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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.

Network217.44.0.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
217.44.0.0
Broadcast address
217.44.63.255
First usable
217.44.0.1
Last usable
217.44.63.254
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
C (default /24)
As numbers
Hex D92C0000 · Integer 3643539456 to 3643555839
Reverse DNS zones
0.44.217.in-addr.arpa
1.44.217.in-addr.arpa
2.44.217.in-addr.arpa
3.44.217.in-addr.arpa
4.44.217.in-addr.arpa
5.44.217.in-addr.arpa
6.44.217.in-addr.arpa
7.44.217.in-addr.arpa
8.44.217.in-addr.arpa
9.44.217.in-addr.arpa
10.44.217.in-addr.arpa
11.44.217.in-addr.arpa
12.44.217.in-addr.arpa
13.44.217.in-addr.arpa
14.44.217.in-addr.arpa
15.44.217.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
Address11011001.00101100.00000000.00000000217.44.0.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network11011001.00101100.00000000.00000000217.44.0.0
Broadcast11011001.00101100.00111111.11111111217.44.63.255
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)

217.44.0.0/18 makes 1,024 subnets of /28; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1217.44.0.0/28217.44.0.1 to 217.44.0.14217.44.0.1514
2217.44.0.16/28217.44.0.17 to 217.44.0.30217.44.0.3114
3217.44.0.32/28217.44.0.33 to 217.44.0.46217.44.0.4714
4217.44.0.48/28217.44.0.49 to 217.44.0.62217.44.0.6314
5217.44.0.64/28217.44.0.65 to 217.44.0.78217.44.0.7914
6217.44.0.80/28217.44.0.81 to 217.44.0.94217.44.0.9514
7217.44.0.96/28217.44.0.97 to 217.44.0.110217.44.0.11114
8217.44.0.112/28217.44.0.113 to 217.44.0.126217.44.0.12714
9217.44.0.128/28217.44.0.129 to 217.44.0.142217.44.0.14314
10217.44.0.144/28217.44.0.145 to 217.44.0.158217.44.0.15914
11217.44.0.160/28217.44.0.161 to 217.44.0.174217.44.0.17514
12217.44.0.176/28217.44.0.177 to 217.44.0.190217.44.0.19114
13217.44.0.192/28217.44.0.193 to 217.44.0.206217.44.0.20714
14217.44.0.208/28217.44.0.209 to 217.44.0.222217.44.0.22314
15217.44.0.224/28217.44.0.225 to 217.44.0.238217.44.0.23914
16217.44.0.240/28217.44.0.241 to 217.44.0.254217.44.0.25514
17217.44.1.0/28217.44.1.1 to 217.44.1.14217.44.1.1514
18217.44.1.16/28217.44.1.17 to 217.44.1.30217.44.1.3114
19217.44.1.32/28217.44.1.33 to 217.44.1.46217.44.1.4714
20217.44.1.48/28217.44.1.49 to 217.44.1.62217.44.1.6314
21217.44.1.64/28217.44.1.65 to 217.44.1.78217.44.1.7914
22217.44.1.80/28217.44.1.81 to 217.44.1.94217.44.1.9514
23217.44.1.96/28217.44.1.97 to 217.44.1.110217.44.1.11114
24217.44.1.112/28217.44.1.113 to 217.44.1.126217.44.1.12714
25217.44.1.128/28217.44.1.129 to 217.44.1.142217.44.1.14314
26217.44.1.144/28217.44.1.145 to 217.44.1.158217.44.1.15914
27217.44.1.160/28217.44.1.161 to 217.44.1.174217.44.1.17514
28217.44.1.176/28217.44.1.177 to 217.44.1.190217.44.1.19114
