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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.

Network153.4.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
153.4.64.0
Broadcast address
153.4.127.255
First usable
153.4.64.1
Last usable
153.4.127.254
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
Public public
Old class
B (default /16)
As numbers
Hex 99044000 · Integer 2567192576 to 2567208959
Reverse DNS zones
64.4.153.in-addr.arpa
65.4.153.in-addr.arpa
66.4.153.in-addr.arpa
67.4.153.in-addr.arpa
68.4.153.in-addr.arpa
69.4.153.in-addr.arpa
70.4.153.in-addr.arpa
71.4.153.in-addr.arpa
72.4.153.in-addr.arpa
73.4.153.in-addr.arpa
74.4.153.in-addr.arpa
75.4.153.in-addr.arpa
76.4.153.in-addr.arpa
77.4.153.in-addr.arpa
78.4.153.in-addr.arpa
79.4.153.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
Address10011001.00000100.01000000.00000000153.4.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network10011001.00000100.01000000.00000000153.4.64.0
Broadcast10011001.00000100.01111111.11111111153.4.127.255
Split into smaller subnets/28
/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)

153.4.64.0/18 makes 1,024 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1153.4.64.0/28153.4.64.1 to 153.4.64.14153.4.64.1514
2153.4.64.16/28153.4.64.17 to 153.4.64.30153.4.64.3114
3153.4.64.32/28153.4.64.33 to 153.4.64.46153.4.64.4714
4153.4.64.48/28153.4.64.49 to 153.4.64.62153.4.64.6314
5153.4.64.64/28153.4.64.65 to 153.4.64.78153.4.64.7914
6153.4.64.80/28153.4.64.81 to 153.4.64.94153.4.64.9514
7153.4.64.96/28153.4.64.97 to 153.4.64.110153.4.64.11114
8153.4.64.112/28153.4.64.113 to 153.4.64.126153.4.64.12714
9153.4.64.128/28153.4.64.129 to 153.4.64.142153.4.64.14314
10153.4.64.144/28153.4.64.145 to 153.4.64.158153.4.64.15914
11153.4.64.160/28153.4.64.161 to 153.4.64.174153.4.64.17514
12153.4.64.176/28153.4.64.177 to 153.4.64.190153.4.64.19114
13153.4.64.192/28153.4.64.193 to 153.4.64.206153.4.64.20714
14153.4.64.208/28153.4.64.209 to 153.4.64.222153.4.64.22314
15153.4.64.224/28153.4.64.225 to 153.4.64.238153.4.64.23914
16153.4.64.240/28153.4.64.241 to 153.4.64.254153.4.64.25514
17153.4.65.0/28153.4.65.1 to 153.4.65.14153.4.65.1514
18153.4.65.16/28153.4.65.17 to 153.4.65.30153.4.65.3114
19153.4.65.32/28153.4.65.33 to 153.4.65.46153.4.65.4714
20153.4.65.48/28153.4.65.49 to 153.4.65.62153.4.65.6314
21153.4.65.64/28153.4.65.65 to 153.4.65.78153.4.65.7914
22153.4.65.80/28153.4.65.81 to 153.4.65.94153.4.65.9514
23153.4.65.96/28153.4.65.97 to 153.4.65.110153.4.65.11114
24153.4.65.112/28153.4.65.113 to 153.4.65.126153.4.65.12714
25153.4.65.128/28153.4.65.129 to 153.4.65.142153.4.65.14314
26153.4.65.144/28153.4.65.145 to 153.4.65.158153.4.65.15914
