83.174	10.2.83.175
60	10.2.83.176/28	10.2.83.177 – 10.2.83.190	10.2.83.191
61	10.2.83.192/28	10.2.83.193 – 10.2.83.206	10.2.83.207
62	10.2.83.208/28	10.2.83.209 – 10.2.83.222	10.2.83.223
63	10.2.83.224/28	10.2.83.225 – 10.2.83.238	10.2.83.239
64	10.2.83.240/28	10.2.83.241 – 10.2.83.254	10.2.83.255
65	10.2.84.0/28	10.2.84.1 – 10.2.84.14	10.2.84.15
66	10.2.84.16/28	10.2.84.17 – 10.2.84.30	10.2.84.31
67	10.2.84.32/28	10.2.84.33 – 10.2.84.46	10.2.84.47
68	10.2.84.48/28	10.2.84.49 – 10.2.84.62	10.2.84.63
69	10.2.84.64/28	10.2.84.65 – 10.2.84.78	10.2.84.79
70	10.2.84.80/28	10.2.84.81 – 10.2.84.94	10.2.84.95
71	10.2.84.96/28	10.2.84.97 – 10.2.84.110	10.2.84.111
72	10.2.84.112/28	10.2.84.113 – 10.2.84.126	10.2.84.127
73	10.2.84.128/28	10.2.84.129 – 10.2.84.142	10.2.84.143
74	10.2.84.144/28	10.2.84.145 – 10.2.84.158	10.2.84.159
75	10.2.84.160/28	10.2.84.161 – 10.2.84.174	10.2.84.175
76	10.2.84.176/28	10.2.84.177 – 10.2.84.190	10.2.84.191
77	10.2.84.192/28	10.2.84.193 – 10.2.84.206	10.2.84.207
78	10.2.84.208/28	10.2.84.209 – 10.2.84.222	10.2.84.223
79	10.2.84.224/28	10.2.84.225 – 10.2.84.238	10.2.84.239
80	10.2.84.240/28	10.2.84.241 – 10.2.84.254	10.2.84.255
81	10.2.85.0/28	10.2.85.1 – 10.2.85.14	10.2.85.15
82	10.2.85.16/28	10.2.85.17 – 10.2.85.30	10.2.85.31
83	10.2.85.32/28	10.2.85.33 – 10.2.85.46	10.2.85.47
84	10.2.85.48/28	10.2.85.49 – 10.2.85.62	10.2.85.63
85	10.2.85.64/28	10.2.85.65 – 10.2.85.78	10.2.85.79
86	10.2.85.80/28	10.2.85.81 – 10.2.85.94	10.2.85.95
87	10.2.85.96/28	10.2.85.97 – 10.2.85.110	10.2.85.111
88	10.2.85.112/28	10.2.85.113 – 10.2.85.126	10.2.85.127
89	10.2.85.128/28	10.2.85.129 – 10.2.85.142	10.2.85.143
90	10.2.85.144/28	10.2.85.145 – 10.2.85.158	10.2.85.159
91	10.2.85.160/28	10.2.85.161 – 10.2.85.174	10.2.85.175
92	10.2.85.176/28	10.2.85.177 – 10.2.85.190	10.2.85.191
93	10.2.85.192/28	10.2.85.193 – 10.2.85.206	10.2.85.207
94	10.2.85.208/28	10.2.85.209 – 10.2.85.222	10.2.85.223
95	10.2.85.224/28	10.2.85.225 – 10.2.85.238	10.2.85.239
96	10.2.85.240/28	10.2.85.241 – 10.2.85.254	10.2.85.255
97	10.2.86.0/28	10.2.86.1 – 10.2.86.14	10.2.86.15
98	10.2.86.16/28	10.2.86.17 – 10.2.86.30	10.2.86.31
99	10.2.86.32/28	10.2.86.33 – 10.2.86.46	10.2.86.47
100	10.2.86.48/28	10.2.86.49 – 10.2.86.62	10.2.86.63
101	10.2.86.64/28	10.2.86.65 – 10.2.86.78	10.2.86.79
102	10.2.86.80/28	10.2.86.81 – 10.2.86.94	10.2.86.95
103	10.2.86.96/28	10.2.86.97 – 10.2.86.110	10.2.86.111
104	10.2.86.112/28	10.2.86.113 – 10.2.86.126	10.2.86.127
105	10.2.86.128/28	10.2.86.129 – 10.2.86.142	10.2.86.143
106	10.2.86.144/28	10.2.86.145 – 10.2.86.158	10.2.86.159
107	10.2.86.160/28	10.2.86.161 – 10.2.86.174	10.2.86.175
108	10.2.86.176/28	10.2.86.177 – 10.2.86.190	10.2.86.191
109	10.2.86.192/28	10.2.86.193 – 10.2.86.206	10.2.86.207
110	10.2.86.208/28	10.2.86.209 – 10.2.86.222	10.2.86.223
111	10.2.86.224/28	10.2.86.225 – 10.2.86.238	10.2.86.239
112	10.2.86.240/28	10.2.86.241 – 10.2.86.254	10.2.86.255
113	10.2.87.0/28	10.2.87.1 – 10.2.87.14	10.2.87.15
114	10.2.87.16/28	10.2.87.17 – 10.2.87.30	10.2.87.31
115	10.2.87.32/28	10.2.87.33 – 10.2.87.46	10.2.87.47
116	10.2.87.48/28	10.2.87.49 – 10.2.87.62	10.2.87.63
117	10.2.87.64/28	10.2.87.65 – 10.2.87.78	10.2.87.79
118	10.2.87.80/28	10.2.87.81 – 10.2.87.94	10.2.87.95
119	10.2.87.96/28	10.2.87.97 – 10.2.87.110	10.2.87.111
120	10.2.87.112/28	10.2.87.113 – 10.2.87.126	10.2.87.127
121	10.2.87.128/28	10.2.87.129 – 10.2.87.142	10.2.87.143
122	10.2.87.144/28	10.2.87.145 – 10.2.87.158	10.2.87.159
123	10.2.87.160/28	10.2.87.161 – 10.2.87.174	10.2.87.175
124	10.2.87.176/28	10.2.87.177 – 10.2.87.190	10.2.87.191
125	10.2.87.192/28	10.2.87.193 – 10.2.87.206	10.2.87.207
126	10.2.87.208/28	10.2.87.209 – 10.2.87.222	10.2.87.223
127	10.2.87.224/28	10.2.87.225 – 10.2.87.238	10.2.87.239
128	10.2.87.240/28	10.2.87.241 – 10.2.87.254	10.2.87.255

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 →