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)10.42.128.0/18

network10.42.128.0/18

broadcast10.42.191.255

first host10.42.128.1

last host10.42.191.254

subnet mask255.255.192.0

wildcard0.0.63.255

addresses16,384

usable hosts16,382

classA

ipcalc 10.42.128.0/18

address00001010.00101010.10000000.00000000

subnet mask11111111.11111111.11000000.00000000

network00001010.00101010.10000000.00000000

broadcast00001010.00101010.10111111.11111111

green = network part, grey = host part

hex0x0a2a8000

decimal170557440

reverse dns0.128.42.10.in-addr.arpa

ipv4-mapped::ffff:a2a:8000

/18 split into /25 · 128 subnets

close ×

#	network	host range	broadcast
1	10.42.128.0/25	10.42.128.1 – 10.42.128.126	10.42.128.127
2	10.42.128.128/25	10.42.128.129 – 10.42.128.254	10.42.128.255
3	10.42.129.0/25	10.42.129.1 – 10.42.129.126	10.42.129.127
4	10.42.129.128/25	10.42.129.129 – 10.42.129.254	10.42.129.255
5	10.42.130.0/25	10.42.130.1 – 10.42.130.126	10.42.130.127
6	10.42.130.128/25	10.42.130.129 – 10.42.130.254	10.42.130.255
7	10.42.131.0/25	10.42.131.1 – 10.42.131.126	10.42.131.127
8	10.42.131.128/25	10.42.131.129 – 10.42.131.254	10.42.131.255
9	10.42.132.0/25	10.42.132.1 – 10.42.132.126	10.42.132.127
10	10.42.132.128/25	10.42.132.129 – 10.42.132.254	10.42.132.255
11	10.42.133.0/25	10.42.133.1 – 10.42.133.126	10.42.133.127
12	10.42.133.128/25	10.42.133.129 – 10.42.133.254	10.42.133.255
13	10.42.134.0/25	10.42.134.1 – 10.42.134.126	10.42.134.127
14	10.42.134.128/25	10.42.134.129 – 10.42.134.254	10.42.134.255
15	10.42.135.0/25	10.42.135.1 – 10.42.135.126	10.42.135.127
16	10.42.135.128/25	10.42.135.129 – 10.42.135.254	10.42.135.255
17	10.42.136.0/25	10.42.136.1 – 10.42.136.126	10.42.136.127
18	10.42.136.128/25	10.42.136.129 – 10.42.136.254	10.42.136.255
19	10.42.137.0/25	10.42.137.1 – 10.42.137.126	10.42.137.127
20	10.42.137.128/25	10.42.137.129 – 10.42.137.254	10.42.137.255
21	10.42.138.0/25	10.42.138.1 – 10.42.138.126	10.42.138.127
22	10.42.138.128/25	10.42.138.129 – 10.42.138.254	10.42.138.255
23	10.42.139.0/25	10.42.139.1 – 10.42.139.126	10.42.139.127
24	10.42.139.128/25	10.42.139.129 – 10.42.139.254	10.42.139.255
25	10.42.140.0/25	10.42.140.1 – 10.42.140.126	10.42.140.127
26	10.42.140.128/25	10.42.140.129 – 10.42.140.254	10.42.140.255
27	10.42.141.0/25	10.42.141.1 – 10.42.141.126	10.42.141.127
28	10.42.141.128/25	10.42.141.129 – 10.42.141.254	10.42.141.255
29	10.42.142.0/25	10.42.142.1 – 10.42.142.126	10.42.142.127
30	10.42.142.128/25	10.42.142.129 – 10.42.142.254	10.42.142.255
31	10.42.143.0/25	10.42.143.1 – 10.42.143.126	10.42.143.127
32	10.42.143.128/25	10.42.143.129 – 10.42.143.254	10.42.143.255
33	10.42.144.0/25	10.42.144.1 – 10.42.144.126	10.42.144.127
34	10.42.144.128/25	10.42.144.129 – 10.42.144.254	10.42.144.255
35	10.42.145.0/25	10.42.145.1 – 10.42.145.126	10.42.145.127
36	10.42.145.128/25	10.42.145.129 – 10.42.145.254	10.42.145.255
37	10.42.146.0/25	10.42.146.1 – 10.42.146.126	10.42.146.127
38	10.42.146.128/25	10.42.146.129 – 10.42.146.254	10.42.146.255
39	10.42.147.0/25	10.42.147.1 – 10.42.147.126	10.42.147.127
40	10.42.147.128/25	10.42.147.129 – 10.42.147.254	10.42.147.255
