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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.

Network254.0.0.0/10
Usable hosts4,194,302
Subnet mask255.192.0.0
Addresses4,194,304
Network address
254.0.0.0
Broadcast address
254.63.255.255
First usable
254.0.0.1
Last usable
254.63.255.254
Usable hosts
4,194,302 (4,194,304 less the network and broadcast addresses)
Subnet mask
255.192.0.0
Wildcard mask
0.63.255.255 (Cisco ACLs, OSPF)
Prefix length
/10
Type
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FE000000 · Integer 4261412864 to 4265607167
Reverse DNS zones
0.254.in-addr.arpa
1.254.in-addr.arpa
2.254.in-addr.arpa
3.254.in-addr.arpa
4.254.in-addr.arpa
5.254.in-addr.arpa
6.254.in-addr.arpa
7.254.in-addr.arpa
8.254.in-addr.arpa
9.254.in-addr.arpa
10.254.in-addr.arpa
11.254.in-addr.arpa
12.254.in-addr.arpa
13.254.in-addr.arpa
14.254.in-addr.arpa
15.254.in-addr.arpa
and 48 more
/10 is not on a 8-bit boundary, so it takes 64 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111110.00000000.00000000.00000000254.0.0.0
Subnet mask11111111.11000000.00000000.00000000255.192.0.0
Network11111110.00000000.00000000.00000000254.0.0.0
Broadcast11111110.00111111.11111111.11111111254.63.255.255
Split into smaller subnets/19
/11 (2)/12 (4)/13 (8)/14 (16)/15 (32)/16 (64)/17 (128)/18 (256)/19 (512)/20 (1,024)/21 (2,048)/22 (4,096)

254.0.0.0/10 makes 512 subnets of /19; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1254.0.0.0/19254.0.0.1 to 254.0.31.254254.0.31.2558,190
2254.0.32.0/19254.0.32.1 to 254.0.63.254254.0.63.2558,190
3254.0.64.0/19254.0.64.1 to 254.0.95.254254.0.95.2558,190
4254.0.96.0/19254.0.96.1 to 254.0.127.254254.0.127.2558,190
5254.0.128.0/19254.0.128.1 to 254.0.159.254254.0.159.2558,190
6254.0.160.0/19254.0.160.1 to 254.0.191.254254.0.191.2558,190
7254.0.192.0/19254.0.192.1 to 254.0.223.254254.0.223.2558,190
8254.0.224.0/19254.0.224.1 to 254.0.255.254254.0.255.2558,190
9254.1.0.0/19254.1.0.1 to 254.1.31.254254.1.31.2558,190
10254.1.32.0/19254.1.32.1 to 254.1.63.254254.1.63.2558,190
11254.1.64.0/19254.1.64.1 to 254.1.95.254254.1.95.2558,190
12254.1.96.0/19254.1.96.1 to 254.1.127.254254.1.127.2558,190
13254.1.128.0/19254.1.128.1 to 254.1.159.254254.1.159.2558,190
14254.1.160.0/19254.1.160.1 to 254.1.191.254254.1.191.2558,190
15254.1.192.0/19254.1.192.1 to 254.1.223.254254.1.223.2558,190
16254.1.224.0/19254.1.224.1 to 254.1.255.254254.1.255.2558,190
17254.2.0.0/19254.2.0.1 to 254.2.31.254254.2.31.2558,190
18254.2.32.0/19254.2.32.1 to 254.2.63.254254.2.63.2558,190
19254.2.64.0/19254.2.64.1 to 254.2.95.254254.2.95.2558,190
20254.2.96.0/19254.2.96.1 to 254.2.127.254254.2.127.2558,190
21254.2.128.0/19254.2.128.1 to 254.2.159.254254.2.159.2558,190
22254.2.160.0/19254.2.160.1 to 254.2.191.254254.2.191.2558,190
23254.2.192.0/19254.2.192.1 to 254.2.223.254254.2.223.2558,190
24254.2.224.0/19254.2.224.1 to 254.2.255.254254.2.255.2558,190
25254.3.0.0/19254.3.0.1 to 254.3.31.254254.3.31.2558,190
26254.3.32.0/19254.3.32.1 to 254.3.63.254254.3.63.2558,190
