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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.

Network181.3.96.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
181.3.96.0
Broadcast address
181.3.127.255
First usable
181.3.96.1
Last usable
181.3.127.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
B (default /16)
As numbers
Hex B5036000 · Integer 3036897280 to 3036905471
Reverse DNS zones
96.3.181.in-addr.arpa
97.3.181.in-addr.arpa
98.3.181.in-addr.arpa
99.3.181.in-addr.arpa
100.3.181.in-addr.arpa
101.3.181.in-addr.arpa
102.3.181.in-addr.arpa
103.3.181.in-addr.arpa
104.3.181.in-addr.arpa
105.3.181.in-addr.arpa
106.3.181.in-addr.arpa
107.3.181.in-addr.arpa
108.3.181.in-addr.arpa
109.3.181.in-addr.arpa
110.3.181.in-addr.arpa
111.3.181.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110101.00000011.01100000.00000000181.3.96.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10110101.00000011.01100000.00000000181.3.96.0
Broadcast10110101.00000011.01111111.11111111181.3.127.255
Split into smaller subnets/30
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

181.3.96.0/19 makes 2,048 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1181.3.96.0/30181.3.96.1 to 181.3.96.2181.3.96.32
2181.3.96.4/30181.3.96.5 to 181.3.96.6181.3.96.72
3181.3.96.8/30181.3.96.9 to 181.3.96.10181.3.96.112
4181.3.96.12/30181.3.96.13 to 181.3.96.14181.3.96.152
5181.3.96.16/30181.3.96.17 to 181.3.96.18181.3.96.192
6181.3.96.20/30181.3.96.21 to 181.3.96.22181.3.96.232
7181.3.96.24/30181.3.96.25 to 181.3.96.26181.3.96.272
8181.3.96.28/30181.3.96.29 to 181.3.96.30181.3.96.312
9181.3.96.32/30181.3.96.33 to 181.3.96.34181.3.96.352
10181.3.96.36/30181.3.96.37 to 181.3.96.38181.3.96.392
11181.3.96.40/30181.3.96.41 to 181.3.96.42181.3.96.432
12181.3.96.44/30181.3.96.45 to 181.3.96.46181.3.96.472
13181.3.96.48/30181.3.96.49 to 181.3.96.50181.3.96.512
14181.3.96.52/30181.3.96.53 to 181.3.96.54181.3.96.552
15181.3.96.56/30181.3.96.57 to 181.3.96.58181.3.96.592
16181.3.96.60/30181.3.96.61 to 181.3.96.62181.3.96.632
17181.3.96.64/30181.3.96.65 to 181.3.96.66181.3.96.672
18181.3.96.68/30181.3.96.69 to 181.3.96.70181.3.96.712
19181.3.96.72/30181.3.96.73 to 181.3.96.74181.3.96.752
20181.3.96.76/30181.3.96.77 to 181.3.96.78181.3.96.792
21181.3.96.80/30181.3.96.81 to 181.3.96.82181.3.96.832
22181.3.96.84/30181.3.96.85 to 181.3.96.86181.3.96.872
23181.3.96.88/30181.3.96.89 to 181.3.96.90181.3.96.912
24181.3.96.92/30181.3.96.93 to 181.3.96.94181.3.96.952
25181.3.96.96/30181.3.96.97 to 181.3.96.98181.3.96.992
26181.3.96.100/30181.3.96.101 to 181.3.96.102181.3.96.1032
27181.3.96.104/30181.3.96.105 to 181.3.96.106181.3.96.1072
