CIDR Netmask
Netmask dec
Netmask hex
Start
End
Start
End
Start
End
Start
End
/24 = 1 x 256 IP
255.255.255.0
FFFFFF00
0
255
/25 = 2 x 128 IP
255.255.255.128
FFFFFF80
0
127
128
255
/26 = 4 x 64 IP
255.255.255.192
FFFFFFC0
0
63
64
127
128
191
192
255
/27 = 8 x 32 IP
255.255.255.224
FFFFFFE0
0
31
32
63
64
95
96
127
128
159
160
191
192
223
224
255
/28 = 16 x 16 IP
255.255.255.240
FFFFFFF0
0
15
16
31
32
47
48
63
64
79
80
95
96
111
112
127
128
143
144
159
160
175
176
191
192
207
208
223
224
239
240
255
/29 = 32 x 8 IP
255.255.255.248
FFFFFFF8
0
7
8
15
16
23
24
31
32
39
40
47
48
55
56
63
64
71
72
79
80
87
88
95
96
103
104
111
112
119
120
127
128
135
136
143
144
151
152
159
160
167
168
175
176
183
184
191
192
199
200
207
208
215
216
223
224
231
232
239
240
247
248
255
/30 = 64 x 4 IP
255.255.255.252
FFFFFFFC
0
3
4
7
8
11
12
15
16
19
20
23
24
27
28
31
32
35
36
39
40
43
44
47
48
51
52
55
56
59
60
63
64
67
68
71
72
75
76
79
80
83
84
87
88
91
92
95
96
99
100
103
104
107
108
111
112
115
116
119
120
123
124
127
128
131
132
135
136
139
140
143
144
147
148
151
152
155
156
159
160
163
164
167
168
171
172
175
176
179
180
183
184
187
188
191
192
195
196
199
200
203
204
207
208
211
212
215
216
219
220
223
224
227
228
231
232
235
236
239
240
243
244
247
248
251
252
255

Reserved Network Ranges


127.0.0.0/8
Loopback the entire class A beginning with 127.

Private IP address space is defined in RFC1918:

10.0.0.0/8
Private the entire class A beginning with 10.
172.16.0.0/12
Private 16 contiguos Class B, from 172.16.0.0/16 through 172.31.0.0/16
192.168.0.0/16
Private 256 contiguos Class C, from 192.168.0.0/24 through 192.168.255.0/24

The IP Netmask Calculator


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