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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.

Network210.28.64.0/18
Usable hosts16,382
Subnet mask255.255.192.0
Addresses16,384
Network address
210.28.64.0
Broadcast address
210.28.127.255
First usable
210.28.64.1
Last usable
210.28.127.254
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
C (default /24)
As numbers
Hex D21C4000 · Integer 3525066752 to 3525083135
Reverse DNS zones
64.28.210.in-addr.arpa
65.28.210.in-addr.arpa
66.28.210.in-addr.arpa
67.28.210.in-addr.arpa
68.28.210.in-addr.arpa
69.28.210.in-addr.arpa
70.28.210.in-addr.arpa
71.28.210.in-addr.arpa
72.28.210.in-addr.arpa
73.28.210.in-addr.arpa
74.28.210.in-addr.arpa
75.28.210.in-addr.arpa
76.28.210.in-addr.arpa
77.28.210.in-addr.arpa
78.28.210.in-addr.arpa
79.28.210.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
Address11010010.00011100.01000000.00000000210.28.64.0
Subnet mask11111111.11111111.11000000.00000000255.255.192.0
Network11010010.00011100.01000000.00000000210.28.64.0
Broadcast11010010.00011100.01111111.11111111210.28.127.255
Split into smaller subnets/30
/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)

210.28.64.0/18 makes 4,096 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1210.28.64.0/30210.28.64.1 to 210.28.64.2210.28.64.32
2210.28.64.4/30210.28.64.5 to 210.28.64.6210.28.64.72
3210.28.64.8/30210.28.64.9 to 210.28.64.10210.28.64.112
4210.28.64.12/30210.28.64.13 to 210.28.64.14210.28.64.152
5210.28.64.16/30210.28.64.17 to 210.28.64.18210.28.64.192
6210.28.64.20/30210.28.64.21 to 210.28.64.22210.28.64.232
7210.28.64.24/30210.28.64.25 to 210.28.64.26210.28.64.272
8210.28.64.28/30210.28.64.29 to 210.28.64.30210.28.64.312
9210.28.64.32/30210.28.64.33 to 210.28.64.34210.28.64.352
10210.28.64.36/30210.28.64.37 to 210.28.64.38210.28.64.392
11210.28.64.40/30210.28.64.41 to 210.28.64.42210.28.64.432
12210.28.64.44/30210.28.64.45 to 210.28.64.46210.28.64.472
13210.28.64.48/30210.28.64.49 to 210.28.64.50210.28.64.512
14210.28.64.52/30210.28.64.53 to 210.28.64.54210.28.64.552
15210.28.64.56/30210.28.64.57 to 210.28.64.58210.28.64.592
16210.28.64.60/30210.28.64.61 to 210.28.64.62210.28.64.632
17210.28.64.64/30210.28.64.65 to 210.28.64.66210.28.64.672
18210.28.64.68/30210.28.64.69 to 210.28.64.70210.28.64.712
19210.28.64.72/30210.28.64.73 to 210.28.64.74210.28.64.752
20210.28.64.76/30210.28.64.77 to 210.28.64.78210.28.64.792
21210.28.64.80/30210.28.64.81 to 210.28.64.82210.28.64.832
22210.28.64.84/30210.28.64.85 to 210.28.64.86210.28.64.872
23210.28.64.88/30210.28.64.89 to 210.28.64.90210.28.64.912
24210.28.64.92/30210.28.64.93 to 210.28.64.94210.28.64.952
25210.28.64.96/30210.28.64.97 to 210.28.64.98210.28.64.992
26210.28.64.100/30210.28.64.101 to 210.28.64.102210.28.64.1032
27210.28.64.104/30210.28.64.105 to 210.28.64.106210.28.64.1072