29217.44.1.192/28217.44.1.193 to 217.44.1.206217.44.1.20714
30217.44.1.208/28217.44.1.209 to 217.44.1.222217.44.1.22314
31217.44.1.224/28217.44.1.225 to 217.44.1.238217.44.1.23914
32217.44.1.240/28217.44.1.241 to 217.44.1.254217.44.1.25514
33217.44.2.0/28217.44.2.1 to 217.44.2.14217.44.2.1514
34217.44.2.16/28217.44.2.17 to 217.44.2.30217.44.2.3114
35217.44.2.32/28217.44.2.33 to 217.44.2.46217.44.2.4714
36217.44.2.48/28217.44.2.49 to 217.44.2.62217.44.2.6314
37217.44.2.64/28217.44.2.65 to 217.44.2.78217.44.2.7914
38217.44.2.80/28217.44.2.81 to 217.44.2.94217.44.2.9514
39217.44.2.96/28217.44.2.97 to 217.44.2.110217.44.2.11114
40217.44.2.112/28217.44.2.113 to 217.44.2.126217.44.2.12714
41217.44.2.128/28217.44.2.129 to 217.44.2.142217.44.2.14314
42217.44.2.144/28217.44.2.145 to 217.44.2.158217.44.2.15914
43217.44.2.160/28217.44.2.161 to 217.44.2.174217.44.2.17514
44217.44.2.176/28217.44.2.177 to 217.44.2.190217.44.2.19114
45217.44.2.192/28217.44.2.193 to 217.44.2.206217.44.2.20714
46217.44.2.208/28217.44.2.209 to 217.44.2.222217.44.2.22314
47217.44.2.224/28217.44.2.225 to 217.44.2.238217.44.2.23914
48217.44.2.240/28217.44.2.241 to 217.44.2.254217.44.2.25514
49217.44.3.0/28217.44.3.1 to 217.44.3.14217.44.3.1514
50217.44.3.16/28217.44.3.17 to 217.44.3.30217.44.3.3114
51217.44.3.32/28217.44.3.33 to 217.44.3.46217.44.3.4714
52217.44.3.48/28217.44.3.49 to 217.44.3.62217.44.3.6314
53217.44.3.64/28217.44.3.65 to 217.44.3.78217.44.3.7914
54217.44.3.80/28217.44.3.81 to 217.44.3.94217.44.3.9514
55217.44.3.96/28217.44.3.97 to 217.44.3.110217.44.3.11114
56217.44.3.112/28217.44.3.113 to 217.44.3.126217.44.3.12714
57217.44.3.128/28217.44.3.129 to 217.44.3.142217.44.3.14314
58217.44.3.144/28217.44.3.145 to 217.44.3.158217.44.3.15914
59217.44.3.160/28217.44.3.161 to 217.44.3.174217.44.3.17514
60217.44.3.176/28217.44.3.177 to 217.44.3.190217.44.3.19114
61217.44.3.192/28217.44.3.193 to 217.44.3.206217.44.3.20714
62217.44.3.208/28217.44.3.209 to 217.44.3.222217.44.3.22314
63217.44.3.224/28217.44.3.225 to 217.44.3.238217.44.3.23914
64217.44.3.240/28217.44.3.241 to 217.44.3.254217.44.3.25514
65217.44.4.0/28217.44.4.1 to 217.44.4.14217.44.4.1514
66217.44.4.16/28217.44.4.17 to 217.44.4.30217.44.4.3114
67217.44.4.32/28217.44.4.33 to 217.44.4.46217.44.4.4714
68217.44.4.48/28217.44.4.49 to 217.44.4.62217.44.4.6314
69217.44.4.64/28217.44.4.65 to 217.44.4.78217.44.4.7914
70217.44.4.80/28217.44.4.81 to 217.44.4.94217.44.4.9514
71217.44.4.96/28217.44.4.97 to 217.44.4.110217.44.4.11114
72217.44.4.112/28217.44.4.113 to 217.44.4.126217.44.4.12714
73217.44.4.128/28217.44.4.129 to 217.44.4.142217.44.4.14314
74217.44.4.144/28217.44.4.145 to 217.44.4.158217.44.4.15914
75217.44.4.160/28217.44.4.161 to 217.44.4.174217.44.4.17514
