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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.

Network170.0.0.0/8
Usable hosts16,777,214
Subnet mask255.0.0.0
Addresses16,777,216
Network address
170.0.0.0
Broadcast address
170.255.255.255
First usable
170.0.0.1
Last usable
170.255.255.254
Usable hosts
16,777,214 (16,777,216 less the network and broadcast addresses)
Subnet mask
255.0.0.0
Wildcard mask
0.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/8
Type
Public public
Old class
B (default /16)
As numbers
Hex AA000000 · Integer 2852126720 to 2868903935
Reverse DNS zone
170.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10101010..00000000.00000000.00000000170.0.0.0
Subnet mask11111111..00000000.00000000.00000000255.0.0.0
Network10101010..00000000.00000000.00000000170.0.0.0
Broadcast10101010..11111111.11111111.11111111170.255.255.255
Split into smaller subnets/20
/9 (2)/10 (4)/11 (8)/12 (16)/13 (32)/14 (64)/15 (128)/16 (256)/17 (512)/18 (1,024)/19 (2,048)/20 (4,096)

170.0.0.0/8 makes 4,096 subnets of /20; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1170.0.0.0/20170.0.0.1 to 170.0.15.254170.0.15.2554,094
2170.0.16.0/20170.0.16.1 to 170.0.31.254170.0.31.2554,094
3170.0.32.0/20170.0.32.1 to 170.0.47.254170.0.47.2554,094
4170.0.48.0/20170.0.48.1 to 170.0.63.254170.0.63.2554,094
5170.0.64.0/20170.0.64.1 to 170.0.79.254170.0.79.2554,094
6170.0.80.0/20170.0.80.1 to 170.0.95.254170.0.95.2554,094
7170.0.96.0/20170.0.96.1 to 170.0.111.254170.0.111.2554,094
8170.0.112.0/20170.0.112.1 to 170.0.127.254170.0.127.2554,094
9170.0.128.0/20170.0.128.1 to 170.0.143.254170.0.143.2554,094
10170.0.144.0/20170.0.144.1 to 170.0.159.254170.0.159.2554,094
11170.0.160.0/20170.0.160.1 to 170.0.175.254170.0.175.2554,094
12170.0.176.0/20170.0.176.1 to 170.0.191.254170.0.191.2554,094
13170.0.192.0/20170.0.192.1 to 170.0.207.254170.0.207.2554,094
14170.0.208.0/20170.0.208.1 to 170.0.223.254170.0.223.2554,094
15170.0.224.0/20170.0.224.1 to 170.0.239.254170.0.239.2554,094
16170.0.240.0/20170.0.240.1 to 170.0.255.254170.0.255.2554,094
17170.1.0.0/20170.1.0.1 to 170.1.15.254170.1.15.2554,094
18170.1.16.0/20170.1.16.1 to 170.1.31.254170.1.31.2554,094
19170.1.32.0/20170.1.32.1 to 170.1.47.254170.1.47.2554,094
20170.1.48.0/20170.1.48.1 to 170.1.63.254170.1.63.2554,094
21170.1.64.0/20170.1.64.1 to 170.1.79.254170.1.79.2554,094
22170.1.80.0/20170.1.80.1 to 170.1.95.254170.1.95.2554,094
23170.1.96.0/20170.1.96.1 to 170.1.111.254170.1.111.2554,094
24170.1.112.0/20170.1.112.1 to 170.1.127.254170.1.127.2554,094
25170.1.128.0/20170.1.128.1 to 170.1.143.254170.1.143.2554,094
26170.1.144.0/20170.1.144.1 to 170.1.159.254170.1.159.2554,094
27170.1.160.0/20170.1.160.1 to 170.1.175.254170.1.175.2554,094
28170.1.176.0/20170.1.176.1 to 170.1.191.254170.1.191.2554,094
29170.1.192.0/20170.1.192.1 to 170.1.207.254170.1.207.2554,094
30170.1.208.0/20170.1.208.1 to 170.1.223.254170.1.223.2554,094
