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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network253.4.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
253.4.64.0
Broadcast address
253.4.127.255
First usable
253.4.64.1
Last usable
253.4.127.254
Usable hosts
16,382 (16,384 less the network and broadcast addresses)
Subnet mask
255.255.192.0
Wildcard mask
0.0.63.255 (Cisco ACLs, OSPF)
Prefix length
/18
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FD044000 · Integer 4244914176 to 4244930559
Reverse DNS zones
64.4.253.in-addr.arpa
65.4.253.in-addr.arpa
66.4.253.in-addr.arpa
67.4.253.in-addr.arpa
68.4.253.in-addr.arpa
69.4.253.in-addr.arpa
70.4.253.in-addr.arpa
71.4.253.in-addr.arpa
72.4.253.in-addr.arpa
73.4.253.in-addr.arpa
74.4.253.in-addr.arpa
75.4.253.in-addr.arpa
76.4.253.in-addr.arpa
77.4.253.in-addr.arpa
78.4.253.in-addr.arpa
79.4.253.in-addr.arpa
and 48 more
/18 is not on a 8-bit boundary, so it takes 64 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111101.00000100.01000000.00000000253.4.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network11111101.00000100.01000000.00000000253.4.64.0
Broadcast11111101.00000100.01111111.11111111253.4.127.255
Split into smaller subnets/27
/19 (2)/20 (4)/21 (8)/22 (16)/23 (32)/24 (64)/25 (128)/26 (256)/27 (512)/28 (1,024)/29 (2,048)/30 (4,096)

253.4.64.0/18 makes 512 subnets of /27; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1253.4.64.0/27253.4.64.1 to 253.4.64.30253.4.64.3130
2253.4.64.32/27253.4.64.33 to 253.4.64.62253.4.64.6330
3253.4.64.64/27253.4.64.65 to 253.4.64.94253.4.64.9530
4253.4.64.96/27253.4.64.97 to 253.4.64.126253.4.64.12730
5253.4.64.128/27253.4.64.129 to 253.4.64.158253.4.64.15930
6253.4.64.160/27253.4.64.161 to 253.4.64.190253.4.64.19130
7253.4.64.192/27253.4.64.193 to 253.4.64.222253.4.64.22330
8253.4.64.224/27253.4.64.225 to 253.4.64.254253.4.64.25530
9253.4.65.0/27253.4.65.1 to 253.4.65.30253.4.65.3130
10253.4.65.32/27253.4.65.33 to 253.4.65.62253.4.65.6330
11253.4.65.64/27253.4.65.65 to 253.4.65.94253.4.65.9530
12253.4.65.96/27253.4.65.97 to 253.4.65.126253.4.65.12730
13253.4.65.128/27253.4.65.129 to 253.4.65.158253.4.65.15930
14253.4.65.160/27253.4.65.161 to 253.4.65.190253.4.65.19130
15253.4.65.192/27253.4.65.193 to 253.4.65.222253.4.65.22330
16253.4.65.224/27253.4.65.225 to 253.4.65.254253.4.65.25530
17253.4.66.0/27253.4.66.1 to 253.4.66.30253.4.66.3130
18253.4.66.32/27253.4.66.33 to 253.4.66.62253.4.66.6330
19253.4.66.64/27253.4.66.65 to 253.4.66.94253.4.66.9530
20253.4.66.96/27253.4.66.97 to 253.4.66.126253.4.66.12730
21253.4.66.128/27253.4.66.129 to 253.4.66.158253.4.66.15930
22253.4.66.160/27253.4.66.161 to 253.4.66.190253.4.66.19130
23253.4.66.192/27253.4.66.193 to 253.4.66.222253.4.66.22330
