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)10.5.24.0/21

network10.5.24.0/21

broadcast10.5.31.255

first host10.5.24.1

last host10.5.31.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.5.24.0/21

address00001010.00000101.00011000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000101.00011000.00000000

broadcast00001010.00000101.00011111.11111111

green = network part, grey = host part

hex0x0a051800

decimal168105984

reverse dns0.24.5.10.in-addr.arpa

ipv4-mapped::ffff:a05:1800

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.5.24.0/28	10.5.24.1 – 10.5.24.14	10.5.24.15
2	10.5.24.16/28	10.5.24.17 – 10.5.24.30	10.5.24.31
3	10.5.24.32/28	10.5.24.33 – 10.5.24.46	10.5.24.47
4	10.5.24.48/28	10.5.24.49 – 10.5.24.62	10.5.24.63
5	10.5.24.64/28	10.5.24.65 – 10.5.24.78	10.5.24.79
6	10.5.24.80/28	10.5.24.81 – 10.5.24.94	10.5.24.95
7	10.5.24.96/28	10.5.24.97 – 10.5.24.110	10.5.24.111
8	10.5.24.112/28	10.5.24.113 – 10.5.24.126	10.5.24.127
9	10.5.24.128/28	10.5.24.129 – 10.5.24.142	10.5.24.143
10	10.5.24.144/28	10.5.24.145 – 10.5.24.158	10.5.24.159
11	10.5.24.160/28	10.5.24.161 – 10.5.24.174	10.5.24.175
12	10.5.24.176/28	10.5.24.177 – 10.5.24.190	10.5.24.191
13	10.5.24.192/28	10.5.24.193 – 10.5.24.206	10.5.24.207
14	10.5.24.208/28	10.5.24.209 – 10.5.24.222	10.5.24.223
15	10.5.24.224/28	10.5.24.225 – 10.5.24.238	10.5.24.239
16	10.5.24.240/28	10.5.24.241 – 10.5.24.254	10.5.24.255
17	10.5.25.0/28	10.5.25.1 – 10.5.25.14	10.5.25.15
18	10.5.25.16/28	10.5.25.17 – 10.5.25.30	10.5.25.31
19	10.5.25.32/28	10.5.25.33 – 10.5.25.46	10.5.25.47
20	10.5.25.48/28	10.5.25.49 – 10.5.25.62	10.5.25.63
21	10.5.25.64/28	10.5.25.65 – 10.5.25.78	10.5.25.79
22	10.5.25.80/28	10.5.25.81 – 10.5.25.94	10.5.25.95
23	10.5.25.96/28	10.5.25.97 – 10.5.25.110	10.5.25.111
24	10.5.25.112/28	10.5.25.113 – 10.5.25.126	10.5.25.127
25	10.5.25.128/28	10.5.25.129 – 10.5.25.142	10.5.25.143
26	10.5.25.144/28	10.5.25.145 – 10.5.25.158	10.5.25.159
27	10.5.25.160/28	10.5.25.161 – 10.5.25.174	10.5.25.175
28	10.5.25.176/28	10.5.25.177 – 10.5.25.190	10.5.25.191
29	10.5.25.192/28	10.5.25.193 – 10.5.25.206	10.5.25.207
30	10.5.25.208/28	10.5.25.209 – 10.5.25.222	10.5.25.223
31	10.5.25.224/28	10.5.25.225 – 10.5.25.238	10.5.25.239
32	10.5.25.240/28	10.5.25.241 – 10.5.25.254	10.5.25.255
33	10.5.26.0/28	10.5.26.1 – 10.5.26.14	10.5.26.15
34	10.5.26.16/28	10.5.26.17 – 10.5.26.30	10.5.26.31
35	10.5.26.32/28	10.5.26.33 – 10.5.26.46	10.5.26.47
36	10.5.26.48/28	10.5.26.49 – 10.5.26.62	10.5.26.63
37	10.5.26.64/28	10.5.26.65 – 10.5.26.78	10.5.26.79
