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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.

Network225.2.64.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
225.2.64.0
Broadcast address
225.2.79.255
First usable
225.2.64.1
Last usable
225.2.79.254
Usable hosts
4,094 (4,096 less the network and broadcast addresses)
Subnet mask
255.255.240.0
Wildcard mask
0.0.15.255 (Cisco ACLs, OSPF)
Prefix length
/20
Type
Multicast 224.0.0.0/4
One-to-many traffic, such as IPTV and routing protocols
Old class
D (multicast)
As numbers
Hex E1024000 · Integer 3775021056 to 3775025151
Reverse DNS zones
64.2.225.in-addr.arpa
65.2.225.in-addr.arpa
66.2.225.in-addr.arpa
67.2.225.in-addr.arpa
68.2.225.in-addr.arpa
69.2.225.in-addr.arpa
70.2.225.in-addr.arpa
71.2.225.in-addr.arpa
72.2.225.in-addr.arpa
73.2.225.in-addr.arpa
74.2.225.in-addr.arpa
75.2.225.in-addr.arpa
76.2.225.in-addr.arpa
77.2.225.in-addr.arpa
78.2.225.in-addr.arpa
79.2.225.in-addr.arpa
/20 is not on a 8-bit boundary, so it takes 16 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11100001.00000010.01000000.00000000225.2.64.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network11100001.00000010.01000000.00000000225.2.64.0
Broadcast11100001.00000010.01001111.11111111225.2.79.255
Split into smaller subnets/30
/21 (2)/22 (4)/23 (8)/24 (16)/25 (32)/26 (64)/27 (128)/28 (256)/29 (512)/30 (1,024)/31 (2,048)/32 (4,096)

225.2.64.0/20 makes 1,024 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1225.2.64.0/30225.2.64.1 to 225.2.64.2225.2.64.32
2225.2.64.4/30225.2.64.5 to 225.2.64.6225.2.64.72
3225.2.64.8/30225.2.64.9 to 225.2.64.10225.2.64.112
4225.2.64.12/30225.2.64.13 to 225.2.64.14225.2.64.152
5225.2.64.16/30225.2.64.17 to 225.2.64.18225.2.64.192
6225.2.64.20/30225.2.64.21 to 225.2.64.22225.2.64.232
7225.2.64.24/30225.2.64.25 to 225.2.64.26225.2.64.272
8225.2.64.28/30225.2.64.29 to 225.2.64.30225.2.64.312
9225.2.64.32/30225.2.64.33 to 225.2.64.34225.2.64.352
10225.2.64.36/30225.2.64.37 to 225.2.64.38225.2.64.392
11225.2.64.40/30225.2.64.41 to 225.2.64.42225.2.64.432
12225.2.64.44/30225.2.64.45 to 225.2.64.46225.2.64.472
13225.2.64.48/30225.2.64.49 to 225.2.64.50225.2.64.512
14225.2.64.52/30225.2.64.53 to 225.2.64.54225.2.64.552
15225.2.64.56/30225.2.64.57 to 225.2.64.58225.2.64.592
16225.2.64.60/30225.2.64.61 to 225.2.64.62225.2.64.632
17225.2.64.64/30225.2.64.65 to 225.2.64.66225.2.64.672
18225.2.64.68/30225.2.64.69 to 225.2.64.70225.2.64.712
19225.2.64.72/30225.2.64.73 to 225.2.64.74225.2.64.752
20225.2.64.76/30225.2.64.77 to 225.2.64.78225.2.64.792
21225.2.64.80/30225.2.64.81 to 225.2.64.82225.2.64.832
22225.2.64.84/30225.2.64.85 to 225.2.64.86225.2.64.872
23225.2.64.88/30225.2.64.89 to 225.2.64.90225.2.64.912