76217.44.4.176/28217.44.4.177 to 217.44.4.190217.44.4.19114
77217.44.4.192/28217.44.4.193 to 217.44.4.206217.44.4.20714
78217.44.4.208/28217.44.4.209 to 217.44.4.222217.44.4.22314
79217.44.4.224/28217.44.4.225 to 217.44.4.238217.44.4.23914
80217.44.4.240/28217.44.4.241 to 217.44.4.254217.44.4.25514
81217.44.5.0/28217.44.5.1 to 217.44.5.14217.44.5.1514
82217.44.5.16/28217.44.5.17 to 217.44.5.30217.44.5.3114
83217.44.5.32/28217.44.5.33 to 217.44.5.46217.44.5.4714
84217.44.5.48/28217.44.5.49 to 217.44.5.62217.44.5.6314
85217.44.5.64/28217.44.5.65 to 217.44.5.78217.44.5.7914
86217.44.5.80/28217.44.5.81 to 217.44.5.94217.44.5.9514
87217.44.5.96/28217.44.5.97 to 217.44.5.110217.44.5.11114
88217.44.5.112/28217.44.5.113 to 217.44.5.126217.44.5.12714
89217.44.5.128/28217.44.5.129 to 217.44.5.142217.44.5.14314
90217.44.5.144/28217.44.5.145 to 217.44.5.158217.44.5.15914
91217.44.5.160/28217.44.5.161 to 217.44.5.174217.44.5.17514
92217.44.5.176/28217.44.5.177 to 217.44.5.190217.44.5.19114
93217.44.5.192/28217.44.5.193 to 217.44.5.206217.44.5.20714
94217.44.5.208/28217.44.5.209 to 217.44.5.222217.44.5.22314
95217.44.5.224/28217.44.5.225 to 217.44.5.238217.44.5.23914
96217.44.5.240/28217.44.5.241 to 217.44.5.254217.44.5.25514
97217.44.6.0/28217.44.6.1 to 217.44.6.14217.44.6.1514
98217.44.6.16/28217.44.6.17 to 217.44.6.30217.44.6.3114
99217.44.6.32/28217.44.6.33 to 217.44.6.46217.44.6.4714
100217.44.6.48/28217.44.6.49 to 217.44.6.62217.44.6.6314
101217.44.6.64/28217.44.6.65 to 217.44.6.78217.44.6.7914
102217.44.6.80/28217.44.6.81 to 217.44.6.94217.44.6.9514
103217.44.6.96/28217.44.6.97 to 217.44.6.110217.44.6.11114
104217.44.6.112/28217.44.6.113 to 217.44.6.126217.44.6.12714
105217.44.6.128/28217.44.6.129 to 217.44.6.142217.44.6.14314
106217.44.6.144/28217.44.6.145 to 217.44.6.158217.44.6.15914
107217.44.6.160/28217.44.6.161 to 217.44.6.174217.44.6.17514
108217.44.6.176/28217.44.6.177 to 217.44.6.190217.44.6.19114
109217.44.6.192/28217.44.6.193 to 217.44.6.206217.44.6.20714
110217.44.6.208/28217.44.6.209 to 217.44.6.222217.44.6.22314
111217.44.6.224/28217.44.6.225 to 217.44.6.238217.44.6.23914
112217.44.6.240/28217.44.6.241 to 217.44.6.254217.44.6.25514
113217.44.7.0/28217.44.7.1 to 217.44.7.14217.44.7.1514
114217.44.7.16/28217.44.7.17 to 217.44.7.30217.44.7.3114
115217.44.7.32/28217.44.7.33 to 217.44.7.46217.44.7.4714
116217.44.7.48/28217.44.7.49 to 217.44.7.62217.44.7.6314
117217.44.7.64/28217.44.7.65 to 217.44.7.78217.44.7.7914
118217.44.7.80/28217.44.7.81 to 217.44.7.94217.44.7.9514
119217.44.7.96/28217.44.7.97 to 217.44.7.110217.44.7.11114
120217.44.7.112/28217.44.7.113 to 217.44.7.126217.44.7.12714
121217.44.7.128/28217.44.7.129 to 217.44.7.142217.44.7.14314
122217.44.7.144/28217.44.7.145 to 217.44.7.158217.44.7.15914
123217.44.7.160/28217.44.7.161 to 217.44.7.174217.44.7.17514