27153.4.65.160/28153.4.65.161 to 153.4.65.174153.4.65.17514
28153.4.65.176/28153.4.65.177 to 153.4.65.190153.4.65.19114
29153.4.65.192/28153.4.65.193 to 153.4.65.206153.4.65.20714
30153.4.65.208/28153.4.65.209 to 153.4.65.222153.4.65.22314
31153.4.65.224/28153.4.65.225 to 153.4.65.238153.4.65.23914
32153.4.65.240/28153.4.65.241 to 153.4.65.254153.4.65.25514
33153.4.66.0/28153.4.66.1 to 153.4.66.14153.4.66.1514
34153.4.66.16/28153.4.66.17 to 153.4.66.30153.4.66.3114
35153.4.66.32/28153.4.66.33 to 153.4.66.46153.4.66.4714
36153.4.66.48/28153.4.66.49 to 153.4.66.62153.4.66.6314
37153.4.66.64/28153.4.66.65 to 153.4.66.78153.4.66.7914
38153.4.66.80/28153.4.66.81 to 153.4.66.94153.4.66.9514
39153.4.66.96/28153.4.66.97 to 153.4.66.110153.4.66.11114
40153.4.66.112/28153.4.66.113 to 153.4.66.126153.4.66.12714
41153.4.66.128/28153.4.66.129 to 153.4.66.142153.4.66.14314
42153.4.66.144/28153.4.66.145 to 153.4.66.158153.4.66.15914
43153.4.66.160/28153.4.66.161 to 153.4.66.174153.4.66.17514
44153.4.66.176/28153.4.66.177 to 153.4.66.190153.4.66.19114
45153.4.66.192/28153.4.66.193 to 153.4.66.206153.4.66.20714
46153.4.66.208/28153.4.66.209 to 153.4.66.222153.4.66.22314
47153.4.66.224/28153.4.66.225 to 153.4.66.238153.4.66.23914
48153.4.66.240/28153.4.66.241 to 153.4.66.254153.4.66.25514
49153.4.67.0/28153.4.67.1 to 153.4.67.14153.4.67.1514
50153.4.67.16/28153.4.67.17 to 153.4.67.30153.4.67.3114
51153.4.67.32/28153.4.67.33 to 153.4.67.46153.4.67.4714
52153.4.67.48/28153.4.67.49 to 153.4.67.62153.4.67.6314
53153.4.67.64/28153.4.67.65 to 153.4.67.78153.4.67.7914
54153.4.67.80/28153.4.67.81 to 153.4.67.94153.4.67.9514
55153.4.67.96/28153.4.67.97 to 153.4.67.110153.4.67.11114
56153.4.67.112/28153.4.67.113 to 153.4.67.126153.4.67.12714
57153.4.67.128/28153.4.67.129 to 153.4.67.142153.4.67.14314
58153.4.67.144/28153.4.67.145 to 153.4.67.158153.4.67.15914
59153.4.67.160/28153.4.67.161 to 153.4.67.174153.4.67.17514
60153.4.67.176/28153.4.67.177 to 153.4.67.190153.4.67.19114
61153.4.67.192/28153.4.67.193 to 153.4.67.206153.4.67.20714
62153.4.67.208/28153.4.67.209 to 153.4.67.222153.4.67.22314
63153.4.67.224/28153.4.67.225 to 153.4.67.238153.4.67.23914
64153.4.67.240/28153.4.67.241 to 153.4.67.254153.4.67.25514
65153.4.68.0/28153.4.68.1 to 153.4.68.14153.4.68.1514
66153.4.68.16/28153.4.68.17 to 153.4.68.30153.4.68.3114
67153.4.68.32/28153.4.68.33 to 153.4.68.46153.4.68.4714
68153.4.68.48/28153.4.68.49 to 153.4.68.62153.4.68.6314
69153.4.68.64/28153.4.68.65 to 153.4.68.78153.4.68.7914
70153.4.68.80/28153.4.68.81 to 153.4.68.94153.4.68.9514
71153.4.68.96/28153.4.68.97 to 153.4.68.110153.4.68.11114
72153.4.68.112/28153.4.68.113 to 153.4.68.126153.4.68.12714
73153.4.68.128/28153.4.68.129 to 153.4.68.142153.4.68.14314
