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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.

Network170.2.96.0/20
Usable hosts4,094
Subnet mask255.255.240.0
Addresses4,096
Network address
170.2.96.0
Broadcast address
170.2.111.255
First usable
170.2.96.1
Last usable
170.2.111.254
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
Public public
Old class
B (default /16)
As numbers
Hex AA026000 · Integer 2852282368 to 2852286463
Reverse DNS zones
96.2.170.in-addr.arpa
97.2.170.in-addr.arpa
98.2.170.in-addr.arpa
99.2.170.in-addr.arpa
100.2.170.in-addr.arpa
101.2.170.in-addr.arpa
102.2.170.in-addr.arpa
103.2.170.in-addr.arpa
104.2.170.in-addr.arpa
105.2.170.in-addr.arpa
106.2.170.in-addr.arpa
107.2.170.in-addr.arpa
108.2.170.in-addr.arpa
109.2.170.in-addr.arpa
110.2.170.in-addr.arpa
111.2.170.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
Address10101010.00000010.01100000.00000000170.2.96.0
Subnet mask11111111.11111111.11110000.00000000255.255.240.0
Network10101010.00000010.01100000.00000000170.2.96.0
Broadcast10101010.00000010.01101111.11111111170.2.111.255
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)

170.2.96.0/20 makes 1,024 subnets of /30; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1170.2.96.0/30170.2.96.1 to 170.2.96.2170.2.96.32
2170.2.96.4/30170.2.96.5 to 170.2.96.6170.2.96.72
3170.2.96.8/30170.2.96.9 to 170.2.96.10170.2.96.112
4170.2.96.12/30170.2.96.13 to 170.2.96.14170.2.96.152
5170.2.96.16/30170.2.96.17 to 170.2.96.18170.2.96.192
6170.2.96.20/30170.2.96.21 to 170.2.96.22170.2.96.232
7170.2.96.24/30170.2.96.25 to 170.2.96.26170.2.96.272
8170.2.96.28/30170.2.96.29 to 170.2.96.30170.2.96.312
9170.2.96.32/30170.2.96.33 to 170.2.96.34170.2.96.352
10170.2.96.36/30170.2.96.37 to 170.2.96.38170.2.96.392
11170.2.96.40/30170.2.96.41 to 170.2.96.42170.2.96.432
12170.2.96.44/30170.2.96.45 to 170.2.96.46170.2.96.472
13170.2.96.48/30170.2.96.49 to 170.2.96.50170.2.96.512
14170.2.96.52/30170.2.96.53 to 170.2.96.54170.2.96.552
15170.2.96.56/30170.2.96.57 to 170.2.96.58170.2.96.592
16170.2.96.60/30170.2.96.61 to 170.2.96.62170.2.96.632
17170.2.96.64/30170.2.96.65 to 170.2.96.66170.2.96.672
18170.2.96.68/30170.2.96.69 to 170.2.96.70170.2.96.712
19170.2.96.72/30170.2.96.73 to 170.2.96.74170.2.96.752
20170.2.96.76/30170.2.96.77 to 170.2.96.78170.2.96.792
21170.2.96.80/30170.2.96.81 to 170.2.96.82170.2.96.832
22170.2.96.84/30170.2.96.85 to 170.2.96.86170.2.96.872
23170.2.96.88/30170.2.96.89 to 170.2.96.90170.2.96.912
24170.2.96.92/30170.2.96.93 to 170.2.96.94170.2.96.952
25170.2.96.96/30170.2.96.97 to 170.2.96.98170.2.96.992
26170.2.96.100/30170.2.96.101 to 170.2.96.102170.2.96.1032
