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)10.2.128.0/17

network10.2.128.0/17

broadcast10.2.255.255

first host10.2.128.1

last host10.2.255.254

subnet mask255.255.128.0

wildcard0.0.127.255

addresses32,768

usable hosts32,766

classA

ipcalc 10.2.128.0/17

address00001010.00000010.10000000.00000000

subnet mask11111111.11111111.10000000.00000000

network00001010.00000010.10000000.00000000

broadcast00001010.00000010.11111111.11111111

green = network part, grey = host part

hex0x0a028000

decimal167936000

reverse dns0.128.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:8000

/17 split into /24 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.128.0/24	10.2.128.1 – 10.2.128.254	10.2.128.255
2	10.2.129.0/24	10.2.129.1 – 10.2.129.254	10.2.129.255
3	10.2.130.0/24	10.2.130.1 – 10.2.130.254	10.2.130.255
4	10.2.131.0/24	10.2.131.1 – 10.2.131.254	10.2.131.255
5	10.2.132.0/24	10.2.132.1 – 10.2.132.254	10.2.132.255
6	10.2.133.0/24	10.2.133.1 – 10.2.133.254	10.2.133.255
7	10.2.134.0/24	10.2.134.1 – 10.2.134.254	10.2.134.255
8	10.2.135.0/24	10.2.135.1 – 10.2.135.254	10.2.135.255
9	10.2.136.0/24	10.2.136.1 – 10.2.136.254	10.2.136.255
10	10.2.137.0/24	10.2.137.1 – 10.2.137.254	10.2.137.255
11	10.2.138.0/24	10.2.138.1 – 10.2.138.254	10.2.138.255
12	10.2.139.0/24	10.2.139.1 – 10.2.139.254	10.2.139.255
13	10.2.140.0/24	10.2.140.1 – 10.2.140.254	10.2.140.255
14	10.2.141.0/24	10.2.141.1 – 10.2.141.254	10.2.141.255
15	10.2.142.0/24	10.2.142.1 – 10.2.142.254	10.2.142.255
16	10.2.143.0/24	10.2.143.1 – 10.2.143.254	10.2.143.255
17	10.2.144.0/24	10.2.144.1 – 10.2.144.254	10.2.144.255
18	10.2.145.0/24	10.2.145.1 – 10.2.145.254	10.2.145.255
19	10.2.146.0/24	10.2.146.1 – 10.2.146.254	10.2.146.255
20	10.2.147.0/24	10.2.147.1 – 10.2.147.254	10.2.147.255
21	10.2.148.0/24	10.2.148.1 – 10.2.148.254	10.2.148.255
22	10.2.149.0/24	10.2.149.1 – 10.2.149.254	10.2.149.255
23	10.2.150.0/24	10.2.150.1 – 10.2.150.254	10.2.150.255
24	10.2.151.0/24	10.2.151.1 – 10.2.151.254	10.2.151.255
25	10.2.152.0/24	10.2.152.1 – 10.2.152.254	10.2.152.255
26	10.2.153.0/24	10.2.153.1 – 10.2.153.254	10.2.153.255
27	10.2.154.0/24	10.2.154.1 – 10.2.154.254	10.2.154.255
28	10.2.155.0/24	10.2.155.1 – 10.2.155.254	10.2.155.255
29	10.2.156.0/24	10.2.156.1 – 10.2.156.254	10.2.156.255
30	10.2.157.0/24	10.2.157.1 – 10.2.157.254	10.2.157.255
31	10.2.158.0/24	10.2.158.1 – 10.2.158.254	10.2.158.255
32	10.2.159.0/24	10.2.159.1 – 10.2.159.254	10.2.159.255
33	10.2.160.0/24	10.2.160.1 – 10.2.160.254	10.2.160.255
34	10.2.161.0/24	10.2.161.1 – 10.2.161.254	10.2.161.255
35	10.2.162.0/24	10.2.162.1 – 10.2.162.254	10.2.162.255
36	10.2.163.0/24	10.2.163.1 – 10.2.163.254	10.2.163.255
37	10.2.164.0/24	10.2.164.1 – 10.2.164.254	10.2.164.255
38	10.2.165.0/24	10.2.165.1 – 10.2.165.254	10.2.165.255
39	10.2.166.0/24	10.2.166.1 – 10.2.166.254	10.2.166.255
