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)10.21.64.0/19

network10.21.64.0/19

broadcast10.21.95.255

first host10.21.64.1

last host10.21.95.254

subnet mask255.255.224.0

wildcard0.0.31.255

addresses8,192

usable hosts8,190

classA

ipcalc 10.21.64.0/19

address00001010.00010101.01000000.00000000

subnet mask11111111.11111111.11100000.00000000

network00001010.00010101.01000000.00000000

broadcast00001010.00010101.01011111.11111111

green = network part, grey = host part

hex0x0a154000

decimal169164800

reverse dns0.64.21.10.in-addr.arpa

ipv4-mapped::ffff:a15:4000

/19 split into /26 · 128 subnets

close ×

#	network	host range	broadcast
1	10.21.64.0/26	10.21.64.1 – 10.21.64.62	10.21.64.63
2	10.21.64.64/26	10.21.64.65 – 10.21.64.126	10.21.64.127
3	10.21.64.128/26	10.21.64.129 – 10.21.64.190	10.21.64.191
4	10.21.64.192/26	10.21.64.193 – 10.21.64.254	10.21.64.255
5	10.21.65.0/26	10.21.65.1 – 10.21.65.62	10.21.65.63
6	10.21.65.64/26	10.21.65.65 – 10.21.65.126	10.21.65.127
7	10.21.65.128/26	10.21.65.129 – 10.21.65.190	10.21.65.191
8	10.21.65.192/26	10.21.65.193 – 10.21.65.254	10.21.65.255
9	10.21.66.0/26	10.21.66.1 – 10.21.66.62	10.21.66.63
10	10.21.66.64/26	10.21.66.65 – 10.21.66.126	10.21.66.127
11	10.21.66.128/26	10.21.66.129 – 10.21.66.190	10.21.66.191
12	10.21.66.192/26	10.21.66.193 – 10.21.66.254	10.21.66.255
13	10.21.67.0/26	10.21.67.1 – 10.21.67.62	10.21.67.63
14	10.21.67.64/26	10.21.67.65 – 10.21.67.126	10.21.67.127
15	10.21.67.128/26	10.21.67.129 – 10.21.67.190	10.21.67.191
16	10.21.67.192/26	10.21.67.193 – 10.21.67.254	10.21.67.255
17	10.21.68.0/26	10.21.68.1 – 10.21.68.62	10.21.68.63
18	10.21.68.64/26	10.21.68.65 – 10.21.68.126	10.21.68.127
19	10.21.68.128/26	10.21.68.129 – 10.21.68.190	10.21.68.191
20	10.21.68.192/26	10.21.68.193 – 10.21.68.254	10.21.68.255
21	10.21.69.0/26	10.21.69.1 – 10.21.69.62	10.21.69.63
22	10.21.69.64/26	10.21.69.65 – 10.21.69.126	10.21.69.127
23	10.21.69.128/26	10.21.69.129 – 10.21.69.190	10.21.69.191
24	10.21.69.192/26	10.21.69.193 – 10.21.69.254	10.21.69.255
25	10.21.70.0/26	10.21.70.1 – 10.21.70.62	10.21.70.63
26	10.21.70.64/26	10.21.70.65 – 10.21.70.126	10.21.70.127
27	10.21.70.128/26	10.21.70.129 – 10.21.70.190	10.21.70.191
28	10.21.70.192/26	10.21.70.193 – 10.21.70.254	10.21.70.255
29	10.21.71.0/26	10.21.71.1 – 10.21.71.62	10.21.71.63
30	10.21.71.64/26	10.21.71.65 – 10.21.71.126	10.21.71.127
31	10.21.71.128/26	10.21.71.129 – 10.21.71.190	10.21.71.191
32	10.21.71.192/26	10.21.71.193 – 10.21.71.254	10.21.71.255
33	10.21.72.0/26	10.21.72.1 – 10.21.72.62	10.21.72.63
34	10.21.72.64/26	10.21.72.65 – 10.21.72.126	10.21.72.127
35	10.21.72.128/26	10.21.72.129 – 10.21.72.190	10.21.72.191
36	10.21.72.192/26	10.21.72.193 – 10.21.72.254	10.21.72.255