124217.44.7.176/28217.44.7.177 to 217.44.7.190217.44.7.19114
125217.44.7.192/28217.44.7.193 to 217.44.7.206217.44.7.20714
126217.44.7.208/28217.44.7.209 to 217.44.7.222217.44.7.22314
127217.44.7.224/28217.44.7.225 to 217.44.7.238217.44.7.23914
128217.44.7.240/28217.44.7.241 to 217.44.7.254217.44.7.25514
129217.44.8.0/28217.44.8.1 to 217.44.8.14217.44.8.1514
130217.44.8.16/28217.44.8.17 to 217.44.8.30217.44.8.3114
131217.44.8.32/28217.44.8.33 to 217.44.8.46217.44.8.4714
132217.44.8.48/28217.44.8.49 to 217.44.8.62217.44.8.6314
133217.44.8.64/28217.44.8.65 to 217.44.8.78217.44.8.7914
134217.44.8.80/28217.44.8.81 to 217.44.8.94217.44.8.9514
135217.44.8.96/28217.44.8.97 to 217.44.8.110217.44.8.11114
136217.44.8.112/28217.44.8.113 to 217.44.8.126217.44.8.12714
137217.44.8.128/28217.44.8.129 to 217.44.8.142217.44.8.14314
138217.44.8.144/28217.44.8.145 to 217.44.8.158217.44.8.15914
139217.44.8.160/28217.44.8.161 to 217.44.8.174217.44.8.17514
140217.44.8.176/28217.44.8.177 to 217.44.8.190217.44.8.19114
141217.44.8.192/28217.44.8.193 to 217.44.8.206217.44.8.20714
142217.44.8.208/28217.44.8.209 to 217.44.8.222217.44.8.22314
143217.44.8.224/28217.44.8.225 to 217.44.8.238217.44.8.23914
144217.44.8.240/28217.44.8.241 to 217.44.8.254217.44.8.25514
145217.44.9.0/28217.44.9.1 to 217.44.9.14217.44.9.1514
146217.44.9.16/28217.44.9.17 to 217.44.9.30217.44.9.3114
147217.44.9.32/28217.44.9.33 to 217.44.9.46217.44.9.4714
148217.44.9.48/28217.44.9.49 to 217.44.9.62217.44.9.6314
149217.44.9.64/28217.44.9.65 to 217.44.9.78217.44.9.7914
150217.44.9.80/28217.44.9.81 to 217.44.9.94217.44.9.9514
151217.44.9.96/28217.44.9.97 to 217.44.9.110217.44.9.11114
152217.44.9.112/28217.44.9.113 to 217.44.9.126217.44.9.12714
153217.44.9.128/28217.44.9.129 to 217.44.9.142217.44.9.14314
154217.44.9.144/28217.44.9.145 to 217.44.9.158217.44.9.15914
155217.44.9.160/28217.44.9.161 to 217.44.9.174217.44.9.17514
156217.44.9.176/28217.44.9.177 to 217.44.9.190217.44.9.19114
157217.44.9.192/28217.44.9.193 to 217.44.9.206217.44.9.20714
158217.44.9.208/28217.44.9.209 to 217.44.9.222217.44.9.22314
159217.44.9.224/28217.44.9.225 to 217.44.9.238217.44.9.23914
160217.44.9.240/28217.44.9.241 to 217.44.9.254217.44.9.25514
161217.44.10.0/28217.44.10.1 to 217.44.10.14217.44.10.1514
162217.44.10.16/28217.44.10.17 to 217.44.10.30217.44.10.3114
163217.44.10.32/28217.44.10.33 to 217.44.10.46217.44.10.4714
164217.44.10.48/28217.44.10.49 to 217.44.10.62217.44.10.6314
165217.44.10.64/28217.44.10.65 to 217.44.10.78217.44.10.7914
166217.44.10.80/28217.44.10.81 to 217.44.10.94217.44.10.9514
167217.44.10.96/28217.44.10.97 to 217.44.10.110217.44.10.11114
168217.44.10.112/28217.44.10.113 to 217.44.10.126217.44.10.12714
169217.44.10.128/28217.44.10.129 to 217.44.10.142217.44.10.14314
