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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.

Network170.0.0.0/7
Usable hosts33,554,430
Subnet mask254.0.0.0
Addresses33,554,432
Network address
170.0.0.0
Broadcast address
171.255.255.255
First usable
170.0.0.1
Last usable
171.255.255.254
Usable hosts
33,554,430 (33,554,432 less the network and broadcast addresses)
Subnet mask
254.0.0.0
Wildcard mask
1.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/7
Type
Public public
Old class
B (default /16)
As numbers
Hex AA000000 · Integer 2852126720 to 2885681151
Reverse DNS zones
170.in-addr.arpa
171.in-addr.arpa
/7 is not on a 8-bit boundary, so it takes 2 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101010.00000000.00000000.00000000170.0.0.0
Subnet mask11111110.00000000.00000000.00000000254.0.0.0
Network10101010.00000000.00000000.00000000170.0.0.0
Broadcast10101011.11111111.11111111.11111111171.255.255.255
Split into smaller subnets/19
/8 (2)/9 (4)/10 (8)/11 (16)/12 (32)/13 (64)/14 (128)/15 (256)/16 (512)/17 (1,024)/18 (2,048)/19 (4,096)

170.0.0.0/7 makes 4,096 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1170.0.0.0/19170.0.0.1 to 170.0.31.254170.0.31.2558,190
2170.0.32.0/19170.0.32.1 to 170.0.63.254170.0.63.2558,190
3170.0.64.0/19170.0.64.1 to 170.0.95.254170.0.95.2558,190
4170.0.96.0/19170.0.96.1 to 170.0.127.254170.0.127.2558,190
5170.0.128.0/19170.0.128.1 to 170.0.159.254170.0.159.2558,190
6170.0.160.0/19170.0.160.1 to 170.0.191.254170.0.191.2558,190
7170.0.192.0/19170.0.192.1 to 170.0.223.254170.0.223.2558,190
8170.0.224.0/19170.0.224.1 to 170.0.255.254170.0.255.2558,190
9170.1.0.0/19170.1.0.1 to 170.1.31.254170.1.31.2558,190
10170.1.32.0/19170.1.32.1 to 170.1.63.254170.1.63.2558,190
11170.1.64.0/19170.1.64.1 to 170.1.95.254170.1.95.2558,190
12170.1.96.0/19170.1.96.1 to 170.1.127.254170.1.127.2558,190
13170.1.128.0/19170.1.128.1 to 170.1.159.254170.1.159.2558,190
14170.1.160.0/19170.1.160.1 to 170.1.191.254170.1.191.2558,190
15170.1.192.0/19170.1.192.1 to 170.1.223.254170.1.223.2558,190
16170.1.224.0/19170.1.224.1 to 170.1.255.254170.1.255.2558,190
17170.2.0.0/19170.2.0.1 to 170.2.31.254170.2.31.2558,190
18170.2.32.0/19170.2.32.1 to 170.2.63.254170.2.63.2558,190
19170.2.64.0/19170.2.64.1 to 170.2.95.254170.2.95.2558,190
20170.2.96.0/19170.2.96.1 to 170.2.127.254170.2.127.2558,190
21170.2.128.0/19170.2.128.1 to 170.2.159.254170.2.159.2558,190
22170.2.160.0/19170.2.160.1 to 170.2.191.254170.2.191.2558,190
23170.2.192.0/19170.2.192.1 to 170.2.223.254170.2.223.2558,190
24170.2.224.0/19170.2.224.1 to 170.2.255.254170.2.255.2558,190
25170.3.0.0/19170.3.0.1 to 170.3.31.254170.3.31.2558,190
26170.3.32.0/19170.3.32.1 to 170.3.63.254170.3.63.2558,190
27170.3.64.0/19170.3.64.1 to 170.3.95.254170.3.95.2558,190
28170.3.96.0/19170.3.96.1 to 170.3.127.254170.3.127.2558,190
29170.3.128.0/19170.3.128.1 to 170.3.159.254170.3.159.2558,190
30170.3.160.0/19170.3.160.1 to 170.3.191.254170.3.191.2558,190