24253.4.66.224/27253.4.66.225 to 253.4.66.254253.4.66.25530
25253.4.67.0/27253.4.67.1 to 253.4.67.30253.4.67.3130
26253.4.67.32/27253.4.67.33 to 253.4.67.62253.4.67.6330
27253.4.67.64/27253.4.67.65 to 253.4.67.94253.4.67.9530
28253.4.67.96/27253.4.67.97 to 253.4.67.126253.4.67.12730
29253.4.67.128/27253.4.67.129 to 253.4.67.158253.4.67.15930
30253.4.67.160/27253.4.67.161 to 253.4.67.190253.4.67.19130
31253.4.67.192/27253.4.67.193 to 253.4.67.222253.4.67.22330
32253.4.67.224/27253.4.67.225 to 253.4.67.254253.4.67.25530
33253.4.68.0/27253.4.68.1 to 253.4.68.30253.4.68.3130
34253.4.68.32/27253.4.68.33 to 253.4.68.62253.4.68.6330
35253.4.68.64/27253.4.68.65 to 253.4.68.94253.4.68.9530
36253.4.68.96/27253.4.68.97 to 253.4.68.126253.4.68.12730
37253.4.68.128/27253.4.68.129 to 253.4.68.158253.4.68.15930
38253.4.68.160/27253.4.68.161 to 253.4.68.190253.4.68.19130
39253.4.68.192/27253.4.68.193 to 253.4.68.222253.4.68.22330
40253.4.68.224/27253.4.68.225 to 253.4.68.254253.4.68.25530
41253.4.69.0/27253.4.69.1 to 253.4.69.30253.4.69.3130
42253.4.69.32/27253.4.69.33 to 253.4.69.62253.4.69.6330
43253.4.69.64/27253.4.69.65 to 253.4.69.94253.4.69.9530
44253.4.69.96/27253.4.69.97 to 253.4.69.126253.4.69.12730
45253.4.69.128/27253.4.69.129 to 253.4.69.158253.4.69.15930
46253.4.69.160/27253.4.69.161 to 253.4.69.190253.4.69.19130
47253.4.69.192/27253.4.69.193 to 253.4.69.222253.4.69.22330
48253.4.69.224/27253.4.69.225 to 253.4.69.254253.4.69.25530
49253.4.70.0/27253.4.70.1 to 253.4.70.30253.4.70.3130
50253.4.70.32/27253.4.70.33 to 253.4.70.62253.4.70.6330
51253.4.70.64/27253.4.70.65 to 253.4.70.94253.4.70.9530
52253.4.70.96/27253.4.70.97 to 253.4.70.126253.4.70.12730
53253.4.70.128/27253.4.70.129 to 253.4.70.158253.4.70.15930
54253.4.70.160/27253.4.70.161 to 253.4.70.190253.4.70.19130
55253.4.70.192/27253.4.70.193 to 253.4.70.222253.4.70.22330
56253.4.70.224/27253.4.70.225 to 253.4.70.254253.4.70.25530
57253.4.71.0/27253.4.71.1 to 253.4.71.30253.4.71.3130
58253.4.71.32/27253.4.71.33 to 253.4.71.62253.4.71.6330
59253.4.71.64/27253.4.71.65 to 253.4.71.94253.4.71.9530
60253.4.71.96/27253.4.71.97 to 253.4.71.126253.4.71.12730
61253.4.71.128/27253.4.71.129 to 253.4.71.158253.4.71.15930
62253.4.71.160/27253.4.71.161 to 253.4.71.190253.4.71.19130
63253.4.71.192/27253.4.71.193 to 253.4.71.222253.4.71.22330
64253.4.71.224/27253.4.71.225 to 253.4.71.254253.4.71.25530
65253.4.72.0/27253.4.72.1 to 253.4.72.30253.4.72.3130
66253.4.72.32/27253.4.72.33 to 253.4.72.62253.4.72.6330
67253.4.72.64/27253.4.72.65 to 253.4.72.94253.4.72.9530
68253.4.72.96/27253.4.72.97 to 253.4.72.126253.4.72.12730
69253.4.72.128/27253.4.72.129 to 253.4.72.158253.4.72.15930
70253.4.72.160/27253.4.72.161 to 253.4.72.190253.4.72.19130
