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)10.31.128.0/18

network10.31.128.0/18

broadcast10.31.191.255

first host10.31.128.1

last host10.31.191.254

subnet mask255.255.192.0

wildcard0.0.63.255

addresses16,384

usable hosts16,382

classA

ipcalc 10.31.128.0/18

address00001010.00011111.10000000.00000000

subnet mask11111111.11111111.11000000.00000000

network00001010.00011111.10000000.00000000

broadcast00001010.00011111.10111111.11111111

green = network part, grey = host part

hex0x0a1f8000

decimal169836544

reverse dns0.128.31.10.in-addr.arpa

ipv4-mapped::ffff:a1f:8000

/18 split into /25 · 128 subnets

close ×

#	network	host range	broadcast
1	10.31.128.0/25	10.31.128.1 – 10.31.128.126	10.31.128.127
2	10.31.128.128/25	10.31.128.129 – 10.31.128.254	10.31.128.255
3	10.31.129.0/25	10.31.129.1 – 10.31.129.126	10.31.129.127
4	10.31.129.128/25	10.31.129.129 – 10.31.129.254	10.31.129.255
5	10.31.130.0/25	10.31.130.1 – 10.31.130.126	10.31.130.127
6	10.31.130.128/25	10.31.130.129 – 10.31.130.254	10.31.130.255
7	10.31.131.0/25	10.31.131.1 – 10.31.131.126	10.31.131.127
8	10.31.131.128/25	10.31.131.129 – 10.31.131.254	10.31.131.255
9	10.31.132.0/25	10.31.132.1 – 10.31.132.126	10.31.132.127
10	10.31.132.128/25	10.31.132.129 – 10.31.132.254	10.31.132.255
11	10.31.133.0/25	10.31.133.1 – 10.31.133.126	10.31.133.127
12	10.31.133.128/25	10.31.133.129 – 10.31.133.254	10.31.133.255
13	10.31.134.0/25	10.31.134.1 – 10.31.134.126	10.31.134.127
14	10.31.134.128/25	10.31.134.129 – 10.31.134.254	10.31.134.255
15	10.31.135.0/25	10.31.135.1 – 10.31.135.126	10.31.135.127
16	10.31.135.128/25	10.31.135.129 – 10.31.135.254	10.31.135.255
17	10.31.136.0/25	10.31.136.1 – 10.31.136.126	10.31.136.127
18	10.31.136.128/25	10.31.136.129 – 10.31.136.254	10.31.136.255
19	10.31.137.0/25	10.31.137.1 – 10.31.137.126	10.31.137.127
20	10.31.137.128/25	10.31.137.129 – 10.31.137.254	10.31.137.255
21	10.31.138.0/25	10.31.138.1 – 10.31.138.126	10.31.138.127
22	10.31.138.128/25	10.31.138.129 – 10.31.138.254	10.31.138.255
23	10.31.139.0/25	10.31.139.1 – 10.31.139.126	10.31.139.127
24	10.31.139.128/25	10.31.139.129 – 10.31.139.254	10.31.139.255
25	10.31.140.0/25	10.31.140.1 – 10.31.140.126	10.31.140.127
26	10.31.140.128/25	10.31.140.129 – 10.31.140.254	10.31.140.255
27	10.31.141.0/25	10.31.141.1 – 10.31.141.126	10.31.141.127
28	10.31.141.128/25	10.31.141.129 – 10.31.141.254	10.31.141.255
29	10.31.142.0/25	10.31.142.1 – 10.31.142.126	10.31.142.127
30	10.31.142.128/25	10.31.142.129 – 10.31.142.254	10.31.142.255
31	10.31.143.0/25	10.31.143.1 – 10.31.143.126	10.31.143.127
32	10.31.143.128/25	10.31.143.129 – 10.31.143.254	10.31.143.255
33	10.31.144.0/25	10.31.144.1 – 10.31.144.126	10.31.144.127
34	10.31.144.128/25	10.31.144.129 – 10.31.144.254	10.31.144.255
35	10.31.145.0/25	10.31.145.1 – 10.31.145.126	10.31.145.127
36	10.31.145.128/25	10.31.145.129 – 10.31.145.254	10.31.145.255