24225.2.64.92/30225.2.64.93 to 225.2.64.94225.2.64.952
25225.2.64.96/30225.2.64.97 to 225.2.64.98225.2.64.992
26225.2.64.100/30225.2.64.101 to 225.2.64.102225.2.64.1032
27225.2.64.104/30225.2.64.105 to 225.2.64.106225.2.64.1072
28225.2.64.108/30225.2.64.109 to 225.2.64.110225.2.64.1112
29225.2.64.112/30225.2.64.113 to 225.2.64.114225.2.64.1152
30225.2.64.116/30225.2.64.117 to 225.2.64.118225.2.64.1192
31225.2.64.120/30225.2.64.121 to 225.2.64.122225.2.64.1232
32225.2.64.124/30225.2.64.125 to 225.2.64.126225.2.64.1272
33225.2.64.128/30225.2.64.129 to 225.2.64.130225.2.64.1312
34225.2.64.132/30225.2.64.133 to 225.2.64.134225.2.64.1352
35225.2.64.136/30225.2.64.137 to 225.2.64.138225.2.64.1392
36225.2.64.140/30225.2.64.141 to 225.2.64.142225.2.64.1432
37225.2.64.144/30225.2.64.145 to 225.2.64.146225.2.64.1472
38225.2.64.148/30225.2.64.149 to 225.2.64.150225.2.64.1512
39225.2.64.152/30225.2.64.153 to 225.2.64.154225.2.64.1552
40225.2.64.156/30225.2.64.157 to 225.2.64.158225.2.64.1592
41225.2.64.160/30225.2.64.161 to 225.2.64.162225.2.64.1632
42225.2.64.164/30225.2.64.165 to 225.2.64.166225.2.64.1672
43225.2.64.168/30225.2.64.169 to 225.2.64.170225.2.64.1712
44225.2.64.172/30225.2.64.173 to 225.2.64.174225.2.64.1752
45225.2.64.176/30225.2.64.177 to 225.2.64.178225.2.64.1792
46225.2.64.180/30225.2.64.181 to 225.2.64.182225.2.64.1832
47225.2.64.184/30225.2.64.185 to 225.2.64.186225.2.64.1872
48225.2.64.188/30225.2.64.189 to 225.2.64.190225.2.64.1912
49225.2.64.192/30225.2.64.193 to 225.2.64.194225.2.64.1952
50225.2.64.196/30225.2.64.197 to 225.2.64.198225.2.64.1992
51225.2.64.200/30225.2.64.201 to 225.2.64.202225.2.64.2032
52225.2.64.204/30225.2.64.205 to 225.2.64.206225.2.64.2072
53225.2.64.208/30225.2.64.209 to 225.2.64.210225.2.64.2112
54225.2.64.212/30225.2.64.213 to 225.2.64.214225.2.64.2152
55225.2.64.216/30225.2.64.217 to 225.2.64.218225.2.64.2192
56225.2.64.220/30225.2.64.221 to 225.2.64.222225.2.64.2232
57225.2.64.224/30225.2.64.225 to 225.2.64.226225.2.64.2272
58225.2.64.228/30225.2.64.229 to 225.2.64.230225.2.64.2312
59225.2.64.232/30225.2.64.233 to 225.2.64.234225.2.64.2352
60225.2.64.236/30225.2.64.237 to 225.2.64.238225.2.64.2392
61225.2.64.240/30225.2.64.241 to 225.2.64.242225.2.64.2432
62225.2.64.244/30225.2.64.245 to 225.2.64.246225.2.64.2472
63225.2.64.248/30225.2.64.249 to 225.2.64.250225.2.64.2512
64225.2.64.252/30225.2.64.253 to 225.2.64.254225.2.64.2552
65225.2.65.0/30225.2.65.1 to 225.2.65.2225.2.65.32
66225.2.65.4/30225.2.65.5 to 225.2.65.6225.2.65.72
67225.2.65.8/30225.2.65.9 to 225.2.65.10225.2.65.112
68225.2.65.12/30225.2.65.13 to 225.2.65.14225.2.65.152
69225.2.65.16/30225.2.65.17 to 225.2.65.18225.2.65.192
70225.2.65.20/30225.2.65.21 to 225.2.65.22225.2.65.232
