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)10.3.32.0/21

network10.3.32.0/21

broadcast10.3.39.255

first host10.3.32.1

last host10.3.39.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.3.32.0/21

address00001010.00000011.00100000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000011.00100000.00000000

broadcast00001010.00000011.00100111.11111111

green = network part, grey = host part

hex0x0a032000

decimal167976960

reverse dns0.32.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:2000

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.3.32.0/28	10.3.32.1 – 10.3.32.14	10.3.32.15
2	10.3.32.16/28	10.3.32.17 – 10.3.32.30	10.3.32.31
3	10.3.32.32/28	10.3.32.33 – 10.3.32.46	10.3.32.47
4	10.3.32.48/28	10.3.32.49 – 10.3.32.62	10.3.32.63
5	10.3.32.64/28	10.3.32.65 – 10.3.32.78	10.3.32.79
6	10.3.32.80/28	10.3.32.81 – 10.3.32.94	10.3.32.95
7	10.3.32.96/28	10.3.32.97 – 10.3.32.110	10.3.32.111
8	10.3.32.112/28	10.3.32.113 – 10.3.32.126	10.3.32.127
9	10.3.32.128/28	10.3.32.129 – 10.3.32.142	10.3.32.143
10	10.3.32.144/28	10.3.32.145 – 10.3.32.158	10.3.32.159
11	10.3.32.160/28	10.3.32.161 – 10.3.32.174	10.3.32.175
12	10.3.32.176/28	10.3.32.177 – 10.3.32.190	10.3.32.191
13	10.3.32.192/28	10.3.32.193 – 10.3.32.206	10.3.32.207
14	10.3.32.208/28	10.3.32.209 – 10.3.32.222	10.3.32.223
15	10.3.32.224/28	10.3.32.225 – 10.3.32.238	10.3.32.239
16	10.3.32.240/28	10.3.32.241 – 10.3.32.254	10.3.32.255
17	10.3.33.0/28	10.3.33.1 – 10.3.33.14	10.3.33.15
18	10.3.33.16/28	10.3.33.17 – 10.3.33.30	10.3.33.31
19	10.3.33.32/28	10.3.33.33 – 10.3.33.46	10.3.33.47
20	10.3.33.48/28	10.3.33.49 – 10.3.33.62	10.3.33.63
21	10.3.33.64/28	10.3.33.65 – 10.3.33.78	10.3.33.79
22	10.3.33.80/28	10.3.33.81 – 10.3.33.94	10.3.33.95
23	10.3.33.96/28	10.3.33.97 – 10.3.33.110	10.3.33.111
24	10.3.33.112/28	10.3.33.113 – 10.3.33.126	10.3.33.127
25	10.3.33.128/28	10.3.33.129 – 10.3.33.142	10.3.33.143
26	10.3.33.144/28	10.3.33.145 – 10.3.33.158	10.3.33.159
27	10.3.33.160/28	10.3.33.161 – 10.3.33.174	10.3.33.175
28	10.3.33.176/28	10.3.33.177 – 10.3.33.190	10.3.33.191
29	10.3.33.192/28	10.3.33.193 – 10.3.33.206	10.3.33.207
30	10.3.33.208/28	10.3.33.209 – 10.3.33.222	10.3.33.223
31	10.3.33.224/28	10.3.33.225 – 10.3.33.238	10.3.33.239
32	10.3.33.240/28	10.3.33.241 – 10.3.33.254	10.3.33.255
33	10.3.34.0/28	10.3.34.1 – 10.3.34.14	10.3.34.15
34	10.3.34.16/28	10.3.34.17 – 10.3.34.30	10.3.34.31
35	10.3.34.32/28	10.3.34.33 – 10.3.34.46	10.3.34.47
36	10.3.34.48/28	10.3.34.49 – 10.3.34.62	10.3.34.63
37	10.3.34.64/28	10.3.34.65 – 10.3.34.78	10.3.34.79