27170.2.96.104/30170.2.96.105 to 170.2.96.106170.2.96.1072
28170.2.96.108/30170.2.96.109 to 170.2.96.110170.2.96.1112
29170.2.96.112/30170.2.96.113 to 170.2.96.114170.2.96.1152
30170.2.96.116/30170.2.96.117 to 170.2.96.118170.2.96.1192
31170.2.96.120/30170.2.96.121 to 170.2.96.122170.2.96.1232
32170.2.96.124/30170.2.96.125 to 170.2.96.126170.2.96.1272
33170.2.96.128/30170.2.96.129 to 170.2.96.130170.2.96.1312
34170.2.96.132/30170.2.96.133 to 170.2.96.134170.2.96.1352
35170.2.96.136/30170.2.96.137 to 170.2.96.138170.2.96.1392
36170.2.96.140/30170.2.96.141 to 170.2.96.142170.2.96.1432
37170.2.96.144/30170.2.96.145 to 170.2.96.146170.2.96.1472
38170.2.96.148/30170.2.96.149 to 170.2.96.150170.2.96.1512
39170.2.96.152/30170.2.96.153 to 170.2.96.154170.2.96.1552
40170.2.96.156/30170.2.96.157 to 170.2.96.158170.2.96.1592
41170.2.96.160/30170.2.96.161 to 170.2.96.162170.2.96.1632
42170.2.96.164/30170.2.96.165 to 170.2.96.166170.2.96.1672
43170.2.96.168/30170.2.96.169 to 170.2.96.170170.2.96.1712
44170.2.96.172/30170.2.96.173 to 170.2.96.174170.2.96.1752
45170.2.96.176/30170.2.96.177 to 170.2.96.178170.2.96.1792
46170.2.96.180/30170.2.96.181 to 170.2.96.182170.2.96.1832
47170.2.96.184/30170.2.96.185 to 170.2.96.186170.2.96.1872
48170.2.96.188/30170.2.96.189 to 170.2.96.190170.2.96.1912
49170.2.96.192/30170.2.96.193 to 170.2.96.194170.2.96.1952
50170.2.96.196/30170.2.96.197 to 170.2.96.198170.2.96.1992
51170.2.96.200/30170.2.96.201 to 170.2.96.202170.2.96.2032
52170.2.96.204/30170.2.96.205 to 170.2.96.206170.2.96.2072
53170.2.96.208/30170.2.96.209 to 170.2.96.210170.2.96.2112
54170.2.96.212/30170.2.96.213 to 170.2.96.214170.2.96.2152
55170.2.96.216/30170.2.96.217 to 170.2.96.218170.2.96.2192
56170.2.96.220/30170.2.96.221 to 170.2.96.222170.2.96.2232
57170.2.96.224/30170.2.96.225 to 170.2.96.226170.2.96.2272
58170.2.96.228/30170.2.96.229 to 170.2.96.230170.2.96.2312
59170.2.96.232/30170.2.96.233 to 170.2.96.234170.2.96.2352
60170.2.96.236/30170.2.96.237 to 170.2.96.238170.2.96.2392
61170.2.96.240/30170.2.96.241 to 170.2.96.242170.2.96.2432
62170.2.96.244/30170.2.96.245 to 170.2.96.246170.2.96.2472
63170.2.96.248/30170.2.96.249 to 170.2.96.250170.2.96.2512
64170.2.96.252/30170.2.96.253 to 170.2.96.254170.2.96.2552
65170.2.97.0/30170.2.97.1 to 170.2.97.2170.2.97.32
66170.2.97.4/30170.2.97.5 to 170.2.97.6170.2.97.72
67170.2.97.8/30170.2.97.9 to 170.2.97.10170.2.97.112
68170.2.97.12/30170.2.97.13 to 170.2.97.14170.2.97.152
69170.2.97.16/30170.2.97.17 to 170.2.97.18170.2.97.192
70170.2.97.20/30170.2.97.21 to 170.2.97.22170.2.97.232
71170.2.97.24/30170.2.97.25 to 170.2.97.26170.2.97.272
72170.2.97.28/30170.2.97.29 to 170.2.97.30170.2.97.312
73170.2.97.32/30170.2.97.33 to 170.2.97.34170.2.97.352