28181.3.96.108/30181.3.96.109 to 181.3.96.110181.3.96.1112
29181.3.96.112/30181.3.96.113 to 181.3.96.114181.3.96.1152
30181.3.96.116/30181.3.96.117 to 181.3.96.118181.3.96.1192
31181.3.96.120/30181.3.96.121 to 181.3.96.122181.3.96.1232
32181.3.96.124/30181.3.96.125 to 181.3.96.126181.3.96.1272
33181.3.96.128/30181.3.96.129 to 181.3.96.130181.3.96.1312
34181.3.96.132/30181.3.96.133 to 181.3.96.134181.3.96.1352
35181.3.96.136/30181.3.96.137 to 181.3.96.138181.3.96.1392
36181.3.96.140/30181.3.96.141 to 181.3.96.142181.3.96.1432
37181.3.96.144/30181.3.96.145 to 181.3.96.146181.3.96.1472
38181.3.96.148/30181.3.96.149 to 181.3.96.150181.3.96.1512
39181.3.96.152/30181.3.96.153 to 181.3.96.154181.3.96.1552
40181.3.96.156/30181.3.96.157 to 181.3.96.158181.3.96.1592
41181.3.96.160/30181.3.96.161 to 181.3.96.162181.3.96.1632
42181.3.96.164/30181.3.96.165 to 181.3.96.166181.3.96.1672
43181.3.96.168/30181.3.96.169 to 181.3.96.170181.3.96.1712
44181.3.96.172/30181.3.96.173 to 181.3.96.174181.3.96.1752
45181.3.96.176/30181.3.96.177 to 181.3.96.178181.3.96.1792
46181.3.96.180/30181.3.96.181 to 181.3.96.182181.3.96.1832
47181.3.96.184/30181.3.96.185 to 181.3.96.186181.3.96.1872
48181.3.96.188/30181.3.96.189 to 181.3.96.190181.3.96.1912
49181.3.96.192/30181.3.96.193 to 181.3.96.194181.3.96.1952
50181.3.96.196/30181.3.96.197 to 181.3.96.198181.3.96.1992
51181.3.96.200/30181.3.96.201 to 181.3.96.202181.3.96.2032
52181.3.96.204/30181.3.96.205 to 181.3.96.206181.3.96.2072
53181.3.96.208/30181.3.96.209 to 181.3.96.210181.3.96.2112
54181.3.96.212/30181.3.96.213 to 181.3.96.214181.3.96.2152
55181.3.96.216/30181.3.96.217 to 181.3.96.218181.3.96.2192
56181.3.96.220/30181.3.96.221 to 181.3.96.222181.3.96.2232
57181.3.96.224/30181.3.96.225 to 181.3.96.226181.3.96.2272
58181.3.96.228/30181.3.96.229 to 181.3.96.230181.3.96.2312
59181.3.96.232/30181.3.96.233 to 181.3.96.234181.3.96.2352
60181.3.96.236/30181.3.96.237 to 181.3.96.238181.3.96.2392
61181.3.96.240/30181.3.96.241 to 181.3.96.242181.3.96.2432
62181.3.96.244/30181.3.96.245 to 181.3.96.246181.3.96.2472
63181.3.96.248/30181.3.96.249 to 181.3.96.250181.3.96.2512
64181.3.96.252/30181.3.96.253 to 181.3.96.254181.3.96.2552
65181.3.97.0/30181.3.97.1 to 181.3.97.2181.3.97.32
66181.3.97.4/30181.3.97.5 to 181.3.97.6181.3.97.72
67181.3.97.8/30181.3.97.9 to 181.3.97.10181.3.97.112
68181.3.97.12/30181.3.97.13 to 181.3.97.14181.3.97.152
69181.3.97.16/30181.3.97.17 to 181.3.97.18181.3.97.192
70181.3.97.20/30181.3.97.21 to 181.3.97.22181.3.97.232
71181.3.97.24/30181.3.97.25 to 181.3.97.26181.3.97.272
72181.3.97.28/30181.3.97.29 to 181.3.97.30181.3.97.312
73181.3.97.32/30181.3.97.33 to 181.3.97.34181.3.97.352