38	10.3.34.80/28	10.3.34.81 – 10.3.34.94	10.3.34.95
39	10.3.34.96/28	10.3.34.97 – 10.3.34.110	10.3.34.111
40	10.3.34.112/28	10.3.34.113 – 10.3.34.126	10.3.34.127
41	10.3.34.128/28	10.3.34.129 – 10.3.34.142	10.3.34.143
42	10.3.34.144/28	10.3.34.145 – 10.3.34.158	10.3.34.159
43	10.3.34.160/28	10.3.34.161 – 10.3.34.174	10.3.34.175
44	10.3.34.176/28	10.3.34.177 – 10.3.34.190	10.3.34.191
45	10.3.34.192/28	10.3.34.193 – 10.3.34.206	10.3.34.207
46	10.3.34.208/28	10.3.34.209 – 10.3.34.222	10.3.34.223
47	10.3.34.224/28	10.3.34.225 – 10.3.34.238	10.3.34.239
48	10.3.34.240/28	10.3.34.241 – 10.3.34.254	10.3.34.255
49	10.3.35.0/28	10.3.35.1 – 10.3.35.14	10.3.35.15
50	10.3.35.16/28	10.3.35.17 – 10.3.35.30	10.3.35.31
51	10.3.35.32/28	10.3.35.33 – 10.3.35.46	10.3.35.47
52	10.3.35.48/28	10.3.35.49 – 10.3.35.62	10.3.35.63
53	10.3.35.64/28	10.3.35.65 – 10.3.35.78	10.3.35.79
54	10.3.35.80/28	10.3.35.81 – 10.3.35.94	10.3.35.95
55	10.3.35.96/28	10.3.35.97 – 10.3.35.110	10.3.35.111
56	10.3.35.112/28	10.3.35.113 – 10.3.35.126	10.3.35.127
57	10.3.35.128/28	10.3.35.129 – 10.3.35.142	10.3.35.143
58	10.3.35.144/28	10.3.35.145 – 10.3.35.158	10.3.35.159
59	10.3.35.160/28	10.3.35.161 – 10.3.35.174	10.3.35.175
60	10.3.35.176/28	10.3.35.177 – 10.3.35.190	10.3.35.191
61	10.3.35.192/28	10.3.35.193 – 10.3.35.206	10.3.35.207
62	10.3.35.208/28	10.3.35.209 – 10.3.35.222	10.3.35.223
63	10.3.35.224/28	10.3.35.225 – 10.3.35.238	10.3.35.239
64	10.3.35.240/28	10.3.35.241 – 10.3.35.254	10.3.35.255
65	10.3.36.0/28	10.3.36.1 – 10.3.36.14	10.3.36.15
66	10.3.36.16/28	10.3.36.17 – 10.3.36.30	10.3.36.31
67	10.3.36.32/28	10.3.36.33 – 10.3.36.46	10.3.36.47
68	10.3.36.48/28	10.3.36.49 – 10.3.36.62	10.3.36.63
69	10.3.36.64/28	10.3.36.65 – 10.3.36.78	10.3.36.79
70	10.3.36.80/28	10.3.36.81 – 10.3.36.94	10.3.36.95
71	10.3.36.96/28	10.3.36.97 – 10.3.36.110	10.3.36.111
72	10.3.36.112/28	10.3.36.113 – 10.3.36.126	10.3.36.127
73	10.3.36.128/28	10.3.36.129 – 10.3.36.142	10.3.36.143
74	10.3.36.144/28	10.3.36.145 – 10.3.36.158	10.3.36.159
75	10.3.36.160/28	10.3.36.161 – 10.3.36.174	10.3.36.175
76	10.3.36.176/28	10.3.36.177 – 10.3.36.190	10.3.36.191
77	10.3.36.192/28	10.3.36.193 – 10.3.36.206	10.3.36.207
78	10.3.36.208/28	10.3.36.209 – 10.3.36.222	10.3.36.223
79	10.3.36.224/28	10.3.36.225 – 10.3.36.238	10.3.36.239
80	10.3.36.240/28	10.3.36.241 – 10.3.36.254	10.3.36.255
81	10.3.37.0/28	10.3.37.1 – 10.3.37.14	10.3.37.15
82	10.3.37.16/28	10.3.37.17 – 10.3.37.30	10.3.37.31
83	10.3.37.32/28	10.3.37.33 – 10.3.37.46	10.3.37.47