28210.28.64.108/30210.28.64.109 to 210.28.64.110210.28.64.1112
29210.28.64.112/30210.28.64.113 to 210.28.64.114210.28.64.1152
30210.28.64.116/30210.28.64.117 to 210.28.64.118210.28.64.1192
31210.28.64.120/30210.28.64.121 to 210.28.64.122210.28.64.1232
32210.28.64.124/30210.28.64.125 to 210.28.64.126210.28.64.1272
33210.28.64.128/30210.28.64.129 to 210.28.64.130210.28.64.1312
34210.28.64.132/30210.28.64.133 to 210.28.64.134210.28.64.1352
35210.28.64.136/30210.28.64.137 to 210.28.64.138210.28.64.1392
36210.28.64.140/30210.28.64.141 to 210.28.64.142210.28.64.1432
37210.28.64.144/30210.28.64.145 to 210.28.64.146210.28.64.1472
38210.28.64.148/30210.28.64.149 to 210.28.64.150210.28.64.1512
39210.28.64.152/30210.28.64.153 to 210.28.64.154210.28.64.1552
40210.28.64.156/30210.28.64.157 to 210.28.64.158210.28.64.1592
41210.28.64.160/30210.28.64.161 to 210.28.64.162210.28.64.1632
42210.28.64.164/30210.28.64.165 to 210.28.64.166210.28.64.1672
43210.28.64.168/30210.28.64.169 to 210.28.64.170210.28.64.1712
44210.28.64.172/30210.28.64.173 to 210.28.64.174210.28.64.1752
45210.28.64.176/30210.28.64.177 to 210.28.64.178210.28.64.1792
46210.28.64.180/30210.28.64.181 to 210.28.64.182210.28.64.1832
47210.28.64.184/30210.28.64.185 to 210.28.64.186210.28.64.1872
48210.28.64.188/30210.28.64.189 to 210.28.64.190210.28.64.1912
49210.28.64.192/30210.28.64.193 to 210.28.64.194210.28.64.1952
50210.28.64.196/30210.28.64.197 to 210.28.64.198210.28.64.1992
51210.28.64.200/30210.28.64.201 to 210.28.64.202210.28.64.2032
52210.28.64.204/30210.28.64.205 to 210.28.64.206210.28.64.2072
53210.28.64.208/30210.28.64.209 to 210.28.64.210210.28.64.2112
54210.28.64.212/30210.28.64.213 to 210.28.64.214210.28.64.2152
55210.28.64.216/30210.28.64.217 to 210.28.64.218210.28.64.2192
56210.28.64.220/30210.28.64.221 to 210.28.64.222210.28.64.2232
57210.28.64.224/30210.28.64.225 to 210.28.64.226210.28.64.2272
58210.28.64.228/30210.28.64.229 to 210.28.64.230210.28.64.2312
59210.28.64.232/30210.28.64.233 to 210.28.64.234210.28.64.2352
60210.28.64.236/30210.28.64.237 to 210.28.64.238210.28.64.2392
61210.28.64.240/30210.28.64.241 to 210.28.64.242210.28.64.2432
62210.28.64.244/30210.28.64.245 to 210.28.64.246210.28.64.2472
63210.28.64.248/30210.28.64.249 to 210.28.64.250210.28.64.2512
64210.28.64.252/30210.28.64.253 to 210.28.64.254210.28.64.2552
65210.28.65.0/30210.28.65.1 to 210.28.65.2210.28.65.32
66210.28.65.4/30210.28.65.5 to 210.28.65.6210.28.65.72
67210.28.65.8/30210.28.65.9 to 210.28.65.10210.28.65.112
68210.28.65.12/30210.28.65.13 to 210.28.65.14210.28.65.152
69210.28.65.16/30210.28.65.17 to 210.28.65.18210.28.65.192
70210.28.65.20/30210.28.65.21 to 210.28.65.22210.28.65.232
71210.28.65.24/30210.28.65.25 to 210.28.65.26210.28.65.272
72210.28.65.28/30210.28.65.29 to 210.28.65.30210.28.65.312
73210.28.65.32/30210.28.65.33 to 210.28.65.34210.28.65.352
