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)10.3.96.0/21

network10.3.96.0/21

broadcast10.3.103.255

first host10.3.96.1

last host10.3.103.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.3.96.0/21

address00001010.00000011.01100000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000011.01100000.00000000

broadcast00001010.00000011.01100111.11111111

green = network part, grey = host part

hex0x0a036000

decimal167993344

reverse dns0.96.3.10.in-addr.arpa

ipv4-mapped::ffff:a03:6000

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.3.96.0/28	10.3.96.1 – 10.3.96.14	10.3.96.15
2	10.3.96.16/28	10.3.96.17 – 10.3.96.30	10.3.96.31
3	10.3.96.32/28	10.3.96.33 – 10.3.96.46	10.3.96.47
4	10.3.96.48/28	10.3.96.49 – 10.3.96.62	10.3.96.63
5	10.3.96.64/28	10.3.96.65 – 10.3.96.78	10.3.96.79
6	10.3.96.80/28	10.3.96.81 – 10.3.96.94	10.3.96.95
7	10.3.96.96/28	10.3.96.97 – 10.3.96.110	10.3.96.111
8	10.3.96.112/28	10.3.96.113 – 10.3.96.126	10.3.96.127
9	10.3.96.128/28	10.3.96.129 – 10.3.96.142	10.3.96.143
10	10.3.96.144/28	10.3.96.145 – 10.3.96.158	10.3.96.159
11	10.3.96.160/28	10.3.96.161 – 10.3.96.174	10.3.96.175
12	10.3.96.176/28	10.3.96.177 – 10.3.96.190	10.3.96.191
13	10.3.96.192/28	10.3.96.193 – 10.3.96.206	10.3.96.207
14	10.3.96.208/28	10.3.96.209 – 10.3.96.222	10.3.96.223
15	10.3.96.224/28	10.3.96.225 – 10.3.96.238	10.3.96.239
16	10.3.96.240/28	10.3.96.241 – 10.3.96.254	10.3.96.255
17	10.3.97.0/28	10.3.97.1 – 10.3.97.14	10.3.97.15
18	10.3.97.16/28	10.3.97.17 – 10.3.97.30	10.3.97.31
19	10.3.97.32/28	10.3.97.33 – 10.3.97.46	10.3.97.47
20	10.3.97.48/28	10.3.97.49 – 10.3.97.62	10.3.97.63
21	10.3.97.64/28	10.3.97.65 – 10.3.97.78	10.3.97.79
22	10.3.97.80/28	10.3.97.81 – 10.3.97.94	10.3.97.95
23	10.3.97.96/28	10.3.97.97 – 10.3.97.110	10.3.97.111
24	10.3.97.112/28	10.3.97.113 – 10.3.97.126	10.3.97.127
25	10.3.97.128/28	10.3.97.129 – 10.3.97.142	10.3.97.143
26	10.3.97.144/28	10.3.97.145 – 10.3.97.158	10.3.97.159
27	10.3.97.160/28	10.3.97.161 – 10.3.97.174	10.3.97.175
28	10.3.97.176/28	10.3.97.177 – 10.3.97.190	10.3.97.191
29	10.3.97.192/28	10.3.97.193 – 10.3.97.206	10.3.97.207
30	10.3.97.208/28	10.3.97.209 – 10.3.97.222	10.3.97.223
31	10.3.97.224/28	10.3.97.225 – 10.3.97.238	10.3.97.239
32	10.3.97.240/28	10.3.97.241 – 10.3.97.254	10.3.97.255
33	10.3.98.0/28	10.3.98.1 – 10.3.98.14	10.3.98.15
34	10.3.98.16/28	10.3.98.17 – 10.3.98.30	10.3.98.31
35	10.3.98.32/28	10.3.98.33 – 10.3.98.46	10.3.98.47
36	10.3.98.48/28	10.3.98.49 – 10.3.98.62	10.3.98.63
37	10.3.98.64/28	10.3.98.65 – 10.3.98.78	10.3.98.79
38	10.3.98.80/28	10.3.98.81 – 10.3.98.94	10.3.98.95