41	10.42.148.0/25	10.42.148.1 – 10.42.148.126	10.42.148.127
42	10.42.148.128/25	10.42.148.129 – 10.42.148.254	10.42.148.255
43	10.42.149.0/25	10.42.149.1 – 10.42.149.126	10.42.149.127
44	10.42.149.128/25	10.42.149.129 – 10.42.149.254	10.42.149.255
45	10.42.150.0/25	10.42.150.1 – 10.42.150.126	10.42.150.127
46	10.42.150.128/25	10.42.150.129 – 10.42.150.254	10.42.150.255
47	10.42.151.0/25	10.42.151.1 – 10.42.151.126	10.42.151.127
48	10.42.151.128/25	10.42.151.129 – 10.42.151.254	10.42.151.255
49	10.42.152.0/25	10.42.152.1 – 10.42.152.126	10.42.152.127
50	10.42.152.128/25	10.42.152.129 – 10.42.152.254	10.42.152.255
51	10.42.153.0/25	10.42.153.1 – 10.42.153.126	10.42.153.127
52	10.42.153.128/25	10.42.153.129 – 10.42.153.254	10.42.153.255
53	10.42.154.0/25	10.42.154.1 – 10.42.154.126	10.42.154.127
54	10.42.154.128/25	10.42.154.129 – 10.42.154.254	10.42.154.255
55	10.42.155.0/25	10.42.155.1 – 10.42.155.126	10.42.155.127
56	10.42.155.128/25	10.42.155.129 – 10.42.155.254	10.42.155.255
57	10.42.156.0/25	10.42.156.1 – 10.42.156.126	10.42.156.127
58	10.42.156.128/25	10.42.156.129 – 10.42.156.254	10.42.156.255
59	10.42.157.0/25	10.42.157.1 – 10.42.157.126	10.42.157.127
60	10.42.157.128/25	10.42.157.129 – 10.42.157.254	10.42.157.255
61	10.42.158.0/25	10.42.158.1 – 10.42.158.126	10.42.158.127
62	10.42.158.128/25	10.42.158.129 – 10.42.158.254	10.42.158.255
63	10.42.159.0/25	10.42.159.1 – 10.42.159.126	10.42.159.127
64	10.42.159.128/25	10.42.159.129 – 10.42.159.254	10.42.159.255
65	10.42.160.0/25	10.42.160.1 – 10.42.160.126	10.42.160.127
66	10.42.160.128/25	10.42.160.129 – 10.42.160.254	10.42.160.255
67	10.42.161.0/25	10.42.161.1 – 10.42.161.126	10.42.161.127
68	10.42.161.128/25	10.42.161.129 – 10.42.161.254	10.42.161.255
69	10.42.162.0/25	10.42.162.1 – 10.42.162.126	10.42.162.127
70	10.42.162.128/25	10.42.162.129 – 10.42.162.254	10.42.162.255
71	10.42.163.0/25	10.42.163.1 – 10.42.163.126	10.42.163.127
72	10.42.163.128/25	10.42.163.129 – 10.42.163.254	10.42.163.255
73	10.42.164.0/25	10.42.164.1 – 10.42.164.126	10.42.164.127
74	10.42.164.128/25	10.42.164.129 – 10.42.164.254	10.42.164.255
75	10.42.165.0/25	10.42.165.1 – 10.42.165.126	10.42.165.127
76	10.42.165.128/25	10.42.165.129 – 10.42.165.254	10.42.165.255
77	10.42.166.0/25	10.42.166.1 – 10.42.166.126	10.42.166.127
78	10.42.166.128/25	10.42.166.129 – 10.42.166.254	10.42.166.255
79	10.42.167.0/25	10.42.167.1 – 10.42.167.126	10.42.167.127
80	10.42.167.128/25	10.42.167.129 – 10.42.167.254	10.42.167.255
81	10.42.168.0/25	10.42.168.1 – 10.42.168.126	10.42.168.127
82	10.42.168.128/25	10.42.168.129 – 10.42.168.254	10.42.168.255
83	10.42.169.0/25	10.42.169.1 – 10.42.169.126	10.42.169.127
84	10.42.169.128/25	10.42.169.129 – 10.42.169.254	10.42.169.255
85	10.42.170.0/25	10.42.170.1 – 10.42.170.126	10.42.170.127
86	10.42.170.128/25	10.42.170.129 – 10.42.170.254	10.42.170.255
87	10.42.171.0/25	10.42.171.1 – 10.42.171.126	10.42.171.127
88	10.42.171.128/25	10.42.171.129 – 10.42.171.254	10.42.171.255
89	10.42.172.0/25	10.42.172.1 – 10.42.172.126	10.42.172.127
90	10.42.172.128/25	10.42.172.129 – 10.42.172.254	10.42.172.255