37	10.31.146.0/25	10.31.146.1 – 10.31.146.126	10.31.146.127
38	10.31.146.128/25	10.31.146.129 – 10.31.146.254	10.31.146.255
39	10.31.147.0/25	10.31.147.1 – 10.31.147.126	10.31.147.127
40	10.31.147.128/25	10.31.147.129 – 10.31.147.254	10.31.147.255
41	10.31.148.0/25	10.31.148.1 – 10.31.148.126	10.31.148.127
42	10.31.148.128/25	10.31.148.129 – 10.31.148.254	10.31.148.255
43	10.31.149.0/25	10.31.149.1 – 10.31.149.126	10.31.149.127
44	10.31.149.128/25	10.31.149.129 – 10.31.149.254	10.31.149.255
45	10.31.150.0/25	10.31.150.1 – 10.31.150.126	10.31.150.127
46	10.31.150.128/25	10.31.150.129 – 10.31.150.254	10.31.150.255
47	10.31.151.0/25	10.31.151.1 – 10.31.151.126	10.31.151.127
48	10.31.151.128/25	10.31.151.129 – 10.31.151.254	10.31.151.255
49	10.31.152.0/25	10.31.152.1 – 10.31.152.126	10.31.152.127
50	10.31.152.128/25	10.31.152.129 – 10.31.152.254	10.31.152.255
51	10.31.153.0/25	10.31.153.1 – 10.31.153.126	10.31.153.127
52	10.31.153.128/25	10.31.153.129 – 10.31.153.254	10.31.153.255
53	10.31.154.0/25	10.31.154.1 – 10.31.154.126	10.31.154.127
54	10.31.154.128/25	10.31.154.129 – 10.31.154.254	10.31.154.255
55	10.31.155.0/25	10.31.155.1 – 10.31.155.126	10.31.155.127
56	10.31.155.128/25	10.31.155.129 – 10.31.155.254	10.31.155.255
57	10.31.156.0/25	10.31.156.1 – 10.31.156.126	10.31.156.127
58	10.31.156.128/25	10.31.156.129 – 10.31.156.254	10.31.156.255
59	10.31.157.0/25	10.31.157.1 – 10.31.157.126	10.31.157.127
60	10.31.157.128/25	10.31.157.129 – 10.31.157.254	10.31.157.255
61	10.31.158.0/25	10.31.158.1 – 10.31.158.126	10.31.158.127
62	10.31.158.128/25	10.31.158.129 – 10.31.158.254	10.31.158.255
63	10.31.159.0/25	10.31.159.1 – 10.31.159.126	10.31.159.127
64	10.31.159.128/25	10.31.159.129 – 10.31.159.254	10.31.159.255
65	10.31.160.0/25	10.31.160.1 – 10.31.160.126	10.31.160.127
66	10.31.160.128/25	10.31.160.129 – 10.31.160.254	10.31.160.255
67	10.31.161.0/25	10.31.161.1 – 10.31.161.126	10.31.161.127
68	10.31.161.128/25	10.31.161.129 – 10.31.161.254	10.31.161.255
69	10.31.162.0/25	10.31.162.1 – 10.31.162.126	10.31.162.127
70	10.31.162.128/25	10.31.162.129 – 10.31.162.254	10.31.162.255
71	10.31.163.0/25	10.31.163.1 – 10.31.163.126	10.31.163.127
72	10.31.163.128/25	10.31.163.129 – 10.31.163.254	10.31.163.255
73	10.31.164.0/25	10.31.164.1 – 10.31.164.126	10.31.164.127
74	10.31.164.128/25	10.31.164.129 – 10.31.164.254	10.31.164.255
75	10.31.165.0/25	10.31.165.1 – 10.31.165.126	10.31.165.127
76	10.31.165.128/25	10.31.165.129 – 10.31.165.254	10.31.165.255
77	10.31.166.0/25	10.31.166.1 – 10.31.166.126	10.31.166.127
78	10.31.166.128/25	10.31.166.129 – 10.31.166.254	10.31.166.255
79	10.31.167.0/25	10.31.167.1 – 10.31.167.126	10.31.167.127
80	10.31.167.128/25	10.31.167.129 – 10.31.167.254	10.31.167.255
81	10.31.168.0/25	10.31.168.1 – 10.31.168.126	10.31.168.127
82	10.31.168.128/25	10.31.168.129 – 10.31.168.254	10.31.168.255
83	10.31.169.0/25	10.31.169.1 – 10.31.169.126	10.31.169.127
