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)10.123.0.0/17

network10.123.0.0/17

broadcast10.123.127.255

first host10.123.0.1

last host10.123.127.254

subnet mask255.255.128.0

wildcard0.0.127.255

addresses32,768

usable hosts32,766

classA

ipcalc 10.123.0.0/17

address00001010.01111011.00000000.00000000

subnet mask11111111.11111111.10000000.00000000

network00001010.01111011.00000000.00000000

broadcast00001010.01111011.01111111.11111111

green = network part, grey = host part

hex0x0a7b0000

decimal175833088

reverse dns0.0.123.10.in-addr.arpa

ipv4-mapped::ffff:a7b:0

/17 split into /24 · 128 subnets

close ×

#	network	host range	broadcast
1	10.123.0.0/24	10.123.0.1 – 10.123.0.254	10.123.0.255
2	10.123.1.0/24	10.123.1.1 – 10.123.1.254	10.123.1.255
3	10.123.2.0/24	10.123.2.1 – 10.123.2.254	10.123.2.255
4	10.123.3.0/24	10.123.3.1 – 10.123.3.254	10.123.3.255
5	10.123.4.0/24	10.123.4.1 – 10.123.4.254	10.123.4.255
6	10.123.5.0/24	10.123.5.1 – 10.123.5.254	10.123.5.255
7	10.123.6.0/24	10.123.6.1 – 10.123.6.254	10.123.6.255
8	10.123.7.0/24	10.123.7.1 – 10.123.7.254	10.123.7.255
9	10.123.8.0/24	10.123.8.1 – 10.123.8.254	10.123.8.255
10	10.123.9.0/24	10.123.9.1 – 10.123.9.254	10.123.9.255
11	10.123.10.0/24	10.123.10.1 – 10.123.10.254	10.123.10.255
12	10.123.11.0/24	10.123.11.1 – 10.123.11.254	10.123.11.255
13	10.123.12.0/24	10.123.12.1 – 10.123.12.254	10.123.12.255
14	10.123.13.0/24	10.123.13.1 – 10.123.13.254	10.123.13.255
15	10.123.14.0/24	10.123.14.1 – 10.123.14.254	10.123.14.255
16	10.123.15.0/24	10.123.15.1 – 10.123.15.254	10.123.15.255
17	10.123.16.0/24	10.123.16.1 – 10.123.16.254	10.123.16.255
18	10.123.17.0/24	10.123.17.1 – 10.123.17.254	10.123.17.255
19	10.123.18.0/24	10.123.18.1 – 10.123.18.254	10.123.18.255
20	10.123.19.0/24	10.123.19.1 – 10.123.19.254	10.123.19.255
21	10.123.20.0/24	10.123.20.1 – 10.123.20.254	10.123.20.255
22	10.123.21.0/24	10.123.21.1 – 10.123.21.254	10.123.21.255
23	10.123.22.0/24	10.123.22.1 – 10.123.22.254	10.123.22.255
24	10.123.23.0/24	10.123.23.1 – 10.123.23.254	10.123.23.255
25	10.123.24.0/24	10.123.24.1 – 10.123.24.254	10.123.24.255
26	10.123.25.0/24	10.123.25.1 – 10.123.25.254	10.123.25.255
27	10.123.26.0/24	10.123.26.1 – 10.123.26.254	10.123.26.255
28	10.123.27.0/24	10.123.27.1 – 10.123.27.254	10.123.27.255
29	10.123.28.0/24	10.123.28.1 – 10.123.28.254	10.123.28.255
30	10.123.29.0/24	10.123.29.1 – 10.123.29.254	10.123.29.255
31	10.123.30.0/24	10.123.30.1 – 10.123.30.254	10.123.30.255
32	10.123.31.0/24	10.123.31.1 – 10.123.31.254	10.123.31.255
33	10.123.32.0/24	10.123.32.1 – 10.123.32.254	10.123.32.255
34	10.123.33.0/24	10.123.33.1 – 10.123.33.254	10.123.33.255
35	10.123.34.0/24	10.123.34.1 – 10.123.34.254	10.123.34.255
36	10.123.35.0/24	10.123.35.1 – 10.123.35.254	10.123.35.255
37	10.123.36.0/24	10.123.36.1 – 10.123.36.254	10.123.36.255