170217.44.10.144/28217.44.10.145 to 217.44.10.158217.44.10.15914
171217.44.10.160/28217.44.10.161 to 217.44.10.174217.44.10.17514
172217.44.10.176/28217.44.10.177 to 217.44.10.190217.44.10.19114
173217.44.10.192/28217.44.10.193 to 217.44.10.206217.44.10.20714
174217.44.10.208/28217.44.10.209 to 217.44.10.222217.44.10.22314
175217.44.10.224/28217.44.10.225 to 217.44.10.238217.44.10.23914
176217.44.10.240/28217.44.10.241 to 217.44.10.254217.44.10.25514
177217.44.11.0/28217.44.11.1 to 217.44.11.14217.44.11.1514
178217.44.11.16/28217.44.11.17 to 217.44.11.30217.44.11.3114
179217.44.11.32/28217.44.11.33 to 217.44.11.46217.44.11.4714
180217.44.11.48/28217.44.11.49 to 217.44.11.62217.44.11.6314
181217.44.11.64/28217.44.11.65 to 217.44.11.78217.44.11.7914
182217.44.11.80/28217.44.11.81 to 217.44.11.94217.44.11.9514
183217.44.11.96/28217.44.11.97 to 217.44.11.110217.44.11.11114
184217.44.11.112/28217.44.11.113 to 217.44.11.126217.44.11.12714
185217.44.11.128/28217.44.11.129 to 217.44.11.142217.44.11.14314
186217.44.11.144/28217.44.11.145 to 217.44.11.158217.44.11.15914
187217.44.11.160/28217.44.11.161 to 217.44.11.174217.44.11.17514
188217.44.11.176/28217.44.11.177 to 217.44.11.190217.44.11.19114
189217.44.11.192/28217.44.11.193 to 217.44.11.206217.44.11.20714
190217.44.11.208/28217.44.11.209 to 217.44.11.222217.44.11.22314
191217.44.11.224/28217.44.11.225 to 217.44.11.238217.44.11.23914
192217.44.11.240/28217.44.11.241 to 217.44.11.254217.44.11.25514
193217.44.12.0/28217.44.12.1 to 217.44.12.14217.44.12.1514
194217.44.12.16/28217.44.12.17 to 217.44.12.30217.44.12.3114
195217.44.12.32/28217.44.12.33 to 217.44.12.46217.44.12.4714
196217.44.12.48/28217.44.12.49 to 217.44.12.62217.44.12.6314
197217.44.12.64/28217.44.12.65 to 217.44.12.78217.44.12.7914
198217.44.12.80/28217.44.12.81 to 217.44.12.94217.44.12.9514
199217.44.12.96/28217.44.12.97 to 217.44.12.110217.44.12.11114
200217.44.12.112/28217.44.12.113 to 217.44.12.126217.44.12.12714
201217.44.12.128/28217.44.12.129 to 217.44.12.142217.44.12.14314
202217.44.12.144/28217.44.12.145 to 217.44.12.158217.44.12.15914
203217.44.12.160/28217.44.12.161 to 217.44.12.174217.44.12.17514
204217.44.12.176/28217.44.12.177 to 217.44.12.190217.44.12.19114
205217.44.12.192/28217.44.12.193 to 217.44.12.206217.44.12.20714
206217.44.12.208/28217.44.12.209 to 217.44.12.222217.44.12.22314
207217.44.12.224/28217.44.12.225 to 217.44.12.238217.44.12.23914
208217.44.12.240/28217.44.12.241 to 217.44.12.254217.44.12.25514
209217.44.13.0/28217.44.13.1 to 217.44.13.14217.44.13.1514
210217.44.13.16/28217.44.13.17 to 217.44.13.30217.44.13.3114
211217.44.13.32/28217.44.13.33 to 217.44.13.46217.44.13.4714
212217.44.13.48/28217.44.13.49 to 217.44.13.62217.44.13.6314
213217.44.13.64/28217.44.13.65 to 217.44.13.78217.44.13.7914