71225.2.65.24/30225.2.65.25 to 225.2.65.26225.2.65.272
72225.2.65.28/30225.2.65.29 to 225.2.65.30225.2.65.312
73225.2.65.32/30225.2.65.33 to 225.2.65.34225.2.65.352
74225.2.65.36/30225.2.65.37 to 225.2.65.38225.2.65.392
75225.2.65.40/30225.2.65.41 to 225.2.65.42225.2.65.432
76225.2.65.44/30225.2.65.45 to 225.2.65.46225.2.65.472
77225.2.65.48/30225.2.65.49 to 225.2.65.50225.2.65.512
78225.2.65.52/30225.2.65.53 to 225.2.65.54225.2.65.552
79225.2.65.56/30225.2.65.57 to 225.2.65.58225.2.65.592
80225.2.65.60/30225.2.65.61 to 225.2.65.62225.2.65.632
81225.2.65.64/30225.2.65.65 to 225.2.65.66225.2.65.672
82225.2.65.68/30225.2.65.69 to 225.2.65.70225.2.65.712
83225.2.65.72/30225.2.65.73 to 225.2.65.74225.2.65.752
84225.2.65.76/30225.2.65.77 to 225.2.65.78225.2.65.792
85225.2.65.80/30225.2.65.81 to 225.2.65.82225.2.65.832
86225.2.65.84/30225.2.65.85 to 225.2.65.86225.2.65.872
87225.2.65.88/30225.2.65.89 to 225.2.65.90225.2.65.912
88225.2.65.92/30225.2.65.93 to 225.2.65.94225.2.65.952
89225.2.65.96/30225.2.65.97 to 225.2.65.98225.2.65.992
90225.2.65.100/30225.2.65.101 to 225.2.65.102225.2.65.1032
91225.2.65.104/30225.2.65.105 to 225.2.65.106225.2.65.1072
92225.2.65.108/30225.2.65.109 to 225.2.65.110225.2.65.1112
93225.2.65.112/30225.2.65.113 to 225.2.65.114225.2.65.1152
94225.2.65.116/30225.2.65.117 to 225.2.65.118225.2.65.1192
95225.2.65.120/30225.2.65.121 to 225.2.65.122225.2.65.1232
96225.2.65.124/30225.2.65.125 to 225.2.65.126225.2.65.1272
97225.2.65.128/30225.2.65.129 to 225.2.65.130225.2.65.1312
98225.2.65.132/30225.2.65.133 to 225.2.65.134225.2.65.1352
99225.2.65.136/30225.2.65.137 to 225.2.65.138225.2.65.1392
100225.2.65.140/30225.2.65.141 to 225.2.65.142225.2.65.1432
101225.2.65.144/30225.2.65.145 to 225.2.65.146225.2.65.1472
102225.2.65.148/30225.2.65.149 to 225.2.65.150225.2.65.1512
103225.2.65.152/30225.2.65.153 to 225.2.65.154225.2.65.1552
104225.2.65.156/30225.2.65.157 to 225.2.65.158225.2.65.1592
105225.2.65.160/30225.2.65.161 to 225.2.65.162225.2.65.1632
106225.2.65.164/30225.2.65.165 to 225.2.65.166225.2.65.1672
107225.2.65.168/30225.2.65.169 to 225.2.65.170225.2.65.1712
108225.2.65.172/30225.2.65.173 to 225.2.65.174225.2.65.1752
109225.2.65.176/30225.2.65.177 to 225.2.65.178225.2.65.1792
110225.2.65.180/30225.2.65.181 to 225.2.65.182225.2.65.1832
111225.2.65.184/30225.2.65.185 to 225.2.65.186225.2.65.1872
112225.2.65.188/30225.2.65.189 to 225.2.65.190225.2.65.1912
113225.2.65.192/30225.2.65.193 to 225.2.65.194225.2.65.1952
114225.2.65.196/30225.2.65.197 to 225.2.65.198225.2.65.1992
115225.2.65.200/30225.2.65.201 to 225.2.65.202225.2.65.2032
116225.2.65.204/30225.2.65.205 to 225.2.65.206225.2.65.2072
117225.2.65.208/30225.2.65.209 to 225.2.65.210225.2.65.2112