74153.4.68.144/28153.4.68.145 to 153.4.68.158153.4.68.15914
75153.4.68.160/28153.4.68.161 to 153.4.68.174153.4.68.17514
76153.4.68.176/28153.4.68.177 to 153.4.68.190153.4.68.19114
77153.4.68.192/28153.4.68.193 to 153.4.68.206153.4.68.20714
78153.4.68.208/28153.4.68.209 to 153.4.68.222153.4.68.22314
79153.4.68.224/28153.4.68.225 to 153.4.68.238153.4.68.23914
80153.4.68.240/28153.4.68.241 to 153.4.68.254153.4.68.25514
81153.4.69.0/28153.4.69.1 to 153.4.69.14153.4.69.1514
82153.4.69.16/28153.4.69.17 to 153.4.69.30153.4.69.3114
83153.4.69.32/28153.4.69.33 to 153.4.69.46153.4.69.4714
84153.4.69.48/28153.4.69.49 to 153.4.69.62153.4.69.6314
85153.4.69.64/28153.4.69.65 to 153.4.69.78153.4.69.7914
86153.4.69.80/28153.4.69.81 to 153.4.69.94153.4.69.9514
87153.4.69.96/28153.4.69.97 to 153.4.69.110153.4.69.11114
88153.4.69.112/28153.4.69.113 to 153.4.69.126153.4.69.12714
89153.4.69.128/28153.4.69.129 to 153.4.69.142153.4.69.14314
90153.4.69.144/28153.4.69.145 to 153.4.69.158153.4.69.15914
91153.4.69.160/28153.4.69.161 to 153.4.69.174153.4.69.17514
92153.4.69.176/28153.4.69.177 to 153.4.69.190153.4.69.19114
93153.4.69.192/28153.4.69.193 to 153.4.69.206153.4.69.20714
94153.4.69.208/28153.4.69.209 to 153.4.69.222153.4.69.22314
95153.4.69.224/28153.4.69.225 to 153.4.69.238153.4.69.23914
96153.4.69.240/28153.4.69.241 to 153.4.69.254153.4.69.25514
97153.4.70.0/28153.4.70.1 to 153.4.70.14153.4.70.1514
98153.4.70.16/28153.4.70.17 to 153.4.70.30153.4.70.3114
99153.4.70.32/28153.4.70.33 to 153.4.70.46153.4.70.4714
100153.4.70.48/28153.4.70.49 to 153.4.70.62153.4.70.6314
101153.4.70.64/28153.4.70.65 to 153.4.70.78153.4.70.7914
102153.4.70.80/28153.4.70.81 to 153.4.70.94153.4.70.9514
103153.4.70.96/28153.4.70.97 to 153.4.70.110153.4.70.11114
104153.4.70.112/28153.4.70.113 to 153.4.70.126153.4.70.12714
105153.4.70.128/28153.4.70.129 to 153.4.70.142153.4.70.14314
106153.4.70.144/28153.4.70.145 to 153.4.70.158153.4.70.15914
107153.4.70.160/28153.4.70.161 to 153.4.70.174153.4.70.17514
108153.4.70.176/28153.4.70.177 to 153.4.70.190153.4.70.19114
109153.4.70.192/28153.4.70.193 to 153.4.70.206153.4.70.20714
110153.4.70.208/28153.4.70.209 to 153.4.70.222153.4.70.22314
111153.4.70.224/28153.4.70.225 to 153.4.70.238153.4.70.23914
112153.4.70.240/28153.4.70.241 to 153.4.70.254153.4.70.25514
113153.4.71.0/28153.4.71.1 to 153.4.71.14153.4.71.1514
114153.4.71.16/28153.4.71.17 to 153.4.71.30153.4.71.3114
115153.4.71.32/28153.4.71.33 to 153.4.71.46153.4.71.4714
116153.4.71.48/28153.4.71.49 to 153.4.71.62153.4.71.6314
117153.4.71.64/28153.4.71.65 to 153.4.71.78153.4.71.7914
118153.4.71.80/28153.4.71.81 to 153.4.71.94153.4.71.9514
119153.4.71.96/28153.4.71.97 to 153.4.71.110153.4.71.11114