39	10.3.98.96/28	10.3.98.97 – 10.3.98.110	10.3.98.111
40	10.3.98.112/28	10.3.98.113 – 10.3.98.126	10.3.98.127
41	10.3.98.128/28	10.3.98.129 – 10.3.98.142	10.3.98.143
42	10.3.98.144/28	10.3.98.145 – 10.3.98.158	10.3.98.159
43	10.3.98.160/28	10.3.98.161 – 10.3.98.174	10.3.98.175
44	10.3.98.176/28	10.3.98.177 – 10.3.98.190	10.3.98.191
45	10.3.98.192/28	10.3.98.193 – 10.3.98.206	10.3.98.207
46	10.3.98.208/28	10.3.98.209 – 10.3.98.222	10.3.98.223
47	10.3.98.224/28	10.3.98.225 – 10.3.98.238	10.3.98.239
48	10.3.98.240/28	10.3.98.241 – 10.3.98.254	10.3.98.255
49	10.3.99.0/28	10.3.99.1 – 10.3.99.14	10.3.99.15
50	10.3.99.16/28	10.3.99.17 – 10.3.99.30	10.3.99.31
51	10.3.99.32/28	10.3.99.33 – 10.3.99.46	10.3.99.47
52	10.3.99.48/28	10.3.99.49 – 10.3.99.62	10.3.99.63
53	10.3.99.64/28	10.3.99.65 – 10.3.99.78	10.3.99.79
54	10.3.99.80/28	10.3.99.81 – 10.3.99.94	10.3.99.95
55	10.3.99.96/28	10.3.99.97 – 10.3.99.110	10.3.99.111
56	10.3.99.112/28	10.3.99.113 – 10.3.99.126	10.3.99.127
57	10.3.99.128/28	10.3.99.129 – 10.3.99.142	10.3.99.143
58	10.3.99.144/28	10.3.99.145 – 10.3.99.158	10.3.99.159
59	10.3.99.160/28	10.3.99.161 – 10.3.99.174	10.3.99.175
60	10.3.99.176/28	10.3.99.177 – 10.3.99.190	10.3.99.191
61	10.3.99.192/28	10.3.99.193 – 10.3.99.206	10.3.99.207
62	10.3.99.208/28	10.3.99.209 – 10.3.99.222	10.3.99.223
63	10.3.99.224/28	10.3.99.225 – 10.3.99.238	10.3.99.239
64	10.3.99.240/28	10.3.99.241 – 10.3.99.254	10.3.99.255
65	10.3.100.0/28	10.3.100.1 – 10.3.100.14	10.3.100.15
66	10.3.100.16/28	10.3.100.17 – 10.3.100.30	10.3.100.31
67	10.3.100.32/28	10.3.100.33 – 10.3.100.46	10.3.100.47
68	10.3.100.48/28	10.3.100.49 – 10.3.100.62	10.3.100.63
69	10.3.100.64/28	10.3.100.65 – 10.3.100.78	10.3.100.79
70	10.3.100.80/28	10.3.100.81 – 10.3.100.94	10.3.100.95
71	10.3.100.96/28	10.3.100.97 – 10.3.100.110	10.3.100.111
72	10.3.100.112/28	10.3.100.113 – 10.3.100.126	10.3.100.127
73	10.3.100.128/28	10.3.100.129 – 10.3.100.142	10.3.100.143
74	10.3.100.144/28	10.3.100.145 – 10.3.100.158	10.3.100.159
75	10.3.100.160/28	10.3.100.161 – 10.3.100.174	10.3.100.175
76	10.3.100.176/28	10.3.100.177 – 10.3.100.190	10.3.100.191
77	10.3.100.192/28	10.3.100.193 – 10.3.100.206	10.3.100.207
78	10.3.100.208/28	10.3.100.209 – 10.3.100.222	10.3.100.223
79	10.3.100.224/28	10.3.100.225 – 10.3.100.238	10.3.100.239
80	10.3.100.240/28	10.3.100.241 – 10.3.100.254	10.3.100.255
81	10.3.101.0/28	10.3.101.1 – 10.3.101.14	10.3.101.15
82	10.3.101.16/28	10.3.101.17 – 10.3.101.30	10.3.101.31
83	10.3.101.32/28	10.3.101.33 – 10.3.101.46	10.3.101.47
84	10.3.101.48/28	10.3.101.49 – 10.3.101.62	10.3.101.63
85	10.3.101.64/28	10.3.101.65 – 10.3.101.78	10.3.101.79