74170.2.97.36/30170.2.97.37 to 170.2.97.38170.2.97.392
75170.2.97.40/30170.2.97.41 to 170.2.97.42170.2.97.432
76170.2.97.44/30170.2.97.45 to 170.2.97.46170.2.97.472
77170.2.97.48/30170.2.97.49 to 170.2.97.50170.2.97.512
78170.2.97.52/30170.2.97.53 to 170.2.97.54170.2.97.552
79170.2.97.56/30170.2.97.57 to 170.2.97.58170.2.97.592
80170.2.97.60/30170.2.97.61 to 170.2.97.62170.2.97.632
81170.2.97.64/30170.2.97.65 to 170.2.97.66170.2.97.672
82170.2.97.68/30170.2.97.69 to 170.2.97.70170.2.97.712
83170.2.97.72/30170.2.97.73 to 170.2.97.74170.2.97.752
84170.2.97.76/30170.2.97.77 to 170.2.97.78170.2.97.792
85170.2.97.80/30170.2.97.81 to 170.2.97.82170.2.97.832
86170.2.97.84/30170.2.97.85 to 170.2.97.86170.2.97.872
87170.2.97.88/30170.2.97.89 to 170.2.97.90170.2.97.912
88170.2.97.92/30170.2.97.93 to 170.2.97.94170.2.97.952
89170.2.97.96/30170.2.97.97 to 170.2.97.98170.2.97.992
90170.2.97.100/30170.2.97.101 to 170.2.97.102170.2.97.1032
91170.2.97.104/30170.2.97.105 to 170.2.97.106170.2.97.1072
92170.2.97.108/30170.2.97.109 to 170.2.97.110170.2.97.1112
93170.2.97.112/30170.2.97.113 to 170.2.97.114170.2.97.1152
94170.2.97.116/30170.2.97.117 to 170.2.97.118170.2.97.1192
95170.2.97.120/30170.2.97.121 to 170.2.97.122170.2.97.1232
96170.2.97.124/30170.2.97.125 to 170.2.97.126170.2.97.1272
97170.2.97.128/30170.2.97.129 to 170.2.97.130170.2.97.1312
98170.2.97.132/30170.2.97.133 to 170.2.97.134170.2.97.1352
99170.2.97.136/30170.2.97.137 to 170.2.97.138170.2.97.1392
100170.2.97.140/30170.2.97.141 to 170.2.97.142170.2.97.1432
101170.2.97.144/30170.2.97.145 to 170.2.97.146170.2.97.1472
102170.2.97.148/30170.2.97.149 to 170.2.97.150170.2.97.1512
103170.2.97.152/30170.2.97.153 to 170.2.97.154170.2.97.1552
104170.2.97.156/30170.2.97.157 to 170.2.97.158170.2.97.1592
105170.2.97.160/30170.2.97.161 to 170.2.97.162170.2.97.1632
106170.2.97.164/30170.2.97.165 to 170.2.97.166170.2.97.1672
107170.2.97.168/30170.2.97.169 to 170.2.97.170170.2.97.1712
108170.2.97.172/30170.2.97.173 to 170.2.97.174170.2.97.1752
109170.2.97.176/30170.2.97.177 to 170.2.97.178170.2.97.1792
110170.2.97.180/30170.2.97.181 to 170.2.97.182170.2.97.1832
111170.2.97.184/30170.2.97.185 to 170.2.97.186170.2.97.1872
112170.2.97.188/30170.2.97.189 to 170.2.97.190170.2.97.1912
113170.2.97.192/30170.2.97.193 to 170.2.97.194170.2.97.1952
114170.2.97.196/30170.2.97.197 to 170.2.97.198170.2.97.1992
115170.2.97.200/30170.2.97.201 to 170.2.97.202170.2.97.2032
116170.2.97.204/30170.2.97.205 to 170.2.97.206170.2.97.2072
117170.2.97.208/30170.2.97.209 to 170.2.97.210170.2.97.2112
118170.2.97.212/30170.2.97.213 to 170.2.97.214170.2.97.2152
119170.2.97.216/30170.2.97.217 to 170.2.97.218170.2.97.2192
