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)10.4.104.0/21

network10.4.104.0/21

broadcast10.4.111.255

first host10.4.104.1

last host10.4.111.254

subnet mask255.255.248.0

wildcard0.0.7.255

addresses2,048

usable hosts2,046

classA

ipcalc 10.4.104.0/21

address00001010.00000100.01101000.00000000

subnet mask11111111.11111111.11111000.00000000

network00001010.00000100.01101000.00000000

broadcast00001010.00000100.01101111.11111111

green = network part, grey = host part

hex0x0a046800

decimal168060928

reverse dns0.104.4.10.in-addr.arpa

ipv4-mapped::ffff:a04:6800

/21 split into /28 · 128 subnets

close ×

#	network	host range	broadcast
1	10.4.104.0/28	10.4.104.1 – 10.4.104.14	10.4.104.15
2	10.4.104.16/28	10.4.104.17 – 10.4.104.30	10.4.104.31
3	10.4.104.32/28	10.4.104.33 – 10.4.104.46	10.4.104.47
4	10.4.104.48/28	10.4.104.49 – 10.4.104.62	10.4.104.63
5	10.4.104.64/28	10.4.104.65 – 10.4.104.78	10.4.104.79
6	10.4.104.80/28	10.4.104.81 – 10.4.104.94	10.4.104.95
7	10.4.104.96/28	10.4.104.97 – 10.4.104.110	10.4.104.111
8	10.4.104.112/28	10.4.104.113 – 10.4.104.126	10.4.104.127
9	10.4.104.128/28	10.4.104.129 – 10.4.104.142	10.4.104.143
10	10.4.104.144/28	10.4.104.145 – 10.4.104.158	10.4.104.159
11	10.4.104.160/28	10.4.104.161 – 10.4.104.174	10.4.104.175
12	10.4.104.176/28	10.4.104.177 – 10.4.104.190	10.4.104.191
13	10.4.104.192/28	10.4.104.193 – 10.4.104.206	10.4.104.207
14	10.4.104.208/28	10.4.104.209 – 10.4.104.222	10.4.104.223
15	10.4.104.224/28	10.4.104.225 – 10.4.104.238	10.4.104.239
16	10.4.104.240/28	10.4.104.241 – 10.4.104.254	10.4.104.255
17	10.4.105.0/28	10.4.105.1 – 10.4.105.14	10.4.105.15
18	10.4.105.16/28	10.4.105.17 – 10.4.105.30	10.4.105.31
19	10.4.105.32/28	10.4.105.33 – 10.4.105.46	10.4.105.47
20	10.4.105.48/28	10.4.105.49 – 10.4.105.62	10.4.105.63
21	10.4.105.64/28	10.4.105.65 – 10.4.105.78	10.4.105.79
22	10.4.105.80/28	10.4.105.81 – 10.4.105.94	10.4.105.95
23	10.4.105.96/28	10.4.105.97 – 10.4.105.110	10.4.105.111
24	10.4.105.112/28	10.4.105.113 – 10.4.105.126	10.4.105.127
25	10.4.105.128/28	10.4.105.129 – 10.4.105.142	10.4.105.143
26	10.4.105.144/28	10.4.105.145 – 10.4.105.158	10.4.105.159
27	10.4.105.160/28	10.4.105.161 – 10.4.105.174	10.4.105.175
28	10.4.105.176/28	10.4.105.177 – 10.4.105.190	10.4.105.191
29	10.4.105.192/28	10.4.105.193 – 10.4.105.206	10.4.105.207
30	10.4.105.208/28	10.4.105.209 – 10.4.105.222	10.4.105.223
31	10.4.105.224/28	10.4.105.225 – 10.4.105.238	10.4.105.239
32	10.4.105.240/28	10.4.105.241 – 10.4.105.254	10.4.105.255
33	10.4.106.0/28	10.4.106.1 – 10.4.106.14	10.4.106.15
34	10.4.106.16/28	10.4.106.17 – 10.4.106.30	10.4.106.31
35	10.4.106.32/28	10.4.106.33 – 10.4.106.46	10.4.106.47
36	10.4.106.48/28	10.4.106.49 – 10.4.106.62	10.4.106.63
