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)10.2.144.0/21

network10.2.144.0/21

broadcast10.2.151.255

first host10.2.144.1

last host10.2.151.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.2.144.0/21

address00001010.00000010.10010000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000010.10010000.00000000

broadcast00001010.00000010.10010111.11111111

green = network part, grey = host part

hex0x0a029000

decimal167940096

reverse dns0.144.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:9000

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.144.0/28	10.2.144.1 – 10.2.144.14	10.2.144.15
2	10.2.144.16/28	10.2.144.17 – 10.2.144.30	10.2.144.31
3	10.2.144.32/28	10.2.144.33 – 10.2.144.46	10.2.144.47
4	10.2.144.48/28	10.2.144.49 – 10.2.144.62	10.2.144.63
5	10.2.144.64/28	10.2.144.65 – 10.2.144.78	10.2.144.79
6	10.2.144.80/28	10.2.144.81 – 10.2.144.94	10.2.144.95
7	10.2.144.96/28	10.2.144.97 – 10.2.144.110	10.2.144.111
8	10.2.144.112/28	10.2.144.113 – 10.2.144.126	10.2.144.127
9	10.2.144.128/28	10.2.144.129 – 10.2.144.142	10.2.144.143
10	10.2.144.144/28	10.2.144.145 – 10.2.144.158	10.2.144.159
11	10.2.144.160/28	10.2.144.161 – 10.2.144.174	10.2.144.175
12	10.2.144.176/28	10.2.144.177 – 10.2.144.190	10.2.144.191
13	10.2.144.192/28	10.2.144.193 – 10.2.144.206	10.2.144.207
14	10.2.144.208/28	10.2.144.209 – 10.2.144.222	10.2.144.223
15	10.2.144.224/28	10.2.144.225 – 10.2.144.238	10.2.144.239
16	10.2.144.240/28	10.2.144.241 – 10.2.144.254	10.2.144.255
17	10.2.145.0/28	10.2.145.1 – 10.2.145.14	10.2.145.15
18	10.2.145.16/28	10.2.145.17 – 10.2.145.30	10.2.145.31
19	10.2.145.32/28	10.2.145.33 – 10.2.145.46	10.2.145.47
20	10.2.145.48/28	10.2.145.49 – 10.2.145.62	10.2.145.63
21	10.2.145.64/28	10.2.145.65 – 10.2.145.78	10.2.145.79
22	10.2.145.80/28	10.2.145.81 – 10.2.145.94	10.2.145.95
23	10.2.145.96/28	10.2.145.97 – 10.2.145.110	10.2.145.111
24	10.2.145.112/28	10.2.145.113 – 10.2.145.126	10.2.145.127
25	10.2.145.128/28	10.2.145.129 – 10.2.145.142	10.2.145.143
26	10.2.145.144/28	10.2.145.145 – 10.2.145.158	10.2.145.159
27	10.2.145.160/28	10.2.145.161 – 10.2.145.174	10.2.145.175
28	10.2.145.176/28	10.2.145.177 – 10.2.145.190	10.2.145.191
29	10.2.145.192/28	10.2.145.193 – 10.2.145.206	10.2.145.207
30	10.2.145.208/28	10.2.145.209 – 10.2.145.222	10.2.145.223
31	10.2.145.224/28	10.2.145.225 – 10.2.145.238	10.2.145.239
32	10.2.145.240/28	10.2.145.241 – 10.2.145.254	10.2.145.255
33	10.2.146.0/28	10.2.146.1 – 10.2.146.14	10.2.146.15
34	10.2.146.16/28	10.2.146.17 – 10.2.146.30	10.2.146.31
35	10.2.146.32/28	10.2.146.33 – 10.2.146.46	10.2.146.47
36	10.2.146.48/28	10.2.146.49 – 10.2.146.62	10.2.146.63
37	10.2.146.64/28	10.2.146.65 – 10.2.146.78	10.2.146.79