31170.3.192.0/19170.3.192.1 to 170.3.223.254170.3.223.2558,190
32170.3.224.0/19170.3.224.1 to 170.3.255.254170.3.255.2558,190
33170.4.0.0/19170.4.0.1 to 170.4.31.254170.4.31.2558,190
34170.4.32.0/19170.4.32.1 to 170.4.63.254170.4.63.2558,190
35170.4.64.0/19170.4.64.1 to 170.4.95.254170.4.95.2558,190
36170.4.96.0/19170.4.96.1 to 170.4.127.254170.4.127.2558,190
37170.4.128.0/19170.4.128.1 to 170.4.159.254170.4.159.2558,190
38170.4.160.0/19170.4.160.1 to 170.4.191.254170.4.191.2558,190
39170.4.192.0/19170.4.192.1 to 170.4.223.254170.4.223.2558,190
40170.4.224.0/19170.4.224.1 to 170.4.255.254170.4.255.2558,190
41170.5.0.0/19170.5.0.1 to 170.5.31.254170.5.31.2558,190
42170.5.32.0/19170.5.32.1 to 170.5.63.254170.5.63.2558,190
43170.5.64.0/19170.5.64.1 to 170.5.95.254170.5.95.2558,190
44170.5.96.0/19170.5.96.1 to 170.5.127.254170.5.127.2558,190
45170.5.128.0/19170.5.128.1 to 170.5.159.254170.5.159.2558,190
46170.5.160.0/19170.5.160.1 to 170.5.191.254170.5.191.2558,190
47170.5.192.0/19170.5.192.1 to 170.5.223.254170.5.223.2558,190
48170.5.224.0/19170.5.224.1 to 170.5.255.254170.5.255.2558,190
49170.6.0.0/19170.6.0.1 to 170.6.31.254170.6.31.2558,190
50170.6.32.0/19170.6.32.1 to 170.6.63.254170.6.63.2558,190
51170.6.64.0/19170.6.64.1 to 170.6.95.254170.6.95.2558,190
52170.6.96.0/19170.6.96.1 to 170.6.127.254170.6.127.2558,190
53170.6.128.0/19170.6.128.1 to 170.6.159.254170.6.159.2558,190
54170.6.160.0/19170.6.160.1 to 170.6.191.254170.6.191.2558,190
55170.6.192.0/19170.6.192.1 to 170.6.223.254170.6.223.2558,190
56170.6.224.0/19170.6.224.1 to 170.6.255.254170.6.255.2558,190
57170.7.0.0/19170.7.0.1 to 170.7.31.254170.7.31.2558,190
58170.7.32.0/19170.7.32.1 to 170.7.63.254170.7.63.2558,190
59170.7.64.0/19170.7.64.1 to 170.7.95.254170.7.95.2558,190
60170.7.96.0/19170.7.96.1 to 170.7.127.254170.7.127.2558,190
61170.7.128.0/19170.7.128.1 to 170.7.159.254170.7.159.2558,190
62170.7.160.0/19170.7.160.1 to 170.7.191.254170.7.191.2558,190
63170.7.192.0/19170.7.192.1 to 170.7.223.254170.7.223.2558,190
64170.7.224.0/19170.7.224.1 to 170.7.255.254170.7.255.2558,190
65170.8.0.0/19170.8.0.1 to 170.8.31.254170.8.31.2558,190
66170.8.32.0/19170.8.32.1 to 170.8.63.254170.8.63.2558,190
67170.8.64.0/19170.8.64.1 to 170.8.95.254170.8.95.2558,190
68170.8.96.0/19170.8.96.1 to 170.8.127.254170.8.127.2558,190
69170.8.128.0/19170.8.128.1 to 170.8.159.254170.8.159.2558,190
70170.8.160.0/19170.8.160.1 to 170.8.191.254170.8.191.2558,190
71170.8.192.0/19170.8.192.1 to 170.8.223.254170.8.223.2558,190
72170.8.224.0/19170.8.224.1 to 170.8.255.254170.8.255.2558,190
73170.9.0.0/19170.9.0.1 to 170.9.31.254170.9.31.2558,190
74170.9.32.0/19170.9.32.1 to 170.9.63.254170.9.63.2558,190
75170.9.64.0/19170.9.64.1 to 170.9.95.254170.9.95.2558,190
76170.9.96.0/19170.9.96.1 to 170.9.127.254170.9.127.2558,190
77170.9.128.0/19170.9.128.1 to 170.9.159.254170.9.159.2558,190
78170.9.160.0/19170.9.160.1 to 170.9.191.254170.9.191.2558,190