74181.3.97.36/30181.3.97.37 to 181.3.97.38181.3.97.392
75181.3.97.40/30181.3.97.41 to 181.3.97.42181.3.97.432
76181.3.97.44/30181.3.97.45 to 181.3.97.46181.3.97.472
77181.3.97.48/30181.3.97.49 to 181.3.97.50181.3.97.512
78181.3.97.52/30181.3.97.53 to 181.3.97.54181.3.97.552
79181.3.97.56/30181.3.97.57 to 181.3.97.58181.3.97.592
80181.3.97.60/30181.3.97.61 to 181.3.97.62181.3.97.632
81181.3.97.64/30181.3.97.65 to 181.3.97.66181.3.97.672
82181.3.97.68/30181.3.97.69 to 181.3.97.70181.3.97.712
83181.3.97.72/30181.3.97.73 to 181.3.97.74181.3.97.752
84181.3.97.76/30181.3.97.77 to 181.3.97.78181.3.97.792
85181.3.97.80/30181.3.97.81 to 181.3.97.82181.3.97.832
86181.3.97.84/30181.3.97.85 to 181.3.97.86181.3.97.872
87181.3.97.88/30181.3.97.89 to 181.3.97.90181.3.97.912
88181.3.97.92/30181.3.97.93 to 181.3.97.94181.3.97.952
89181.3.97.96/30181.3.97.97 to 181.3.97.98181.3.97.992
90181.3.97.100/30181.3.97.101 to 181.3.97.102181.3.97.1032
91181.3.97.104/30181.3.97.105 to 181.3.97.106181.3.97.1072
92181.3.97.108/30181.3.97.109 to 181.3.97.110181.3.97.1112
93181.3.97.112/30181.3.97.113 to 181.3.97.114181.3.97.1152
94181.3.97.116/30181.3.97.117 to 181.3.97.118181.3.97.1192
95181.3.97.120/30181.3.97.121 to 181.3.97.122181.3.97.1232
96181.3.97.124/30181.3.97.125 to 181.3.97.126181.3.97.1272
97181.3.97.128/30181.3.97.129 to 181.3.97.130181.3.97.1312
98181.3.97.132/30181.3.97.133 to 181.3.97.134181.3.97.1352
99181.3.97.136/30181.3.97.137 to 181.3.97.138181.3.97.1392
100181.3.97.140/30181.3.97.141 to 181.3.97.142181.3.97.1432
101181.3.97.144/30181.3.97.145 to 181.3.97.146181.3.97.1472
102181.3.97.148/30181.3.97.149 to 181.3.97.150181.3.97.1512
103181.3.97.152/30181.3.97.153 to 181.3.97.154181.3.97.1552
104181.3.97.156/30181.3.97.157 to 181.3.97.158181.3.97.1592
105181.3.97.160/30181.3.97.161 to 181.3.97.162181.3.97.1632
106181.3.97.164/30181.3.97.165 to 181.3.97.166181.3.97.1672
107181.3.97.168/30181.3.97.169 to 181.3.97.170181.3.97.1712
108181.3.97.172/30181.3.97.173 to 181.3.97.174181.3.97.1752
109181.3.97.176/30181.3.97.177 to 181.3.97.178181.3.97.1792
110181.3.97.180/30181.3.97.181 to 181.3.97.182181.3.97.1832
111181.3.97.184/30181.3.97.185 to 181.3.97.186181.3.97.1872
112181.3.97.188/30181.3.97.189 to 181.3.97.190181.3.97.1912
113181.3.97.192/30181.3.97.193 to 181.3.97.194181.3.97.1952
114181.3.97.196/30181.3.97.197 to 181.3.97.198181.3.97.1992
115181.3.97.200/30181.3.97.201 to 181.3.97.202181.3.97.2032
116181.3.97.204/30181.3.97.205 to 181.3.97.206181.3.97.2072
117181.3.97.208/30181.3.97.209 to 181.3.97.210181.3.97.2112
118181.3.97.212/30181.3.97.213 to 181.3.97.214181.3.97.2152
119181.3.97.216/30181.3.97.217 to 181.3.97.218181.3.97.2192
120181.3.97.220/30181.3.97.221 to 181.3.97.222181.3.97.2232