37	10.4.106.64/28	10.4.106.65 – 10.4.106.78	10.4.106.79
38	10.4.106.80/28	10.4.106.81 – 10.4.106.94	10.4.106.95
39	10.4.106.96/28	10.4.106.97 – 10.4.106.110	10.4.106.111
40	10.4.106.112/28	10.4.106.113 – 10.4.106.126	10.4.106.127
41	10.4.106.128/28	10.4.106.129 – 10.4.106.142	10.4.106.143
42	10.4.106.144/28	10.4.106.145 – 10.4.106.158	10.4.106.159
43	10.4.106.160/28	10.4.106.161 – 10.4.106.174	10.4.106.175
44	10.4.106.176/28	10.4.106.177 – 10.4.106.190	10.4.106.191
45	10.4.106.192/28	10.4.106.193 – 10.4.106.206	10.4.106.207
46	10.4.106.208/28	10.4.106.209 – 10.4.106.222	10.4.106.223
47	10.4.106.224/28	10.4.106.225 – 10.4.106.238	10.4.106.239
48	10.4.106.240/28	10.4.106.241 – 10.4.106.254	10.4.106.255
49	10.4.107.0/28	10.4.107.1 – 10.4.107.14	10.4.107.15
50	10.4.107.16/28	10.4.107.17 – 10.4.107.30	10.4.107.31
51	10.4.107.32/28	10.4.107.33 – 10.4.107.46	10.4.107.47
52	10.4.107.48/28	10.4.107.49 – 10.4.107.62	10.4.107.63
53	10.4.107.64/28	10.4.107.65 – 10.4.107.78	10.4.107.79
54	10.4.107.80/28	10.4.107.81 – 10.4.107.94	10.4.107.95
55	10.4.107.96/28	10.4.107.97 – 10.4.107.110	10.4.107.111
56	10.4.107.112/28	10.4.107.113 – 10.4.107.126	10.4.107.127
57	10.4.107.128/28	10.4.107.129 – 10.4.107.142	10.4.107.143
58	10.4.107.144/28	10.4.107.145 – 10.4.107.158	10.4.107.159
59	10.4.107.160/28	10.4.107.161 – 10.4.107.174	10.4.107.175
60	10.4.107.176/28	10.4.107.177 – 10.4.107.190	10.4.107.191
61	10.4.107.192/28	10.4.107.193 – 10.4.107.206	10.4.107.207
62	10.4.107.208/28	10.4.107.209 – 10.4.107.222	10.4.107.223
63	10.4.107.224/28	10.4.107.225 – 10.4.107.238	10.4.107.239
64	10.4.107.240/28	10.4.107.241 – 10.4.107.254	10.4.107.255
65	10.4.108.0/28	10.4.108.1 – 10.4.108.14	10.4.108.15
66	10.4.108.16/28	10.4.108.17 – 10.4.108.30	10.4.108.31
67	10.4.108.32/28	10.4.108.33 – 10.4.108.46	10.4.108.47
68	10.4.108.48/28	10.4.108.49 – 10.4.108.62	10.4.108.63
69	10.4.108.64/28	10.4.108.65 – 10.4.108.78	10.4.108.79
70	10.4.108.80/28	10.4.108.81 – 10.4.108.94	10.4.108.95
71	10.4.108.96/28	10.4.108.97 – 10.4.108.110	10.4.108.111
72	10.4.108.112/28	10.4.108.113 – 10.4.108.126	10.4.108.127
73	10.4.108.128/28	10.4.108.129 – 10.4.108.142	10.4.108.143
74	10.4.108.144/28	10.4.108.145 – 10.4.108.158	10.4.108.159
75	10.4.108.160/28	10.4.108.161 – 10.4.108.174	10.4.108.175
76	10.4.108.176/28	10.4.108.177 – 10.4.108.190	10.4.108.191
77	10.4.108.192/28	10.4.108.193 – 10.4.108.206	10.4.108.207
78	10.4.108.208/28	10.4.108.209 – 10.4.108.222	10.4.108.223
79	10.4.108.224/28	10.4.108.225 – 10.4.108.238	10.4.108.239
80	10.4.108.240/28	10.4.108.241 – 10.4.108.254	10.4.108.255
81	10.4.109.0/28	10.4.109.1 – 10.4.109.14	10.4.109.15
82	10.4.109.16/28	10.4.109.17 – 10.4.109.30	10.4.109.31
83	10.4.109.32/28	10.4.109.33 – 10.4.109.46	10.4.109.47