214217.44.13.80/28217.44.13.81 to 217.44.13.94217.44.13.9514
215217.44.13.96/28217.44.13.97 to 217.44.13.110217.44.13.11114
216217.44.13.112/28217.44.13.113 to 217.44.13.126217.44.13.12714
217217.44.13.128/28217.44.13.129 to 217.44.13.142217.44.13.14314
218217.44.13.144/28217.44.13.145 to 217.44.13.158217.44.13.15914
219217.44.13.160/28217.44.13.161 to 217.44.13.174217.44.13.17514
220217.44.13.176/28217.44.13.177 to 217.44.13.190217.44.13.19114
221217.44.13.192/28217.44.13.193 to 217.44.13.206217.44.13.20714
222217.44.13.208/28217.44.13.209 to 217.44.13.222217.44.13.22314
223217.44.13.224/28217.44.13.225 to 217.44.13.238217.44.13.23914
224217.44.13.240/28217.44.13.241 to 217.44.13.254217.44.13.25514
225217.44.14.0/28217.44.14.1 to 217.44.14.14217.44.14.1514
226217.44.14.16/28217.44.14.17 to 217.44.14.30217.44.14.3114
227217.44.14.32/28217.44.14.33 to 217.44.14.46217.44.14.4714
228217.44.14.48/28217.44.14.49 to 217.44.14.62217.44.14.6314
229217.44.14.64/28217.44.14.65 to 217.44.14.78217.44.14.7914
230217.44.14.80/28217.44.14.81 to 217.44.14.94217.44.14.9514
231217.44.14.96/28217.44.14.97 to 217.44.14.110217.44.14.11114
232217.44.14.112/28217.44.14.113 to 217.44.14.126217.44.14.12714
233217.44.14.128/28217.44.14.129 to 217.44.14.142217.44.14.14314
234217.44.14.144/28217.44.14.145 to 217.44.14.158217.44.14.15914
235217.44.14.160/28217.44.14.161 to 217.44.14.174217.44.14.17514
236217.44.14.176/28217.44.14.177 to 217.44.14.190217.44.14.19114
237217.44.14.192/28217.44.14.193 to 217.44.14.206217.44.14.20714
238217.44.14.208/28217.44.14.209 to 217.44.14.222217.44.14.22314
239217.44.14.224/28217.44.14.225 to 217.44.14.238217.44.14.23914
240217.44.14.240/28217.44.14.241 to 217.44.14.254217.44.14.25514
241217.44.15.0/28217.44.15.1 to 217.44.15.14217.44.15.1514
242217.44.15.16/28217.44.15.17 to 217.44.15.30217.44.15.3114
243217.44.15.32/28217.44.15.33 to 217.44.15.46217.44.15.4714
244217.44.15.48/28217.44.15.49 to 217.44.15.62217.44.15.6314
245217.44.15.64/28217.44.15.65 to 217.44.15.78217.44.15.7914
246217.44.15.80/28217.44.15.81 to 217.44.15.94217.44.15.9514
247217.44.15.96/28217.44.15.97 to 217.44.15.110217.44.15.11114
248217.44.15.112/28217.44.15.113 to 217.44.15.126217.44.15.12714
249217.44.15.128/28217.44.15.129 to 217.44.15.142217.44.15.14314
250217.44.15.144/28217.44.15.145 to 217.44.15.158217.44.15.15914
251217.44.15.160/28217.44.15.161 to 217.44.15.174217.44.15.17514
252217.44.15.176/28217.44.15.177 to 217.44.15.190217.44.15.19114
253217.44.15.192/28217.44.15.193 to 217.44.15.206217.44.15.20714
254217.44.15.208/28217.44.15.209 to 217.44.15.222217.44.15.22314
255217.44.15.224/28217.44.15.225 to 217.44.15.238217.44.15.23914
256217.44.15.240/28217.44.15.241 to 217.44.15.254217.44.15.25514

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.