121181.3.97.224/30181.3.97.225 to 181.3.97.226181.3.97.2272
122181.3.97.228/30181.3.97.229 to 181.3.97.230181.3.97.2312
123181.3.97.232/30181.3.97.233 to 181.3.97.234181.3.97.2352
124181.3.97.236/30181.3.97.237 to 181.3.97.238181.3.97.2392
125181.3.97.240/30181.3.97.241 to 181.3.97.242181.3.97.2432
126181.3.97.244/30181.3.97.245 to 181.3.97.246181.3.97.2472
127181.3.97.248/30181.3.97.249 to 181.3.97.250181.3.97.2512
128181.3.97.252/30181.3.97.253 to 181.3.97.254181.3.97.2552
129181.3.98.0/30181.3.98.1 to 181.3.98.2181.3.98.32
130181.3.98.4/30181.3.98.5 to 181.3.98.6181.3.98.72
131181.3.98.8/30181.3.98.9 to 181.3.98.10181.3.98.112
132181.3.98.12/30181.3.98.13 to 181.3.98.14181.3.98.152
133181.3.98.16/30181.3.98.17 to 181.3.98.18181.3.98.192
134181.3.98.20/30181.3.98.21 to 181.3.98.22181.3.98.232
135181.3.98.24/30181.3.98.25 to 181.3.98.26181.3.98.272
136181.3.98.28/30181.3.98.29 to 181.3.98.30181.3.98.312
137181.3.98.32/30181.3.98.33 to 181.3.98.34181.3.98.352
138181.3.98.36/30181.3.98.37 to 181.3.98.38181.3.98.392
139181.3.98.40/30181.3.98.41 to 181.3.98.42181.3.98.432
140181.3.98.44/30181.3.98.45 to 181.3.98.46181.3.98.472
141181.3.98.48/30181.3.98.49 to 181.3.98.50181.3.98.512
142181.3.98.52/30181.3.98.53 to 181.3.98.54181.3.98.552
143181.3.98.56/30181.3.98.57 to 181.3.98.58181.3.98.592
144181.3.98.60/30181.3.98.61 to 181.3.98.62181.3.98.632
145181.3.98.64/30181.3.98.65 to 181.3.98.66181.3.98.672
146181.3.98.68/30181.3.98.69 to 181.3.98.70181.3.98.712
147181.3.98.72/30181.3.98.73 to 181.3.98.74181.3.98.752
148181.3.98.76/30181.3.98.77 to 181.3.98.78181.3.98.792
149181.3.98.80/30181.3.98.81 to 181.3.98.82181.3.98.832
150181.3.98.84/30181.3.98.85 to 181.3.98.86181.3.98.872
151181.3.98.88/30181.3.98.89 to 181.3.98.90181.3.98.912
152181.3.98.92/30181.3.98.93 to 181.3.98.94181.3.98.952
153181.3.98.96/30181.3.98.97 to 181.3.98.98181.3.98.992
154181.3.98.100/30181.3.98.101 to 181.3.98.102181.3.98.1032
155181.3.98.104/30181.3.98.105 to 181.3.98.106181.3.98.1072
156181.3.98.108/30181.3.98.109 to 181.3.98.110181.3.98.1112
157181.3.98.112/30181.3.98.113 to 181.3.98.114181.3.98.1152
158181.3.98.116/30181.3.98.117 to 181.3.98.118181.3.98.1192
159181.3.98.120/30181.3.98.121 to 181.3.98.122181.3.98.1232
160181.3.98.124/30181.3.98.125 to 181.3.98.126181.3.98.1272
161181.3.98.128/30181.3.98.129 to 181.3.98.130181.3.98.1312
162181.3.98.132/30181.3.98.133 to 181.3.98.134181.3.98.1352
163181.3.98.136/30181.3.98.137 to 181.3.98.138181.3.98.1392
164181.3.98.140/30181.3.98.141 to 181.3.98.142181.3.98.1432
165181.3.98.144/30181.3.98.145 to 181.3.98.146181.3.98.1472
166181.3.98.148/30181.3.98.149 to 181.3.98.150181.3.98.1512