38	10.123.37.0/24	10.123.37.1 – 10.123.37.254	10.123.37.255
39	10.123.38.0/24	10.123.38.1 – 10.123.38.254	10.123.38.255
40	10.123.39.0/24	10.123.39.1 – 10.123.39.254	10.123.39.255
41	10.123.40.0/24	10.123.40.1 – 10.123.40.254	10.123.40.255
42	10.123.41.0/24	10.123.41.1 – 10.123.41.254	10.123.41.255
43	10.123.42.0/24	10.123.42.1 – 10.123.42.254	10.123.42.255
44	10.123.43.0/24	10.123.43.1 – 10.123.43.254	10.123.43.255
45	10.123.44.0/24	10.123.44.1 – 10.123.44.254	10.123.44.255
46	10.123.45.0/24	10.123.45.1 – 10.123.45.254	10.123.45.255
47	10.123.46.0/24	10.123.46.1 – 10.123.46.254	10.123.46.255
48	10.123.47.0/24	10.123.47.1 – 10.123.47.254	10.123.47.255
49	10.123.48.0/24	10.123.48.1 – 10.123.48.254	10.123.48.255
50	10.123.49.0/24	10.123.49.1 – 10.123.49.254	10.123.49.255
51	10.123.50.0/24	10.123.50.1 – 10.123.50.254	10.123.50.255
52	10.123.51.0/24	10.123.51.1 – 10.123.51.254	10.123.51.255
53	10.123.52.0/24	10.123.52.1 – 10.123.52.254	10.123.52.255
54	10.123.53.0/24	10.123.53.1 – 10.123.53.254	10.123.53.255
55	10.123.54.0/24	10.123.54.1 – 10.123.54.254	10.123.54.255
56	10.123.55.0/24	10.123.55.1 – 10.123.55.254	10.123.55.255
57	10.123.56.0/24	10.123.56.1 – 10.123.56.254	10.123.56.255
58	10.123.57.0/24	10.123.57.1 – 10.123.57.254	10.123.57.255
59	10.123.58.0/24	10.123.58.1 – 10.123.58.254	10.123.58.255
60	10.123.59.0/24	10.123.59.1 – 10.123.59.254	10.123.59.255
61	10.123.60.0/24	10.123.60.1 – 10.123.60.254	10.123.60.255
62	10.123.61.0/24	10.123.61.1 – 10.123.61.254	10.123.61.255
63	10.123.62.0/24	10.123.62.1 – 10.123.62.254	10.123.62.255
64	10.123.63.0/24	10.123.63.1 – 10.123.63.254	10.123.63.255
65	10.123.64.0/24	10.123.64.1 – 10.123.64.254	10.123.64.255
66	10.123.65.0/24	10.123.65.1 – 10.123.65.254	10.123.65.255
67	10.123.66.0/24	10.123.66.1 – 10.123.66.254	10.123.66.255
68	10.123.67.0/24	10.123.67.1 – 10.123.67.254	10.123.67.255
69	10.123.68.0/24	10.123.68.1 – 10.123.68.254	10.123.68.255
70	10.123.69.0/24	10.123.69.1 – 10.123.69.254	10.123.69.255
71	10.123.70.0/24	10.123.70.1 – 10.123.70.254	10.123.70.255
72	10.123.71.0/24	10.123.71.1 – 10.123.71.254	10.123.71.255
73	10.123.72.0/24	10.123.72.1 – 10.123.72.254	10.123.72.255
74	10.123.73.0/24	10.123.73.1 – 10.123.73.254	10.123.73.255
75	10.123.74.0/24	10.123.74.1 – 10.123.74.254	10.123.74.255
76	10.123.75.0/24	10.123.75.1 – 10.123.75.254	10.123.75.255
77	10.123.76.0/24	10.123.76.1 – 10.123.76.254	10.123.76.255
78	10.123.77.0/24	10.123.77.1 – 10.123.77.254	10.123.77.255
79	10.123.78.0/24	10.123.78.1 – 10.123.78.254	10.123.78.255
80	10.123.79.0/24	10.123.79.1 – 10.123.79.254	10.123.79.255
81	10.123.80.0/24	10.123.80.1 – 10.123.80.254	10.123.80.255
82	10.123.81.0/24	10.123.81.1 – 10.123.81.254	10.123.81.255
83	10.123.82.0/24	10.123.82.1 – 10.123.82.254	10.123.82.255
84	10.123.83.0/24	10.123.83.1 – 10.123.83.254	10.123.83.255