118225.2.65.212/30225.2.65.213 to 225.2.65.214225.2.65.2152
119225.2.65.216/30225.2.65.217 to 225.2.65.218225.2.65.2192
120225.2.65.220/30225.2.65.221 to 225.2.65.222225.2.65.2232
121225.2.65.224/30225.2.65.225 to 225.2.65.226225.2.65.2272
122225.2.65.228/30225.2.65.229 to 225.2.65.230225.2.65.2312
123225.2.65.232/30225.2.65.233 to 225.2.65.234225.2.65.2352
124225.2.65.236/30225.2.65.237 to 225.2.65.238225.2.65.2392
125225.2.65.240/30225.2.65.241 to 225.2.65.242225.2.65.2432
126225.2.65.244/30225.2.65.245 to 225.2.65.246225.2.65.2472
127225.2.65.248/30225.2.65.249 to 225.2.65.250225.2.65.2512
128225.2.65.252/30225.2.65.253 to 225.2.65.254225.2.65.2552
129225.2.66.0/30225.2.66.1 to 225.2.66.2225.2.66.32
130225.2.66.4/30225.2.66.5 to 225.2.66.6225.2.66.72
131225.2.66.8/30225.2.66.9 to 225.2.66.10225.2.66.112
132225.2.66.12/30225.2.66.13 to 225.2.66.14225.2.66.152
133225.2.66.16/30225.2.66.17 to 225.2.66.18225.2.66.192
134225.2.66.20/30225.2.66.21 to 225.2.66.22225.2.66.232
135225.2.66.24/30225.2.66.25 to 225.2.66.26225.2.66.272
136225.2.66.28/30225.2.66.29 to 225.2.66.30225.2.66.312
137225.2.66.32/30225.2.66.33 to 225.2.66.34225.2.66.352
138225.2.66.36/30225.2.66.37 to 225.2.66.38225.2.66.392
139225.2.66.40/30225.2.66.41 to 225.2.66.42225.2.66.432
140225.2.66.44/30225.2.66.45 to 225.2.66.46225.2.66.472
141225.2.66.48/30225.2.66.49 to 225.2.66.50225.2.66.512
142225.2.66.52/30225.2.66.53 to 225.2.66.54225.2.66.552
143225.2.66.56/30225.2.66.57 to 225.2.66.58225.2.66.592
144225.2.66.60/30225.2.66.61 to 225.2.66.62225.2.66.632
145225.2.66.64/30225.2.66.65 to 225.2.66.66225.2.66.672
146225.2.66.68/30225.2.66.69 to 225.2.66.70225.2.66.712
147225.2.66.72/30225.2.66.73 to 225.2.66.74225.2.66.752
148225.2.66.76/30225.2.66.77 to 225.2.66.78225.2.66.792
149225.2.66.80/30225.2.66.81 to 225.2.66.82225.2.66.832
150225.2.66.84/30225.2.66.85 to 225.2.66.86225.2.66.872
151225.2.66.88/30225.2.66.89 to 225.2.66.90225.2.66.912
152225.2.66.92/30225.2.66.93 to 225.2.66.94225.2.66.952
153225.2.66.96/30225.2.66.97 to 225.2.66.98225.2.66.992
154225.2.66.100/30225.2.66.101 to 225.2.66.102225.2.66.1032
155225.2.66.104/30225.2.66.105 to 225.2.66.106225.2.66.1072
156225.2.66.108/30225.2.66.109 to 225.2.66.110225.2.66.1112
157225.2.66.112/30225.2.66.113 to 225.2.66.114225.2.66.1152
158225.2.66.116/30225.2.66.117 to 225.2.66.118225.2.66.1192
159225.2.66.120/30225.2.66.121 to 225.2.66.122225.2.66.1232
160225.2.66.124/30225.2.66.125 to 225.2.66.126225.2.66.1272
161225.2.66.128/30225.2.66.129 to 225.2.66.130225.2.66.1312
162225.2.66.132/30225.2.66.133 to 225.2.66.134225.2.66.1352
163225.2.66.136/30225.2.66.137 to 225.2.66.138225.2.66.1392
164225.2.66.140/30225.2.66.141 to 225.2.66.142225.2.66.1432