167181.3.98.152/30181.3.98.153 to 181.3.98.154181.3.98.1552
168181.3.98.156/30181.3.98.157 to 181.3.98.158181.3.98.1592
169181.3.98.160/30181.3.98.161 to 181.3.98.162181.3.98.1632
170181.3.98.164/30181.3.98.165 to 181.3.98.166181.3.98.1672
171181.3.98.168/30181.3.98.169 to 181.3.98.170181.3.98.1712
172181.3.98.172/30181.3.98.173 to 181.3.98.174181.3.98.1752
173181.3.98.176/30181.3.98.177 to 181.3.98.178181.3.98.1792
174181.3.98.180/30181.3.98.181 to 181.3.98.182181.3.98.1832
175181.3.98.184/30181.3.98.185 to 181.3.98.186181.3.98.1872
176181.3.98.188/30181.3.98.189 to 181.3.98.190181.3.98.1912
177181.3.98.192/30181.3.98.193 to 181.3.98.194181.3.98.1952
178181.3.98.196/30181.3.98.197 to 181.3.98.198181.3.98.1992
179181.3.98.200/30181.3.98.201 to 181.3.98.202181.3.98.2032
180181.3.98.204/30181.3.98.205 to 181.3.98.206181.3.98.2072
181181.3.98.208/30181.3.98.209 to 181.3.98.210181.3.98.2112
182181.3.98.212/30181.3.98.213 to 181.3.98.214181.3.98.2152
183181.3.98.216/30181.3.98.217 to 181.3.98.218181.3.98.2192
184181.3.98.220/30181.3.98.221 to 181.3.98.222181.3.98.2232
185181.3.98.224/30181.3.98.225 to 181.3.98.226181.3.98.2272
186181.3.98.228/30181.3.98.229 to 181.3.98.230181.3.98.2312
187181.3.98.232/30181.3.98.233 to 181.3.98.234181.3.98.2352
188181.3.98.236/30181.3.98.237 to 181.3.98.238181.3.98.2392
189181.3.98.240/30181.3.98.241 to 181.3.98.242181.3.98.2432
190181.3.98.244/30181.3.98.245 to 181.3.98.246181.3.98.2472
191181.3.98.248/30181.3.98.249 to 181.3.98.250181.3.98.2512
192181.3.98.252/30181.3.98.253 to 181.3.98.254181.3.98.2552
193181.3.99.0/30181.3.99.1 to 181.3.99.2181.3.99.32
194181.3.99.4/30181.3.99.5 to 181.3.99.6181.3.99.72
195181.3.99.8/30181.3.99.9 to 181.3.99.10181.3.99.112
196181.3.99.12/30181.3.99.13 to 181.3.99.14181.3.99.152
197181.3.99.16/30181.3.99.17 to 181.3.99.18181.3.99.192
198181.3.99.20/30181.3.99.21 to 181.3.99.22181.3.99.232
199181.3.99.24/30181.3.99.25 to 181.3.99.26181.3.99.272
200181.3.99.28/30181.3.99.29 to 181.3.99.30181.3.99.312
201181.3.99.32/30181.3.99.33 to 181.3.99.34181.3.99.352
202181.3.99.36/30181.3.99.37 to 181.3.99.38181.3.99.392
203181.3.99.40/30181.3.99.41 to 181.3.99.42181.3.99.432
204181.3.99.44/30181.3.99.45 to 181.3.99.46181.3.99.472
205181.3.99.48/30181.3.99.49 to 181.3.99.50181.3.99.512
206181.3.99.52/30181.3.99.53 to 181.3.99.54181.3.99.552
207181.3.99.56/30181.3.99.57 to 181.3.99.58181.3.99.592
208181.3.99.60/30181.3.99.61 to 181.3.99.62181.3.99.632
209181.3.99.64/30181.3.99.65 to 181.3.99.66181.3.99.672
210181.3.99.68/30181.3.99.69 to 181.3.99.70181.3.99.712
211181.3.99.72/30181.3.99.73 to 181.3.99.74181.3.99.752
212181.3.99.76/30181.3.99.77 to 181.3.99.78181.3.99.792