38	10.2.146.80/28	10.2.146.81 – 10.2.146.94	10.2.146.95
39	10.2.146.96/28	10.2.146.97 – 10.2.146.110	10.2.146.111
40	10.2.146.112/28	10.2.146.113 – 10.2.146.126	10.2.146.127
41	10.2.146.128/28	10.2.146.129 – 10.2.146.142	10.2.146.143
42	10.2.146.144/28	10.2.146.145 – 10.2.146.158	10.2.146.159
43	10.2.146.160/28	10.2.146.161 – 10.2.146.174	10.2.146.175
44	10.2.146.176/28	10.2.146.177 – 10.2.146.190	10.2.146.191
45	10.2.146.192/28	10.2.146.193 – 10.2.146.206	10.2.146.207
46	10.2.146.208/28	10.2.146.209 – 10.2.146.222	10.2.146.223
47	10.2.146.224/28	10.2.146.225 – 10.2.146.238	10.2.146.239
48	10.2.146.240/28	10.2.146.241 – 10.2.146.254	10.2.146.255
49	10.2.147.0/28	10.2.147.1 – 10.2.147.14	10.2.147.15
50	10.2.147.16/28	10.2.147.17 – 10.2.147.30	10.2.147.31
51	10.2.147.32/28	10.2.147.33 – 10.2.147.46	10.2.147.47
52	10.2.147.48/28	10.2.147.49 – 10.2.147.62	10.2.147.63
53	10.2.147.64/28	10.2.147.65 – 10.2.147.78	10.2.147.79
54	10.2.147.80/28	10.2.147.81 – 10.2.147.94	10.2.147.95
55	10.2.147.96/28	10.2.147.97 – 10.2.147.110	10.2.147.111
56	10.2.147.112/28	10.2.147.113 – 10.2.147.126	10.2.147.127
57	10.2.147.128/28	10.2.147.129 – 10.2.147.142	10.2.147.143
58	10.2.147.144/28	10.2.147.145 – 10.2.147.158	10.2.147.159
59	10.2.147.160/28	10.2.147.161 – 10.2.147.174	10.2.147.175
60	10.2.147.176/28	10.2.147.177 – 10.2.147.190	10.2.147.191
61	10.2.147.192/28	10.2.147.193 – 10.2.147.206	10.2.147.207
62	10.2.147.208/28	10.2.147.209 – 10.2.147.222	10.2.147.223
63	10.2.147.224/28	10.2.147.225 – 10.2.147.238	10.2.147.239
64	10.2.147.240/28	10.2.147.241 – 10.2.147.254	10.2.147.255
65	10.2.148.0/28	10.2.148.1 – 10.2.148.14	10.2.148.15
66	10.2.148.16/28	10.2.148.17 – 10.2.148.30	10.2.148.31
67	10.2.148.32/28	10.2.148.33 – 10.2.148.46	10.2.148.47
68	10.2.148.48/28	10.2.148.49 – 10.2.148.62	10.2.148.63
69	10.2.148.64/28	10.2.148.65 – 10.2.148.78	10.2.148.79
70	10.2.148.80/28	10.2.148.81 – 10.2.148.94	10.2.148.95
71	10.2.148.96/28	10.2.148.97 – 10.2.148.110	10.2.148.111
72	10.2.148.112/28	10.2.148.113 – 10.2.148.126	10.2.148.127
73	10.2.148.128/28	10.2.148.129 – 10.2.148.142	10.2.148.143
74	10.2.148.144/28	10.2.148.145 – 10.2.148.158	10.2.148.159
75	10.2.148.160/28	10.2.148.161 – 10.2.148.174	10.2.148.175
76	10.2.148.176/28	10.2.148.177 – 10.2.148.190	10.2.148.191
77	10.2.148.192/28	10.2.148.193 – 10.2.148.206	10.2.148.207
78	10.2.148.208/28	10.2.148.209 – 10.2.148.222	10.2.148.223
79	10.2.148.224/28	10.2.148.225 – 10.2.148.238	10.2.148.239
80	10.2.148.240/28	10.2.148.241 – 10.2.148.254	10.2.148.255
81	10.2.149.0/28	10.2.149.1 – 10.2.149.14	10.2.149.15
82	10.2.149.16/28	10.2.149.17 – 10.2.149.30	10.2.149.31
83	10.2.149.32/28	10.2.149.33 – 10.2.149.46	10.2.149.47