85	10.123.84.0/24	10.123.84.1 – 10.123.84.254	10.123.84.255
86	10.123.85.0/24	10.123.85.1 – 10.123.85.254	10.123.85.255
87	10.123.86.0/24	10.123.86.1 – 10.123.86.254	10.123.86.255
88	10.123.87.0/24	10.123.87.1 – 10.123.87.254	10.123.87.255
89	10.123.88.0/24	10.123.88.1 – 10.123.88.254	10.123.88.255
90	10.123.89.0/24	10.123.89.1 – 10.123.89.254	10.123.89.255
91	10.123.90.0/24	10.123.90.1 – 10.123.90.254	10.123.90.255
92	10.123.91.0/24	10.123.91.1 – 10.123.91.254	10.123.91.255
93	10.123.92.0/24	10.123.92.1 – 10.123.92.254	10.123.92.255
94	10.123.93.0/24	10.123.93.1 – 10.123.93.254	10.123.93.255
95	10.123.94.0/24	10.123.94.1 – 10.123.94.254	10.123.94.255
96	10.123.95.0/24	10.123.95.1 – 10.123.95.254	10.123.95.255
97	10.123.96.0/24	10.123.96.1 – 10.123.96.254	10.123.96.255
98	10.123.97.0/24	10.123.97.1 – 10.123.97.254	10.123.97.255
99	10.123.98.0/24	10.123.98.1 – 10.123.98.254	10.123.98.255
100	10.123.99.0/24	10.123.99.1 – 10.123.99.254	10.123.99.255
101	10.123.100.0/24	10.123.100.1 – 10.123.100.254	10.123.100.255
102	10.123.101.0/24	10.123.101.1 – 10.123.101.254	10.123.101.255
103	10.123.102.0/24	10.123.102.1 – 10.123.102.254	10.123.102.255
104	10.123.103.0/24	10.123.103.1 – 10.123.103.254	10.123.103.255
105	10.123.104.0/24	10.123.104.1 – 10.123.104.254	10.123.104.255
106	10.123.105.0/24	10.123.105.1 – 10.123.105.254	10.123.105.255
107	10.123.106.0/24	10.123.106.1 – 10.123.106.254	10.123.106.255
108	10.123.107.0/24	10.123.107.1 – 10.123.107.254	10.123.107.255
109	10.123.108.0/24	10.123.108.1 – 10.123.108.254	10.123.108.255
110	10.123.109.0/24	10.123.109.1 – 10.123.109.254	10.123.109.255
111	10.123.110.0/24	10.123.110.1 – 10.123.110.254	10.123.110.255
112	10.123.111.0/24	10.123.111.1 – 10.123.111.254	10.123.111.255
113	10.123.112.0/24	10.123.112.1 – 10.123.112.254	10.123.112.255
114	10.123.113.0/24	10.123.113.1 – 10.123.113.254	10.123.113.255
115	10.123.114.0/24	10.123.114.1 – 10.123.114.254	10.123.114.255
116	10.123.115.0/24	10.123.115.1 – 10.123.115.254	10.123.115.255
117	10.123.116.0/24	10.123.116.1 – 10.123.116.254	10.123.116.255
118	10.123.117.0/24	10.123.117.1 – 10.123.117.254	10.123.117.255
119	10.123.118.0/24	10.123.118.1 – 10.123.118.254	10.123.118.255
120	10.123.119.0/24	10.123.119.1 – 10.123.119.254	10.123.119.255
121	10.123.120.0/24	10.123.120.1 – 10.123.120.254	10.123.120.255
122	10.123.121.0/24	10.123.121.1 – 10.123.121.254	10.123.121.255
123	10.123.122.0/24	10.123.122.1 – 10.123.122.254	10.123.122.255
124	10.123.123.0/24	10.123.123.1 – 10.123.123.254	10.123.123.255
125	10.123.124.0/24	10.123.124.1 – 10.123.124.254	10.123.124.255
126	10.123.125.0/24	10.123.125.1 – 10.123.125.254	10.123.125.255
127	10.123.126.0/24	10.123.126.1 – 10.123.126.254	10.123.126.255
128	10.123.127.0/24	10.123.127.1 – 10.123.127.254	10.123.127.255

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 →