120153.4.71.112/28153.4.71.113 to 153.4.71.126153.4.71.12714
121153.4.71.128/28153.4.71.129 to 153.4.71.142153.4.71.14314
122153.4.71.144/28153.4.71.145 to 153.4.71.158153.4.71.15914
123153.4.71.160/28153.4.71.161 to 153.4.71.174153.4.71.17514
124153.4.71.176/28153.4.71.177 to 153.4.71.190153.4.71.19114
125153.4.71.192/28153.4.71.193 to 153.4.71.206153.4.71.20714
126153.4.71.208/28153.4.71.209 to 153.4.71.222153.4.71.22314
127153.4.71.224/28153.4.71.225 to 153.4.71.238153.4.71.23914
128153.4.71.240/28153.4.71.241 to 153.4.71.254153.4.71.25514
129153.4.72.0/28153.4.72.1 to 153.4.72.14153.4.72.1514
130153.4.72.16/28153.4.72.17 to 153.4.72.30153.4.72.3114
131153.4.72.32/28153.4.72.33 to 153.4.72.46153.4.72.4714
132153.4.72.48/28153.4.72.49 to 153.4.72.62153.4.72.6314
133153.4.72.64/28153.4.72.65 to 153.4.72.78153.4.72.7914
134153.4.72.80/28153.4.72.81 to 153.4.72.94153.4.72.9514
135153.4.72.96/28153.4.72.97 to 153.4.72.110153.4.72.11114
136153.4.72.112/28153.4.72.113 to 153.4.72.126153.4.72.12714
137153.4.72.128/28153.4.72.129 to 153.4.72.142153.4.72.14314
138153.4.72.144/28153.4.72.145 to 153.4.72.158153.4.72.15914
139153.4.72.160/28153.4.72.161 to 153.4.72.174153.4.72.17514
140153.4.72.176/28153.4.72.177 to 153.4.72.190153.4.72.19114
141153.4.72.192/28153.4.72.193 to 153.4.72.206153.4.72.20714
142153.4.72.208/28153.4.72.209 to 153.4.72.222153.4.72.22314
143153.4.72.224/28153.4.72.225 to 153.4.72.238153.4.72.23914
144153.4.72.240/28153.4.72.241 to 153.4.72.254153.4.72.25514
145153.4.73.0/28153.4.73.1 to 153.4.73.14153.4.73.1514
146153.4.73.16/28153.4.73.17 to 153.4.73.30153.4.73.3114
147153.4.73.32/28153.4.73.33 to 153.4.73.46153.4.73.4714
148153.4.73.48/28153.4.73.49 to 153.4.73.62153.4.73.6314
149153.4.73.64/28153.4.73.65 to 153.4.73.78153.4.73.7914
150153.4.73.80/28153.4.73.81 to 153.4.73.94153.4.73.9514
151153.4.73.96/28153.4.73.97 to 153.4.73.110153.4.73.11114
152153.4.73.112/28153.4.73.113 to 153.4.73.126153.4.73.12714
153153.4.73.128/28153.4.73.129 to 153.4.73.142153.4.73.14314
154153.4.73.144/28153.4.73.145 to 153.4.73.158153.4.73.15914
155153.4.73.160/28153.4.73.161 to 153.4.73.174153.4.73.17514
156153.4.73.176/28153.4.73.177 to 153.4.73.190153.4.73.19114
157153.4.73.192/28153.4.73.193 to 153.4.73.206153.4.73.20714
158153.4.73.208/28153.4.73.209 to 153.4.73.222153.4.73.22314
159153.4.73.224/28153.4.73.225 to 153.4.73.238153.4.73.23914
160153.4.73.240/28153.4.73.241 to 153.4.73.254153.4.73.25514
161153.4.74.0/28153.4.74.1 to 153.4.74.14153.4.74.1514
162153.4.74.16/28153.4.74.17 to 153.4.74.30153.4.74.3114
163153.4.74.32/28153.4.74.33 to 153.4.74.46153.4.74.4714
164153.4.74.48/28153.4.74.49 to 153.4.74.62153.4.74.6314
165153.4.74.64/28153.4.74.65 to 153.4.74.78153.4.74.7914