37	10.21.73.0/26	10.21.73.1 – 10.21.73.62	10.21.73.63
38	10.21.73.64/26	10.21.73.65 – 10.21.73.126	10.21.73.127
39	10.21.73.128/26	10.21.73.129 – 10.21.73.190	10.21.73.191
40	10.21.73.192/26	10.21.73.193 – 10.21.73.254	10.21.73.255
41	10.21.74.0/26	10.21.74.1 – 10.21.74.62	10.21.74.63
42	10.21.74.64/26	10.21.74.65 – 10.21.74.126	10.21.74.127
43	10.21.74.128/26	10.21.74.129 – 10.21.74.190	10.21.74.191
44	10.21.74.192/26	10.21.74.193 – 10.21.74.254	10.21.74.255
45	10.21.75.0/26	10.21.75.1 – 10.21.75.62	10.21.75.63
46	10.21.75.64/26	10.21.75.65 – 10.21.75.126	10.21.75.127
47	10.21.75.128/26	10.21.75.129 – 10.21.75.190	10.21.75.191
48	10.21.75.192/26	10.21.75.193 – 10.21.75.254	10.21.75.255
49	10.21.76.0/26	10.21.76.1 – 10.21.76.62	10.21.76.63
50	10.21.76.64/26	10.21.76.65 – 10.21.76.126	10.21.76.127
51	10.21.76.128/26	10.21.76.129 – 10.21.76.190	10.21.76.191
52	10.21.76.192/26	10.21.76.193 – 10.21.76.254	10.21.76.255
53	10.21.77.0/26	10.21.77.1 – 10.21.77.62	10.21.77.63
54	10.21.77.64/26	10.21.77.65 – 10.21.77.126	10.21.77.127
55	10.21.77.128/26	10.21.77.129 – 10.21.77.190	10.21.77.191
56	10.21.77.192/26	10.21.77.193 – 10.21.77.254	10.21.77.255
57	10.21.78.0/26	10.21.78.1 – 10.21.78.62	10.21.78.63
58	10.21.78.64/26	10.21.78.65 – 10.21.78.126	10.21.78.127
59	10.21.78.128/26	10.21.78.129 – 10.21.78.190	10.21.78.191
60	10.21.78.192/26	10.21.78.193 – 10.21.78.254	10.21.78.255
61	10.21.79.0/26	10.21.79.1 – 10.21.79.62	10.21.79.63
62	10.21.79.64/26	10.21.79.65 – 10.21.79.126	10.21.79.127
63	10.21.79.128/26	10.21.79.129 – 10.21.79.190	10.21.79.191
64	10.21.79.192/26	10.21.79.193 – 10.21.79.254	10.21.79.255
65	10.21.80.0/26	10.21.80.1 – 10.21.80.62	10.21.80.63
66	10.21.80.64/26	10.21.80.65 – 10.21.80.126	10.21.80.127
67	10.21.80.128/26	10.21.80.129 – 10.21.80.190	10.21.80.191
68	10.21.80.192/26	10.21.80.193 – 10.21.80.254	10.21.80.255
69	10.21.81.0/26	10.21.81.1 – 10.21.81.62	10.21.81.63
70	10.21.81.64/26	10.21.81.65 – 10.21.81.126	10.21.81.127
71	10.21.81.128/26	10.21.81.129 – 10.21.81.190	10.21.81.191
72	10.21.81.192/26	10.21.81.193 – 10.21.81.254	10.21.81.255
73	10.21.82.0/26	10.21.82.1 – 10.21.82.62	10.21.82.63
74	10.21.82.64/26	10.21.82.65 – 10.21.82.126	10.21.82.127
75	10.21.82.128/26	10.21.82.129 – 10.21.82.190	10.21.82.191
76	10.21.82.192/26	10.21.82.193 – 10.21.82.254	10.21.82.255
77	10.21.83.0/26	10.21.83.1 – 10.21.83.62	10.21.83.63
78	10.21.83.64/26	10.21.83.65 – 10.21.83.126	10.21.83.127
79	10.21.83.128/26	10.21.83.129 – 10.21.83.190	10.21.83.191
80	10.21.83.192/26	10.21.83.193 – 10.21.83.254	10.21.83.255
81	10.21.84.0/26	10.21.84.1 – 10.21.84.62	10.21.84.63
82	10.21.84.64/26	10.21.84.65 – 10.21.84.126	10.21.84.127
83	10.21.84.128/26	10.21.84.129 – 10.21.84.190	10.21.84.191