38	10.5.26.80/28	10.5.26.81 – 10.5.26.94	10.5.26.95
39	10.5.26.96/28	10.5.26.97 – 10.5.26.110	10.5.26.111
40	10.5.26.112/28	10.5.26.113 – 10.5.26.126	10.5.26.127
41	10.5.26.128/28	10.5.26.129 – 10.5.26.142	10.5.26.143
42	10.5.26.144/28	10.5.26.145 – 10.5.26.158	10.5.26.159
43	10.5.26.160/28	10.5.26.161 – 10.5.26.174	10.5.26.175
44	10.5.26.176/28	10.5.26.177 – 10.5.26.190	10.5.26.191
45	10.5.26.192/28	10.5.26.193 – 10.5.26.206	10.5.26.207
46	10.5.26.208/28	10.5.26.209 – 10.5.26.222	10.5.26.223
47	10.5.26.224/28	10.5.26.225 – 10.5.26.238	10.5.26.239
48	10.5.26.240/28	10.5.26.241 – 10.5.26.254	10.5.26.255
49	10.5.27.0/28	10.5.27.1 – 10.5.27.14	10.5.27.15
50	10.5.27.16/28	10.5.27.17 – 10.5.27.30	10.5.27.31
51	10.5.27.32/28	10.5.27.33 – 10.5.27.46	10.5.27.47
52	10.5.27.48/28	10.5.27.49 – 10.5.27.62	10.5.27.63
53	10.5.27.64/28	10.5.27.65 – 10.5.27.78	10.5.27.79
54	10.5.27.80/28	10.5.27.81 – 10.5.27.94	10.5.27.95
55	10.5.27.96/28	10.5.27.97 – 10.5.27.110	10.5.27.111
56	10.5.27.112/28	10.5.27.113 – 10.5.27.126	10.5.27.127
57	10.5.27.128/28	10.5.27.129 – 10.5.27.142	10.5.27.143
58	10.5.27.144/28	10.5.27.145 – 10.5.27.158	10.5.27.159
59	10.5.27.160/28	10.5.27.161 – 10.5.27.174	10.5.27.175
60	10.5.27.176/28	10.5.27.177 – 10.5.27.190	10.5.27.191
61	10.5.27.192/28	10.5.27.193 – 10.5.27.206	10.5.27.207
62	10.5.27.208/28	10.5.27.209 – 10.5.27.222	10.5.27.223
63	10.5.27.224/28	10.5.27.225 – 10.5.27.238	10.5.27.239
64	10.5.27.240/28	10.5.27.241 – 10.5.27.254	10.5.27.255
65	10.5.28.0/28	10.5.28.1 – 10.5.28.14	10.5.28.15
66	10.5.28.16/28	10.5.28.17 – 10.5.28.30	10.5.28.31
67	10.5.28.32/28	10.5.28.33 – 10.5.28.46	10.5.28.47
68	10.5.28.48/28	10.5.28.49 – 10.5.28.62	10.5.28.63
69	10.5.28.64/28	10.5.28.65 – 10.5.28.78	10.5.28.79
70	10.5.28.80/28	10.5.28.81 – 10.5.28.94	10.5.28.95
71	10.5.28.96/28	10.5.28.97 – 10.5.28.110	10.5.28.111
72	10.5.28.112/28	10.5.28.113 – 10.5.28.126	10.5.28.127
73	10.5.28.128/28	10.5.28.129 – 10.5.28.142	10.5.28.143
74	10.5.28.144/28	10.5.28.145 – 10.5.28.158	10.5.28.159
75	10.5.28.160/28	10.5.28.161 – 10.5.28.174	10.5.28.175
76	10.5.28.176/28	10.5.28.177 – 10.5.28.190	10.5.28.191
77	10.5.28.192/28	10.5.28.193 – 10.5.28.206	10.5.28.207
78	10.5.28.208/28	10.5.28.209 – 10.5.28.222	10.5.28.223
79	10.5.28.224/28	10.5.28.225 – 10.5.28.238	10.5.28.239
80	10.5.28.240/28	10.5.28.241 – 10.5.28.254	10.5.28.255
81	10.5.29.0/28	10.5.29.1 – 10.5.29.14	10.5.29.15
82	10.5.29.16/28	10.5.29.17 – 10.5.29.30	10.5.29.31
83	10.5.29.32/28	10.5.29.33 – 10.5.29.46	10.5.29.47
