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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.

Network254.0.0.0/9
Usable hosts8,388,606
Subnet mask255.128.0.0
Addresses8,388,608
Network address
254.0.0.0
Broadcast address
254.127.255.255
First usable
254.0.0.1
Last usable
254.127.255.254
Usable hosts
8,388,606 (8,388,608 less the network and broadcast addresses)
Subnet mask
255.128.0.0
Wildcard mask
0.127.255.255 (Cisco ACLs, OSPF)
Prefix length
/9
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 4269801471
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 112 more
/9 is not on a 8-bit boundary, so it takes 128 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11111110.00000000.00000000.00000000254.0.0.0
Subnet mask11111111.10000000.00000000.00000000255.128.0.0
Network11111110.00000000.00000000.00000000254.0.0.0
Broadcast11111110.01111111.11111111.11111111254.127.255.255
Split into smaller subnets/17
/10 (2)/11 (4)/12 (8)/13 (16)/14 (32)/15 (64)/16 (128)/17 (256)/18 (512)/19 (1,024)/20 (2,048)/21 (4,096)

254.0.0.0/9 makes 256 subnets of /17.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1254.0.0.0/17254.0.0.1 to 254.0.127.254254.0.127.25532,766
2254.0.128.0/17254.0.128.1 to 254.0.255.254254.0.255.25532,766
3254.1.0.0/17254.1.0.1 to 254.1.127.254254.1.127.25532,766
4254.1.128.0/17254.1.128.1 to 254.1.255.254254.1.255.25532,766
5254.2.0.0/17254.2.0.1 to 254.2.127.254254.2.127.25532,766
6254.2.128.0/17254.2.128.1 to 254.2.255.254254.2.255.25532,766
7254.3.0.0/17254.3.0.1 to 254.3.127.254254.3.127.25532,766
8254.3.128.0/17254.3.128.1 to 254.3.255.254254.3.255.25532,766
9254.4.0.0/17254.4.0.1 to 254.4.127.254254.4.127.25532,766
10254.4.128.0/17254.4.128.1 to 254.4.255.254254.4.255.25532,766
11254.5.0.0/17254.5.0.1 to 254.5.127.254254.5.127.25532,766
12254.5.128.0/17254.5.128.1 to 254.5.255.254254.5.255.25532,766
13254.6.0.0/17254.6.0.1 to 254.6.127.254254.6.127.25532,766
14254.6.128.0/17254.6.128.1 to 254.6.255.254254.6.255.25532,766
15254.7.0.0/17254.7.0.1 to 254.7.127.254254.7.127.25532,766
16254.7.128.0/17254.7.128.1 to 254.7.255.254254.7.255.25532,766
17254.8.0.0/17254.8.0.1 to 254.8.127.254254.8.127.25532,766
18254.8.128.0/17254.8.128.1 to 254.8.255.254254.8.255.25532,766
19254.9.0.0/17254.9.0.1 to 254.9.127.254254.9.127.25532,766
20254.9.128.0/17254.9.128.1 to 254.9.255.254254.9.255.25532,766
21254.10.0.0/17254.10.0.1 to 254.10.127.254254.10.127.25532,766
22254.10.128.0/17254.10.128.1 to 254.10.255.254254.10.255.25532,766
23254.11.0.0/17254.11.0.1 to 254.11.127.254254.11.127.25532,766
24254.11.128.0/17254.11.128.1 to 254.11.255.254254.11.255.25532,766
25254.12.0.0/17254.12.0.1 to 254.12.127.254254.12.127.25532,766
26254.12.128.0/17254.12.128.1 to 254.12.255.254254.12.255.25532,766
27254.13.0.0/17254.13.0.1 to 254.13.127.254254.13.127.25532,766
28254.13.128.0/17254.13.128.1 to 254.13.255.254254.13.255.25532,766
29254.14.0.0/17254.14.0.1 to 254.14.127.254254.14.127.25532,766
30254.14.128.0/17254.14.128.1 to 254.14.255.254254.14.255.25532,766
31254.15.0.0/17254.15.0.1 to 254.15.127.254254.15.127.25532,766