71253.4.72.192/27253.4.72.193 to 253.4.72.222253.4.72.22330
72253.4.72.224/27253.4.72.225 to 253.4.72.254253.4.72.25530
73253.4.73.0/27253.4.73.1 to 253.4.73.30253.4.73.3130
74253.4.73.32/27253.4.73.33 to 253.4.73.62253.4.73.6330
75253.4.73.64/27253.4.73.65 to 253.4.73.94253.4.73.9530
76253.4.73.96/27253.4.73.97 to 253.4.73.126253.4.73.12730
77253.4.73.128/27253.4.73.129 to 253.4.73.158253.4.73.15930
78253.4.73.160/27253.4.73.161 to 253.4.73.190253.4.73.19130
79253.4.73.192/27253.4.73.193 to 253.4.73.222253.4.73.22330
80253.4.73.224/27253.4.73.225 to 253.4.73.254253.4.73.25530
81253.4.74.0/27253.4.74.1 to 253.4.74.30253.4.74.3130
82253.4.74.32/27253.4.74.33 to 253.4.74.62253.4.74.6330
83253.4.74.64/27253.4.74.65 to 253.4.74.94253.4.74.9530
84253.4.74.96/27253.4.74.97 to 253.4.74.126253.4.74.12730
85253.4.74.128/27253.4.74.129 to 253.4.74.158253.4.74.15930
86253.4.74.160/27253.4.74.161 to 253.4.74.190253.4.74.19130
87253.4.74.192/27253.4.74.193 to 253.4.74.222253.4.74.22330
88253.4.74.224/27253.4.74.225 to 253.4.74.254253.4.74.25530
89253.4.75.0/27253.4.75.1 to 253.4.75.30253.4.75.3130
90253.4.75.32/27253.4.75.33 to 253.4.75.62253.4.75.6330
91253.4.75.64/27253.4.75.65 to 253.4.75.94253.4.75.9530
92253.4.75.96/27253.4.75.97 to 253.4.75.126253.4.75.12730
93253.4.75.128/27253.4.75.129 to 253.4.75.158253.4.75.15930
94253.4.75.160/27253.4.75.161 to 253.4.75.190253.4.75.19130
95253.4.75.192/27253.4.75.193 to 253.4.75.222253.4.75.22330
96253.4.75.224/27253.4.75.225 to 253.4.75.254253.4.75.25530
97253.4.76.0/27253.4.76.1 to 253.4.76.30253.4.76.3130
98253.4.76.32/27253.4.76.33 to 253.4.76.62253.4.76.6330
99253.4.76.64/27253.4.76.65 to 253.4.76.94253.4.76.9530
100253.4.76.96/27253.4.76.97 to 253.4.76.126253.4.76.12730
101253.4.76.128/27253.4.76.129 to 253.4.76.158253.4.76.15930
102253.4.76.160/27253.4.76.161 to 253.4.76.190253.4.76.19130
103253.4.76.192/27253.4.76.193 to 253.4.76.222253.4.76.22330
104253.4.76.224/27253.4.76.225 to 253.4.76.254253.4.76.25530
105253.4.77.0/27253.4.77.1 to 253.4.77.30253.4.77.3130
106253.4.77.32/27253.4.77.33 to 253.4.77.62253.4.77.6330
107253.4.77.64/27253.4.77.65 to 253.4.77.94253.4.77.9530
108253.4.77.96/27253.4.77.97 to 253.4.77.126253.4.77.12730
109253.4.77.128/27253.4.77.129 to 253.4.77.158253.4.77.15930
110253.4.77.160/27253.4.77.161 to 253.4.77.190253.4.77.19130
111253.4.77.192/27253.4.77.193 to 253.4.77.222253.4.77.22330
112253.4.77.224/27253.4.77.225 to 253.4.77.254253.4.77.25530
113253.4.78.0/27253.4.78.1 to 253.4.78.30253.4.78.3130
114253.4.78.32/27253.4.78.33 to 253.4.78.62253.4.78.6330
115253.4.78.64/27253.4.78.65 to 253.4.78.94253.4.78.9530
116253.4.78.96/27253.4.78.97 to 253.4.78.126253.4.78.12730
117253.4.78.128/27253.4.78.129 to 253.4.78.158253.4.78.15930