79170.9.192.0/19170.9.192.1 to 170.9.223.254170.9.223.2558,190
80170.9.224.0/19170.9.224.1 to 170.9.255.254170.9.255.2558,190
81170.10.0.0/19170.10.0.1 to 170.10.31.254170.10.31.2558,190
82170.10.32.0/19170.10.32.1 to 170.10.63.254170.10.63.2558,190
83170.10.64.0/19170.10.64.1 to 170.10.95.254170.10.95.2558,190
84170.10.96.0/19170.10.96.1 to 170.10.127.254170.10.127.2558,190
85170.10.128.0/19170.10.128.1 to 170.10.159.254170.10.159.2558,190
86170.10.160.0/19170.10.160.1 to 170.10.191.254170.10.191.2558,190
87170.10.192.0/19170.10.192.1 to 170.10.223.254170.10.223.2558,190
88170.10.224.0/19170.10.224.1 to 170.10.255.254170.10.255.2558,190
89170.11.0.0/19170.11.0.1 to 170.11.31.254170.11.31.2558,190
90170.11.32.0/19170.11.32.1 to 170.11.63.254170.11.63.2558,190
91170.11.64.0/19170.11.64.1 to 170.11.95.254170.11.95.2558,190
92170.11.96.0/19170.11.96.1 to 170.11.127.254170.11.127.2558,190
93170.11.128.0/19170.11.128.1 to 170.11.159.254170.11.159.2558,190
94170.11.160.0/19170.11.160.1 to 170.11.191.254170.11.191.2558,190
95170.11.192.0/19170.11.192.1 to 170.11.223.254170.11.223.2558,190
96170.11.224.0/19170.11.224.1 to 170.11.255.254170.11.255.2558,190
97170.12.0.0/19170.12.0.1 to 170.12.31.254170.12.31.2558,190
98170.12.32.0/19170.12.32.1 to 170.12.63.254170.12.63.2558,190
99170.12.64.0/19170.12.64.1 to 170.12.95.254170.12.95.2558,190
100170.12.96.0/19170.12.96.1 to 170.12.127.254170.12.127.2558,190
101170.12.128.0/19170.12.128.1 to 170.12.159.254170.12.159.2558,190
102170.12.160.0/19170.12.160.1 to 170.12.191.254170.12.191.2558,190
103170.12.192.0/19170.12.192.1 to 170.12.223.254170.12.223.2558,190
104170.12.224.0/19170.12.224.1 to 170.12.255.254170.12.255.2558,190
105170.13.0.0/19170.13.0.1 to 170.13.31.254170.13.31.2558,190
106170.13.32.0/19170.13.32.1 to 170.13.63.254170.13.63.2558,190
107170.13.64.0/19170.13.64.1 to 170.13.95.254170.13.95.2558,190
108170.13.96.0/19170.13.96.1 to 170.13.127.254170.13.127.2558,190
109170.13.128.0/19170.13.128.1 to 170.13.159.254170.13.159.2558,190
110170.13.160.0/19170.13.160.1 to 170.13.191.254170.13.191.2558,190
111170.13.192.0/19170.13.192.1 to 170.13.223.254170.13.223.2558,190
112170.13.224.0/19170.13.224.1 to 170.13.255.254170.13.255.2558,190
113170.14.0.0/19170.14.0.1 to 170.14.31.254170.14.31.2558,190
114170.14.32.0/19170.14.32.1 to 170.14.63.254170.14.63.2558,190
115170.14.64.0/19170.14.64.1 to 170.14.95.254170.14.95.2558,190
116170.14.96.0/19170.14.96.1 to 170.14.127.254170.14.127.2558,190
117170.14.128.0/19170.14.128.1 to 170.14.159.254170.14.159.2558,190
118170.14.160.0/19170.14.160.1 to 170.14.191.254170.14.191.2558,190
119170.14.192.0/19170.14.192.1 to 170.14.223.254170.14.223.2558,190
120170.14.224.0/19170.14.224.1 to 170.14.255.254170.14.255.2558,190
121170.15.0.0/19170.15.0.1 to 170.15.31.254170.15.31.2558,190
122170.15.32.0/19170.15.32.1 to 170.15.63.254170.15.63.2558,190
123170.15.64.0/19170.15.64.1 to 170.15.95.254170.15.95.2558,190