32254.15.128.0/17254.15.128.1 to 254.15.255.254254.15.255.25532,766
33254.16.0.0/17254.16.0.1 to 254.16.127.254254.16.127.25532,766
34254.16.128.0/17254.16.128.1 to 254.16.255.254254.16.255.25532,766
35254.17.0.0/17254.17.0.1 to 254.17.127.254254.17.127.25532,766
36254.17.128.0/17254.17.128.1 to 254.17.255.254254.17.255.25532,766
37254.18.0.0/17254.18.0.1 to 254.18.127.254254.18.127.25532,766
38254.18.128.0/17254.18.128.1 to 254.18.255.254254.18.255.25532,766
39254.19.0.0/17254.19.0.1 to 254.19.127.254254.19.127.25532,766
40254.19.128.0/17254.19.128.1 to 254.19.255.254254.19.255.25532,766
41254.20.0.0/17254.20.0.1 to 254.20.127.254254.20.127.25532,766
42254.20.128.0/17254.20.128.1 to 254.20.255.254254.20.255.25532,766
43254.21.0.0/17254.21.0.1 to 254.21.127.254254.21.127.25532,766
44254.21.128.0/17254.21.128.1 to 254.21.255.254254.21.255.25532,766
45254.22.0.0/17254.22.0.1 to 254.22.127.254254.22.127.25532,766
46254.22.128.0/17254.22.128.1 to 254.22.255.254254.22.255.25532,766
47254.23.0.0/17254.23.0.1 to 254.23.127.254254.23.127.25532,766
48254.23.128.0/17254.23.128.1 to 254.23.255.254254.23.255.25532,766
49254.24.0.0/17254.24.0.1 to 254.24.127.254254.24.127.25532,766
50254.24.128.0/17254.24.128.1 to 254.24.255.254254.24.255.25532,766
51254.25.0.0/17254.25.0.1 to 254.25.127.254254.25.127.25532,766
52254.25.128.0/17254.25.128.1 to 254.25.255.254254.25.255.25532,766
53254.26.0.0/17254.26.0.1 to 254.26.127.254254.26.127.25532,766
54254.26.128.0/17254.26.128.1 to 254.26.255.254254.26.255.25532,766
55254.27.0.0/17254.27.0.1 to 254.27.127.254254.27.127.25532,766
56254.27.128.0/17254.27.128.1 to 254.27.255.254254.27.255.25532,766
57254.28.0.0/17254.28.0.1 to 254.28.127.254254.28.127.25532,766
58254.28.128.0/17254.28.128.1 to 254.28.255.254254.28.255.25532,766
59254.29.0.0/17254.29.0.1 to 254.29.127.254254.29.127.25532,766
60254.29.128.0/17254.29.128.1 to 254.29.255.254254.29.255.25532,766
61254.30.0.0/17254.30.0.1 to 254.30.127.254254.30.127.25532,766
62254.30.128.0/17254.30.128.1 to 254.30.255.254254.30.255.25532,766
63254.31.0.0/17254.31.0.1 to 254.31.127.254254.31.127.25532,766
64254.31.128.0/17254.31.128.1 to 254.31.255.254254.31.255.25532,766
65254.32.0.0/17254.32.0.1 to 254.32.127.254254.32.127.25532,766
66254.32.128.0/17254.32.128.1 to 254.32.255.254254.32.255.25532,766
67254.33.0.0/17254.33.0.1 to 254.33.127.254254.33.127.25532,766
68254.33.128.0/17254.33.128.1 to 254.33.255.254254.33.255.25532,766
69254.34.0.0/17254.34.0.1 to 254.34.127.254254.34.127.25532,766
70254.34.128.0/17254.34.128.1 to 254.34.255.254254.34.255.25532,766
71254.35.0.0/17254.35.0.1 to 254.35.127.254254.35.127.25532,766
72254.35.128.0/17254.35.128.1 to 254.35.255.254254.35.255.25532,766
73254.36.0.0/17254.36.0.1 to 254.36.127.254254.36.127.25532,766
74254.36.128.0/17254.36.128.1 to 254.36.255.254254.36.255.25532,766
75254.37.0.0/17254.37.0.1 to 254.37.127.254254.37.127.25532,766
76254.37.128.0/17254.37.128.1 to 254.37.255.254254.37.255.25532,766
77254.38.0.0/17254.38.0.1 to 254.38.127.254254.38.127.25532,766