40	10.2.167.0/24	10.2.167.1 – 10.2.167.254	10.2.167.255
41	10.2.168.0/24	10.2.168.1 – 10.2.168.254	10.2.168.255
42	10.2.169.0/24	10.2.169.1 – 10.2.169.254	10.2.169.255
43	10.2.170.0/24	10.2.170.1 – 10.2.170.254	10.2.170.255
44	10.2.171.0/24	10.2.171.1 – 10.2.171.254	10.2.171.255
45	10.2.172.0/24	10.2.172.1 – 10.2.172.254	10.2.172.255
46	10.2.173.0/24	10.2.173.1 – 10.2.173.254	10.2.173.255
47	10.2.174.0/24	10.2.174.1 – 10.2.174.254	10.2.174.255
48	10.2.175.0/24	10.2.175.1 – 10.2.175.254	10.2.175.255
49	10.2.176.0/24	10.2.176.1 – 10.2.176.254	10.2.176.255
50	10.2.177.0/24	10.2.177.1 – 10.2.177.254	10.2.177.255
51	10.2.178.0/24	10.2.178.1 – 10.2.178.254	10.2.178.255
52	10.2.179.0/24	10.2.179.1 – 10.2.179.254	10.2.179.255
53	10.2.180.0/24	10.2.180.1 – 10.2.180.254	10.2.180.255
54	10.2.181.0/24	10.2.181.1 – 10.2.181.254	10.2.181.255
55	10.2.182.0/24	10.2.182.1 – 10.2.182.254	10.2.182.255
56	10.2.183.0/24	10.2.183.1 – 10.2.183.254	10.2.183.255
57	10.2.184.0/24	10.2.184.1 – 10.2.184.254	10.2.184.255
58	10.2.185.0/24	10.2.185.1 – 10.2.185.254	10.2.185.255
59	10.2.186.0/24	10.2.186.1 – 10.2.186.254	10.2.186.255
60	10.2.187.0/24	10.2.187.1 – 10.2.187.254	10.2.187.255
61	10.2.188.0/24	10.2.188.1 – 10.2.188.254	10.2.188.255
62	10.2.189.0/24	10.2.189.1 – 10.2.189.254	10.2.189.255
63	10.2.190.0/24	10.2.190.1 – 10.2.190.254	10.2.190.255
64	10.2.191.0/24	10.2.191.1 – 10.2.191.254	10.2.191.255
65	10.2.192.0/24	10.2.192.1 – 10.2.192.254	10.2.192.255
66	10.2.193.0/24	10.2.193.1 – 10.2.193.254	10.2.193.255
67	10.2.194.0/24	10.2.194.1 – 10.2.194.254	10.2.194.255
68	10.2.195.0/24	10.2.195.1 – 10.2.195.254	10.2.195.255
69	10.2.196.0/24	10.2.196.1 – 10.2.196.254	10.2.196.255
70	10.2.197.0/24	10.2.197.1 – 10.2.197.254	10.2.197.255
71	10.2.198.0/24	10.2.198.1 – 10.2.198.254	10.2.198.255
72	10.2.199.0/24	10.2.199.1 – 10.2.199.254	10.2.199.255
73	10.2.200.0/24	10.2.200.1 – 10.2.200.254	10.2.200.255
74	10.2.201.0/24	10.2.201.1 – 10.2.201.254	10.2.201.255
75	10.2.202.0/24	10.2.202.1 – 10.2.202.254	10.2.202.255
76	10.2.203.0/24	10.2.203.1 – 10.2.203.254	10.2.203.255
77	10.2.204.0/24	10.2.204.1 – 10.2.204.254	10.2.204.255
78	10.2.205.0/24	10.2.205.1 – 10.2.205.254	10.2.205.255
79	10.2.206.0/24	10.2.206.1 – 10.2.206.254	10.2.206.255
80	10.2.207.0/24	10.2.207.1 – 10.2.207.254	10.2.207.255
81	10.2.208.0/24	10.2.208.1 – 10.2.208.254	10.2.208.255
82	10.2.209.0/24	10.2.209.1 – 10.2.209.254	10.2.209.255
83	10.2.210.0/24	10.2.210.1 – 10.2.210.254	10.2.210.255
84	10.2.211.0/24	10.2.211.1 – 10.2.211.254	10.2.211.255
85	10.2.212.0/24	10.2.212.1 – 10.2.212.254	10.2.212.255
86	10.2.213.0/24	10.2.213.1 – 10.2.213.254	10.2.213.255
87	10.2.214.0/24	10.2.214.1 – 10.2.214.254	10.2.214.255
88	10.2.215.0/24	10.2.215.1 – 10.2.215.254	10.2.215.255
89	10.2.216.0/24	10.2.216.1 – 10.2.216.254	10.2.216.255
90	10.2.217.0/24	10.2.217.1 – 10.2.217.254	10.2.217.255
91	10.2.218.0/24	10.2.218.1 – 10.2.218.254	10.2.218.255