84	10.2.149.48/28	10.2.149.49 – 10.2.149.62	10.2.149.63
85	10.2.149.64/28	10.2.149.65 – 10.2.149.78	10.2.149.79
86	10.2.149.80/28	10.2.149.81 – 10.2.149.94	10.2.149.95
87	10.2.149.96/28	10.2.149.97 – 10.2.149.110	10.2.149.111
88	10.2.149.112/28	10.2.149.113 – 10.2.149.126	10.2.149.127
89	10.2.149.128/28	10.2.149.129 – 10.2.149.142	10.2.149.143
90	10.2.149.144/28	10.2.149.145 – 10.2.149.158	10.2.149.159
91	10.2.149.160/28	10.2.149.161 – 10.2.149.174	10.2.149.175
92	10.2.149.176/28	10.2.149.177 – 10.2.149.190	10.2.149.191
93	10.2.149.192/28	10.2.149.193 – 10.2.149.206	10.2.149.207
94	10.2.149.208/28	10.2.149.209 – 10.2.149.222	10.2.149.223
95	10.2.149.224/28	10.2.149.225 – 10.2.149.238	10.2.149.239
96	10.2.149.240/28	10.2.149.241 – 10.2.149.254	10.2.149.255
97	10.2.150.0/28	10.2.150.1 – 10.2.150.14	10.2.150.15
98	10.2.150.16/28	10.2.150.17 – 10.2.150.30	10.2.150.31
99	10.2.150.32/28	10.2.150.33 – 10.2.150.46	10.2.150.47
100	10.2.150.48/28	10.2.150.49 – 10.2.150.62	10.2.150.63
101	10.2.150.64/28	10.2.150.65 – 10.2.150.78	10.2.150.79
102	10.2.150.80/28	10.2.150.81 – 10.2.150.94	10.2.150.95
103	10.2.150.96/28	10.2.150.97 – 10.2.150.110	10.2.150.111
104	10.2.150.112/28	10.2.150.113 – 10.2.150.126	10.2.150.127
105	10.2.150.128/28	10.2.150.129 – 10.2.150.142	10.2.150.143
106	10.2.150.144/28	10.2.150.145 – 10.2.150.158	10.2.150.159
107	10.2.150.160/28	10.2.150.161 – 10.2.150.174	10.2.150.175
108	10.2.150.176/28	10.2.150.177 – 10.2.150.190	10.2.150.191
109	10.2.150.192/28	10.2.150.193 – 10.2.150.206	10.2.150.207
110	10.2.150.208/28	10.2.150.209 – 10.2.150.222	10.2.150.223
111	10.2.150.224/28	10.2.150.225 – 10.2.150.238	10.2.150.239
112	10.2.150.240/28	10.2.150.241 – 10.2.150.254	10.2.150.255
113	10.2.151.0/28	10.2.151.1 – 10.2.151.14	10.2.151.15
114	10.2.151.16/28	10.2.151.17 – 10.2.151.30	10.2.151.31
115	10.2.151.32/28	10.2.151.33 – 10.2.151.46	10.2.151.47
116	10.2.151.48/28	10.2.151.49 – 10.2.151.62	10.2.151.63
117	10.2.151.64/28	10.2.151.65 – 10.2.151.78	10.2.151.79
118	10.2.151.80/28	10.2.151.81 – 10.2.151.94	10.2.151.95
119	10.2.151.96/28	10.2.151.97 – 10.2.151.110	10.2.151.111
120	10.2.151.112/28	10.2.151.113 – 10.2.151.126	10.2.151.127
121	10.2.151.128/28	10.2.151.129 – 10.2.151.142	10.2.151.143
122	10.2.151.144/28	10.2.151.145 – 10.2.151.158	10.2.151.159
123	10.2.151.160/28	10.2.151.161 – 10.2.151.174	10.2.151.175
124	10.2.151.176/28	10.2.151.177 – 10.2.151.190	10.2.151.191
125	10.2.151.192/28	10.2.151.193 – 10.2.151.206	10.2.151.207
126	10.2.151.208/28	10.2.151.209 – 10.2.151.222	10.2.151.223
127	10.2.151.224/28	10.2.151.225 – 10.2.151.238	10.2.151.239
128	10.2.151.240/28	10.2.151.241 – 10.2.151.254	10.2.151.255

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 →