74210.28.65.36/30210.28.65.37 to 210.28.65.38210.28.65.392
75210.28.65.40/30210.28.65.41 to 210.28.65.42210.28.65.432
76210.28.65.44/30210.28.65.45 to 210.28.65.46210.28.65.472
77210.28.65.48/30210.28.65.49 to 210.28.65.50210.28.65.512
78210.28.65.52/30210.28.65.53 to 210.28.65.54210.28.65.552
79210.28.65.56/30210.28.65.57 to 210.28.65.58210.28.65.592
80210.28.65.60/30210.28.65.61 to 210.28.65.62210.28.65.632
81210.28.65.64/30210.28.65.65 to 210.28.65.66210.28.65.672
82210.28.65.68/30210.28.65.69 to 210.28.65.70210.28.65.712
83210.28.65.72/30210.28.65.73 to 210.28.65.74210.28.65.752
84210.28.65.76/30210.28.65.77 to 210.28.65.78210.28.65.792
85210.28.65.80/30210.28.65.81 to 210.28.65.82210.28.65.832
86210.28.65.84/30210.28.65.85 to 210.28.65.86210.28.65.872
87210.28.65.88/30210.28.65.89 to 210.28.65.90210.28.65.912
88210.28.65.92/30210.28.65.93 to 210.28.65.94210.28.65.952
89210.28.65.96/30210.28.65.97 to 210.28.65.98210.28.65.992
90210.28.65.100/30210.28.65.101 to 210.28.65.102210.28.65.1032
91210.28.65.104/30210.28.65.105 to 210.28.65.106210.28.65.1072
92210.28.65.108/30210.28.65.109 to 210.28.65.110210.28.65.1112
93210.28.65.112/30210.28.65.113 to 210.28.65.114210.28.65.1152
94210.28.65.116/30210.28.65.117 to 210.28.65.118210.28.65.1192
95210.28.65.120/30210.28.65.121 to 210.28.65.122210.28.65.1232
96210.28.65.124/30210.28.65.125 to 210.28.65.126210.28.65.1272
97210.28.65.128/30210.28.65.129 to 210.28.65.130210.28.65.1312
98210.28.65.132/30210.28.65.133 to 210.28.65.134210.28.65.1352
99210.28.65.136/30210.28.65.137 to 210.28.65.138210.28.65.1392
100210.28.65.140/30210.28.65.141 to 210.28.65.142210.28.65.1432
101210.28.65.144/30210.28.65.145 to 210.28.65.146210.28.65.1472
102210.28.65.148/30210.28.65.149 to 210.28.65.150210.28.65.1512
103210.28.65.152/30210.28.65.153 to 210.28.65.154210.28.65.1552
104210.28.65.156/30210.28.65.157 to 210.28.65.158210.28.65.1592
105210.28.65.160/30210.28.65.161 to 210.28.65.162210.28.65.1632
106210.28.65.164/30210.28.65.165 to 210.28.65.166210.28.65.1672
107210.28.65.168/30210.28.65.169 to 210.28.65.170210.28.65.1712
108210.28.65.172/30210.28.65.173 to 210.28.65.174210.28.65.1752
109210.28.65.176/30210.28.65.177 to 210.28.65.178210.28.65.1792
110210.28.65.180/30210.28.65.181 to 210.28.65.182210.28.65.1832
111210.28.65.184/30210.28.65.185 to 210.28.65.186210.28.65.1872
112210.28.65.188/30210.28.65.189 to 210.28.65.190210.28.65.1912
113210.28.65.192/30210.28.65.193 to 210.28.65.194210.28.65.1952
114210.28.65.196/30210.28.65.197 to 210.28.65.198210.28.65.1992
115210.28.65.200/30210.28.65.201 to 210.28.65.202210.28.65.2032
116210.28.65.204/30210.28.65.205 to 210.28.65.206210.28.65.2072
117210.28.65.208/30210.28.65.209 to 210.28.65.210210.28.65.2112
118210.28.65.212/30210.28.65.213 to 210.28.65.214210.28.65.2152
119210.28.65.216/30210.28.65.217 to 210.28.65.218210.28.65.2192