118253.4.78.160/27253.4.78.161 to 253.4.78.190253.4.78.19130
119253.4.78.192/27253.4.78.193 to 253.4.78.222253.4.78.22330
120253.4.78.224/27253.4.78.225 to 253.4.78.254253.4.78.25530
121253.4.79.0/27253.4.79.1 to 253.4.79.30253.4.79.3130
122253.4.79.32/27253.4.79.33 to 253.4.79.62253.4.79.6330
123253.4.79.64/27253.4.79.65 to 253.4.79.94253.4.79.9530
124253.4.79.96/27253.4.79.97 to 253.4.79.126253.4.79.12730
125253.4.79.128/27253.4.79.129 to 253.4.79.158253.4.79.15930
126253.4.79.160/27253.4.79.161 to 253.4.79.190253.4.79.19130
127253.4.79.192/27253.4.79.193 to 253.4.79.222253.4.79.22330
128253.4.79.224/27253.4.79.225 to 253.4.79.254253.4.79.25530
129253.4.80.0/27253.4.80.1 to 253.4.80.30253.4.80.3130
130253.4.80.32/27253.4.80.33 to 253.4.80.62253.4.80.6330
131253.4.80.64/27253.4.80.65 to 253.4.80.94253.4.80.9530
132253.4.80.96/27253.4.80.97 to 253.4.80.126253.4.80.12730
133253.4.80.128/27253.4.80.129 to 253.4.80.158253.4.80.15930
134253.4.80.160/27253.4.80.161 to 253.4.80.190253.4.80.19130
135253.4.80.192/27253.4.80.193 to 253.4.80.222253.4.80.22330
136253.4.80.224/27253.4.80.225 to 253.4.80.254253.4.80.25530
137253.4.81.0/27253.4.81.1 to 253.4.81.30253.4.81.3130
138253.4.81.32/27253.4.81.33 to 253.4.81.62253.4.81.6330
139253.4.81.64/27253.4.81.65 to 253.4.81.94253.4.81.9530
140253.4.81.96/27253.4.81.97 to 253.4.81.126253.4.81.12730
141253.4.81.128/27253.4.81.129 to 253.4.81.158253.4.81.15930
142253.4.81.160/27253.4.81.161 to 253.4.81.190253.4.81.19130
143253.4.81.192/27253.4.81.193 to 253.4.81.222253.4.81.22330
144253.4.81.224/27253.4.81.225 to 253.4.81.254253.4.81.25530
145253.4.82.0/27253.4.82.1 to 253.4.82.30253.4.82.3130
146253.4.82.32/27253.4.82.33 to 253.4.82.62253.4.82.6330
147253.4.82.64/27253.4.82.65 to 253.4.82.94253.4.82.9530
148253.4.82.96/27253.4.82.97 to 253.4.82.126253.4.82.12730
149253.4.82.128/27253.4.82.129 to 253.4.82.158253.4.82.15930
150253.4.82.160/27253.4.82.161 to 253.4.82.190253.4.82.19130
151253.4.82.192/27253.4.82.193 to 253.4.82.222253.4.82.22330
152253.4.82.224/27253.4.82.225 to 253.4.82.254253.4.82.25530
153253.4.83.0/27253.4.83.1 to 253.4.83.30253.4.83.3130
154253.4.83.32/27253.4.83.33 to 253.4.83.62253.4.83.6330
155253.4.83.64/27253.4.83.65 to 253.4.83.94253.4.83.9530
156253.4.83.96/27253.4.83.97 to 253.4.83.126253.4.83.12730
157253.4.83.128/27253.4.83.129 to 253.4.83.158253.4.83.15930
158253.4.83.160/27253.4.83.161 to 253.4.83.190253.4.83.19130
159253.4.83.192/27253.4.83.193 to 253.4.83.222253.4.83.22330
160253.4.83.224/27253.4.83.225 to 253.4.83.254253.4.83.25530
161253.4.84.0/27253.4.84.1 to 253.4.84.30253.4.84.3130
162253.4.84.32/27253.4.84.33 to 253.4.84.62253.4.84.6330
163253.4.84.64/27253.4.84.65 to 253.4.84.94253.4.84.9530
164253.4.84.96/27253.4.84.97 to 253.4.84.126253.4.84.12730