31170.1.224.0/20170.1.224.1 to 170.1.239.254170.1.239.2554,094
32170.1.240.0/20170.1.240.1 to 170.1.255.254170.1.255.2554,094
33170.2.0.0/20170.2.0.1 to 170.2.15.254170.2.15.2554,094
34170.2.16.0/20170.2.16.1 to 170.2.31.254170.2.31.2554,094
35170.2.32.0/20170.2.32.1 to 170.2.47.254170.2.47.2554,094
36170.2.48.0/20170.2.48.1 to 170.2.63.254170.2.63.2554,094
37170.2.64.0/20170.2.64.1 to 170.2.79.254170.2.79.2554,094
38170.2.80.0/20170.2.80.1 to 170.2.95.254170.2.95.2554,094
39170.2.96.0/20170.2.96.1 to 170.2.111.254170.2.111.2554,094
40170.2.112.0/20170.2.112.1 to 170.2.127.254170.2.127.2554,094
41170.2.128.0/20170.2.128.1 to 170.2.143.254170.2.143.2554,094
42170.2.144.0/20170.2.144.1 to 170.2.159.254170.2.159.2554,094
43170.2.160.0/20170.2.160.1 to 170.2.175.254170.2.175.2554,094
44170.2.176.0/20170.2.176.1 to 170.2.191.254170.2.191.2554,094
45170.2.192.0/20170.2.192.1 to 170.2.207.254170.2.207.2554,094
46170.2.208.0/20170.2.208.1 to 170.2.223.254170.2.223.2554,094
47170.2.224.0/20170.2.224.1 to 170.2.239.254170.2.239.2554,094
48170.2.240.0/20170.2.240.1 to 170.2.255.254170.2.255.2554,094
49170.3.0.0/20170.3.0.1 to 170.3.15.254170.3.15.2554,094
50170.3.16.0/20170.3.16.1 to 170.3.31.254170.3.31.2554,094
51170.3.32.0/20170.3.32.1 to 170.3.47.254170.3.47.2554,094
52170.3.48.0/20170.3.48.1 to 170.3.63.254170.3.63.2554,094
53170.3.64.0/20170.3.64.1 to 170.3.79.254170.3.79.2554,094
54170.3.80.0/20170.3.80.1 to 170.3.95.254170.3.95.2554,094
55170.3.96.0/20170.3.96.1 to 170.3.111.254170.3.111.2554,094
56170.3.112.0/20170.3.112.1 to 170.3.127.254170.3.127.2554,094
57170.3.128.0/20170.3.128.1 to 170.3.143.254170.3.143.2554,094
58170.3.144.0/20170.3.144.1 to 170.3.159.254170.3.159.2554,094
59170.3.160.0/20170.3.160.1 to 170.3.175.254170.3.175.2554,094
60170.3.176.0/20170.3.176.1 to 170.3.191.254170.3.191.2554,094
61170.3.192.0/20170.3.192.1 to 170.3.207.254170.3.207.2554,094
62170.3.208.0/20170.3.208.1 to 170.3.223.254170.3.223.2554,094
63170.3.224.0/20170.3.224.1 to 170.3.239.254170.3.239.2554,094
64170.3.240.0/20170.3.240.1 to 170.3.255.254170.3.255.2554,094
65170.4.0.0/20170.4.0.1 to 170.4.15.254170.4.15.2554,094
66170.4.16.0/20170.4.16.1 to 170.4.31.254170.4.31.2554,094
67170.4.32.0/20170.4.32.1 to 170.4.47.254170.4.47.2554,094
68170.4.48.0/20170.4.48.1 to 170.4.63.254170.4.63.2554,094
69170.4.64.0/20170.4.64.1 to 170.4.79.254170.4.79.2554,094
70170.4.80.0/20170.4.80.1 to 170.4.95.254170.4.95.2554,094
71170.4.96.0/20170.4.96.1 to 170.4.111.254170.4.111.2554,094
72170.4.112.0/20170.4.112.1 to 170.4.127.254170.4.127.2554,094
73170.4.128.0/20170.4.128.1 to 170.4.143.254170.4.143.2554,094
74170.4.144.0/20170.4.144.1 to 170.4.159.254170.4.159.2554,094
75170.4.160.0/20170.4.160.1 to 170.4.175.254170.4.175.2554,094
76170.4.176.0/20170.4.176.1 to 170.4.191.254170.4.191.2554,094
77170.4.192.0/20170.4.192.1 to 170.4.207.254170.4.207.2554,094