27254.3.64.0/19254.3.64.1 to 254.3.95.254254.3.95.2558,190
28254.3.96.0/19254.3.96.1 to 254.3.127.254254.3.127.2558,190
29254.3.128.0/19254.3.128.1 to 254.3.159.254254.3.159.2558,190
30254.3.160.0/19254.3.160.1 to 254.3.191.254254.3.191.2558,190
31254.3.192.0/19254.3.192.1 to 254.3.223.254254.3.223.2558,190
32254.3.224.0/19254.3.224.1 to 254.3.255.254254.3.255.2558,190
33254.4.0.0/19254.4.0.1 to 254.4.31.254254.4.31.2558,190
34254.4.32.0/19254.4.32.1 to 254.4.63.254254.4.63.2558,190
35254.4.64.0/19254.4.64.1 to 254.4.95.254254.4.95.2558,190
36254.4.96.0/19254.4.96.1 to 254.4.127.254254.4.127.2558,190
37254.4.128.0/19254.4.128.1 to 254.4.159.254254.4.159.2558,190
38254.4.160.0/19254.4.160.1 to 254.4.191.254254.4.191.2558,190
39254.4.192.0/19254.4.192.1 to 254.4.223.254254.4.223.2558,190
40254.4.224.0/19254.4.224.1 to 254.4.255.254254.4.255.2558,190
41254.5.0.0/19254.5.0.1 to 254.5.31.254254.5.31.2558,190
42254.5.32.0/19254.5.32.1 to 254.5.63.254254.5.63.2558,190
43254.5.64.0/19254.5.64.1 to 254.5.95.254254.5.95.2558,190
44254.5.96.0/19254.5.96.1 to 254.5.127.254254.5.127.2558,190
45254.5.128.0/19254.5.128.1 to 254.5.159.254254.5.159.2558,190
46254.5.160.0/19254.5.160.1 to 254.5.191.254254.5.191.2558,190
47254.5.192.0/19254.5.192.1 to 254.5.223.254254.5.223.2558,190
48254.5.224.0/19254.5.224.1 to 254.5.255.254254.5.255.2558,190
49254.6.0.0/19254.6.0.1 to 254.6.31.254254.6.31.2558,190
50254.6.32.0/19254.6.32.1 to 254.6.63.254254.6.63.2558,190
51254.6.64.0/19254.6.64.1 to 254.6.95.254254.6.95.2558,190
52254.6.96.0/19254.6.96.1 to 254.6.127.254254.6.127.2558,190
53254.6.128.0/19254.6.128.1 to 254.6.159.254254.6.159.2558,190
54254.6.160.0/19254.6.160.1 to 254.6.191.254254.6.191.2558,190
55254.6.192.0/19254.6.192.1 to 254.6.223.254254.6.223.2558,190
56254.6.224.0/19254.6.224.1 to 254.6.255.254254.6.255.2558,190
57254.7.0.0/19254.7.0.1 to 254.7.31.254254.7.31.2558,190
58254.7.32.0/19254.7.32.1 to 254.7.63.254254.7.63.2558,190
59254.7.64.0/19254.7.64.1 to 254.7.95.254254.7.95.2558,190
60254.7.96.0/19254.7.96.1 to 254.7.127.254254.7.127.2558,190
61254.7.128.0/19254.7.128.1 to 254.7.159.254254.7.159.2558,190
62254.7.160.0/19254.7.160.1 to 254.7.191.254254.7.191.2558,190
63254.7.192.0/19254.7.192.1 to 254.7.223.254254.7.223.2558,190
64254.7.224.0/19254.7.224.1 to 254.7.255.254254.7.255.2558,190
65254.8.0.0/19254.8.0.1 to 254.8.31.254254.8.31.2558,190
66254.8.32.0/19254.8.32.1 to 254.8.63.254254.8.63.2558,190
67254.8.64.0/19254.8.64.1 to 254.8.95.254254.8.95.2558,190
68254.8.96.0/19254.8.96.1 to 254.8.127.254254.8.127.2558,190
69254.8.128.0/19254.8.128.1 to 254.8.159.254254.8.159.2558,190
70254.8.160.0/19254.8.160.1 to 254.8.191.254254.8.191.2558,190
71254.8.192.0/19254.8.192.1 to 254.8.223.254254.8.223.2558,190
72254.8.224.0/19254.8.224.1 to 254.8.255.254254.8.255.2558,190
73254.9.0.0/19254.9.0.1 to 254.9.31.254254.9.31.2558,190
74254.9.32.0/19254.9.32.1 to 254.9.63.254254.9.63.2558,190
75254.9.64.0/19254.9.64.1 to 254.9.95.254254.9.95.2558,190