86	10.3.101.80/28	10.3.101.81 – 10.3.101.94	10.3.101.95
87	10.3.101.96/28	10.3.101.97 – 10.3.101.110	10.3.101.111
88	10.3.101.112/28	10.3.101.113 – 10.3.101.126	10.3.101.127
89	10.3.101.128/28	10.3.101.129 – 10.3.101.142	10.3.101.143
90	10.3.101.144/28	10.3.101.145 – 10.3.101.158	10.3.101.159
91	10.3.101.160/28	10.3.101.161 – 10.3.101.174	10.3.101.175
92	10.3.101.176/28	10.3.101.177 – 10.3.101.190	10.3.101.191
93	10.3.101.192/28	10.3.101.193 – 10.3.101.206	10.3.101.207
94	10.3.101.208/28	10.3.101.209 – 10.3.101.222	10.3.101.223
95	10.3.101.224/28	10.3.101.225 – 10.3.101.238	10.3.101.239
96	10.3.101.240/28	10.3.101.241 – 10.3.101.254	10.3.101.255
97	10.3.102.0/28	10.3.102.1 – 10.3.102.14	10.3.102.15
98	10.3.102.16/28	10.3.102.17 – 10.3.102.30	10.3.102.31
99	10.3.102.32/28	10.3.102.33 – 10.3.102.46	10.3.102.47
100	10.3.102.48/28	10.3.102.49 – 10.3.102.62	10.3.102.63
101	10.3.102.64/28	10.3.102.65 – 10.3.102.78	10.3.102.79
102	10.3.102.80/28	10.3.102.81 – 10.3.102.94	10.3.102.95
103	10.3.102.96/28	10.3.102.97 – 10.3.102.110	10.3.102.111
104	10.3.102.112/28	10.3.102.113 – 10.3.102.126	10.3.102.127
105	10.3.102.128/28	10.3.102.129 – 10.3.102.142	10.3.102.143
106	10.3.102.144/28	10.3.102.145 – 10.3.102.158	10.3.102.159
107	10.3.102.160/28	10.3.102.161 – 10.3.102.174	10.3.102.175
108	10.3.102.176/28	10.3.102.177 – 10.3.102.190	10.3.102.191
109	10.3.102.192/28	10.3.102.193 – 10.3.102.206	10.3.102.207
110	10.3.102.208/28	10.3.102.209 – 10.3.102.222	10.3.102.223
111	10.3.102.224/28	10.3.102.225 – 10.3.102.238	10.3.102.239
112	10.3.102.240/28	10.3.102.241 – 10.3.102.254	10.3.102.255
113	10.3.103.0/28	10.3.103.1 – 10.3.103.14	10.3.103.15
114	10.3.103.16/28	10.3.103.17 – 10.3.103.30	10.3.103.31
115	10.3.103.32/28	10.3.103.33 – 10.3.103.46	10.3.103.47
116	10.3.103.48/28	10.3.103.49 – 10.3.103.62	10.3.103.63
117	10.3.103.64/28	10.3.103.65 – 10.3.103.78	10.3.103.79
118	10.3.103.80/28	10.3.103.81 – 10.3.103.94	10.3.103.95
119	10.3.103.96/28	10.3.103.97 – 10.3.103.110	10.3.103.111
120	10.3.103.112/28	10.3.103.113 – 10.3.103.126	10.3.103.127
121	10.3.103.128/28	10.3.103.129 – 10.3.103.142	10.3.103.143
122	10.3.103.144/28	10.3.103.145 – 10.3.103.158	10.3.103.159
123	10.3.103.160/28	10.3.103.161 – 10.3.103.174	10.3.103.175
124	10.3.103.176/28	10.3.103.177 – 10.3.103.190	10.3.103.191
125	10.3.103.192/28	10.3.103.193 – 10.3.103.206	10.3.103.207
126	10.3.103.208/28	10.3.103.209 – 10.3.103.222	10.3.103.223
127	10.3.103.224/28	10.3.103.225 – 10.3.103.238	10.3.103.239
128	10.3.103.240/28	10.3.103.241 – 10.3.103.254	10.3.103.255

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 →