78254.38.128.0/17254.38.128.1 to 254.38.255.254254.38.255.25532,766
79254.39.0.0/17254.39.0.1 to 254.39.127.254254.39.127.25532,766
80254.39.128.0/17254.39.128.1 to 254.39.255.254254.39.255.25532,766
81254.40.0.0/17254.40.0.1 to 254.40.127.254254.40.127.25532,766
82254.40.128.0/17254.40.128.1 to 254.40.255.254254.40.255.25532,766
83254.41.0.0/17254.41.0.1 to 254.41.127.254254.41.127.25532,766
84254.41.128.0/17254.41.128.1 to 254.41.255.254254.41.255.25532,766
85254.42.0.0/17254.42.0.1 to 254.42.127.254254.42.127.25532,766
86254.42.128.0/17254.42.128.1 to 254.42.255.254254.42.255.25532,766
87254.43.0.0/17254.43.0.1 to 254.43.127.254254.43.127.25532,766
88254.43.128.0/17254.43.128.1 to 254.43.255.254254.43.255.25532,766
89254.44.0.0/17254.44.0.1 to 254.44.127.254254.44.127.25532,766
90254.44.128.0/17254.44.128.1 to 254.44.255.254254.44.255.25532,766
91254.45.0.0/17254.45.0.1 to 254.45.127.254254.45.127.25532,766
92254.45.128.0/17254.45.128.1 to 254.45.255.254254.45.255.25532,766
93254.46.0.0/17254.46.0.1 to 254.46.127.254254.46.127.25532,766
94254.46.128.0/17254.46.128.1 to 254.46.255.254254.46.255.25532,766
95254.47.0.0/17254.47.0.1 to 254.47.127.254254.47.127.25532,766
96254.47.128.0/17254.47.128.1 to 254.47.255.254254.47.255.25532,766
97254.48.0.0/17254.48.0.1 to 254.48.127.254254.48.127.25532,766
98254.48.128.0/17254.48.128.1 to 254.48.255.254254.48.255.25532,766
99254.49.0.0/17254.49.0.1 to 254.49.127.254254.49.127.25532,766
100254.49.128.0/17254.49.128.1 to 254.49.255.254254.49.255.25532,766
101254.50.0.0/17254.50.0.1 to 254.50.127.254254.50.127.25532,766
102254.50.128.0/17254.50.128.1 to 254.50.255.254254.50.255.25532,766
103254.51.0.0/17254.51.0.1 to 254.51.127.254254.51.127.25532,766
104254.51.128.0/17254.51.128.1 to 254.51.255.254254.51.255.25532,766
105254.52.0.0/17254.52.0.1 to 254.52.127.254254.52.127.25532,766
106254.52.128.0/17254.52.128.1 to 254.52.255.254254.52.255.25532,766
107254.53.0.0/17254.53.0.1 to 254.53.127.254254.53.127.25532,766
108254.53.128.0/17254.53.128.1 to 254.53.255.254254.53.255.25532,766
109254.54.0.0/17254.54.0.1 to 254.54.127.254254.54.127.25532,766
110254.54.128.0/17254.54.128.1 to 254.54.255.254254.54.255.25532,766
111254.55.0.0/17254.55.0.1 to 254.55.127.254254.55.127.25532,766
112254.55.128.0/17254.55.128.1 to 254.55.255.254254.55.255.25532,766
113254.56.0.0/17254.56.0.1 to 254.56.127.254254.56.127.25532,766
114254.56.128.0/17254.56.128.1 to 254.56.255.254254.56.255.25532,766
115254.57.0.0/17254.57.0.1 to 254.57.127.254254.57.127.25532,766
116254.57.128.0/17254.57.128.1 to 254.57.255.254254.57.255.25532,766
117254.58.0.0/17254.58.0.1 to 254.58.127.254254.58.127.25532,766
118254.58.128.0/17254.58.128.1 to 254.58.255.254254.58.255.25532,766
119254.59.0.0/17254.59.0.1 to 254.59.127.254254.59.127.25532,766
120254.59.128.0/17254.59.128.1 to 254.59.255.254254.59.255.25532,766
121254.60.0.0/17254.60.0.1 to 254.60.127.254254.60.127.25532,766
122254.60.128.0/17254.60.128.1 to 254.60.255.254254.60.255.25532,766
123254.61.0.0/17254.61.0.1 to 254.61.127.254254.61.127.25532,766