84	10.4.109.48/28	10.4.109.49 – 10.4.109.62	10.4.109.63
85	10.4.109.64/28	10.4.109.65 – 10.4.109.78	10.4.109.79
86	10.4.109.80/28	10.4.109.81 – 10.4.109.94	10.4.109.95
87	10.4.109.96/28	10.4.109.97 – 10.4.109.110	10.4.109.111
88	10.4.109.112/28	10.4.109.113 – 10.4.109.126	10.4.109.127
89	10.4.109.128/28	10.4.109.129 – 10.4.109.142	10.4.109.143
90	10.4.109.144/28	10.4.109.145 – 10.4.109.158	10.4.109.159
91	10.4.109.160/28	10.4.109.161 – 10.4.109.174	10.4.109.175
92	10.4.109.176/28	10.4.109.177 – 10.4.109.190	10.4.109.191
93	10.4.109.192/28	10.4.109.193 – 10.4.109.206	10.4.109.207
94	10.4.109.208/28	10.4.109.209 – 10.4.109.222	10.4.109.223
95	10.4.109.224/28	10.4.109.225 – 10.4.109.238	10.4.109.239
96	10.4.109.240/28	10.4.109.241 – 10.4.109.254	10.4.109.255
97	10.4.110.0/28	10.4.110.1 – 10.4.110.14	10.4.110.15
98	10.4.110.16/28	10.4.110.17 – 10.4.110.30	10.4.110.31
99	10.4.110.32/28	10.4.110.33 – 10.4.110.46	10.4.110.47
100	10.4.110.48/28	10.4.110.49 – 10.4.110.62	10.4.110.63
101	10.4.110.64/28	10.4.110.65 – 10.4.110.78	10.4.110.79
102	10.4.110.80/28	10.4.110.81 – 10.4.110.94	10.4.110.95
103	10.4.110.96/28	10.4.110.97 – 10.4.110.110	10.4.110.111
104	10.4.110.112/28	10.4.110.113 – 10.4.110.126	10.4.110.127
105	10.4.110.128/28	10.4.110.129 – 10.4.110.142	10.4.110.143
106	10.4.110.144/28	10.4.110.145 – 10.4.110.158	10.4.110.159
107	10.4.110.160/28	10.4.110.161 – 10.4.110.174	10.4.110.175
108	10.4.110.176/28	10.4.110.177 – 10.4.110.190	10.4.110.191
109	10.4.110.192/28	10.4.110.193 – 10.4.110.206	10.4.110.207
110	10.4.110.208/28	10.4.110.209 – 10.4.110.222	10.4.110.223
111	10.4.110.224/28	10.4.110.225 – 10.4.110.238	10.4.110.239
112	10.4.110.240/28	10.4.110.241 – 10.4.110.254	10.4.110.255
113	10.4.111.0/28	10.4.111.1 – 10.4.111.14	10.4.111.15
114	10.4.111.16/28	10.4.111.17 – 10.4.111.30	10.4.111.31
115	10.4.111.32/28	10.4.111.33 – 10.4.111.46	10.4.111.47
116	10.4.111.48/28	10.4.111.49 – 10.4.111.62	10.4.111.63
117	10.4.111.64/28	10.4.111.65 – 10.4.111.78	10.4.111.79
118	10.4.111.80/28	10.4.111.81 – 10.4.111.94	10.4.111.95
119	10.4.111.96/28	10.4.111.97 – 10.4.111.110	10.4.111.111
120	10.4.111.112/28	10.4.111.113 – 10.4.111.126	10.4.111.127
121	10.4.111.128/28	10.4.111.129 – 10.4.111.142	10.4.111.143
122	10.4.111.144/28	10.4.111.145 – 10.4.111.158	10.4.111.159
123	10.4.111.160/28	10.4.111.161 – 10.4.111.174	10.4.111.175
124	10.4.111.176/28	10.4.111.177 – 10.4.111.190	10.4.111.191
125	10.4.111.192/28	10.4.111.193 – 10.4.111.206	10.4.111.207
126	10.4.111.208/28	10.4.111.209 – 10.4.111.222	10.4.111.223
127	10.4.111.224/28	10.4.111.225 – 10.4.111.238	10.4.111.239
128	10.4.111.240/28	10.4.111.241 – 10.4.111.254	10.4.111.255

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 →