91	10.42.173.0/25	10.42.173.1 – 10.42.173.126	10.42.173.127
92	10.42.173.128/25	10.42.173.129 – 10.42.173.254	10.42.173.255
93	10.42.174.0/25	10.42.174.1 – 10.42.174.126	10.42.174.127
94	10.42.174.128/25	10.42.174.129 – 10.42.174.254	10.42.174.255
95	10.42.175.0/25	10.42.175.1 – 10.42.175.126	10.42.175.127
96	10.42.175.128/25	10.42.175.129 – 10.42.175.254	10.42.175.255
97	10.42.176.0/25	10.42.176.1 – 10.42.176.126	10.42.176.127
98	10.42.176.128/25	10.42.176.129 – 10.42.176.254	10.42.176.255
99	10.42.177.0/25	10.42.177.1 – 10.42.177.126	10.42.177.127
100	10.42.177.128/25	10.42.177.129 – 10.42.177.254	10.42.177.255
101	10.42.178.0/25	10.42.178.1 – 10.42.178.126	10.42.178.127
102	10.42.178.128/25	10.42.178.129 – 10.42.178.254	10.42.178.255
103	10.42.179.0/25	10.42.179.1 – 10.42.179.126	10.42.179.127
104	10.42.179.128/25	10.42.179.129 – 10.42.179.254	10.42.179.255
105	10.42.180.0/25	10.42.180.1 – 10.42.180.126	10.42.180.127
106	10.42.180.128/25	10.42.180.129 – 10.42.180.254	10.42.180.255
107	10.42.181.0/25	10.42.181.1 – 10.42.181.126	10.42.181.127
108	10.42.181.128/25	10.42.181.129 – 10.42.181.254	10.42.181.255
109	10.42.182.0/25	10.42.182.1 – 10.42.182.126	10.42.182.127
110	10.42.182.128/25	10.42.182.129 – 10.42.182.254	10.42.182.255
111	10.42.183.0/25	10.42.183.1 – 10.42.183.126	10.42.183.127
112	10.42.183.128/25	10.42.183.129 – 10.42.183.254	10.42.183.255
113	10.42.184.0/25	10.42.184.1 – 10.42.184.126	10.42.184.127
114	10.42.184.128/25	10.42.184.129 – 10.42.184.254	10.42.184.255
115	10.42.185.0/25	10.42.185.1 – 10.42.185.126	10.42.185.127
116	10.42.185.128/25	10.42.185.129 – 10.42.185.254	10.42.185.255
117	10.42.186.0/25	10.42.186.1 – 10.42.186.126	10.42.186.127
118	10.42.186.128/25	10.42.186.129 – 10.42.186.254	10.42.186.255
119	10.42.187.0/25	10.42.187.1 – 10.42.187.126	10.42.187.127
120	10.42.187.128/25	10.42.187.129 – 10.42.187.254	10.42.187.255
121	10.42.188.0/25	10.42.188.1 – 10.42.188.126	10.42.188.127
122	10.42.188.128/25	10.42.188.129 – 10.42.188.254	10.42.188.255
123	10.42.189.0/25	10.42.189.1 – 10.42.189.126	10.42.189.127
124	10.42.189.128/25	10.42.189.129 – 10.42.189.254	10.42.189.255
125	10.42.190.0/25	10.42.190.1 – 10.42.190.126	10.42.190.127
126	10.42.190.128/25	10.42.190.129 – 10.42.190.254	10.42.190.255
127	10.42.191.0/25	10.42.191.1 – 10.42.191.126	10.42.191.127
128	10.42.191.128/25	10.42.191.129 – 10.42.191.254	10.42.191.255

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 /18
/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	1
/19	255.255.224.0	8,192	8,190	2 split →
/20	255.255.240.0	4,096	4,094	4 split →
/21	255.255.248.0	2,048	2,046	8 split →
/22	255.255.252.0	1,024	1,022	16 split →
/23	255.255.254.0	512	510	32 split →
/24	255.255.255.0	256	254	64 split →
/25	255.255.255.128	128	126	128 split →
/26	255.255.255.192	64	62	256 split →
/27	255.255.255.224	32	30	512 split →
/28	255.255.255.240	16	14	1,024 split →
/29	255.255.255.248	8	6	2,048 split →
/30	255.255.255.252	4	2	4,096 split →
/31	255.255.255.254	2	2	8,192 split →
/32	255.255.255.255	1	1	16,384 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 →