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)10.0.51.0/25

network10.0.51.0/25

broadcast10.0.51.127

first host10.0.51.1

last host10.0.51.126

subnet mask255.255.255.128

wildcard0.0.0.127

addresses128

usable hosts126

classA

ipcalc 10.0.51.0/25

address00001010.00000000.00110011.00000000

subnet mask11111111.11111111.11111111.10000000

network00001010.00000000.00110011.00000000

broadcast00001010.00000000.00110011.01111111

green = network part, grey = host part

hex0x0a003300

decimal167785216

reverse dns0.51.0.10.in-addr.arpa

ipv4-mapped::ffff:a00:3300

/25 split into /32 · 128 subnets

close ×

#	network	host range	broadcast
1	10.0.51.0/32	10.0.51.0 – 10.0.51.0	10.0.51.0
2	10.0.51.1/32	10.0.51.1 – 10.0.51.1	10.0.51.1
3	10.0.51.2/32	10.0.51.2 – 10.0.51.2	10.0.51.2
4	10.0.51.3/32	10.0.51.3 – 10.0.51.3	10.0.51.3
5	10.0.51.4/32	10.0.51.4 – 10.0.51.4	10.0.51.4
6	10.0.51.5/32	10.0.51.5 – 10.0.51.5	10.0.51.5
7	10.0.51.6/32	10.0.51.6 – 10.0.51.6	10.0.51.6
8	10.0.51.7/32	10.0.51.7 – 10.0.51.7	10.0.51.7
9	10.0.51.8/32	10.0.51.8 – 10.0.51.8	10.0.51.8
10	10.0.51.9/32	10.0.51.9 – 10.0.51.9	10.0.51.9
11	10.0.51.10/32	10.0.51.10 – 10.0.51.10	10.0.51.10
12	10.0.51.11/32	10.0.51.11 – 10.0.51.11	10.0.51.11
13	10.0.51.12/32	10.0.51.12 – 10.0.51.12	10.0.51.12
14	10.0.51.13/32	10.0.51.13 – 10.0.51.13	10.0.51.13
15	10.0.51.14/32	10.0.51.14 – 10.0.51.14	10.0.51.14
16	10.0.51.15/32	10.0.51.15 – 10.0.51.15	10.0.51.15
17	10.0.51.16/32	10.0.51.16 – 10.0.51.16	10.0.51.16
18	10.0.51.17/32	10.0.51.17 – 10.0.51.17	10.0.51.17
19	10.0.51.18/32	10.0.51.18 – 10.0.51.18	10.0.51.18
20	10.0.51.19/32	10.0.51.19 – 10.0.51.19	10.0.51.19
21	10.0.51.20/32	10.0.51.20 – 10.0.51.20	10.0.51.20
22	10.0.51.21/32	10.0.51.21 – 10.0.51.21	10.0.51.21
23	10.0.51.22/32	10.0.51.22 – 10.0.51.22	10.0.51.22
24	10.0.51.23/32	10.0.51.23 – 10.0.51.23	10.0.51.23
25	10.0.51.24/32	10.0.51.24 – 10.0.51.24	10.0.51.24
26	10.0.51.25/32	10.0.51.25 – 10.0.51.25	10.0.51.25
27	10.0.51.26/32	10.0.51.26 – 10.0.51.26	10.0.51.26
28	10.0.51.27/32	10.0.51.27 – 10.0.51.27	10.0.51.27
29	10.0.51.28/32	10.0.51.28 – 10.0.51.28	10.0.51.28
30	10.0.51.29/32	10.0.51.29 – 10.0.51.29	10.0.51.29
31	10.0.51.30/32	10.0.51.30 – 10.0.51.30	10.0.51.30
32	10.0.51.31/32	10.0.51.31 – 10.0.51.31	10.0.51.31
33	10.0.51.32/32	10.0.51.32 – 10.0.51.32	10.0.51.32
34	10.0.51.33/32	10.0.51.33 – 10.0.51.33	10.0.51.33
35	10.0.51.34/32	10.0.51.34 – 10.0.51.34	10.0.51.34
36	10.0.51.35/32	10.0.51.35 – 10.0.51.35	10.0.51.35