165253.4.84.128/27253.4.84.129 to 253.4.84.158253.4.84.15930
166253.4.84.160/27253.4.84.161 to 253.4.84.190253.4.84.19130
167253.4.84.192/27253.4.84.193 to 253.4.84.222253.4.84.22330
168253.4.84.224/27253.4.84.225 to 253.4.84.254253.4.84.25530
169253.4.85.0/27253.4.85.1 to 253.4.85.30253.4.85.3130
170253.4.85.32/27253.4.85.33 to 253.4.85.62253.4.85.6330
171253.4.85.64/27253.4.85.65 to 253.4.85.94253.4.85.9530
172253.4.85.96/27253.4.85.97 to 253.4.85.126253.4.85.12730
173253.4.85.128/27253.4.85.129 to 253.4.85.158253.4.85.15930
174253.4.85.160/27253.4.85.161 to 253.4.85.190253.4.85.19130
175253.4.85.192/27253.4.85.193 to 253.4.85.222253.4.85.22330
176253.4.85.224/27253.4.85.225 to 253.4.85.254253.4.85.25530
177253.4.86.0/27253.4.86.1 to 253.4.86.30253.4.86.3130
178253.4.86.32/27253.4.86.33 to 253.4.86.62253.4.86.6330
179253.4.86.64/27253.4.86.65 to 253.4.86.94253.4.86.9530
180253.4.86.96/27253.4.86.97 to 253.4.86.126253.4.86.12730
181253.4.86.128/27253.4.86.129 to 253.4.86.158253.4.86.15930
182253.4.86.160/27253.4.86.161 to 253.4.86.190253.4.86.19130
183253.4.86.192/27253.4.86.193 to 253.4.86.222253.4.86.22330
184253.4.86.224/27253.4.86.225 to 253.4.86.254253.4.86.25530
185253.4.87.0/27253.4.87.1 to 253.4.87.30253.4.87.3130
186253.4.87.32/27253.4.87.33 to 253.4.87.62253.4.87.6330
187253.4.87.64/27253.4.87.65 to 253.4.87.94253.4.87.9530
188253.4.87.96/27253.4.87.97 to 253.4.87.126253.4.87.12730
189253.4.87.128/27253.4.87.129 to 253.4.87.158253.4.87.15930
190253.4.87.160/27253.4.87.161 to 253.4.87.190253.4.87.19130
191253.4.87.192/27253.4.87.193 to 253.4.87.222253.4.87.22330
192253.4.87.224/27253.4.87.225 to 253.4.87.254253.4.87.25530
193253.4.88.0/27253.4.88.1 to 253.4.88.30253.4.88.3130
194253.4.88.32/27253.4.88.33 to 253.4.88.62253.4.88.6330
195253.4.88.64/27253.4.88.65 to 253.4.88.94253.4.88.9530
196253.4.88.96/27253.4.88.97 to 253.4.88.126253.4.88.12730
197253.4.88.128/27253.4.88.129 to 253.4.88.158253.4.88.15930
198253.4.88.160/27253.4.88.161 to 253.4.88.190253.4.88.19130
199253.4.88.192/27253.4.88.193 to 253.4.88.222253.4.88.22330
200253.4.88.224/27253.4.88.225 to 253.4.88.254253.4.88.25530
201253.4.89.0/27253.4.89.1 to 253.4.89.30253.4.89.3130
202253.4.89.32/27253.4.89.33 to 253.4.89.62253.4.89.6330
203253.4.89.64/27253.4.89.65 to 253.4.89.94253.4.89.9530
204253.4.89.96/27253.4.89.97 to 253.4.89.126253.4.89.12730
205253.4.89.128/27253.4.89.129 to 253.4.89.158253.4.89.15930
206253.4.89.160/27253.4.89.161 to 253.4.89.190253.4.89.19130
207253.4.89.192/27253.4.89.193 to 253.4.89.222253.4.89.22330
208253.4.89.224/27253.4.89.225 to 253.4.89.254253.4.89.25530
209253.4.90.0/27253.4.90.1 to 253.4.90.30253.4.90.3130
210253.4.90.32/27253.4.90.33 to 253.4.90.62253.4.90.6330