78170.4.208.0/20170.4.208.1 to 170.4.223.254170.4.223.2554,094
79170.4.224.0/20170.4.224.1 to 170.4.239.254170.4.239.2554,094
80170.4.240.0/20170.4.240.1 to 170.4.255.254170.4.255.2554,094
81170.5.0.0/20170.5.0.1 to 170.5.15.254170.5.15.2554,094
82170.5.16.0/20170.5.16.1 to 170.5.31.254170.5.31.2554,094
83170.5.32.0/20170.5.32.1 to 170.5.47.254170.5.47.2554,094
84170.5.48.0/20170.5.48.1 to 170.5.63.254170.5.63.2554,094
85170.5.64.0/20170.5.64.1 to 170.5.79.254170.5.79.2554,094
86170.5.80.0/20170.5.80.1 to 170.5.95.254170.5.95.2554,094
87170.5.96.0/20170.5.96.1 to 170.5.111.254170.5.111.2554,094
88170.5.112.0/20170.5.112.1 to 170.5.127.254170.5.127.2554,094
89170.5.128.0/20170.5.128.1 to 170.5.143.254170.5.143.2554,094
90170.5.144.0/20170.5.144.1 to 170.5.159.254170.5.159.2554,094
91170.5.160.0/20170.5.160.1 to 170.5.175.254170.5.175.2554,094
92170.5.176.0/20170.5.176.1 to 170.5.191.254170.5.191.2554,094
93170.5.192.0/20170.5.192.1 to 170.5.207.254170.5.207.2554,094
94170.5.208.0/20170.5.208.1 to 170.5.223.254170.5.223.2554,094
95170.5.224.0/20170.5.224.1 to 170.5.239.254170.5.239.2554,094
96170.5.240.0/20170.5.240.1 to 170.5.255.254170.5.255.2554,094
97170.6.0.0/20170.6.0.1 to 170.6.15.254170.6.15.2554,094
98170.6.16.0/20170.6.16.1 to 170.6.31.254170.6.31.2554,094
99170.6.32.0/20170.6.32.1 to 170.6.47.254170.6.47.2554,094
100170.6.48.0/20170.6.48.1 to 170.6.63.254170.6.63.2554,094
101170.6.64.0/20170.6.64.1 to 170.6.79.254170.6.79.2554,094
102170.6.80.0/20170.6.80.1 to 170.6.95.254170.6.95.2554,094
103170.6.96.0/20170.6.96.1 to 170.6.111.254170.6.111.2554,094
104170.6.112.0/20170.6.112.1 to 170.6.127.254170.6.127.2554,094
105170.6.128.0/20170.6.128.1 to 170.6.143.254170.6.143.2554,094
106170.6.144.0/20170.6.144.1 to 170.6.159.254170.6.159.2554,094
107170.6.160.0/20170.6.160.1 to 170.6.175.254170.6.175.2554,094
108170.6.176.0/20170.6.176.1 to 170.6.191.254170.6.191.2554,094
109170.6.192.0/20170.6.192.1 to 170.6.207.254170.6.207.2554,094
110170.6.208.0/20170.6.208.1 to 170.6.223.254170.6.223.2554,094
111170.6.224.0/20170.6.224.1 to 170.6.239.254170.6.239.2554,094
112170.6.240.0/20170.6.240.1 to 170.6.255.254170.6.255.2554,094
113170.7.0.0/20170.7.0.1 to 170.7.15.254170.7.15.2554,094
114170.7.16.0/20170.7.16.1 to 170.7.31.254170.7.31.2554,094
115170.7.32.0/20170.7.32.1 to 170.7.47.254170.7.47.2554,094
116170.7.48.0/20170.7.48.1 to 170.7.63.254170.7.63.2554,094
117170.7.64.0/20170.7.64.1 to 170.7.79.254170.7.79.2554,094
118170.7.80.0/20170.7.80.1 to 170.7.95.254170.7.95.2554,094
119170.7.96.0/20170.7.96.1 to 170.7.111.254170.7.111.2554,094
120170.7.112.0/20170.7.112.1 to 170.7.127.254170.7.127.2554,094
121170.7.128.0/20170.7.128.1 to 170.7.143.254170.7.143.2554,094
122170.7.144.0/20170.7.144.1 to 170.7.159.254170.7.159.2554,094
123170.7.160.0/20170.7.160.1 to 170.7.175.254170.7.175.2554,094
124170.7.176.0/20170.7.176.1 to 170.7.191.254170.7.191.2554,094