76254.9.96.0/19254.9.96.1 to 254.9.127.254254.9.127.2558,190
77254.9.128.0/19254.9.128.1 to 254.9.159.254254.9.159.2558,190
78254.9.160.0/19254.9.160.1 to 254.9.191.254254.9.191.2558,190
79254.9.192.0/19254.9.192.1 to 254.9.223.254254.9.223.2558,190
80254.9.224.0/19254.9.224.1 to 254.9.255.254254.9.255.2558,190
81254.10.0.0/19254.10.0.1 to 254.10.31.254254.10.31.2558,190
82254.10.32.0/19254.10.32.1 to 254.10.63.254254.10.63.2558,190
83254.10.64.0/19254.10.64.1 to 254.10.95.254254.10.95.2558,190
84254.10.96.0/19254.10.96.1 to 254.10.127.254254.10.127.2558,190
85254.10.128.0/19254.10.128.1 to 254.10.159.254254.10.159.2558,190
86254.10.160.0/19254.10.160.1 to 254.10.191.254254.10.191.2558,190
87254.10.192.0/19254.10.192.1 to 254.10.223.254254.10.223.2558,190
88254.10.224.0/19254.10.224.1 to 254.10.255.254254.10.255.2558,190
89254.11.0.0/19254.11.0.1 to 254.11.31.254254.11.31.2558,190
90254.11.32.0/19254.11.32.1 to 254.11.63.254254.11.63.2558,190
91254.11.64.0/19254.11.64.1 to 254.11.95.254254.11.95.2558,190
92254.11.96.0/19254.11.96.1 to 254.11.127.254254.11.127.2558,190
93254.11.128.0/19254.11.128.1 to 254.11.159.254254.11.159.2558,190
94254.11.160.0/19254.11.160.1 to 254.11.191.254254.11.191.2558,190
95254.11.192.0/19254.11.192.1 to 254.11.223.254254.11.223.2558,190
96254.11.224.0/19254.11.224.1 to 254.11.255.254254.11.255.2558,190
97254.12.0.0/19254.12.0.1 to 254.12.31.254254.12.31.2558,190
98254.12.32.0/19254.12.32.1 to 254.12.63.254254.12.63.2558,190
99254.12.64.0/19254.12.64.1 to 254.12.95.254254.12.95.2558,190
100254.12.96.0/19254.12.96.1 to 254.12.127.254254.12.127.2558,190
101254.12.128.0/19254.12.128.1 to 254.12.159.254254.12.159.2558,190
102254.12.160.0/19254.12.160.1 to 254.12.191.254254.12.191.2558,190
103254.12.192.0/19254.12.192.1 to 254.12.223.254254.12.223.2558,190
104254.12.224.0/19254.12.224.1 to 254.12.255.254254.12.255.2558,190
105254.13.0.0/19254.13.0.1 to 254.13.31.254254.13.31.2558,190
106254.13.32.0/19254.13.32.1 to 254.13.63.254254.13.63.2558,190
107254.13.64.0/19254.13.64.1 to 254.13.95.254254.13.95.2558,190
108254.13.96.0/19254.13.96.1 to 254.13.127.254254.13.127.2558,190
109254.13.128.0/19254.13.128.1 to 254.13.159.254254.13.159.2558,190
110254.13.160.0/19254.13.160.1 to 254.13.191.254254.13.191.2558,190
111254.13.192.0/19254.13.192.1 to 254.13.223.254254.13.223.2558,190
112254.13.224.0/19254.13.224.1 to 254.13.255.254254.13.255.2558,190
113254.14.0.0/19254.14.0.1 to 254.14.31.254254.14.31.2558,190
114254.14.32.0/19254.14.32.1 to 254.14.63.254254.14.63.2558,190
115254.14.64.0/19254.14.64.1 to 254.14.95.254254.14.95.2558,190
116254.14.96.0/19254.14.96.1 to 254.14.127.254254.14.127.2558,190
117254.14.128.0/19254.14.128.1 to 254.14.159.254254.14.159.2558,190
118254.14.160.0/19254.14.160.1 to 254.14.191.254254.14.191.2558,190
119254.14.192.0/19254.14.192.1 to 254.14.223.254254.14.223.2558,190
120254.14.224.0/19254.14.224.1 to 254.14.255.254254.14.255.2558,190
121254.15.0.0/19254.15.0.1 to 254.15.31.254254.15.31.2558,190