124254.61.128.0/17254.61.128.1 to 254.61.255.254254.61.255.25532,766
125254.62.0.0/17254.62.0.1 to 254.62.127.254254.62.127.25532,766
126254.62.128.0/17254.62.128.1 to 254.62.255.254254.62.255.25532,766
127254.63.0.0/17254.63.0.1 to 254.63.127.254254.63.127.25532,766
128254.63.128.0/17254.63.128.1 to 254.63.255.254254.63.255.25532,766
129254.64.0.0/17254.64.0.1 to 254.64.127.254254.64.127.25532,766
130254.64.128.0/17254.64.128.1 to 254.64.255.254254.64.255.25532,766
131254.65.0.0/17254.65.0.1 to 254.65.127.254254.65.127.25532,766
132254.65.128.0/17254.65.128.1 to 254.65.255.254254.65.255.25532,766
133254.66.0.0/17254.66.0.1 to 254.66.127.254254.66.127.25532,766
134254.66.128.0/17254.66.128.1 to 254.66.255.254254.66.255.25532,766
135254.67.0.0/17254.67.0.1 to 254.67.127.254254.67.127.25532,766
136254.67.128.0/17254.67.128.1 to 254.67.255.254254.67.255.25532,766
137254.68.0.0/17254.68.0.1 to 254.68.127.254254.68.127.25532,766
138254.68.128.0/17254.68.128.1 to 254.68.255.254254.68.255.25532,766
139254.69.0.0/17254.69.0.1 to 254.69.127.254254.69.127.25532,766
140254.69.128.0/17254.69.128.1 to 254.69.255.254254.69.255.25532,766
141254.70.0.0/17254.70.0.1 to 254.70.127.254254.70.127.25532,766
142254.70.128.0/17254.70.128.1 to 254.70.255.254254.70.255.25532,766
143254.71.0.0/17254.71.0.1 to 254.71.127.254254.71.127.25532,766
144254.71.128.0/17254.71.128.1 to 254.71.255.254254.71.255.25532,766
145254.72.0.0/17254.72.0.1 to 254.72.127.254254.72.127.25532,766
146254.72.128.0/17254.72.128.1 to 254.72.255.254254.72.255.25532,766
147254.73.0.0/17254.73.0.1 to 254.73.127.254254.73.127.25532,766
148254.73.128.0/17254.73.128.1 to 254.73.255.254254.73.255.25532,766
149254.74.0.0/17254.74.0.1 to 254.74.127.254254.74.127.25532,766
150254.74.128.0/17254.74.128.1 to 254.74.255.254254.74.255.25532,766
151254.75.0.0/17254.75.0.1 to 254.75.127.254254.75.127.25532,766
152254.75.128.0/17254.75.128.1 to 254.75.255.254254.75.255.25532,766
153254.76.0.0/17254.76.0.1 to 254.76.127.254254.76.127.25532,766
154254.76.128.0/17254.76.128.1 to 254.76.255.254254.76.255.25532,766
155254.77.0.0/17254.77.0.1 to 254.77.127.254254.77.127.25532,766
156254.77.128.0/17254.77.128.1 to 254.77.255.254254.77.255.25532,766
157254.78.0.0/17254.78.0.1 to 254.78.127.254254.78.127.25532,766
158254.78.128.0/17254.78.128.1 to 254.78.255.254254.78.255.25532,766
159254.79.0.0/17254.79.0.1 to 254.79.127.254254.79.127.25532,766
160254.79.128.0/17254.79.128.1 to 254.79.255.254254.79.255.25532,766
161254.80.0.0/17254.80.0.1 to 254.80.127.254254.80.127.25532,766
162254.80.128.0/17254.80.128.1 to 254.80.255.254254.80.255.25532,766
163254.81.0.0/17254.81.0.1 to 254.81.127.254254.81.127.25532,766
164254.81.128.0/17254.81.128.1 to 254.81.255.254254.81.255.25532,766
165254.82.0.0/17254.82.0.1 to 254.82.127.254254.82.127.25532,766
166254.82.128.0/17254.82.128.1 to 254.82.255.254254.82.255.25532,766
167254.83.0.0/17254.83.0.1 to 254.83.127.254254.83.127.25532,766
168254.83.128.0/17254.83.128.1 to 254.83.255.254254.83.255.25532,766
169254.84.0.0/17254.84.0.1 to 254.84.127.254254.84.127.25532,766