165225.2.66.144/30225.2.66.145 to 225.2.66.146225.2.66.1472
166225.2.66.148/30225.2.66.149 to 225.2.66.150225.2.66.1512
167225.2.66.152/30225.2.66.153 to 225.2.66.154225.2.66.1552
168225.2.66.156/30225.2.66.157 to 225.2.66.158225.2.66.1592
169225.2.66.160/30225.2.66.161 to 225.2.66.162225.2.66.1632
170225.2.66.164/30225.2.66.165 to 225.2.66.166225.2.66.1672
171225.2.66.168/30225.2.66.169 to 225.2.66.170225.2.66.1712
172225.2.66.172/30225.2.66.173 to 225.2.66.174225.2.66.1752
173225.2.66.176/30225.2.66.177 to 225.2.66.178225.2.66.1792
174225.2.66.180/30225.2.66.181 to 225.2.66.182225.2.66.1832
175225.2.66.184/30225.2.66.185 to 225.2.66.186225.2.66.1872
176225.2.66.188/30225.2.66.189 to 225.2.66.190225.2.66.1912
177225.2.66.192/30225.2.66.193 to 225.2.66.194225.2.66.1952
178225.2.66.196/30225.2.66.197 to 225.2.66.198225.2.66.1992
179225.2.66.200/30225.2.66.201 to 225.2.66.202225.2.66.2032
180225.2.66.204/30225.2.66.205 to 225.2.66.206225.2.66.2072
181225.2.66.208/30225.2.66.209 to 225.2.66.210225.2.66.2112
182225.2.66.212/30225.2.66.213 to 225.2.66.214225.2.66.2152
183225.2.66.216/30225.2.66.217 to 225.2.66.218225.2.66.2192
184225.2.66.220/30225.2.66.221 to 225.2.66.222225.2.66.2232
185225.2.66.224/30225.2.66.225 to 225.2.66.226225.2.66.2272
186225.2.66.228/30225.2.66.229 to 225.2.66.230225.2.66.2312
187225.2.66.232/30225.2.66.233 to 225.2.66.234225.2.66.2352
188225.2.66.236/30225.2.66.237 to 225.2.66.238225.2.66.2392
189225.2.66.240/30225.2.66.241 to 225.2.66.242225.2.66.2432
190225.2.66.244/30225.2.66.245 to 225.2.66.246225.2.66.2472
191225.2.66.248/30225.2.66.249 to 225.2.66.250225.2.66.2512
192225.2.66.252/30225.2.66.253 to 225.2.66.254225.2.66.2552
193225.2.67.0/30225.2.67.1 to 225.2.67.2225.2.67.32
194225.2.67.4/30225.2.67.5 to 225.2.67.6225.2.67.72
195225.2.67.8/30225.2.67.9 to 225.2.67.10225.2.67.112
196225.2.67.12/30225.2.67.13 to 225.2.67.14225.2.67.152
197225.2.67.16/30225.2.67.17 to 225.2.67.18225.2.67.192
198225.2.67.20/30225.2.67.21 to 225.2.67.22225.2.67.232
199225.2.67.24/30225.2.67.25 to 225.2.67.26225.2.67.272
200225.2.67.28/30225.2.67.29 to 225.2.67.30225.2.67.312
201225.2.67.32/30225.2.67.33 to 225.2.67.34225.2.67.352
202225.2.67.36/30225.2.67.37 to 225.2.67.38225.2.67.392
203225.2.67.40/30225.2.67.41 to 225.2.67.42225.2.67.432
204225.2.67.44/30225.2.67.45 to 225.2.67.46225.2.67.472
205225.2.67.48/30225.2.67.49 to 225.2.67.50225.2.67.512
206225.2.67.52/30225.2.67.53 to 225.2.67.54225.2.67.552
207225.2.67.56/30225.2.67.57 to 225.2.67.58225.2.67.592
208225.2.67.60/30225.2.67.61 to 225.2.67.62225.2.67.632
209225.2.67.64/30225.2.67.65 to 225.2.67.66225.2.67.672
210225.2.67.68/30225.2.67.69 to 225.2.67.70225.2.67.712
211225.2.67.72/30225.2.67.73 to 225.2.67.74225.2.67.752