84	10.31.169.128/25	10.31.169.129 – 10.31.169.254	10.31.169.255
85	10.31.170.0/25	10.31.170.1 – 10.31.170.126	10.31.170.127
86	10.31.170.128/25	10.31.170.129 – 10.31.170.254	10.31.170.255
87	10.31.171.0/25	10.31.171.1 – 10.31.171.126	10.31.171.127
88	10.31.171.128/25	10.31.171.129 – 10.31.171.254	10.31.171.255
89	10.31.172.0/25	10.31.172.1 – 10.31.172.126	10.31.172.127
90	10.31.172.128/25	10.31.172.129 – 10.31.172.254	10.31.172.255
91	10.31.173.0/25	10.31.173.1 – 10.31.173.126	10.31.173.127
92	10.31.173.128/25	10.31.173.129 – 10.31.173.254	10.31.173.255
93	10.31.174.0/25	10.31.174.1 – 10.31.174.126	10.31.174.127
94	10.31.174.128/25	10.31.174.129 – 10.31.174.254	10.31.174.255
95	10.31.175.0/25	10.31.175.1 – 10.31.175.126	10.31.175.127
96	10.31.175.128/25	10.31.175.129 – 10.31.175.254	10.31.175.255
97	10.31.176.0/25	10.31.176.1 – 10.31.176.126	10.31.176.127
98	10.31.176.128/25	10.31.176.129 – 10.31.176.254	10.31.176.255
99	10.31.177.0/25	10.31.177.1 – 10.31.177.126	10.31.177.127
100	10.31.177.128/25	10.31.177.129 – 10.31.177.254	10.31.177.255
101	10.31.178.0/25	10.31.178.1 – 10.31.178.126	10.31.178.127
102	10.31.178.128/25	10.31.178.129 – 10.31.178.254	10.31.178.255
103	10.31.179.0/25	10.31.179.1 – 10.31.179.126	10.31.179.127
104	10.31.179.128/25	10.31.179.129 – 10.31.179.254	10.31.179.255
105	10.31.180.0/25	10.31.180.1 – 10.31.180.126	10.31.180.127
106	10.31.180.128/25	10.31.180.129 – 10.31.180.254	10.31.180.255
107	10.31.181.0/25	10.31.181.1 – 10.31.181.126	10.31.181.127
108	10.31.181.128/25	10.31.181.129 – 10.31.181.254	10.31.181.255
109	10.31.182.0/25	10.31.182.1 – 10.31.182.126	10.31.182.127
110	10.31.182.128/25	10.31.182.129 – 10.31.182.254	10.31.182.255
111	10.31.183.0/25	10.31.183.1 – 10.31.183.126	10.31.183.127
112	10.31.183.128/25	10.31.183.129 – 10.31.183.254	10.31.183.255
113	10.31.184.0/25	10.31.184.1 – 10.31.184.126	10.31.184.127
114	10.31.184.128/25	10.31.184.129 – 10.31.184.254	10.31.184.255
115	10.31.185.0/25	10.31.185.1 – 10.31.185.126	10.31.185.127
116	10.31.185.128/25	10.31.185.129 – 10.31.185.254	10.31.185.255
117	10.31.186.0/25	10.31.186.1 – 10.31.186.126	10.31.186.127
118	10.31.186.128/25	10.31.186.129 – 10.31.186.254	10.31.186.255
119	10.31.187.0/25	10.31.187.1 – 10.31.187.126	10.31.187.127
120	10.31.187.128/25	10.31.187.129 – 10.31.187.254	10.31.187.255
121	10.31.188.0/25	10.31.188.1 – 10.31.188.126	10.31.188.127
122	10.31.188.128/25	10.31.188.129 – 10.31.188.254	10.31.188.255
123	10.31.189.0/25	10.31.189.1 – 10.31.189.126	10.31.189.127
124	10.31.189.128/25	10.31.189.129 – 10.31.189.254	10.31.189.255
125	10.31.190.0/25	10.31.190.1 – 10.31.190.126	10.31.190.127
126	10.31.190.128/25	10.31.190.129 – 10.31.190.254	10.31.190.255
127	10.31.191.0/25	10.31.191.1 – 10.31.191.126	10.31.191.127
128	10.31.191.128/25	10.31.191.129 – 10.31.191.254	10.31.191.255

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 →