84	10.3.37.48/28	10.3.37.49 – 10.3.37.62	10.3.37.63
85	10.3.37.64/28	10.3.37.65 – 10.3.37.78	10.3.37.79
86	10.3.37.80/28	10.3.37.81 – 10.3.37.94	10.3.37.95
87	10.3.37.96/28	10.3.37.97 – 10.3.37.110	10.3.37.111
88	10.3.37.112/28	10.3.37.113 – 10.3.37.126	10.3.37.127
89	10.3.37.128/28	10.3.37.129 – 10.3.37.142	10.3.37.143
90	10.3.37.144/28	10.3.37.145 – 10.3.37.158	10.3.37.159
91	10.3.37.160/28	10.3.37.161 – 10.3.37.174	10.3.37.175
92	10.3.37.176/28	10.3.37.177 – 10.3.37.190	10.3.37.191
93	10.3.37.192/28	10.3.37.193 – 10.3.37.206	10.3.37.207
94	10.3.37.208/28	10.3.37.209 – 10.3.37.222	10.3.37.223
95	10.3.37.224/28	10.3.37.225 – 10.3.37.238	10.3.37.239
96	10.3.37.240/28	10.3.37.241 – 10.3.37.254	10.3.37.255
97	10.3.38.0/28	10.3.38.1 – 10.3.38.14	10.3.38.15
98	10.3.38.16/28	10.3.38.17 – 10.3.38.30	10.3.38.31
99	10.3.38.32/28	10.3.38.33 – 10.3.38.46	10.3.38.47
100	10.3.38.48/28	10.3.38.49 – 10.3.38.62	10.3.38.63
101	10.3.38.64/28	10.3.38.65 – 10.3.38.78	10.3.38.79
102	10.3.38.80/28	10.3.38.81 – 10.3.38.94	10.3.38.95
103	10.3.38.96/28	10.3.38.97 – 10.3.38.110	10.3.38.111
104	10.3.38.112/28	10.3.38.113 – 10.3.38.126	10.3.38.127
105	10.3.38.128/28	10.3.38.129 – 10.3.38.142	10.3.38.143
106	10.3.38.144/28	10.3.38.145 – 10.3.38.158	10.3.38.159
107	10.3.38.160/28	10.3.38.161 – 10.3.38.174	10.3.38.175
108	10.3.38.176/28	10.3.38.177 – 10.3.38.190	10.3.38.191
109	10.3.38.192/28	10.3.38.193 – 10.3.38.206	10.3.38.207
110	10.3.38.208/28	10.3.38.209 – 10.3.38.222	10.3.38.223
111	10.3.38.224/28	10.3.38.225 – 10.3.38.238	10.3.38.239
112	10.3.38.240/28	10.3.38.241 – 10.3.38.254	10.3.38.255
113	10.3.39.0/28	10.3.39.1 – 10.3.39.14	10.3.39.15
114	10.3.39.16/28	10.3.39.17 – 10.3.39.30	10.3.39.31
115	10.3.39.32/28	10.3.39.33 – 10.3.39.46	10.3.39.47
116	10.3.39.48/28	10.3.39.49 – 10.3.39.62	10.3.39.63
117	10.3.39.64/28	10.3.39.65 – 10.3.39.78	10.3.39.79
118	10.3.39.80/28	10.3.39.81 – 10.3.39.94	10.3.39.95
119	10.3.39.96/28	10.3.39.97 – 10.3.39.110	10.3.39.111
120	10.3.39.112/28	10.3.39.113 – 10.3.39.126	10.3.39.127
121	10.3.39.128/28	10.3.39.129 – 10.3.39.142	10.3.39.143
122	10.3.39.144/28	10.3.39.145 – 10.3.39.158	10.3.39.159
123	10.3.39.160/28	10.3.39.161 – 10.3.39.174	10.3.39.175
124	10.3.39.176/28	10.3.39.177 – 10.3.39.190	10.3.39.191
125	10.3.39.192/28	10.3.39.193 – 10.3.39.206	10.3.39.207
126	10.3.39.208/28	10.3.39.209 – 10.3.39.222	10.3.39.223
127	10.3.39.224/28	10.3.39.225 – 10.3.39.238	10.3.39.239
128	10.3.39.240/28	10.3.39.241 – 10.3.39.254	10.3.39.255

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 →