125170.7.192.0/20170.7.192.1 to 170.7.207.254170.7.207.2554,094
126170.7.208.0/20170.7.208.1 to 170.7.223.254170.7.223.2554,094
127170.7.224.0/20170.7.224.1 to 170.7.239.254170.7.239.2554,094
128170.7.240.0/20170.7.240.1 to 170.7.255.254170.7.255.2554,094
129170.8.0.0/20170.8.0.1 to 170.8.15.254170.8.15.2554,094
130170.8.16.0/20170.8.16.1 to 170.8.31.254170.8.31.2554,094
131170.8.32.0/20170.8.32.1 to 170.8.47.254170.8.47.2554,094
132170.8.48.0/20170.8.48.1 to 170.8.63.254170.8.63.2554,094
133170.8.64.0/20170.8.64.1 to 170.8.79.254170.8.79.2554,094
134170.8.80.0/20170.8.80.1 to 170.8.95.254170.8.95.2554,094
135170.8.96.0/20170.8.96.1 to 170.8.111.254170.8.111.2554,094
136170.8.112.0/20170.8.112.1 to 170.8.127.254170.8.127.2554,094
137170.8.128.0/20170.8.128.1 to 170.8.143.254170.8.143.2554,094
138170.8.144.0/20170.8.144.1 to 170.8.159.254170.8.159.2554,094
139170.8.160.0/20170.8.160.1 to 170.8.175.254170.8.175.2554,094
140170.8.176.0/20170.8.176.1 to 170.8.191.254170.8.191.2554,094
141170.8.192.0/20170.8.192.1 to 170.8.207.254170.8.207.2554,094
142170.8.208.0/20170.8.208.1 to 170.8.223.254170.8.223.2554,094
143170.8.224.0/20170.8.224.1 to 170.8.239.254170.8.239.2554,094
144170.8.240.0/20170.8.240.1 to 170.8.255.254170.8.255.2554,094
145170.9.0.0/20170.9.0.1 to 170.9.15.254170.9.15.2554,094
146170.9.16.0/20170.9.16.1 to 170.9.31.254170.9.31.2554,094
147170.9.32.0/20170.9.32.1 to 170.9.47.254170.9.47.2554,094
148170.9.48.0/20170.9.48.1 to 170.9.63.254170.9.63.2554,094
149170.9.64.0/20170.9.64.1 to 170.9.79.254170.9.79.2554,094
150170.9.80.0/20170.9.80.1 to 170.9.95.254170.9.95.2554,094
151170.9.96.0/20170.9.96.1 to 170.9.111.254170.9.111.2554,094
152170.9.112.0/20170.9.112.1 to 170.9.127.254170.9.127.2554,094
153170.9.128.0/20170.9.128.1 to 170.9.143.254170.9.143.2554,094
154170.9.144.0/20170.9.144.1 to 170.9.159.254170.9.159.2554,094
155170.9.160.0/20170.9.160.1 to 170.9.175.254170.9.175.2554,094
156170.9.176.0/20170.9.176.1 to 170.9.191.254170.9.191.2554,094
157170.9.192.0/20170.9.192.1 to 170.9.207.254170.9.207.2554,094
158170.9.208.0/20170.9.208.1 to 170.9.223.254170.9.223.2554,094
159170.9.224.0/20170.9.224.1 to 170.9.239.254170.9.239.2554,094
160170.9.240.0/20170.9.240.1 to 170.9.255.254170.9.255.2554,094
161170.10.0.0/20170.10.0.1 to 170.10.15.254170.10.15.2554,094
162170.10.16.0/20170.10.16.1 to 170.10.31.254170.10.31.2554,094
163170.10.32.0/20170.10.32.1 to 170.10.47.254170.10.47.2554,094
164170.10.48.0/20170.10.48.1 to 170.10.63.254170.10.63.2554,094
165170.10.64.0/20170.10.64.1 to 170.10.79.254170.10.79.2554,094
166170.10.80.0/20170.10.80.1 to 170.10.95.254170.10.95.2554,094
167170.10.96.0/20170.10.96.1 to 170.10.111.254170.10.111.2554,094
168170.10.112.0/20170.10.112.1 to 170.10.127.254170.10.127.2554,094
169170.10.128.0/20170.10.128.1 to 170.10.143.254170.10.143.2554,094
170170.10.144.0/20170.10.144.1 to 170.10.159.254170.10.159.2554,094