122254.15.32.0/19254.15.32.1 to 254.15.63.254254.15.63.2558,190
123254.15.64.0/19254.15.64.1 to 254.15.95.254254.15.95.2558,190
124254.15.96.0/19254.15.96.1 to 254.15.127.254254.15.127.2558,190
125254.15.128.0/19254.15.128.1 to 254.15.159.254254.15.159.2558,190
126254.15.160.0/19254.15.160.1 to 254.15.191.254254.15.191.2558,190
127254.15.192.0/19254.15.192.1 to 254.15.223.254254.15.223.2558,190
128254.15.224.0/19254.15.224.1 to 254.15.255.254254.15.255.2558,190
129254.16.0.0/19254.16.0.1 to 254.16.31.254254.16.31.2558,190
130254.16.32.0/19254.16.32.1 to 254.16.63.254254.16.63.2558,190
131254.16.64.0/19254.16.64.1 to 254.16.95.254254.16.95.2558,190
132254.16.96.0/19254.16.96.1 to 254.16.127.254254.16.127.2558,190
133254.16.128.0/19254.16.128.1 to 254.16.159.254254.16.159.2558,190
134254.16.160.0/19254.16.160.1 to 254.16.191.254254.16.191.2558,190
135254.16.192.0/19254.16.192.1 to 254.16.223.254254.16.223.2558,190
136254.16.224.0/19254.16.224.1 to 254.16.255.254254.16.255.2558,190
137254.17.0.0/19254.17.0.1 to 254.17.31.254254.17.31.2558,190
138254.17.32.0/19254.17.32.1 to 254.17.63.254254.17.63.2558,190
139254.17.64.0/19254.17.64.1 to 254.17.95.254254.17.95.2558,190
140254.17.96.0/19254.17.96.1 to 254.17.127.254254.17.127.2558,190
141254.17.128.0/19254.17.128.1 to 254.17.159.254254.17.159.2558,190
142254.17.160.0/19254.17.160.1 to 254.17.191.254254.17.191.2558,190
143254.17.192.0/19254.17.192.1 to 254.17.223.254254.17.223.2558,190
144254.17.224.0/19254.17.224.1 to 254.17.255.254254.17.255.2558,190
145254.18.0.0/19254.18.0.1 to 254.18.31.254254.18.31.2558,190
146254.18.32.0/19254.18.32.1 to 254.18.63.254254.18.63.2558,190
147254.18.64.0/19254.18.64.1 to 254.18.95.254254.18.95.2558,190
148254.18.96.0/19254.18.96.1 to 254.18.127.254254.18.127.2558,190
149254.18.128.0/19254.18.128.1 to 254.18.159.254254.18.159.2558,190
150254.18.160.0/19254.18.160.1 to 254.18.191.254254.18.191.2558,190
151254.18.192.0/19254.18.192.1 to 254.18.223.254254.18.223.2558,190
152254.18.224.0/19254.18.224.1 to 254.18.255.254254.18.255.2558,190
153254.19.0.0/19254.19.0.1 to 254.19.31.254254.19.31.2558,190
154254.19.32.0/19254.19.32.1 to 254.19.63.254254.19.63.2558,190
155254.19.64.0/19254.19.64.1 to 254.19.95.254254.19.95.2558,190
156254.19.96.0/19254.19.96.1 to 254.19.127.254254.19.127.2558,190
157254.19.128.0/19254.19.128.1 to 254.19.159.254254.19.159.2558,190
158254.19.160.0/19254.19.160.1 to 254.19.191.254254.19.191.2558,190
159254.19.192.0/19254.19.192.1 to 254.19.223.254254.19.223.2558,190
160254.19.224.0/19254.19.224.1 to 254.19.255.254254.19.255.2558,190
161254.20.0.0/19254.20.0.1 to 254.20.31.254254.20.31.2558,190
162254.20.32.0/19254.20.32.1 to 254.20.63.254254.20.63.2558,190
163254.20.64.0/19254.20.64.1 to 254.20.95.254254.20.95.2558,190
164254.20.96.0/19254.20.96.1 to 254.20.127.254254.20.127.2558,190
165254.20.128.0/19254.20.128.1 to 254.20.159.254254.20.159.2558,190
166254.20.160.0/19254.20.160.1 to 254.20.191.254254.20.191.2558,190