166153.4.74.80/28153.4.74.81 to 153.4.74.94153.4.74.9514
167153.4.74.96/28153.4.74.97 to 153.4.74.110153.4.74.11114
168153.4.74.112/28153.4.74.113 to 153.4.74.126153.4.74.12714
169153.4.74.128/28153.4.74.129 to 153.4.74.142153.4.74.14314
170153.4.74.144/28153.4.74.145 to 153.4.74.158153.4.74.15914
171153.4.74.160/28153.4.74.161 to 153.4.74.174153.4.74.17514
172153.4.74.176/28153.4.74.177 to 153.4.74.190153.4.74.19114
173153.4.74.192/28153.4.74.193 to 153.4.74.206153.4.74.20714
174153.4.74.208/28153.4.74.209 to 153.4.74.222153.4.74.22314
175153.4.74.224/28153.4.74.225 to 153.4.74.238153.4.74.23914
176153.4.74.240/28153.4.74.241 to 153.4.74.254153.4.74.25514
177153.4.75.0/28153.4.75.1 to 153.4.75.14153.4.75.1514
178153.4.75.16/28153.4.75.17 to 153.4.75.30153.4.75.3114
179153.4.75.32/28153.4.75.33 to 153.4.75.46153.4.75.4714
180153.4.75.48/28153.4.75.49 to 153.4.75.62153.4.75.6314
181153.4.75.64/28153.4.75.65 to 153.4.75.78153.4.75.7914
182153.4.75.80/28153.4.75.81 to 153.4.75.94153.4.75.9514
183153.4.75.96/28153.4.75.97 to 153.4.75.110153.4.75.11114
184153.4.75.112/28153.4.75.113 to 153.4.75.126153.4.75.12714
185153.4.75.128/28153.4.75.129 to 153.4.75.142153.4.75.14314
186153.4.75.144/28153.4.75.145 to 153.4.75.158153.4.75.15914
187153.4.75.160/28153.4.75.161 to 153.4.75.174153.4.75.17514
188153.4.75.176/28153.4.75.177 to 153.4.75.190153.4.75.19114
189153.4.75.192/28153.4.75.193 to 153.4.75.206153.4.75.20714
190153.4.75.208/28153.4.75.209 to 153.4.75.222153.4.75.22314
191153.4.75.224/28153.4.75.225 to 153.4.75.238153.4.75.23914
192153.4.75.240/28153.4.75.241 to 153.4.75.254153.4.75.25514
193153.4.76.0/28153.4.76.1 to 153.4.76.14153.4.76.1514
194153.4.76.16/28153.4.76.17 to 153.4.76.30153.4.76.3114
195153.4.76.32/28153.4.76.33 to 153.4.76.46153.4.76.4714
196153.4.76.48/28153.4.76.49 to 153.4.76.62153.4.76.6314
197153.4.76.64/28153.4.76.65 to 153.4.76.78153.4.76.7914
198153.4.76.80/28153.4.76.81 to 153.4.76.94153.4.76.9514
199153.4.76.96/28153.4.76.97 to 153.4.76.110153.4.76.11114
200153.4.76.112/28153.4.76.113 to 153.4.76.126153.4.76.12714
201153.4.76.128/28153.4.76.129 to 153.4.76.142153.4.76.14314
202153.4.76.144/28153.4.76.145 to 153.4.76.158153.4.76.15914
203153.4.76.160/28153.4.76.161 to 153.4.76.174153.4.76.17514
204153.4.76.176/28153.4.76.177 to 153.4.76.190153.4.76.19114
205153.4.76.192/28153.4.76.193 to 153.4.76.206153.4.76.20714
206153.4.76.208/28153.4.76.209 to 153.4.76.222153.4.76.22314
207153.4.76.224/28153.4.76.225 to 153.4.76.238153.4.76.23914
208153.4.76.240/28153.4.76.241 to 153.4.76.254153.4.76.25514
209153.4.77.0/28153.4.77.1 to 153.4.77.14153.4.77.1514
210153.4.77.16/28153.4.77.17 to 153.4.77.30153.4.77.3114
211153.4.77.32/28153.4.77.33 to 153.4.77.46153.4.77.4714
