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)10.2.181.0/25

network10.2.181.0/25

broadcast10.2.181.127

first host10.2.181.1

last host10.2.181.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.2.181.0/25

address00001010.00000010.10110101.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000010.10110101.00000000

broadcast00001010.00000010.10110101.01111111

green = network part, grey = host part

hex0x0a02b500

decimal167949568

reverse dns0.181.2.10.in-addr.arpa

ipv4-mapped::ffff:a02:b500

/25 split into /32 · 128 subnets

close ×

#	network	host range	broadcast
1	10.2.181.0/32	10.2.181.0 – 10.2.181.0	10.2.181.0
2	10.2.181.1/32	10.2.181.1 – 10.2.181.1	10.2.181.1
3	10.2.181.2/32	10.2.181.2 – 10.2.181.2	10.2.181.2
4	10.2.181.3/32	10.2.181.3 – 10.2.181.3	10.2.181.3
5	10.2.181.4/32	10.2.181.4 – 10.2.181.4	10.2.181.4
6	10.2.181.5/32	10.2.181.5 – 10.2.181.5	10.2.181.5
7	10.2.181.6/32	10.2.181.6 – 10.2.181.6	10.2.181.6
8	10.2.181.7/32	10.2.181.7 – 10.2.181.7	10.2.181.7
9	10.2.181.8/32	10.2.181.8 – 10.2.181.8	10.2.181.8
10	10.2.181.9/32	10.2.181.9 – 10.2.181.9	10.2.181.9
11	10.2.181.10/32	10.2.181.10 – 10.2.181.10	10.2.181.10
12	10.2.181.11/32	10.2.181.11 – 10.2.181.11	10.2.181.11
13	10.2.181.12/32	10.2.181.12 – 10.2.181.12	10.2.181.12
14	10.2.181.13/32	10.2.181.13 – 10.2.181.13	10.2.181.13
15	10.2.181.14/32	10.2.181.14 – 10.2.181.14	10.2.181.14
16	10.2.181.15/32	10.2.181.15 – 10.2.181.15	10.2.181.15
17	10.2.181.16/32	10.2.181.16 – 10.2.181.16	10.2.181.16
18	10.2.181.17/32	10.2.181.17 – 10.2.181.17	10.2.181.17
19	10.2.181.18/32	10.2.181.18 – 10.2.181.18	10.2.181.18
20	10.2.181.19/32	10.2.181.19 – 10.2.181.19	10.2.181.19
21	10.2.181.20/32	10.2.181.20 – 10.2.181.20	10.2.181.20
22	10.2.181.21/32	10.2.181.21 – 10.2.181.21	10.2.181.21
23	10.2.181.22/32	10.2.181.22 – 10.2.181.22	10.2.181.22
24	10.2.181.23/32	10.2.181.23 – 10.2.181.23	10.2.181.23
25	10.2.181.24/32	10.2.181.24 – 10.2.181.24	10.2.181.24
26	10.2.181.25/32	10.2.181.25 – 10.2.181.25	10.2.181.25
27	10.2.181.26/32	10.2.181.26 – 10.2.181.26	10.2.181.26
28	10.2.181.27/32	10.2.181.27 – 10.2.181.27	10.2.181.27
29	10.2.181.28/32	10.2.181.28 – 10.2.181.28	10.2.181.28
30	10.2.181.29/32	10.2.181.29 – 10.2.181.29	10.2.181.29
31	10.2.181.30/32	10.2.181.30 – 10.2.181.30	10.2.181.30
32	10.2.181.31/32	10.2.181.31 – 10.2.181.31	10.2.181.31
33	10.2.181.32/32	10.2.181.32 – 10.2.181.32	10.2.181.32
34	10.2.181.33/32	10.2.181.33 – 10.2.181.33	10.2.181.33
35	10.2.181.34/32	10.2.181.34 – 10.2.181.34	10.2.181.34
36	10.2.181.35/32	10.2.181.35 – 10.2.181.35	10.2.181.35
37	10.2.181.36/32	10.2.181.36 – 10.2.181.36	10.2.181.36