120170.2.97.220/30170.2.97.221 to 170.2.97.222170.2.97.2232
121170.2.97.224/30170.2.97.225 to 170.2.97.226170.2.97.2272
122170.2.97.228/30170.2.97.229 to 170.2.97.230170.2.97.2312
123170.2.97.232/30170.2.97.233 to 170.2.97.234170.2.97.2352
124170.2.97.236/30170.2.97.237 to 170.2.97.238170.2.97.2392
125170.2.97.240/30170.2.97.241 to 170.2.97.242170.2.97.2432
126170.2.97.244/30170.2.97.245 to 170.2.97.246170.2.97.2472
127170.2.97.248/30170.2.97.249 to 170.2.97.250170.2.97.2512
128170.2.97.252/30170.2.97.253 to 170.2.97.254170.2.97.2552
129170.2.98.0/30170.2.98.1 to 170.2.98.2170.2.98.32
130170.2.98.4/30170.2.98.5 to 170.2.98.6170.2.98.72
131170.2.98.8/30170.2.98.9 to 170.2.98.10170.2.98.112
132170.2.98.12/30170.2.98.13 to 170.2.98.14170.2.98.152
133170.2.98.16/30170.2.98.17 to 170.2.98.18170.2.98.192
134170.2.98.20/30170.2.98.21 to 170.2.98.22170.2.98.232
135170.2.98.24/30170.2.98.25 to 170.2.98.26170.2.98.272
136170.2.98.28/30170.2.98.29 to 170.2.98.30170.2.98.312
137170.2.98.32/30170.2.98.33 to 170.2.98.34170.2.98.352
138170.2.98.36/30170.2.98.37 to 170.2.98.38170.2.98.392
139170.2.98.40/30170.2.98.41 to 170.2.98.42170.2.98.432
140170.2.98.44/30170.2.98.45 to 170.2.98.46170.2.98.472
141170.2.98.48/30170.2.98.49 to 170.2.98.50170.2.98.512
142170.2.98.52/30170.2.98.53 to 170.2.98.54170.2.98.552
143170.2.98.56/30170.2.98.57 to 170.2.98.58170.2.98.592
144170.2.98.60/30170.2.98.61 to 170.2.98.62170.2.98.632
145170.2.98.64/30170.2.98.65 to 170.2.98.66170.2.98.672
146170.2.98.68/30170.2.98.69 to 170.2.98.70170.2.98.712
147170.2.98.72/30170.2.98.73 to 170.2.98.74170.2.98.752
148170.2.98.76/30170.2.98.77 to 170.2.98.78170.2.98.792
149170.2.98.80/30170.2.98.81 to 170.2.98.82170.2.98.832
150170.2.98.84/30170.2.98.85 to 170.2.98.86170.2.98.872
151170.2.98.88/30170.2.98.89 to 170.2.98.90170.2.98.912
152170.2.98.92/30170.2.98.93 to 170.2.98.94170.2.98.952
153170.2.98.96/30170.2.98.97 to 170.2.98.98170.2.98.992
154170.2.98.100/30170.2.98.101 to 170.2.98.102170.2.98.1032
155170.2.98.104/30170.2.98.105 to 170.2.98.106170.2.98.1072
156170.2.98.108/30170.2.98.109 to 170.2.98.110170.2.98.1112
157170.2.98.112/30170.2.98.113 to 170.2.98.114170.2.98.1152
158170.2.98.116/30170.2.98.117 to 170.2.98.118170.2.98.1192
159170.2.98.120/30170.2.98.121 to 170.2.98.122170.2.98.1232
160170.2.98.124/30170.2.98.125 to 170.2.98.126170.2.98.1272
161170.2.98.128/30170.2.98.129 to 170.2.98.130170.2.98.1312
162170.2.98.132/30170.2.98.133 to 170.2.98.134170.2.98.1352
163170.2.98.136/30170.2.98.137 to 170.2.98.138170.2.98.1392
164170.2.98.140/30170.2.98.141 to 170.2.98.142170.2.98.1432
165170.2.98.144/30170.2.98.145 to 170.2.98.146170.2.98.1472
166170.2.98.148/30170.2.98.149 to 170.2.98.150170.2.98.1512