120210.28.65.220/30210.28.65.221 to 210.28.65.222210.28.65.2232
121210.28.65.224/30210.28.65.225 to 210.28.65.226210.28.65.2272
122210.28.65.228/30210.28.65.229 to 210.28.65.230210.28.65.2312
123210.28.65.232/30210.28.65.233 to 210.28.65.234210.28.65.2352
124210.28.65.236/30210.28.65.237 to 210.28.65.238210.28.65.2392
125210.28.65.240/30210.28.65.241 to 210.28.65.242210.28.65.2432
126210.28.65.244/30210.28.65.245 to 210.28.65.246210.28.65.2472
127210.28.65.248/30210.28.65.249 to 210.28.65.250210.28.65.2512
128210.28.65.252/30210.28.65.253 to 210.28.65.254210.28.65.2552
129210.28.66.0/30210.28.66.1 to 210.28.66.2210.28.66.32
130210.28.66.4/30210.28.66.5 to 210.28.66.6210.28.66.72
131210.28.66.8/30210.28.66.9 to 210.28.66.10210.28.66.112
132210.28.66.12/30210.28.66.13 to 210.28.66.14210.28.66.152
133210.28.66.16/30210.28.66.17 to 210.28.66.18210.28.66.192
134210.28.66.20/30210.28.66.21 to 210.28.66.22210.28.66.232
135210.28.66.24/30210.28.66.25 to 210.28.66.26210.28.66.272
136210.28.66.28/30210.28.66.29 to 210.28.66.30210.28.66.312
137210.28.66.32/30210.28.66.33 to 210.28.66.34210.28.66.352
138210.28.66.36/30210.28.66.37 to 210.28.66.38210.28.66.392
139210.28.66.40/30210.28.66.41 to 210.28.66.42210.28.66.432
140210.28.66.44/30210.28.66.45 to 210.28.66.46210.28.66.472
141210.28.66.48/30210.28.66.49 to 210.28.66.50210.28.66.512
142210.28.66.52/30210.28.66.53 to 210.28.66.54210.28.66.552
143210.28.66.56/30210.28.66.57 to 210.28.66.58210.28.66.592
144210.28.66.60/30210.28.66.61 to 210.28.66.62210.28.66.632
145210.28.66.64/30210.28.66.65 to 210.28.66.66210.28.66.672
146210.28.66.68/30210.28.66.69 to 210.28.66.70210.28.66.712
147210.28.66.72/30210.28.66.73 to 210.28.66.74210.28.66.752
148210.28.66.76/30210.28.66.77 to 210.28.66.78210.28.66.792
149210.28.66.80/30210.28.66.81 to 210.28.66.82210.28.66.832
150210.28.66.84/30210.28.66.85 to 210.28.66.86210.28.66.872
151210.28.66.88/30210.28.66.89 to 210.28.66.90210.28.66.912
152210.28.66.92/30210.28.66.93 to 210.28.66.94210.28.66.952
153210.28.66.96/30210.28.66.97 to 210.28.66.98210.28.66.992
154210.28.66.100/30210.28.66.101 to 210.28.66.102210.28.66.1032
155210.28.66.104/30210.28.66.105 to 210.28.66.106210.28.66.1072
156210.28.66.108/30210.28.66.109 to 210.28.66.110210.28.66.1112
157210.28.66.112/30210.28.66.113 to 210.28.66.114210.28.66.1152
158210.28.66.116/30210.28.66.117 to 210.28.66.118210.28.66.1192
159210.28.66.120/30210.28.66.121 to 210.28.66.122210.28.66.1232
160210.28.66.124/30210.28.66.125 to 210.28.66.126210.28.66.1272
161210.28.66.128/30210.28.66.129 to 210.28.66.130210.28.66.1312
162210.28.66.132/30210.28.66.133 to 210.28.66.134210.28.66.1352
163210.28.66.136/30210.28.66.137 to 210.28.66.138210.28.66.1392
164210.28.66.140/30210.28.66.141 to 210.28.66.142210.28.66.1432
165210.28.66.144/30210.28.66.145 to 210.28.66.146210.28.66.1472
166210.28.66.148/30210.28.66.149 to 210.28.66.150210.28.66.1512