38	10.2.181.37/32	10.2.181.37 – 10.2.181.37	10.2.181.37
39	10.2.181.38/32	10.2.181.38 – 10.2.181.38	10.2.181.38
40	10.2.181.39/32	10.2.181.39 – 10.2.181.39	10.2.181.39
41	10.2.181.40/32	10.2.181.40 – 10.2.181.40	10.2.181.40
42	10.2.181.41/32	10.2.181.41 – 10.2.181.41	10.2.181.41
43	10.2.181.42/32	10.2.181.42 – 10.2.181.42	10.2.181.42
44	10.2.181.43/32	10.2.181.43 – 10.2.181.43	10.2.181.43
45	10.2.181.44/32	10.2.181.44 – 10.2.181.44	10.2.181.44
46	10.2.181.45/32	10.2.181.45 – 10.2.181.45	10.2.181.45
47	10.2.181.46/32	10.2.181.46 – 10.2.181.46	10.2.181.46
48	10.2.181.47/32	10.2.181.47 – 10.2.181.47	10.2.181.47
49	10.2.181.48/32	10.2.181.48 – 10.2.181.48	10.2.181.48
50	10.2.181.49/32	10.2.181.49 – 10.2.181.49	10.2.181.49
51	10.2.181.50/32	10.2.181.50 – 10.2.181.50	10.2.181.50
52	10.2.181.51/32	10.2.181.51 – 10.2.181.51	10.2.181.51
53	10.2.181.52/32	10.2.181.52 – 10.2.181.52	10.2.181.52
54	10.2.181.53/32	10.2.181.53 – 10.2.181.53	10.2.181.53
55	10.2.181.54/32	10.2.181.54 – 10.2.181.54	10.2.181.54
56	10.2.181.55/32	10.2.181.55 – 10.2.181.55	10.2.181.55
57	10.2.181.56/32	10.2.181.56 – 10.2.181.56	10.2.181.56
58	10.2.181.57/32	10.2.181.57 – 10.2.181.57	10.2.181.57
59	10.2.181.58/32	10.2.181.58 – 10.2.181.58	10.2.181.58
60	10.2.181.59/32	10.2.181.59 – 10.2.181.59	10.2.181.59
61	10.2.181.60/32	10.2.181.60 – 10.2.181.60	10.2.181.60
62	10.2.181.61/32	10.2.181.61 – 10.2.181.61	10.2.181.61
63	10.2.181.62/32	10.2.181.62 – 10.2.181.62	10.2.181.62
64	10.2.181.63/32	10.2.181.63 – 10.2.181.63	10.2.181.63
65	10.2.181.64/32	10.2.181.64 – 10.2.181.64	10.2.181.64
66	10.2.181.65/32	10.2.181.65 – 10.2.181.65	10.2.181.65
67	10.2.181.66/32	10.2.181.66 – 10.2.181.66	10.2.181.66
68	10.2.181.67/32	10.2.181.67 – 10.2.181.67	10.2.181.67
69	10.2.181.68/32	10.2.181.68 – 10.2.181.68	10.2.181.68
70	10.2.181.69/32	10.2.181.69 – 10.2.181.69	10.2.181.69
71	10.2.181.70/32	10.2.181.70 – 10.2.181.70	10.2.181.70
72	10.2.181.71/32	10.2.181.71 – 10.2.181.71	10.2.181.71
73	10.2.181.72/32	10.2.181.72 – 10.2.181.72	10.2.181.72
74	10.2.181.73/32	10.2.181.73 – 10.2.181.73	10.2.181.73
75	10.2.181.74/32	10.2.181.74 – 10.2.181.74	10.2.181.74
76	10.2.181.75/32	10.2.181.75 – 10.2.181.75	10.2.181.75
77	10.2.181.76/32	10.2.181.76 – 10.2.181.76	10.2.181.76
78	10.2.181.77/32	10.2.181.77 – 10.2.181.77	10.2.181.77
79	10.2.181.78/32	10.2.181.78 – 10.2.181.78	10.2.181.78
80	10.2.181.79/32	10.2.181.79 – 10.2.181.79	10.2.181.79
81	10.2.181.80/32	10.2.181.80 – 10.2.181.80	10.2.181.80
82	10.2.181.81/32	10.2.181.81 – 10.2.181.81	10.2.181.81
83	10.2.181.82/32	10.2.181.82 – 10.2.181.82	10.2.181.82
84	10.2.181.83/32	10.2.181.83 – 10.2.181.83	10.2.181.83