92	10.2.219.0/24	10.2.219.1 – 10.2.219.254	10.2.219.255
93	10.2.220.0/24	10.2.220.1 – 10.2.220.254	10.2.220.255
94	10.2.221.0/24	10.2.221.1 – 10.2.221.254	10.2.221.255
95	10.2.222.0/24	10.2.222.1 – 10.2.222.254	10.2.222.255
96	10.2.223.0/24	10.2.223.1 – 10.2.223.254	10.2.223.255
97	10.2.224.0/24	10.2.224.1 – 10.2.224.254	10.2.224.255
98	10.2.225.0/24	10.2.225.1 – 10.2.225.254	10.2.225.255
99	10.2.226.0/24	10.2.226.1 – 10.2.226.254	10.2.226.255
100	10.2.227.0/24	10.2.227.1 – 10.2.227.254	10.2.227.255
101	10.2.228.0/24	10.2.228.1 – 10.2.228.254	10.2.228.255
102	10.2.229.0/24	10.2.229.1 – 10.2.229.254	10.2.229.255
103	10.2.230.0/24	10.2.230.1 – 10.2.230.254	10.2.230.255
104	10.2.231.0/24	10.2.231.1 – 10.2.231.254	10.2.231.255
105	10.2.232.0/24	10.2.232.1 – 10.2.232.254	10.2.232.255
106	10.2.233.0/24	10.2.233.1 – 10.2.233.254	10.2.233.255
107	10.2.234.0/24	10.2.234.1 – 10.2.234.254	10.2.234.255
108	10.2.235.0/24	10.2.235.1 – 10.2.235.254	10.2.235.255
109	10.2.236.0/24	10.2.236.1 – 10.2.236.254	10.2.236.255
110	10.2.237.0/24	10.2.237.1 – 10.2.237.254	10.2.237.255
111	10.2.238.0/24	10.2.238.1 – 10.2.238.254	10.2.238.255
112	10.2.239.0/24	10.2.239.1 – 10.2.239.254	10.2.239.255
113	10.2.240.0/24	10.2.240.1 – 10.2.240.254	10.2.240.255
114	10.2.241.0/24	10.2.241.1 – 10.2.241.254	10.2.241.255
115	10.2.242.0/24	10.2.242.1 – 10.2.242.254	10.2.242.255
116	10.2.243.0/24	10.2.243.1 – 10.2.243.254	10.2.243.255
117	10.2.244.0/24	10.2.244.1 – 10.2.244.254	10.2.244.255
118	10.2.245.0/24	10.2.245.1 – 10.2.245.254	10.2.245.255
119	10.2.246.0/24	10.2.246.1 – 10.2.246.254	10.2.246.255
120	10.2.247.0/24	10.2.247.1 – 10.2.247.254	10.2.247.255
121	10.2.248.0/24	10.2.248.1 – 10.2.248.254	10.2.248.255
122	10.2.249.0/24	10.2.249.1 – 10.2.249.254	10.2.249.255
123	10.2.250.0/24	10.2.250.1 – 10.2.250.254	10.2.250.255
124	10.2.251.0/24	10.2.251.1 – 10.2.251.254	10.2.251.255
125	10.2.252.0/24	10.2.252.1 – 10.2.252.254	10.2.252.255
126	10.2.253.0/24	10.2.253.1 – 10.2.253.254	10.2.253.255
127	10.2.254.0/24	10.2.254.1 – 10.2.254.254	10.2.254.255
128	10.2.255.0/24	10.2.255.1 – 10.2.255.254	10.2.255.255

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 /17
/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	1
/18	255.255.192.0	16,384	16,382	2 split →
/19	255.255.224.0	8,192	8,190	4 split →
/20	255.255.240.0	4,096	4,094	8 split →
/21	255.255.248.0	2,048	2,046	16 split →
/22	255.255.252.0	1,024	1,022	32 split →
/23	255.255.254.0	512	510	64 split →
/24	255.255.255.0	256	254	128 split →
/25	255.255.255.128	128	126	256 split →
/26	255.255.255.192	64	62	512 split →
/27	255.255.255.224	32	30	1,024 split →
/28	255.255.255.240	16	14	2,048 split →
/29	255.255.255.248	8	6	4,096 split →
/30	255.255.255.252	4	2	8,192 split →
/31	255.255.255.254	2	2	16,384 split →
/32	255.255.255.255	1	1	32,768 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 →