167210.28.66.152/30210.28.66.153 to 210.28.66.154210.28.66.1552
168210.28.66.156/30210.28.66.157 to 210.28.66.158210.28.66.1592
169210.28.66.160/30210.28.66.161 to 210.28.66.162210.28.66.1632
170210.28.66.164/30210.28.66.165 to 210.28.66.166210.28.66.1672
171210.28.66.168/30210.28.66.169 to 210.28.66.170210.28.66.1712
172210.28.66.172/30210.28.66.173 to 210.28.66.174210.28.66.1752
173210.28.66.176/30210.28.66.177 to 210.28.66.178210.28.66.1792
174210.28.66.180/30210.28.66.181 to 210.28.66.182210.28.66.1832
175210.28.66.184/30210.28.66.185 to 210.28.66.186210.28.66.1872
176210.28.66.188/30210.28.66.189 to 210.28.66.190210.28.66.1912
177210.28.66.192/30210.28.66.193 to 210.28.66.194210.28.66.1952
178210.28.66.196/30210.28.66.197 to 210.28.66.198210.28.66.1992
179210.28.66.200/30210.28.66.201 to 210.28.66.202210.28.66.2032
180210.28.66.204/30210.28.66.205 to 210.28.66.206210.28.66.2072
181210.28.66.208/30210.28.66.209 to 210.28.66.210210.28.66.2112
182210.28.66.212/30210.28.66.213 to 210.28.66.214210.28.66.2152
183210.28.66.216/30210.28.66.217 to 210.28.66.218210.28.66.2192
184210.28.66.220/30210.28.66.221 to 210.28.66.222210.28.66.2232
185210.28.66.224/30210.28.66.225 to 210.28.66.226210.28.66.2272
186210.28.66.228/30210.28.66.229 to 210.28.66.230210.28.66.2312
187210.28.66.232/30210.28.66.233 to 210.28.66.234210.28.66.2352
188210.28.66.236/30210.28.66.237 to 210.28.66.238210.28.66.2392
189210.28.66.240/30210.28.66.241 to 210.28.66.242210.28.66.2432
190210.28.66.244/30210.28.66.245 to 210.28.66.246210.28.66.2472
191210.28.66.248/30210.28.66.249 to 210.28.66.250210.28.66.2512
192210.28.66.252/30210.28.66.253 to 210.28.66.254210.28.66.2552
193210.28.67.0/30210.28.67.1 to 210.28.67.2210.28.67.32
194210.28.67.4/30210.28.67.5 to 210.28.67.6210.28.67.72
195210.28.67.8/30210.28.67.9 to 210.28.67.10210.28.67.112
196210.28.67.12/30210.28.67.13 to 210.28.67.14210.28.67.152
197210.28.67.16/30210.28.67.17 to 210.28.67.18210.28.67.192
198210.28.67.20/30210.28.67.21 to 210.28.67.22210.28.67.232
199210.28.67.24/30210.28.67.25 to 210.28.67.26210.28.67.272
200210.28.67.28/30210.28.67.29 to 210.28.67.30210.28.67.312
201210.28.67.32/30210.28.67.33 to 210.28.67.34210.28.67.352
202210.28.67.36/30210.28.67.37 to 210.28.67.38210.28.67.392
203210.28.67.40/30210.28.67.41 to 210.28.67.42210.28.67.432
204210.28.67.44/30210.28.67.45 to 210.28.67.46210.28.67.472
205210.28.67.48/30210.28.67.49 to 210.28.67.50210.28.67.512
206210.28.67.52/30210.28.67.53 to 210.28.67.54210.28.67.552
207210.28.67.56/30210.28.67.57 to 210.28.67.58210.28.67.592
208210.28.67.60/30210.28.67.61 to 210.28.67.62210.28.67.632
209210.28.67.64/30210.28.67.65 to 210.28.67.66210.28.67.672
210210.28.67.68/30210.28.67.69 to 210.28.67.70210.28.67.712
211210.28.67.72/30210.28.67.73 to 210.28.67.74210.28.67.752
212210.28.67.76/30210.28.67.77 to 210.28.67.78210.28.67.792