170254.84.128.0/17254.84.128.1 to 254.84.255.254254.84.255.25532,766
171254.85.0.0/17254.85.0.1 to 254.85.127.254254.85.127.25532,766
172254.85.128.0/17254.85.128.1 to 254.85.255.254254.85.255.25532,766
173254.86.0.0/17254.86.0.1 to 254.86.127.254254.86.127.25532,766
174254.86.128.0/17254.86.128.1 to 254.86.255.254254.86.255.25532,766
175254.87.0.0/17254.87.0.1 to 254.87.127.254254.87.127.25532,766
176254.87.128.0/17254.87.128.1 to 254.87.255.254254.87.255.25532,766
177254.88.0.0/17254.88.0.1 to 254.88.127.254254.88.127.25532,766
178254.88.128.0/17254.88.128.1 to 254.88.255.254254.88.255.25532,766
179254.89.0.0/17254.89.0.1 to 254.89.127.254254.89.127.25532,766
180254.89.128.0/17254.89.128.1 to 254.89.255.254254.89.255.25532,766
181254.90.0.0/17254.90.0.1 to 254.90.127.254254.90.127.25532,766
182254.90.128.0/17254.90.128.1 to 254.90.255.254254.90.255.25532,766
183254.91.0.0/17254.91.0.1 to 254.91.127.254254.91.127.25532,766
184254.91.128.0/17254.91.128.1 to 254.91.255.254254.91.255.25532,766
185254.92.0.0/17254.92.0.1 to 254.92.127.254254.92.127.25532,766
186254.92.128.0/17254.92.128.1 to 254.92.255.254254.92.255.25532,766
187254.93.0.0/17254.93.0.1 to 254.93.127.254254.93.127.25532,766
188254.93.128.0/17254.93.128.1 to 254.93.255.254254.93.255.25532,766
189254.94.0.0/17254.94.0.1 to 254.94.127.254254.94.127.25532,766
190254.94.128.0/17254.94.128.1 to 254.94.255.254254.94.255.25532,766
191254.95.0.0/17254.95.0.1 to 254.95.127.254254.95.127.25532,766
192254.95.128.0/17254.95.128.1 to 254.95.255.254254.95.255.25532,766
193254.96.0.0/17254.96.0.1 to 254.96.127.254254.96.127.25532,766
194254.96.128.0/17254.96.128.1 to 254.96.255.254254.96.255.25532,766
195254.97.0.0/17254.97.0.1 to 254.97.127.254254.97.127.25532,766
196254.97.128.0/17254.97.128.1 to 254.97.255.254254.97.255.25532,766
197254.98.0.0/17254.98.0.1 to 254.98.127.254254.98.127.25532,766
198254.98.128.0/17254.98.128.1 to 254.98.255.254254.98.255.25532,766
199254.99.0.0/17254.99.0.1 to 254.99.127.254254.99.127.25532,766
200254.99.128.0/17254.99.128.1 to 254.99.255.254254.99.255.25532,766
201254.100.0.0/17254.100.0.1 to 254.100.127.254254.100.127.25532,766
202254.100.128.0/17254.100.128.1 to 254.100.255.254254.100.255.25532,766
203254.101.0.0/17254.101.0.1 to 254.101.127.254254.101.127.25532,766
204254.101.128.0/17254.101.128.1 to 254.101.255.254254.101.255.25532,766
205254.102.0.0/17254.102.0.1 to 254.102.127.254254.102.127.25532,766
206254.102.128.0/17254.102.128.1 to 254.102.255.254254.102.255.25532,766
207254.103.0.0/17254.103.0.1 to 254.103.127.254254.103.127.25532,766
208254.103.128.0/17254.103.128.1 to 254.103.255.254254.103.255.25532,766
209254.104.0.0/17254.104.0.1 to 254.104.127.254254.104.127.25532,766
210254.104.128.0/17254.104.128.1 to 254.104.255.254254.104.255.25532,766
211254.105.0.0/17254.105.0.1 to 254.105.127.254254.105.127.25532,766
212254.105.128.0/17254.105.128.1 to 254.105.255.254254.105.255.25532,766
213254.106.0.0/17254.106.0.1 to 254.106.127.254254.106.127.25532,766
214254.106.128.0/17254.106.128.1 to 254.106.255.254254.106.255.25532,766