171170.10.160.0/20170.10.160.1 to 170.10.175.254170.10.175.2554,094
172170.10.176.0/20170.10.176.1 to 170.10.191.254170.10.191.2554,094
173170.10.192.0/20170.10.192.1 to 170.10.207.254170.10.207.2554,094
174170.10.208.0/20170.10.208.1 to 170.10.223.254170.10.223.2554,094
175170.10.224.0/20170.10.224.1 to 170.10.239.254170.10.239.2554,094
176170.10.240.0/20170.10.240.1 to 170.10.255.254170.10.255.2554,094
177170.11.0.0/20170.11.0.1 to 170.11.15.254170.11.15.2554,094
178170.11.16.0/20170.11.16.1 to 170.11.31.254170.11.31.2554,094
179170.11.32.0/20170.11.32.1 to 170.11.47.254170.11.47.2554,094
180170.11.48.0/20170.11.48.1 to 170.11.63.254170.11.63.2554,094
181170.11.64.0/20170.11.64.1 to 170.11.79.254170.11.79.2554,094
182170.11.80.0/20170.11.80.1 to 170.11.95.254170.11.95.2554,094
183170.11.96.0/20170.11.96.1 to 170.11.111.254170.11.111.2554,094
184170.11.112.0/20170.11.112.1 to 170.11.127.254170.11.127.2554,094
185170.11.128.0/20170.11.128.1 to 170.11.143.254170.11.143.2554,094
186170.11.144.0/20170.11.144.1 to 170.11.159.254170.11.159.2554,094
187170.11.160.0/20170.11.160.1 to 170.11.175.254170.11.175.2554,094
188170.11.176.0/20170.11.176.1 to 170.11.191.254170.11.191.2554,094
189170.11.192.0/20170.11.192.1 to 170.11.207.254170.11.207.2554,094
190170.11.208.0/20170.11.208.1 to 170.11.223.254170.11.223.2554,094
191170.11.224.0/20170.11.224.1 to 170.11.239.254170.11.239.2554,094
192170.11.240.0/20170.11.240.1 to 170.11.255.254170.11.255.2554,094
193170.12.0.0/20170.12.0.1 to 170.12.15.254170.12.15.2554,094
194170.12.16.0/20170.12.16.1 to 170.12.31.254170.12.31.2554,094
195170.12.32.0/20170.12.32.1 to 170.12.47.254170.12.47.2554,094
196170.12.48.0/20170.12.48.1 to 170.12.63.254170.12.63.2554,094
197170.12.64.0/20170.12.64.1 to 170.12.79.254170.12.79.2554,094
198170.12.80.0/20170.12.80.1 to 170.12.95.254170.12.95.2554,094
199170.12.96.0/20170.12.96.1 to 170.12.111.254170.12.111.2554,094
200170.12.112.0/20170.12.112.1 to 170.12.127.254170.12.127.2554,094
201170.12.128.0/20170.12.128.1 to 170.12.143.254170.12.143.2554,094
202170.12.144.0/20170.12.144.1 to 170.12.159.254170.12.159.2554,094
203170.12.160.0/20170.12.160.1 to 170.12.175.254170.12.175.2554,094
204170.12.176.0/20170.12.176.1 to 170.12.191.254170.12.191.2554,094
205170.12.192.0/20170.12.192.1 to 170.12.207.254170.12.207.2554,094
206170.12.208.0/20170.12.208.1 to 170.12.223.254170.12.223.2554,094
207170.12.224.0/20170.12.224.1 to 170.12.239.254170.12.239.2554,094
208170.12.240.0/20170.12.240.1 to 170.12.255.254170.12.255.2554,094
209170.13.0.0/20170.13.0.1 to 170.13.15.254170.13.15.2554,094
210170.13.16.0/20170.13.16.1 to 170.13.31.254170.13.31.2554,094
211170.13.32.0/20170.13.32.1 to 170.13.47.254170.13.47.2554,094
212170.13.48.0/20170.13.48.1 to 170.13.63.254170.13.63.2554,094
213170.13.64.0/20170.13.64.1 to 170.13.79.254170.13.79.2554,094