84	10.21.84.192/26	10.21.84.193 – 10.21.84.254	10.21.84.255
85	10.21.85.0/26	10.21.85.1 – 10.21.85.62	10.21.85.63
86	10.21.85.64/26	10.21.85.65 – 10.21.85.126	10.21.85.127
87	10.21.85.128/26	10.21.85.129 – 10.21.85.190	10.21.85.191
88	10.21.85.192/26	10.21.85.193 – 10.21.85.254	10.21.85.255
89	10.21.86.0/26	10.21.86.1 – 10.21.86.62	10.21.86.63
90	10.21.86.64/26	10.21.86.65 – 10.21.86.126	10.21.86.127
91	10.21.86.128/26	10.21.86.129 – 10.21.86.190	10.21.86.191
92	10.21.86.192/26	10.21.86.193 – 10.21.86.254	10.21.86.255
93	10.21.87.0/26	10.21.87.1 – 10.21.87.62	10.21.87.63
94	10.21.87.64/26	10.21.87.65 – 10.21.87.126	10.21.87.127
95	10.21.87.128/26	10.21.87.129 – 10.21.87.190	10.21.87.191
96	10.21.87.192/26	10.21.87.193 – 10.21.87.254	10.21.87.255
97	10.21.88.0/26	10.21.88.1 – 10.21.88.62	10.21.88.63
98	10.21.88.64/26	10.21.88.65 – 10.21.88.126	10.21.88.127
99	10.21.88.128/26	10.21.88.129 – 10.21.88.190	10.21.88.191
100	10.21.88.192/26	10.21.88.193 – 10.21.88.254	10.21.88.255
101	10.21.89.0/26	10.21.89.1 – 10.21.89.62	10.21.89.63
102	10.21.89.64/26	10.21.89.65 – 10.21.89.126	10.21.89.127
103	10.21.89.128/26	10.21.89.129 – 10.21.89.190	10.21.89.191
104	10.21.89.192/26	10.21.89.193 – 10.21.89.254	10.21.89.255
105	10.21.90.0/26	10.21.90.1 – 10.21.90.62	10.21.90.63
106	10.21.90.64/26	10.21.90.65 – 10.21.90.126	10.21.90.127
107	10.21.90.128/26	10.21.90.129 – 10.21.90.190	10.21.90.191
108	10.21.90.192/26	10.21.90.193 – 10.21.90.254	10.21.90.255
109	10.21.91.0/26	10.21.91.1 – 10.21.91.62	10.21.91.63
110	10.21.91.64/26	10.21.91.65 – 10.21.91.126	10.21.91.127
111	10.21.91.128/26	10.21.91.129 – 10.21.91.190	10.21.91.191
112	10.21.91.192/26	10.21.91.193 – 10.21.91.254	10.21.91.255
113	10.21.92.0/26	10.21.92.1 – 10.21.92.62	10.21.92.63
114	10.21.92.64/26	10.21.92.65 – 10.21.92.126	10.21.92.127
115	10.21.92.128/26	10.21.92.129 – 10.21.92.190	10.21.92.191
116	10.21.92.192/26	10.21.92.193 – 10.21.92.254	10.21.92.255
117	10.21.93.0/26	10.21.93.1 – 10.21.93.62	10.21.93.63
118	10.21.93.64/26	10.21.93.65 – 10.21.93.126	10.21.93.127
119	10.21.93.128/26	10.21.93.129 – 10.21.93.190	10.21.93.191
120	10.21.93.192/26	10.21.93.193 – 10.21.93.254	10.21.93.255
121	10.21.94.0/26	10.21.94.1 – 10.21.94.62	10.21.94.63
122	10.21.94.64/26	10.21.94.65 – 10.21.94.126	10.21.94.127
123	10.21.94.128/26	10.21.94.129 – 10.21.94.190	10.21.94.191
124	10.21.94.192/26	10.21.94.193 – 10.21.94.254	10.21.94.255
125	10.21.95.0/26	10.21.95.1 – 10.21.95.62	10.21.95.63
126	10.21.95.64/26	10.21.95.65 – 10.21.95.126	10.21.95.127
127	10.21.95.128/26	10.21.95.129 – 10.21.95.190	10.21.95.191
128	10.21.95.192/26	10.21.95.193 – 10.21.95.254	10.21.95.255

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