215254.107.0.0/17254.107.0.1 to 254.107.127.254254.107.127.25532,766
216254.107.128.0/17254.107.128.1 to 254.107.255.254254.107.255.25532,766
217254.108.0.0/17254.108.0.1 to 254.108.127.254254.108.127.25532,766
218254.108.128.0/17254.108.128.1 to 254.108.255.254254.108.255.25532,766
219254.109.0.0/17254.109.0.1 to 254.109.127.254254.109.127.25532,766
220254.109.128.0/17254.109.128.1 to 254.109.255.254254.109.255.25532,766
221254.110.0.0/17254.110.0.1 to 254.110.127.254254.110.127.25532,766
222254.110.128.0/17254.110.128.1 to 254.110.255.254254.110.255.25532,766
223254.111.0.0/17254.111.0.1 to 254.111.127.254254.111.127.25532,766
224254.111.128.0/17254.111.128.1 to 254.111.255.254254.111.255.25532,766
225254.112.0.0/17254.112.0.1 to 254.112.127.254254.112.127.25532,766
226254.112.128.0/17254.112.128.1 to 254.112.255.254254.112.255.25532,766
227254.113.0.0/17254.113.0.1 to 254.113.127.254254.113.127.25532,766
228254.113.128.0/17254.113.128.1 to 254.113.255.254254.113.255.25532,766
229254.114.0.0/17254.114.0.1 to 254.114.127.254254.114.127.25532,766
230254.114.128.0/17254.114.128.1 to 254.114.255.254254.114.255.25532,766
231254.115.0.0/17254.115.0.1 to 254.115.127.254254.115.127.25532,766
232254.115.128.0/17254.115.128.1 to 254.115.255.254254.115.255.25532,766
233254.116.0.0/17254.116.0.1 to 254.116.127.254254.116.127.25532,766
234254.116.128.0/17254.116.128.1 to 254.116.255.254254.116.255.25532,766
235254.117.0.0/17254.117.0.1 to 254.117.127.254254.117.127.25532,766
236254.117.128.0/17254.117.128.1 to 254.117.255.254254.117.255.25532,766
237254.118.0.0/17254.118.0.1 to 254.118.127.254254.118.127.25532,766
238254.118.128.0/17254.118.128.1 to 254.118.255.254254.118.255.25532,766
239254.119.0.0/17254.119.0.1 to 254.119.127.254254.119.127.25532,766
240254.119.128.0/17254.119.128.1 to 254.119.255.254254.119.255.25532,766
241254.120.0.0/17254.120.0.1 to 254.120.127.254254.120.127.25532,766
242254.120.128.0/17254.120.128.1 to 254.120.255.254254.120.255.25532,766
243254.121.0.0/17254.121.0.1 to 254.121.127.254254.121.127.25532,766
244254.121.128.0/17254.121.128.1 to 254.121.255.254254.121.255.25532,766
245254.122.0.0/17254.122.0.1 to 254.122.127.254254.122.127.25532,766
246254.122.128.0/17254.122.128.1 to 254.122.255.254254.122.255.25532,766
247254.123.0.0/17254.123.0.1 to 254.123.127.254254.123.127.25532,766
248254.123.128.0/17254.123.128.1 to 254.123.255.254254.123.255.25532,766
249254.124.0.0/17254.124.0.1 to 254.124.127.254254.124.127.25532,766
250254.124.128.0/17254.124.128.1 to 254.124.255.254254.124.255.25532,766
251254.125.0.0/17254.125.0.1 to 254.125.127.254254.125.127.25532,766
252254.125.128.0/17254.125.128.1 to 254.125.255.254254.125.255.25532,766
253254.126.0.0/17254.126.0.1 to 254.126.127.254254.126.127.25532,766
254254.126.128.0/17254.126.128.1 to 254.126.255.254254.126.255.25532,766
255254.127.0.0/17254.127.0.1 to 254.127.127.254254.127.127.25532,766
256254.127.128.0/17254.127.128.1 to 254.127.255.254254.127.255.25532,766

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.