85	10.2.181.84/32	10.2.181.84 – 10.2.181.84	10.2.181.84
86	10.2.181.85/32	10.2.181.85 – 10.2.181.85	10.2.181.85
87	10.2.181.86/32	10.2.181.86 – 10.2.181.86	10.2.181.86
88	10.2.181.87/32	10.2.181.87 – 10.2.181.87	10.2.181.87
89	10.2.181.88/32	10.2.181.88 – 10.2.181.88	10.2.181.88
90	10.2.181.89/32	10.2.181.89 – 10.2.181.89	10.2.181.89
91	10.2.181.90/32	10.2.181.90 – 10.2.181.90	10.2.181.90
92	10.2.181.91/32	10.2.181.91 – 10.2.181.91	10.2.181.91
93	10.2.181.92/32	10.2.181.92 – 10.2.181.92	10.2.181.92
94	10.2.181.93/32	10.2.181.93 – 10.2.181.93	10.2.181.93
95	10.2.181.94/32	10.2.181.94 – 10.2.181.94	10.2.181.94
96	10.2.181.95/32	10.2.181.95 – 10.2.181.95	10.2.181.95
97	10.2.181.96/32	10.2.181.96 – 10.2.181.96	10.2.181.96
98	10.2.181.97/32	10.2.181.97 – 10.2.181.97	10.2.181.97
99	10.2.181.98/32	10.2.181.98 – 10.2.181.98	10.2.181.98
100	10.2.181.99/32	10.2.181.99 – 10.2.181.99	10.2.181.99
101	10.2.181.100/32	10.2.181.100 – 10.2.181.100	10.2.181.100
102	10.2.181.101/32	10.2.181.101 – 10.2.181.101	10.2.181.101
103	10.2.181.102/32	10.2.181.102 – 10.2.181.102	10.2.181.102
104	10.2.181.103/32	10.2.181.103 – 10.2.181.103	10.2.181.103
105	10.2.181.104/32	10.2.181.104 – 10.2.181.104	10.2.181.104
106	10.2.181.105/32	10.2.181.105 – 10.2.181.105	10.2.181.105
107	10.2.181.106/32	10.2.181.106 – 10.2.181.106	10.2.181.106
108	10.2.181.107/32	10.2.181.107 – 10.2.181.107	10.2.181.107
109	10.2.181.108/32	10.2.181.108 – 10.2.181.108	10.2.181.108
110	10.2.181.109/32	10.2.181.109 – 10.2.181.109	10.2.181.109
111	10.2.181.110/32	10.2.181.110 – 10.2.181.110	10.2.181.110
112	10.2.181.111/32	10.2.181.111 – 10.2.181.111	10.2.181.111
113	10.2.181.112/32	10.2.181.112 – 10.2.181.112	10.2.181.112
114	10.2.181.113/32	10.2.181.113 – 10.2.181.113	10.2.181.113
115	10.2.181.114/32	10.2.181.114 – 10.2.181.114	10.2.181.114
116	10.2.181.115/32	10.2.181.115 – 10.2.181.115	10.2.181.115
117	10.2.181.116/32	10.2.181.116 – 10.2.181.116	10.2.181.116
118	10.2.181.117/32	10.2.181.117 – 10.2.181.117	10.2.181.117
119	10.2.181.118/32	10.2.181.118 – 10.2.181.118	10.2.181.118
120	10.2.181.119/32	10.2.181.119 – 10.2.181.119	10.2.181.119
121	10.2.181.120/32	10.2.181.120 – 10.2.181.120	10.2.181.120
122	10.2.181.121/32	10.2.181.121 – 10.2.181.121	10.2.181.121
123	10.2.181.122/32	10.2.181.122 – 10.2.181.122	10.2.181.122
124	10.2.181.123/32	10.2.181.123 – 10.2.181.123	10.2.181.123
125	10.2.181.124/32	10.2.181.124 – 10.2.181.124	10.2.181.124
126	10.2.181.125/32	10.2.181.125 – 10.2.181.125	10.2.181.125
127	10.2.181.126/32	10.2.181.126 – 10.2.181.126	10.2.181.126
128	10.2.181.127/32	10.2.181.127 – 10.2.181.127	10.2.181.127

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