167170.2.98.152/30170.2.98.153 to 170.2.98.154170.2.98.1552
168170.2.98.156/30170.2.98.157 to 170.2.98.158170.2.98.1592
169170.2.98.160/30170.2.98.161 to 170.2.98.162170.2.98.1632
170170.2.98.164/30170.2.98.165 to 170.2.98.166170.2.98.1672
171170.2.98.168/30170.2.98.169 to 170.2.98.170170.2.98.1712
172170.2.98.172/30170.2.98.173 to 170.2.98.174170.2.98.1752
173170.2.98.176/30170.2.98.177 to 170.2.98.178170.2.98.1792
174170.2.98.180/30170.2.98.181 to 170.2.98.182170.2.98.1832
175170.2.98.184/30170.2.98.185 to 170.2.98.186170.2.98.1872
176170.2.98.188/30170.2.98.189 to 170.2.98.190170.2.98.1912
177170.2.98.192/30170.2.98.193 to 170.2.98.194170.2.98.1952
178170.2.98.196/30170.2.98.197 to 170.2.98.198170.2.98.1992
179170.2.98.200/30170.2.98.201 to 170.2.98.202170.2.98.2032
180170.2.98.204/30170.2.98.205 to 170.2.98.206170.2.98.2072
181170.2.98.208/30170.2.98.209 to 170.2.98.210170.2.98.2112
182170.2.98.212/30170.2.98.213 to 170.2.98.214170.2.98.2152
183170.2.98.216/30170.2.98.217 to 170.2.98.218170.2.98.2192
184170.2.98.220/30170.2.98.221 to 170.2.98.222170.2.98.2232
185170.2.98.224/30170.2.98.225 to 170.2.98.226170.2.98.2272
186170.2.98.228/30170.2.98.229 to 170.2.98.230170.2.98.2312
187170.2.98.232/30170.2.98.233 to 170.2.98.234170.2.98.2352
188170.2.98.236/30170.2.98.237 to 170.2.98.238170.2.98.2392
189170.2.98.240/30170.2.98.241 to 170.2.98.242170.2.98.2432
190170.2.98.244/30170.2.98.245 to 170.2.98.246170.2.98.2472
191170.2.98.248/30170.2.98.249 to 170.2.98.250170.2.98.2512
192170.2.98.252/30170.2.98.253 to 170.2.98.254170.2.98.2552
193170.2.99.0/30170.2.99.1 to 170.2.99.2170.2.99.32
194170.2.99.4/30170.2.99.5 to 170.2.99.6170.2.99.72
195170.2.99.8/30170.2.99.9 to 170.2.99.10170.2.99.112
196170.2.99.12/30170.2.99.13 to 170.2.99.14170.2.99.152
197170.2.99.16/30170.2.99.17 to 170.2.99.18170.2.99.192
198170.2.99.20/30170.2.99.21 to 170.2.99.22170.2.99.232
199170.2.99.24/30170.2.99.25 to 170.2.99.26170.2.99.272
200170.2.99.28/30170.2.99.29 to 170.2.99.30170.2.99.312
201170.2.99.32/30170.2.99.33 to 170.2.99.34170.2.99.352
202170.2.99.36/30170.2.99.37 to 170.2.99.38170.2.99.392
203170.2.99.40/30170.2.99.41 to 170.2.99.42170.2.99.432
204170.2.99.44/30170.2.99.45 to 170.2.99.46170.2.99.472
205170.2.99.48/30170.2.99.49 to 170.2.99.50170.2.99.512
206170.2.99.52/30170.2.99.53 to 170.2.99.54170.2.99.552
207170.2.99.56/30170.2.99.57 to 170.2.99.58170.2.99.592
208170.2.99.60/30170.2.99.61 to 170.2.99.62170.2.99.632
209170.2.99.64/30170.2.99.65 to 170.2.99.66170.2.99.672
210170.2.99.68/30170.2.99.69 to 170.2.99.70170.2.99.712
211170.2.99.72/30170.2.99.73 to 170.2.99.74170.2.99.752
212170.2.99.76/30170.2.99.77 to 170.2.99.78170.2.99.792