214170.13.80.0/20170.13.80.1 to 170.13.95.254170.13.95.2554,094
215170.13.96.0/20170.13.96.1 to 170.13.111.254170.13.111.2554,094
216170.13.112.0/20170.13.112.1 to 170.13.127.254170.13.127.2554,094
217170.13.128.0/20170.13.128.1 to 170.13.143.254170.13.143.2554,094
218170.13.144.0/20170.13.144.1 to 170.13.159.254170.13.159.2554,094
219170.13.160.0/20170.13.160.1 to 170.13.175.254170.13.175.2554,094
220170.13.176.0/20170.13.176.1 to 170.13.191.254170.13.191.2554,094
221170.13.192.0/20170.13.192.1 to 170.13.207.254170.13.207.2554,094
222170.13.208.0/20170.13.208.1 to 170.13.223.254170.13.223.2554,094
223170.13.224.0/20170.13.224.1 to 170.13.239.254170.13.239.2554,094
224170.13.240.0/20170.13.240.1 to 170.13.255.254170.13.255.2554,094
225170.14.0.0/20170.14.0.1 to 170.14.15.254170.14.15.2554,094
226170.14.16.0/20170.14.16.1 to 170.14.31.254170.14.31.2554,094
227170.14.32.0/20170.14.32.1 to 170.14.47.254170.14.47.2554,094
228170.14.48.0/20170.14.48.1 to 170.14.63.254170.14.63.2554,094
229170.14.64.0/20170.14.64.1 to 170.14.79.254170.14.79.2554,094
230170.14.80.0/20170.14.80.1 to 170.14.95.254170.14.95.2554,094
231170.14.96.0/20170.14.96.1 to 170.14.111.254170.14.111.2554,094
232170.14.112.0/20170.14.112.1 to 170.14.127.254170.14.127.2554,094
233170.14.128.0/20170.14.128.1 to 170.14.143.254170.14.143.2554,094
234170.14.144.0/20170.14.144.1 to 170.14.159.254170.14.159.2554,094
235170.14.160.0/20170.14.160.1 to 170.14.175.254170.14.175.2554,094
236170.14.176.0/20170.14.176.1 to 170.14.191.254170.14.191.2554,094
237170.14.192.0/20170.14.192.1 to 170.14.207.254170.14.207.2554,094
238170.14.208.0/20170.14.208.1 to 170.14.223.254170.14.223.2554,094
239170.14.224.0/20170.14.224.1 to 170.14.239.254170.14.239.2554,094
240170.14.240.0/20170.14.240.1 to 170.14.255.254170.14.255.2554,094
241170.15.0.0/20170.15.0.1 to 170.15.15.254170.15.15.2554,094
242170.15.16.0/20170.15.16.1 to 170.15.31.254170.15.31.2554,094
243170.15.32.0/20170.15.32.1 to 170.15.47.254170.15.47.2554,094
244170.15.48.0/20170.15.48.1 to 170.15.63.254170.15.63.2554,094
245170.15.64.0/20170.15.64.1 to 170.15.79.254170.15.79.2554,094
246170.15.80.0/20170.15.80.1 to 170.15.95.254170.15.95.2554,094
247170.15.96.0/20170.15.96.1 to 170.15.111.254170.15.111.2554,094
248170.15.112.0/20170.15.112.1 to 170.15.127.254170.15.127.2554,094
249170.15.128.0/20170.15.128.1 to 170.15.143.254170.15.143.2554,094
250170.15.144.0/20170.15.144.1 to 170.15.159.254170.15.159.2554,094
251170.15.160.0/20170.15.160.1 to 170.15.175.254170.15.175.2554,094
252170.15.176.0/20170.15.176.1 to 170.15.191.254170.15.191.2554,094
253170.15.192.0/20170.15.192.1 to 170.15.207.254170.15.207.2554,094
254170.15.208.0/20170.15.208.1 to 170.15.223.254170.15.223.2554,094
255170.15.224.0/20170.15.224.1 to 170.15.239.254170.15.239.2554,094
256170.15.240.0/20170.15.240.1 to 170.15.255.254170.15.255.2554,094

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.