167254.20.192.0/19254.20.192.1 to 254.20.223.254254.20.223.2558,190
168254.20.224.0/19254.20.224.1 to 254.20.255.254254.20.255.2558,190
169254.21.0.0/19254.21.0.1 to 254.21.31.254254.21.31.2558,190
170254.21.32.0/19254.21.32.1 to 254.21.63.254254.21.63.2558,190
171254.21.64.0/19254.21.64.1 to 254.21.95.254254.21.95.2558,190
172254.21.96.0/19254.21.96.1 to 254.21.127.254254.21.127.2558,190
173254.21.128.0/19254.21.128.1 to 254.21.159.254254.21.159.2558,190
174254.21.160.0/19254.21.160.1 to 254.21.191.254254.21.191.2558,190
175254.21.192.0/19254.21.192.1 to 254.21.223.254254.21.223.2558,190
176254.21.224.0/19254.21.224.1 to 254.21.255.254254.21.255.2558,190
177254.22.0.0/19254.22.0.1 to 254.22.31.254254.22.31.2558,190
178254.22.32.0/19254.22.32.1 to 254.22.63.254254.22.63.2558,190
179254.22.64.0/19254.22.64.1 to 254.22.95.254254.22.95.2558,190
180254.22.96.0/19254.22.96.1 to 254.22.127.254254.22.127.2558,190
181254.22.128.0/19254.22.128.1 to 254.22.159.254254.22.159.2558,190
182254.22.160.0/19254.22.160.1 to 254.22.191.254254.22.191.2558,190
183254.22.192.0/19254.22.192.1 to 254.22.223.254254.22.223.2558,190
184254.22.224.0/19254.22.224.1 to 254.22.255.254254.22.255.2558,190
185254.23.0.0/19254.23.0.1 to 254.23.31.254254.23.31.2558,190
186254.23.32.0/19254.23.32.1 to 254.23.63.254254.23.63.2558,190
187254.23.64.0/19254.23.64.1 to 254.23.95.254254.23.95.2558,190
188254.23.96.0/19254.23.96.1 to 254.23.127.254254.23.127.2558,190
189254.23.128.0/19254.23.128.1 to 254.23.159.254254.23.159.2558,190
190254.23.160.0/19254.23.160.1 to 254.23.191.254254.23.191.2558,190
191254.23.192.0/19254.23.192.1 to 254.23.223.254254.23.223.2558,190
192254.23.224.0/19254.23.224.1 to 254.23.255.254254.23.255.2558,190
193254.24.0.0/19254.24.0.1 to 254.24.31.254254.24.31.2558,190
194254.24.32.0/19254.24.32.1 to 254.24.63.254254.24.63.2558,190
195254.24.64.0/19254.24.64.1 to 254.24.95.254254.24.95.2558,190
196254.24.96.0/19254.24.96.1 to 254.24.127.254254.24.127.2558,190
197254.24.128.0/19254.24.128.1 to 254.24.159.254254.24.159.2558,190
198254.24.160.0/19254.24.160.1 to 254.24.191.254254.24.191.2558,190
199254.24.192.0/19254.24.192.1 to 254.24.223.254254.24.223.2558,190
200254.24.224.0/19254.24.224.1 to 254.24.255.254254.24.255.2558,190
201254.25.0.0/19254.25.0.1 to 254.25.31.254254.25.31.2558,190
202254.25.32.0/19254.25.32.1 to 254.25.63.254254.25.63.2558,190
203254.25.64.0/19254.25.64.1 to 254.25.95.254254.25.95.2558,190
204254.25.96.0/19254.25.96.1 to 254.25.127.254254.25.127.2558,190
205254.25.128.0/19254.25.128.1 to 254.25.159.254254.25.159.2558,190
206254.25.160.0/19254.25.160.1 to 254.25.191.254254.25.191.2558,190
207254.25.192.0/19254.25.192.1 to 254.25.223.254254.25.223.2558,190
208254.25.224.0/19254.25.224.1 to 254.25.255.254254.25.255.2558,190
209254.26.0.0/19254.26.0.1 to 254.26.31.254254.26.31.2558,190
210254.26.32.0/19254.26.32.1 to 254.26.63.254254.26.63.2558,190
211254.26.64.0/19254.26.64.1 to 254.26.95.254254.26.95.2558,190
212254.26.96.0/19254.26.96.1 to 254.26.127.254254.26.127.2558,190