212153.4.77.48/28153.4.77.49 to 153.4.77.62153.4.77.6314
213153.4.77.64/28153.4.77.65 to 153.4.77.78153.4.77.7914
214153.4.77.80/28153.4.77.81 to 153.4.77.94153.4.77.9514
215153.4.77.96/28153.4.77.97 to 153.4.77.110153.4.77.11114
216153.4.77.112/28153.4.77.113 to 153.4.77.126153.4.77.12714
217153.4.77.128/28153.4.77.129 to 153.4.77.142153.4.77.14314
218153.4.77.144/28153.4.77.145 to 153.4.77.158153.4.77.15914
219153.4.77.160/28153.4.77.161 to 153.4.77.174153.4.77.17514
220153.4.77.176/28153.4.77.177 to 153.4.77.190153.4.77.19114
221153.4.77.192/28153.4.77.193 to 153.4.77.206153.4.77.20714
222153.4.77.208/28153.4.77.209 to 153.4.77.222153.4.77.22314
223153.4.77.224/28153.4.77.225 to 153.4.77.238153.4.77.23914
224153.4.77.240/28153.4.77.241 to 153.4.77.254153.4.77.25514
225153.4.78.0/28153.4.78.1 to 153.4.78.14153.4.78.1514
226153.4.78.16/28153.4.78.17 to 153.4.78.30153.4.78.3114
227153.4.78.32/28153.4.78.33 to 153.4.78.46153.4.78.4714
228153.4.78.48/28153.4.78.49 to 153.4.78.62153.4.78.6314
229153.4.78.64/28153.4.78.65 to 153.4.78.78153.4.78.7914
230153.4.78.80/28153.4.78.81 to 153.4.78.94153.4.78.9514
231153.4.78.96/28153.4.78.97 to 153.4.78.110153.4.78.11114
232153.4.78.112/28153.4.78.113 to 153.4.78.126153.4.78.12714
233153.4.78.128/28153.4.78.129 to 153.4.78.142153.4.78.14314
234153.4.78.144/28153.4.78.145 to 153.4.78.158153.4.78.15914
235153.4.78.160/28153.4.78.161 to 153.4.78.174153.4.78.17514
236153.4.78.176/28153.4.78.177 to 153.4.78.190153.4.78.19114
237153.4.78.192/28153.4.78.193 to 153.4.78.206153.4.78.20714
238153.4.78.208/28153.4.78.209 to 153.4.78.222153.4.78.22314
239153.4.78.224/28153.4.78.225 to 153.4.78.238153.4.78.23914
240153.4.78.240/28153.4.78.241 to 153.4.78.254153.4.78.25514
241153.4.79.0/28153.4.79.1 to 153.4.79.14153.4.79.1514
242153.4.79.16/28153.4.79.17 to 153.4.79.30153.4.79.3114
243153.4.79.32/28153.4.79.33 to 153.4.79.46153.4.79.4714
244153.4.79.48/28153.4.79.49 to 153.4.79.62153.4.79.6314
245153.4.79.64/28153.4.79.65 to 153.4.79.78153.4.79.7914
246153.4.79.80/28153.4.79.81 to 153.4.79.94153.4.79.9514
247153.4.79.96/28153.4.79.97 to 153.4.79.110153.4.79.11114
248153.4.79.112/28153.4.79.113 to 153.4.79.126153.4.79.12714
249153.4.79.128/28153.4.79.129 to 153.4.79.142153.4.79.14314
250153.4.79.144/28153.4.79.145 to 153.4.79.158153.4.79.15914
251153.4.79.160/28153.4.79.161 to 153.4.79.174153.4.79.17514
252153.4.79.176/28153.4.79.177 to 153.4.79.190153.4.79.19114
253153.4.79.192/28153.4.79.193 to 153.4.79.206153.4.79.20714
254153.4.79.208/28153.4.79.209 to 153.4.79.222153.4.79.22314
255153.4.79.224/28153.4.79.225 to 153.4.79.238153.4.79.23914
256153.4.79.240/28153.4.79.241 to 153.4.79.254153.4.79.25514

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.