213210.28.67.80/30210.28.67.81 to 210.28.67.82210.28.67.832
214210.28.67.84/30210.28.67.85 to 210.28.67.86210.28.67.872
215210.28.67.88/30210.28.67.89 to 210.28.67.90210.28.67.912
216210.28.67.92/30210.28.67.93 to 210.28.67.94210.28.67.952
217210.28.67.96/30210.28.67.97 to 210.28.67.98210.28.67.992
218210.28.67.100/30210.28.67.101 to 210.28.67.102210.28.67.1032
219210.28.67.104/30210.28.67.105 to 210.28.67.106210.28.67.1072
220210.28.67.108/30210.28.67.109 to 210.28.67.110210.28.67.1112
221210.28.67.112/30210.28.67.113 to 210.28.67.114210.28.67.1152
222210.28.67.116/30210.28.67.117 to 210.28.67.118210.28.67.1192
223210.28.67.120/30210.28.67.121 to 210.28.67.122210.28.67.1232
224210.28.67.124/30210.28.67.125 to 210.28.67.126210.28.67.1272
225210.28.67.128/30210.28.67.129 to 210.28.67.130210.28.67.1312
226210.28.67.132/30210.28.67.133 to 210.28.67.134210.28.67.1352
227210.28.67.136/30210.28.67.137 to 210.28.67.138210.28.67.1392
228210.28.67.140/30210.28.67.141 to 210.28.67.142210.28.67.1432
229210.28.67.144/30210.28.67.145 to 210.28.67.146210.28.67.1472
230210.28.67.148/30210.28.67.149 to 210.28.67.150210.28.67.1512
231210.28.67.152/30210.28.67.153 to 210.28.67.154210.28.67.1552
232210.28.67.156/30210.28.67.157 to 210.28.67.158210.28.67.1592
233210.28.67.160/30210.28.67.161 to 210.28.67.162210.28.67.1632
234210.28.67.164/30210.28.67.165 to 210.28.67.166210.28.67.1672
235210.28.67.168/30210.28.67.169 to 210.28.67.170210.28.67.1712
236210.28.67.172/30210.28.67.173 to 210.28.67.174210.28.67.1752
237210.28.67.176/30210.28.67.177 to 210.28.67.178210.28.67.1792
238210.28.67.180/30210.28.67.181 to 210.28.67.182210.28.67.1832
239210.28.67.184/30210.28.67.185 to 210.28.67.186210.28.67.1872
240210.28.67.188/30210.28.67.189 to 210.28.67.190210.28.67.1912
241210.28.67.192/30210.28.67.193 to 210.28.67.194210.28.67.1952
242210.28.67.196/30210.28.67.197 to 210.28.67.198210.28.67.1992
243210.28.67.200/30210.28.67.201 to 210.28.67.202210.28.67.2032
244210.28.67.204/30210.28.67.205 to 210.28.67.206210.28.67.2072
245210.28.67.208/30210.28.67.209 to 210.28.67.210210.28.67.2112
246210.28.67.212/30210.28.67.213 to 210.28.67.214210.28.67.2152
247210.28.67.216/30210.28.67.217 to 210.28.67.218210.28.67.2192
248210.28.67.220/30210.28.67.221 to 210.28.67.222210.28.67.2232
249210.28.67.224/30210.28.67.225 to 210.28.67.226210.28.67.2272
250210.28.67.228/30210.28.67.229 to 210.28.67.230210.28.67.2312
251210.28.67.232/30210.28.67.233 to 210.28.67.234210.28.67.2352
252210.28.67.236/30210.28.67.237 to 210.28.67.238210.28.67.2392
253210.28.67.240/30210.28.67.241 to 210.28.67.242210.28.67.2432
254210.28.67.244/30210.28.67.245 to 210.28.67.246210.28.67.2472
255210.28.67.248/30210.28.67.249 to 210.28.67.250210.28.67.2512
256210.28.67.252/30210.28.67.253 to 210.28.67.254210.28.67.2552

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.