213170.2.99.80/30170.2.99.81 to 170.2.99.82170.2.99.832
214170.2.99.84/30170.2.99.85 to 170.2.99.86170.2.99.872
215170.2.99.88/30170.2.99.89 to 170.2.99.90170.2.99.912
216170.2.99.92/30170.2.99.93 to 170.2.99.94170.2.99.952
217170.2.99.96/30170.2.99.97 to 170.2.99.98170.2.99.992
218170.2.99.100/30170.2.99.101 to 170.2.99.102170.2.99.1032
219170.2.99.104/30170.2.99.105 to 170.2.99.106170.2.99.1072
220170.2.99.108/30170.2.99.109 to 170.2.99.110170.2.99.1112
221170.2.99.112/30170.2.99.113 to 170.2.99.114170.2.99.1152
222170.2.99.116/30170.2.99.117 to 170.2.99.118170.2.99.1192
223170.2.99.120/30170.2.99.121 to 170.2.99.122170.2.99.1232
224170.2.99.124/30170.2.99.125 to 170.2.99.126170.2.99.1272
225170.2.99.128/30170.2.99.129 to 170.2.99.130170.2.99.1312
226170.2.99.132/30170.2.99.133 to 170.2.99.134170.2.99.1352
227170.2.99.136/30170.2.99.137 to 170.2.99.138170.2.99.1392
228170.2.99.140/30170.2.99.141 to 170.2.99.142170.2.99.1432
229170.2.99.144/30170.2.99.145 to 170.2.99.146170.2.99.1472
230170.2.99.148/30170.2.99.149 to 170.2.99.150170.2.99.1512
231170.2.99.152/30170.2.99.153 to 170.2.99.154170.2.99.1552
232170.2.99.156/30170.2.99.157 to 170.2.99.158170.2.99.1592
233170.2.99.160/30170.2.99.161 to 170.2.99.162170.2.99.1632
234170.2.99.164/30170.2.99.165 to 170.2.99.166170.2.99.1672
235170.2.99.168/30170.2.99.169 to 170.2.99.170170.2.99.1712
236170.2.99.172/30170.2.99.173 to 170.2.99.174170.2.99.1752
237170.2.99.176/30170.2.99.177 to 170.2.99.178170.2.99.1792
238170.2.99.180/30170.2.99.181 to 170.2.99.182170.2.99.1832
239170.2.99.184/30170.2.99.185 to 170.2.99.186170.2.99.1872
240170.2.99.188/30170.2.99.189 to 170.2.99.190170.2.99.1912
241170.2.99.192/30170.2.99.193 to 170.2.99.194170.2.99.1952
242170.2.99.196/30170.2.99.197 to 170.2.99.198170.2.99.1992
243170.2.99.200/30170.2.99.201 to 170.2.99.202170.2.99.2032
244170.2.99.204/30170.2.99.205 to 170.2.99.206170.2.99.2072
245170.2.99.208/30170.2.99.209 to 170.2.99.210170.2.99.2112
246170.2.99.212/30170.2.99.213 to 170.2.99.214170.2.99.2152
247170.2.99.216/30170.2.99.217 to 170.2.99.218170.2.99.2192
248170.2.99.220/30170.2.99.221 to 170.2.99.222170.2.99.2232
249170.2.99.224/30170.2.99.225 to 170.2.99.226170.2.99.2272
250170.2.99.228/30170.2.99.229 to 170.2.99.230170.2.99.2312
251170.2.99.232/30170.2.99.233 to 170.2.99.234170.2.99.2352
252170.2.99.236/30170.2.99.237 to 170.2.99.238170.2.99.2392
253170.2.99.240/30170.2.99.241 to 170.2.99.242170.2.99.2432
254170.2.99.244/30170.2.99.245 to 170.2.99.246170.2.99.2472
255170.2.99.248/30170.2.99.249 to 170.2.99.250170.2.99.2512
256170.2.99.252/30170.2.99.253 to 170.2.99.254170.2.99.2552

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.