124170.15.96.0/19170.15.96.1 to 170.15.127.254170.15.127.2558,190
125170.15.128.0/19170.15.128.1 to 170.15.159.254170.15.159.2558,190
126170.15.160.0/19170.15.160.1 to 170.15.191.254170.15.191.2558,190
127170.15.192.0/19170.15.192.1 to 170.15.223.254170.15.223.2558,190
128170.15.224.0/19170.15.224.1 to 170.15.255.254170.15.255.2558,190
129170.16.0.0/19170.16.0.1 to 170.16.31.254170.16.31.2558,190
130170.16.32.0/19170.16.32.1 to 170.16.63.254170.16.63.2558,190
131170.16.64.0/19170.16.64.1 to 170.16.95.254170.16.95.2558,190
132170.16.96.0/19170.16.96.1 to 170.16.127.254170.16.127.2558,190
133170.16.128.0/19170.16.128.1 to 170.16.159.254170.16.159.2558,190
134170.16.160.0/19170.16.160.1 to 170.16.191.254170.16.191.2558,190
135170.16.192.0/19170.16.192.1 to 170.16.223.254170.16.223.2558,190
136170.16.224.0/19170.16.224.1 to 170.16.255.254170.16.255.2558,190
137170.17.0.0/19170.17.0.1 to 170.17.31.254170.17.31.2558,190
138170.17.32.0/19170.17.32.1 to 170.17.63.254170.17.63.2558,190
139170.17.64.0/19170.17.64.1 to 170.17.95.254170.17.95.2558,190
140170.17.96.0/19170.17.96.1 to 170.17.127.254170.17.127.2558,190
141170.17.128.0/19170.17.128.1 to 170.17.159.254170.17.159.2558,190
142170.17.160.0/19170.17.160.1 to 170.17.191.254170.17.191.2558,190
143170.17.192.0/19170.17.192.1 to 170.17.223.254170.17.223.2558,190
144170.17.224.0/19170.17.224.1 to 170.17.255.254170.17.255.2558,190
145170.18.0.0/19170.18.0.1 to 170.18.31.254170.18.31.2558,190
146170.18.32.0/19170.18.32.1 to 170.18.63.254170.18.63.2558,190
147170.18.64.0/19170.18.64.1 to 170.18.95.254170.18.95.2558,190
148170.18.96.0/19170.18.96.1 to 170.18.127.254170.18.127.2558,190
149170.18.128.0/19170.18.128.1 to 170.18.159.254170.18.159.2558,190
150170.18.160.0/19170.18.160.1 to 170.18.191.254170.18.191.2558,190
151170.18.192.0/19170.18.192.1 to 170.18.223.254170.18.223.2558,190
152170.18.224.0/19170.18.224.1 to 170.18.255.254170.18.255.2558,190
153170.19.0.0/19170.19.0.1 to 170.19.31.254170.19.31.2558,190
154170.19.32.0/19170.19.32.1 to 170.19.63.254170.19.63.2558,190
155170.19.64.0/19170.19.64.1 to 170.19.95.254170.19.95.2558,190
156170.19.96.0/19170.19.96.1 to 170.19.127.254170.19.127.2558,190
157170.19.128.0/19170.19.128.1 to 170.19.159.254170.19.159.2558,190
158170.19.160.0/19170.19.160.1 to 170.19.191.254170.19.191.2558,190
159170.19.192.0/19170.19.192.1 to 170.19.223.254170.19.223.2558,190
160170.19.224.0/19170.19.224.1 to 170.19.255.254170.19.255.2558,190
161170.20.0.0/19170.20.0.1 to 170.20.31.254170.20.31.2558,190
162170.20.32.0/19170.20.32.1 to 170.20.63.254170.20.63.2558,190
163170.20.64.0/19170.20.64.1 to 170.20.95.254170.20.95.2558,190
164170.20.96.0/19170.20.96.1 to 170.20.127.254170.20.127.2558,190
165170.20.128.0/19170.20.128.1 to 170.20.159.254170.20.159.2558,190
166170.20.160.0/19170.20.160.1 to 170.20.191.254170.20.191.2558,190
167170.20.192.0/19170.20.192.1 to 170.20.223.254170.20.223.2558,190
168170.20.224.0/19170.20.224.1 to 170.20.255.254170.20.255.2558,190