37	10.0.51.36/32	10.0.51.36 – 10.0.51.36	10.0.51.36
38	10.0.51.37/32	10.0.51.37 – 10.0.51.37	10.0.51.37
39	10.0.51.38/32	10.0.51.38 – 10.0.51.38	10.0.51.38
40	10.0.51.39/32	10.0.51.39 – 10.0.51.39	10.0.51.39
41	10.0.51.40/32	10.0.51.40 – 10.0.51.40	10.0.51.40
42	10.0.51.41/32	10.0.51.41 – 10.0.51.41	10.0.51.41
43	10.0.51.42/32	10.0.51.42 – 10.0.51.42	10.0.51.42
44	10.0.51.43/32	10.0.51.43 – 10.0.51.43	10.0.51.43
45	10.0.51.44/32	10.0.51.44 – 10.0.51.44	10.0.51.44
46	10.0.51.45/32	10.0.51.45 – 10.0.51.45	10.0.51.45
47	10.0.51.46/32	10.0.51.46 – 10.0.51.46	10.0.51.46
48	10.0.51.47/32	10.0.51.47 – 10.0.51.47	10.0.51.47
49	10.0.51.48/32	10.0.51.48 – 10.0.51.48	10.0.51.48
50	10.0.51.49/32	10.0.51.49 – 10.0.51.49	10.0.51.49
51	10.0.51.50/32	10.0.51.50 – 10.0.51.50	10.0.51.50
52	10.0.51.51/32	10.0.51.51 – 10.0.51.51	10.0.51.51
53	10.0.51.52/32	10.0.51.52 – 10.0.51.52	10.0.51.52
54	10.0.51.53/32	10.0.51.53 – 10.0.51.53	10.0.51.53
55	10.0.51.54/32	10.0.51.54 – 10.0.51.54	10.0.51.54
56	10.0.51.55/32	10.0.51.55 – 10.0.51.55	10.0.51.55
57	10.0.51.56/32	10.0.51.56 – 10.0.51.56	10.0.51.56
58	10.0.51.57/32	10.0.51.57 – 10.0.51.57	10.0.51.57
59	10.0.51.58/32	10.0.51.58 – 10.0.51.58	10.0.51.58
60	10.0.51.59/32	10.0.51.59 – 10.0.51.59	10.0.51.59
61	10.0.51.60/32	10.0.51.60 – 10.0.51.60	10.0.51.60
62	10.0.51.61/32	10.0.51.61 – 10.0.51.61	10.0.51.61
63	10.0.51.62/32	10.0.51.62 – 10.0.51.62	10.0.51.62
64	10.0.51.63/32	10.0.51.63 – 10.0.51.63	10.0.51.63
65	10.0.51.64/32	10.0.51.64 – 10.0.51.64	10.0.51.64
66	10.0.51.65/32	10.0.51.65 – 10.0.51.65	10.0.51.65
67	10.0.51.66/32	10.0.51.66 – 10.0.51.66	10.0.51.66
68	10.0.51.67/32	10.0.51.67 – 10.0.51.67	10.0.51.67
69	10.0.51.68/32	10.0.51.68 – 10.0.51.68	10.0.51.68
70	10.0.51.69/32	10.0.51.69 – 10.0.51.69	10.0.51.69
71	10.0.51.70/32	10.0.51.70 – 10.0.51.70	10.0.51.70
72	10.0.51.71/32	10.0.51.71 – 10.0.51.71	10.0.51.71
73	10.0.51.72/32	10.0.51.72 – 10.0.51.72	10.0.51.72
74	10.0.51.73/32	10.0.51.73 – 10.0.51.73	10.0.51.73
75	10.0.51.74/32	10.0.51.74 – 10.0.51.74	10.0.51.74
76	10.0.51.75/32	10.0.51.75 – 10.0.51.75	10.0.51.75
77	10.0.51.76/32	10.0.51.76 – 10.0.51.76	10.0.51.76
78	10.0.51.77/32	10.0.51.77 – 10.0.51.77	10.0.51.77
79	10.0.51.78/32	10.0.51.78 – 10.0.51.78	10.0.51.78
80	10.0.51.79/32	10.0.51.79 – 10.0.51.79	10.0.51.79
81	10.0.51.80/32	10.0.51.80 – 10.0.51.80	10.0.51.80
82	10.0.51.81/32	10.0.51.81 – 10.0.51.81	10.0.51.81
83	10.0.51.82/32	10.0.51.82 – 10.0.51.82	10.0.51.82
84	10.0.51.83/32	10.0.51.83 – 10.0.51.83	10.0.51.83