84	10.5.29.48/28	10.5.29.49 – 10.5.29.62	10.5.29.63
85	10.5.29.64/28	10.5.29.65 – 10.5.29.78	10.5.29.79
86	10.5.29.80/28	10.5.29.81 – 10.5.29.94	10.5.29.95
87	10.5.29.96/28	10.5.29.97 – 10.5.29.110	10.5.29.111
88	10.5.29.112/28	10.5.29.113 – 10.5.29.126	10.5.29.127
89	10.5.29.128/28	10.5.29.129 – 10.5.29.142	10.5.29.143
90	10.5.29.144/28	10.5.29.145 – 10.5.29.158	10.5.29.159
91	10.5.29.160/28	10.5.29.161 – 10.5.29.174	10.5.29.175
92	10.5.29.176/28	10.5.29.177 – 10.5.29.190	10.5.29.191
93	10.5.29.192/28	10.5.29.193 – 10.5.29.206	10.5.29.207
94	10.5.29.208/28	10.5.29.209 – 10.5.29.222	10.5.29.223
95	10.5.29.224/28	10.5.29.225 – 10.5.29.238	10.5.29.239
96	10.5.29.240/28	10.5.29.241 – 10.5.29.254	10.5.29.255
97	10.5.30.0/28	10.5.30.1 – 10.5.30.14	10.5.30.15
98	10.5.30.16/28	10.5.30.17 – 10.5.30.30	10.5.30.31
99	10.5.30.32/28	10.5.30.33 – 10.5.30.46	10.5.30.47
100	10.5.30.48/28	10.5.30.49 – 10.5.30.62	10.5.30.63
101	10.5.30.64/28	10.5.30.65 – 10.5.30.78	10.5.30.79
102	10.5.30.80/28	10.5.30.81 – 10.5.30.94	10.5.30.95
103	10.5.30.96/28	10.5.30.97 – 10.5.30.110	10.5.30.111
104	10.5.30.112/28	10.5.30.113 – 10.5.30.126	10.5.30.127
105	10.5.30.128/28	10.5.30.129 – 10.5.30.142	10.5.30.143
106	10.5.30.144/28	10.5.30.145 – 10.5.30.158	10.5.30.159
107	10.5.30.160/28	10.5.30.161 – 10.5.30.174	10.5.30.175
108	10.5.30.176/28	10.5.30.177 – 10.5.30.190	10.5.30.191
109	10.5.30.192/28	10.5.30.193 – 10.5.30.206	10.5.30.207
110	10.5.30.208/28	10.5.30.209 – 10.5.30.222	10.5.30.223
111	10.5.30.224/28	10.5.30.225 – 10.5.30.238	10.5.30.239
112	10.5.30.240/28	10.5.30.241 – 10.5.30.254	10.5.30.255
113	10.5.31.0/28	10.5.31.1 – 10.5.31.14	10.5.31.15
114	10.5.31.16/28	10.5.31.17 – 10.5.31.30	10.5.31.31
115	10.5.31.32/28	10.5.31.33 – 10.5.31.46	10.5.31.47
116	10.5.31.48/28	10.5.31.49 – 10.5.31.62	10.5.31.63
117	10.5.31.64/28	10.5.31.65 – 10.5.31.78	10.5.31.79
118	10.5.31.80/28	10.5.31.81 – 10.5.31.94	10.5.31.95
119	10.5.31.96/28	10.5.31.97 – 10.5.31.110	10.5.31.111
120	10.5.31.112/28	10.5.31.113 – 10.5.31.126	10.5.31.127
121	10.5.31.128/28	10.5.31.129 – 10.5.31.142	10.5.31.143
122	10.5.31.144/28	10.5.31.145 – 10.5.31.158	10.5.31.159
123	10.5.31.160/28	10.5.31.161 – 10.5.31.174	10.5.31.175
124	10.5.31.176/28	10.5.31.177 – 10.5.31.190	10.5.31.191
125	10.5.31.192/28	10.5.31.193 – 10.5.31.206	10.5.31.207
126	10.5.31.208/28	10.5.31.209 – 10.5.31.222	10.5.31.223
127	10.5.31.224/28	10.5.31.225 – 10.5.31.238	10.5.31.239
128	10.5.31.240/28	10.5.31.241 – 10.5.31.254	10.5.31.255

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 →