213254.26.128.0/19254.26.128.1 to 254.26.159.254254.26.159.2558,190
214254.26.160.0/19254.26.160.1 to 254.26.191.254254.26.191.2558,190
215254.26.192.0/19254.26.192.1 to 254.26.223.254254.26.223.2558,190
216254.26.224.0/19254.26.224.1 to 254.26.255.254254.26.255.2558,190
217254.27.0.0/19254.27.0.1 to 254.27.31.254254.27.31.2558,190
218254.27.32.0/19254.27.32.1 to 254.27.63.254254.27.63.2558,190
219254.27.64.0/19254.27.64.1 to 254.27.95.254254.27.95.2558,190
220254.27.96.0/19254.27.96.1 to 254.27.127.254254.27.127.2558,190
221254.27.128.0/19254.27.128.1 to 254.27.159.254254.27.159.2558,190
222254.27.160.0/19254.27.160.1 to 254.27.191.254254.27.191.2558,190
223254.27.192.0/19254.27.192.1 to 254.27.223.254254.27.223.2558,190
224254.27.224.0/19254.27.224.1 to 254.27.255.254254.27.255.2558,190
225254.28.0.0/19254.28.0.1 to 254.28.31.254254.28.31.2558,190
226254.28.32.0/19254.28.32.1 to 254.28.63.254254.28.63.2558,190
227254.28.64.0/19254.28.64.1 to 254.28.95.254254.28.95.2558,190
228254.28.96.0/19254.28.96.1 to 254.28.127.254254.28.127.2558,190
229254.28.128.0/19254.28.128.1 to 254.28.159.254254.28.159.2558,190
230254.28.160.0/19254.28.160.1 to 254.28.191.254254.28.191.2558,190
231254.28.192.0/19254.28.192.1 to 254.28.223.254254.28.223.2558,190
232254.28.224.0/19254.28.224.1 to 254.28.255.254254.28.255.2558,190
233254.29.0.0/19254.29.0.1 to 254.29.31.254254.29.31.2558,190
234254.29.32.0/19254.29.32.1 to 254.29.63.254254.29.63.2558,190
235254.29.64.0/19254.29.64.1 to 254.29.95.254254.29.95.2558,190
236254.29.96.0/19254.29.96.1 to 254.29.127.254254.29.127.2558,190
237254.29.128.0/19254.29.128.1 to 254.29.159.254254.29.159.2558,190
238254.29.160.0/19254.29.160.1 to 254.29.191.254254.29.191.2558,190
239254.29.192.0/19254.29.192.1 to 254.29.223.254254.29.223.2558,190
240254.29.224.0/19254.29.224.1 to 254.29.255.254254.29.255.2558,190
241254.30.0.0/19254.30.0.1 to 254.30.31.254254.30.31.2558,190
242254.30.32.0/19254.30.32.1 to 254.30.63.254254.30.63.2558,190
243254.30.64.0/19254.30.64.1 to 254.30.95.254254.30.95.2558,190
244254.30.96.0/19254.30.96.1 to 254.30.127.254254.30.127.2558,190
245254.30.128.0/19254.30.128.1 to 254.30.159.254254.30.159.2558,190
246254.30.160.0/19254.30.160.1 to 254.30.191.254254.30.191.2558,190
247254.30.192.0/19254.30.192.1 to 254.30.223.254254.30.223.2558,190
248254.30.224.0/19254.30.224.1 to 254.30.255.254254.30.255.2558,190
249254.31.0.0/19254.31.0.1 to 254.31.31.254254.31.31.2558,190
250254.31.32.0/19254.31.32.1 to 254.31.63.254254.31.63.2558,190
251254.31.64.0/19254.31.64.1 to 254.31.95.254254.31.95.2558,190
252254.31.96.0/19254.31.96.1 to 254.31.127.254254.31.127.2558,190
253254.31.128.0/19254.31.128.1 to 254.31.159.254254.31.159.2558,190
254254.31.160.0/19254.31.160.1 to 254.31.191.254254.31.191.2558,190
255254.31.192.0/19254.31.192.1 to 254.31.223.254254.31.223.2558,190
256254.31.224.0/19254.31.224.1 to 254.31.255.254254.31.255.2558,190

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.