213181.3.99.80/30181.3.99.81 to 181.3.99.82181.3.99.832
214181.3.99.84/30181.3.99.85 to 181.3.99.86181.3.99.872
215181.3.99.88/30181.3.99.89 to 181.3.99.90181.3.99.912
216181.3.99.92/30181.3.99.93 to 181.3.99.94181.3.99.952
217181.3.99.96/30181.3.99.97 to 181.3.99.98181.3.99.992
218181.3.99.100/30181.3.99.101 to 181.3.99.102181.3.99.1032
219181.3.99.104/30181.3.99.105 to 181.3.99.106181.3.99.1072
220181.3.99.108/30181.3.99.109 to 181.3.99.110181.3.99.1112
221181.3.99.112/30181.3.99.113 to 181.3.99.114181.3.99.1152
222181.3.99.116/30181.3.99.117 to 181.3.99.118181.3.99.1192
223181.3.99.120/30181.3.99.121 to 181.3.99.122181.3.99.1232
224181.3.99.124/30181.3.99.125 to 181.3.99.126181.3.99.1272
225181.3.99.128/30181.3.99.129 to 181.3.99.130181.3.99.1312
226181.3.99.132/30181.3.99.133 to 181.3.99.134181.3.99.1352
227181.3.99.136/30181.3.99.137 to 181.3.99.138181.3.99.1392
228181.3.99.140/30181.3.99.141 to 181.3.99.142181.3.99.1432
229181.3.99.144/30181.3.99.145 to 181.3.99.146181.3.99.1472
230181.3.99.148/30181.3.99.149 to 181.3.99.150181.3.99.1512
231181.3.99.152/30181.3.99.153 to 181.3.99.154181.3.99.1552
232181.3.99.156/30181.3.99.157 to 181.3.99.158181.3.99.1592
233181.3.99.160/30181.3.99.161 to 181.3.99.162181.3.99.1632
234181.3.99.164/30181.3.99.165 to 181.3.99.166181.3.99.1672
235181.3.99.168/30181.3.99.169 to 181.3.99.170181.3.99.1712
236181.3.99.172/30181.3.99.173 to 181.3.99.174181.3.99.1752
237181.3.99.176/30181.3.99.177 to 181.3.99.178181.3.99.1792
238181.3.99.180/30181.3.99.181 to 181.3.99.182181.3.99.1832
239181.3.99.184/30181.3.99.185 to 181.3.99.186181.3.99.1872
240181.3.99.188/30181.3.99.189 to 181.3.99.190181.3.99.1912
241181.3.99.192/30181.3.99.193 to 181.3.99.194181.3.99.1952
242181.3.99.196/30181.3.99.197 to 181.3.99.198181.3.99.1992
243181.3.99.200/30181.3.99.201 to 181.3.99.202181.3.99.2032
244181.3.99.204/30181.3.99.205 to 181.3.99.206181.3.99.2072
245181.3.99.208/30181.3.99.209 to 181.3.99.210181.3.99.2112
246181.3.99.212/30181.3.99.213 to 181.3.99.214181.3.99.2152
247181.3.99.216/30181.3.99.217 to 181.3.99.218181.3.99.2192
248181.3.99.220/30181.3.99.221 to 181.3.99.222181.3.99.2232
249181.3.99.224/30181.3.99.225 to 181.3.99.226181.3.99.2272
250181.3.99.228/30181.3.99.229 to 181.3.99.230181.3.99.2312
251181.3.99.232/30181.3.99.233 to 181.3.99.234181.3.99.2352
252181.3.99.236/30181.3.99.237 to 181.3.99.238181.3.99.2392
253181.3.99.240/30181.3.99.241 to 181.3.99.242181.3.99.2432
254181.3.99.244/30181.3.99.245 to 181.3.99.246181.3.99.2472
255181.3.99.248/30181.3.99.249 to 181.3.99.250181.3.99.2512
256181.3.99.252/30181.3.99.253 to 181.3.99.254181.3.99.2552

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.