169170.21.0.0/19170.21.0.1 to 170.21.31.254170.21.31.2558,190
170170.21.32.0/19170.21.32.1 to 170.21.63.254170.21.63.2558,190
171170.21.64.0/19170.21.64.1 to 170.21.95.254170.21.95.2558,190
172170.21.96.0/19170.21.96.1 to 170.21.127.254170.21.127.2558,190
173170.21.128.0/19170.21.128.1 to 170.21.159.254170.21.159.2558,190
174170.21.160.0/19170.21.160.1 to 170.21.191.254170.21.191.2558,190
175170.21.192.0/19170.21.192.1 to 170.21.223.254170.21.223.2558,190
176170.21.224.0/19170.21.224.1 to 170.21.255.254170.21.255.2558,190
177170.22.0.0/19170.22.0.1 to 170.22.31.254170.22.31.2558,190
178170.22.32.0/19170.22.32.1 to 170.22.63.254170.22.63.2558,190
179170.22.64.0/19170.22.64.1 to 170.22.95.254170.22.95.2558,190
180170.22.96.0/19170.22.96.1 to 170.22.127.254170.22.127.2558,190
181170.22.128.0/19170.22.128.1 to 170.22.159.254170.22.159.2558,190
182170.22.160.0/19170.22.160.1 to 170.22.191.254170.22.191.2558,190
183170.22.192.0/19170.22.192.1 to 170.22.223.254170.22.223.2558,190
184170.22.224.0/19170.22.224.1 to 170.22.255.254170.22.255.2558,190
185170.23.0.0/19170.23.0.1 to 170.23.31.254170.23.31.2558,190
186170.23.32.0/19170.23.32.1 to 170.23.63.254170.23.63.2558,190
187170.23.64.0/19170.23.64.1 to 170.23.95.254170.23.95.2558,190
188170.23.96.0/19170.23.96.1 to 170.23.127.254170.23.127.2558,190
189170.23.128.0/19170.23.128.1 to 170.23.159.254170.23.159.2558,190
190170.23.160.0/19170.23.160.1 to 170.23.191.254170.23.191.2558,190
191170.23.192.0/19170.23.192.1 to 170.23.223.254170.23.223.2558,190
192170.23.224.0/19170.23.224.1 to 170.23.255.254170.23.255.2558,190
193170.24.0.0/19170.24.0.1 to 170.24.31.254170.24.31.2558,190
194170.24.32.0/19170.24.32.1 to 170.24.63.254170.24.63.2558,190
195170.24.64.0/19170.24.64.1 to 170.24.95.254170.24.95.2558,190
196170.24.96.0/19170.24.96.1 to 170.24.127.254170.24.127.2558,190
197170.24.128.0/19170.24.128.1 to 170.24.159.254170.24.159.2558,190
198170.24.160.0/19170.24.160.1 to 170.24.191.254170.24.191.2558,190
199170.24.192.0/19170.24.192.1 to 170.24.223.254170.24.223.2558,190
200170.24.224.0/19170.24.224.1 to 170.24.255.254170.24.255.2558,190
201170.25.0.0/19170.25.0.1 to 170.25.31.254170.25.31.2558,190
202170.25.32.0/19170.25.32.1 to 170.25.63.254170.25.63.2558,190
203170.25.64.0/19170.25.64.1 to 170.25.95.254170.25.95.2558,190
204170.25.96.0/19170.25.96.1 to 170.25.127.254170.25.127.2558,190
205170.25.128.0/19170.25.128.1 to 170.25.159.254170.25.159.2558,190
206170.25.160.0/19170.25.160.1 to 170.25.191.254170.25.191.2558,190
207170.25.192.0/19170.25.192.1 to 170.25.223.254170.25.223.2558,190
208170.25.224.0/19170.25.224.1 to 170.25.255.254170.25.255.2558,190
209170.26.0.0/19170.26.0.1 to 170.26.31.254170.26.31.2558,190
210170.26.32.0/19170.26.32.1 to 170.26.63.254170.26.63.2558,190
211170.26.64.0/19170.26.64.1 to 170.26.95.254170.26.95.2558,190
212170.26.96.0/19170.26.96.1 to 170.26.127.254170.26.127.2558,190