212225.2.67.76/30225.2.67.77 to 225.2.67.78225.2.67.792
213225.2.67.80/30225.2.67.81 to 225.2.67.82225.2.67.832
214225.2.67.84/30225.2.67.85 to 225.2.67.86225.2.67.872
215225.2.67.88/30225.2.67.89 to 225.2.67.90225.2.67.912
216225.2.67.92/30225.2.67.93 to 225.2.67.94225.2.67.952
217225.2.67.96/30225.2.67.97 to 225.2.67.98225.2.67.992
218225.2.67.100/30225.2.67.101 to 225.2.67.102225.2.67.1032
219225.2.67.104/30225.2.67.105 to 225.2.67.106225.2.67.1072
220225.2.67.108/30225.2.67.109 to 225.2.67.110225.2.67.1112
221225.2.67.112/30225.2.67.113 to 225.2.67.114225.2.67.1152
222225.2.67.116/30225.2.67.117 to 225.2.67.118225.2.67.1192
223225.2.67.120/30225.2.67.121 to 225.2.67.122225.2.67.1232
224225.2.67.124/30225.2.67.125 to 225.2.67.126225.2.67.1272
225225.2.67.128/30225.2.67.129 to 225.2.67.130225.2.67.1312
226225.2.67.132/30225.2.67.133 to 225.2.67.134225.2.67.1352
227225.2.67.136/30225.2.67.137 to 225.2.67.138225.2.67.1392
228225.2.67.140/30225.2.67.141 to 225.2.67.142225.2.67.1432
229225.2.67.144/30225.2.67.145 to 225.2.67.146225.2.67.1472
230225.2.67.148/30225.2.67.149 to 225.2.67.150225.2.67.1512
231225.2.67.152/30225.2.67.153 to 225.2.67.154225.2.67.1552
232225.2.67.156/30225.2.67.157 to 225.2.67.158225.2.67.1592
233225.2.67.160/30225.2.67.161 to 225.2.67.162225.2.67.1632
234225.2.67.164/30225.2.67.165 to 225.2.67.166225.2.67.1672
235225.2.67.168/30225.2.67.169 to 225.2.67.170225.2.67.1712
236225.2.67.172/30225.2.67.173 to 225.2.67.174225.2.67.1752
237225.2.67.176/30225.2.67.177 to 225.2.67.178225.2.67.1792
238225.2.67.180/30225.2.67.181 to 225.2.67.182225.2.67.1832
239225.2.67.184/30225.2.67.185 to 225.2.67.186225.2.67.1872
240225.2.67.188/30225.2.67.189 to 225.2.67.190225.2.67.1912
241225.2.67.192/30225.2.67.193 to 225.2.67.194225.2.67.1952
242225.2.67.196/30225.2.67.197 to 225.2.67.198225.2.67.1992
243225.2.67.200/30225.2.67.201 to 225.2.67.202225.2.67.2032
244225.2.67.204/30225.2.67.205 to 225.2.67.206225.2.67.2072
245225.2.67.208/30225.2.67.209 to 225.2.67.210225.2.67.2112
246225.2.67.212/30225.2.67.213 to 225.2.67.214225.2.67.2152
247225.2.67.216/30225.2.67.217 to 225.2.67.218225.2.67.2192
248225.2.67.220/30225.2.67.221 to 225.2.67.222225.2.67.2232
249225.2.67.224/30225.2.67.225 to 225.2.67.226225.2.67.2272
250225.2.67.228/30225.2.67.229 to 225.2.67.230225.2.67.2312
251225.2.67.232/30225.2.67.233 to 225.2.67.234225.2.67.2352
252225.2.67.236/30225.2.67.237 to 225.2.67.238225.2.67.2392
253225.2.67.240/30225.2.67.241 to 225.2.67.242225.2.67.2432
254225.2.67.244/30225.2.67.245 to 225.2.67.246225.2.67.2472
255225.2.67.248/30225.2.67.249 to 225.2.67.250225.2.67.2512
256225.2.67.252/30225.2.67.253 to 225.2.67.254225.2.67.2552

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.