211253.4.90.64/27253.4.90.65 to 253.4.90.94253.4.90.9530
212253.4.90.96/27253.4.90.97 to 253.4.90.126253.4.90.12730
213253.4.90.128/27253.4.90.129 to 253.4.90.158253.4.90.15930
214253.4.90.160/27253.4.90.161 to 253.4.90.190253.4.90.19130
215253.4.90.192/27253.4.90.193 to 253.4.90.222253.4.90.22330
216253.4.90.224/27253.4.90.225 to 253.4.90.254253.4.90.25530
217253.4.91.0/27253.4.91.1 to 253.4.91.30253.4.91.3130
218253.4.91.32/27253.4.91.33 to 253.4.91.62253.4.91.6330
219253.4.91.64/27253.4.91.65 to 253.4.91.94253.4.91.9530
220253.4.91.96/27253.4.91.97 to 253.4.91.126253.4.91.12730
221253.4.91.128/27253.4.91.129 to 253.4.91.158253.4.91.15930
222253.4.91.160/27253.4.91.161 to 253.4.91.190253.4.91.19130
223253.4.91.192/27253.4.91.193 to 253.4.91.222253.4.91.22330
224253.4.91.224/27253.4.91.225 to 253.4.91.254253.4.91.25530
225253.4.92.0/27253.4.92.1 to 253.4.92.30253.4.92.3130
226253.4.92.32/27253.4.92.33 to 253.4.92.62253.4.92.6330
227253.4.92.64/27253.4.92.65 to 253.4.92.94253.4.92.9530
228253.4.92.96/27253.4.92.97 to 253.4.92.126253.4.92.12730
229253.4.92.128/27253.4.92.129 to 253.4.92.158253.4.92.15930
230253.4.92.160/27253.4.92.161 to 253.4.92.190253.4.92.19130
231253.4.92.192/27253.4.92.193 to 253.4.92.222253.4.92.22330
232253.4.92.224/27253.4.92.225 to 253.4.92.254253.4.92.25530
233253.4.93.0/27253.4.93.1 to 253.4.93.30253.4.93.3130
234253.4.93.32/27253.4.93.33 to 253.4.93.62253.4.93.6330
235253.4.93.64/27253.4.93.65 to 253.4.93.94253.4.93.9530
236253.4.93.96/27253.4.93.97 to 253.4.93.126253.4.93.12730
237253.4.93.128/27253.4.93.129 to 253.4.93.158253.4.93.15930
238253.4.93.160/27253.4.93.161 to 253.4.93.190253.4.93.19130
239253.4.93.192/27253.4.93.193 to 253.4.93.222253.4.93.22330
240253.4.93.224/27253.4.93.225 to 253.4.93.254253.4.93.25530
241253.4.94.0/27253.4.94.1 to 253.4.94.30253.4.94.3130
242253.4.94.32/27253.4.94.33 to 253.4.94.62253.4.94.6330
243253.4.94.64/27253.4.94.65 to 253.4.94.94253.4.94.9530
244253.4.94.96/27253.4.94.97 to 253.4.94.126253.4.94.12730
245253.4.94.128/27253.4.94.129 to 253.4.94.158253.4.94.15930
246253.4.94.160/27253.4.94.161 to 253.4.94.190253.4.94.19130
247253.4.94.192/27253.4.94.193 to 253.4.94.222253.4.94.22330
248253.4.94.224/27253.4.94.225 to 253.4.94.254253.4.94.25530
249253.4.95.0/27253.4.95.1 to 253.4.95.30253.4.95.3130
250253.4.95.32/27253.4.95.33 to 253.4.95.62253.4.95.6330
251253.4.95.64/27253.4.95.65 to 253.4.95.94253.4.95.9530
252253.4.95.96/27253.4.95.97 to 253.4.95.126253.4.95.12730
253253.4.95.128/27253.4.95.129 to 253.4.95.158253.4.95.15930
254253.4.95.160/27253.4.95.161 to 253.4.95.190253.4.95.19130
255253.4.95.192/27253.4.95.193 to 253.4.95.222253.4.95.22330
256253.4.95.224/27253.4.95.225 to 253.4.95.254253.4.95.25530

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.