85	10.0.51.84/32	10.0.51.84 – 10.0.51.84	10.0.51.84
86	10.0.51.85/32	10.0.51.85 – 10.0.51.85	10.0.51.85
87	10.0.51.86/32	10.0.51.86 – 10.0.51.86	10.0.51.86
88	10.0.51.87/32	10.0.51.87 – 10.0.51.87	10.0.51.87
89	10.0.51.88/32	10.0.51.88 – 10.0.51.88	10.0.51.88
90	10.0.51.89/32	10.0.51.89 – 10.0.51.89	10.0.51.89
91	10.0.51.90/32	10.0.51.90 – 10.0.51.90	10.0.51.90
92	10.0.51.91/32	10.0.51.91 – 10.0.51.91	10.0.51.91
93	10.0.51.92/32	10.0.51.92 – 10.0.51.92	10.0.51.92
94	10.0.51.93/32	10.0.51.93 – 10.0.51.93	10.0.51.93
95	10.0.51.94/32	10.0.51.94 – 10.0.51.94	10.0.51.94
96	10.0.51.95/32	10.0.51.95 – 10.0.51.95	10.0.51.95
97	10.0.51.96/32	10.0.51.96 – 10.0.51.96	10.0.51.96
98	10.0.51.97/32	10.0.51.97 – 10.0.51.97	10.0.51.97
99	10.0.51.98/32	10.0.51.98 – 10.0.51.98	10.0.51.98
100	10.0.51.99/32	10.0.51.99 – 10.0.51.99	10.0.51.99
101	10.0.51.100/32	10.0.51.100 – 10.0.51.100	10.0.51.100
102	10.0.51.101/32	10.0.51.101 – 10.0.51.101	10.0.51.101
103	10.0.51.102/32	10.0.51.102 – 10.0.51.102	10.0.51.102
104	10.0.51.103/32	10.0.51.103 – 10.0.51.103	10.0.51.103
105	10.0.51.104/32	10.0.51.104 – 10.0.51.104	10.0.51.104
106	10.0.51.105/32	10.0.51.105 – 10.0.51.105	10.0.51.105
107	10.0.51.106/32	10.0.51.106 – 10.0.51.106	10.0.51.106
108	10.0.51.107/32	10.0.51.107 – 10.0.51.107	10.0.51.107
109	10.0.51.108/32	10.0.51.108 – 10.0.51.108	10.0.51.108
110	10.0.51.109/32	10.0.51.109 – 10.0.51.109	10.0.51.109
111	10.0.51.110/32	10.0.51.110 – 10.0.51.110	10.0.51.110
112	10.0.51.111/32	10.0.51.111 – 10.0.51.111	10.0.51.111
113	10.0.51.112/32	10.0.51.112 – 10.0.51.112	10.0.51.112
114	10.0.51.113/32	10.0.51.113 – 10.0.51.113	10.0.51.113
115	10.0.51.114/32	10.0.51.114 – 10.0.51.114	10.0.51.114
116	10.0.51.115/32	10.0.51.115 – 10.0.51.115	10.0.51.115
117	10.0.51.116/32	10.0.51.116 – 10.0.51.116	10.0.51.116
118	10.0.51.117/32	10.0.51.117 – 10.0.51.117	10.0.51.117
119	10.0.51.118/32	10.0.51.118 – 10.0.51.118	10.0.51.118
120	10.0.51.119/32	10.0.51.119 – 10.0.51.119	10.0.51.119
121	10.0.51.120/32	10.0.51.120 – 10.0.51.120	10.0.51.120
122	10.0.51.121/32	10.0.51.121 – 10.0.51.121	10.0.51.121
123	10.0.51.122/32	10.0.51.122 – 10.0.51.122	10.0.51.122
124	10.0.51.123/32	10.0.51.123 – 10.0.51.123	10.0.51.123
125	10.0.51.124/32	10.0.51.124 – 10.0.51.124	10.0.51.124
126	10.0.51.125/32	10.0.51.125 – 10.0.51.125	10.0.51.125
127	10.0.51.126/32	10.0.51.126 – 10.0.51.126	10.0.51.126
128	10.0.51.127/32	10.0.51.127 – 10.0.51.127	10.0.51.127

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 →