213170.26.128.0/19170.26.128.1 to 170.26.159.254170.26.159.2558,190
214170.26.160.0/19170.26.160.1 to 170.26.191.254170.26.191.2558,190
215170.26.192.0/19170.26.192.1 to 170.26.223.254170.26.223.2558,190
216170.26.224.0/19170.26.224.1 to 170.26.255.254170.26.255.2558,190
217170.27.0.0/19170.27.0.1 to 170.27.31.254170.27.31.2558,190
218170.27.32.0/19170.27.32.1 to 170.27.63.254170.27.63.2558,190
219170.27.64.0/19170.27.64.1 to 170.27.95.254170.27.95.2558,190
220170.27.96.0/19170.27.96.1 to 170.27.127.254170.27.127.2558,190
221170.27.128.0/19170.27.128.1 to 170.27.159.254170.27.159.2558,190
222170.27.160.0/19170.27.160.1 to 170.27.191.254170.27.191.2558,190
223170.27.192.0/19170.27.192.1 to 170.27.223.254170.27.223.2558,190
224170.27.224.0/19170.27.224.1 to 170.27.255.254170.27.255.2558,190
225170.28.0.0/19170.28.0.1 to 170.28.31.254170.28.31.2558,190
226170.28.32.0/19170.28.32.1 to 170.28.63.254170.28.63.2558,190
227170.28.64.0/19170.28.64.1 to 170.28.95.254170.28.95.2558,190
228170.28.96.0/19170.28.96.1 to 170.28.127.254170.28.127.2558,190
229170.28.128.0/19170.28.128.1 to 170.28.159.254170.28.159.2558,190
230170.28.160.0/19170.28.160.1 to 170.28.191.254170.28.191.2558,190
231170.28.192.0/19170.28.192.1 to 170.28.223.254170.28.223.2558,190
232170.28.224.0/19170.28.224.1 to 170.28.255.254170.28.255.2558,190
233170.29.0.0/19170.29.0.1 to 170.29.31.254170.29.31.2558,190
234170.29.32.0/19170.29.32.1 to 170.29.63.254170.29.63.2558,190
235170.29.64.0/19170.29.64.1 to 170.29.95.254170.29.95.2558,190
236170.29.96.0/19170.29.96.1 to 170.29.127.254170.29.127.2558,190
237170.29.128.0/19170.29.128.1 to 170.29.159.254170.29.159.2558,190
238170.29.160.0/19170.29.160.1 to 170.29.191.254170.29.191.2558,190
239170.29.192.0/19170.29.192.1 to 170.29.223.254170.29.223.2558,190
240170.29.224.0/19170.29.224.1 to 170.29.255.254170.29.255.2558,190
241170.30.0.0/19170.30.0.1 to 170.30.31.254170.30.31.2558,190
242170.30.32.0/19170.30.32.1 to 170.30.63.254170.30.63.2558,190
243170.30.64.0/19170.30.64.1 to 170.30.95.254170.30.95.2558,190
244170.30.96.0/19170.30.96.1 to 170.30.127.254170.30.127.2558,190
245170.30.128.0/19170.30.128.1 to 170.30.159.254170.30.159.2558,190
246170.30.160.0/19170.30.160.1 to 170.30.191.254170.30.191.2558,190
247170.30.192.0/19170.30.192.1 to 170.30.223.254170.30.223.2558,190
248170.30.224.0/19170.30.224.1 to 170.30.255.254170.30.255.2558,190
249170.31.0.0/19170.31.0.1 to 170.31.31.254170.31.31.2558,190
250170.31.32.0/19170.31.32.1 to 170.31.63.254170.31.63.2558,190
251170.31.64.0/19170.31.64.1 to 170.31.95.254170.31.95.2558,190
252170.31.96.0/19170.31.96.1 to 170.31.127.254170.31.127.2558,190
253170.31.128.0/19170.31.128.1 to 170.31.159.254170.31.159.2558,190
254170.31.160.0/19170.31.160.1 to 170.31.191.254170.31.191.2558,190
255170.31.192.0/19170.31.192.1 to 170.31.223.254170.31.223.2558,190
256170.31.224.0/19170.31.224.1 to 170.31.255.254170.31.255.2558,190

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.