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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.

Network108.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
108.0.0.0
Broadcast address
111.255.255.255
First usable
108.0.0.1
Last usable
111.255.255.254
Usable hosts
67,108,862 (67,108,864 less the network and broadcast addresses)
Subnet mask
252.0.0.0
Wildcard mask
3.255.255.255 (Cisco ACLs, OSPF)
Prefix length
/6
Type
Public public
Old class
A (default /8)
As numbers
Hex 6C000000 · Integer 1811939328 to 1879048191
Reverse DNS zones
108.in-addr.arpa
109.in-addr.arpa
110.in-addr.arpa
111.in-addr.arpa
/6 is not on a 8-bit boundary, so it takes 4 /8 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01101100.00000000.00000000.00000000108.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network01101100.00000000.00000000.00000000108.0.0.0
Broadcast01101111.11111111.11111111.11111111111.255.255.255
Split into smaller subnets/17
/7 (2)/8 (4)/9 (8)/10 (16)/11 (32)/12 (64)/13 (128)/14 (256)/15 (512)/16 (1,024)/17 (2,048)/18 (4,096)

108.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1108.0.0.0/17108.0.0.1 to 108.0.127.254108.0.127.25532,766
2108.0.128.0/17108.0.128.1 to 108.0.255.254108.0.255.25532,766
3108.1.0.0/17108.1.0.1 to 108.1.127.254108.1.127.25532,766
4108.1.128.0/17108.1.128.1 to 108.1.255.254108.1.255.25532,766
5108.2.0.0/17108.2.0.1 to 108.2.127.254108.2.127.25532,766
6108.2.128.0/17108.2.128.1 to 108.2.255.254108.2.255.25532,766
7108.3.0.0/17108.3.0.1 to 108.3.127.254108.3.127.25532,766
8108.3.128.0/17108.3.128.1 to 108.3.255.254108.3.255.25532,766
9108.4.0.0/17108.4.0.1 to 108.4.127.254108.4.127.25532,766
10108.4.128.0/17108.4.128.1 to 108.4.255.254108.4.255.25532,766
11108.5.0.0/17108.5.0.1 to 108.5.127.254108.5.127.25532,766
12108.5.128.0/17108.5.128.1 to 108.5.255.254108.5.255.25532,766
13108.6.0.0/17108.6.0.1 to 108.6.127.254108.6.127.25532,766
14108.6.128.0/17108.6.128.1 to 108.6.255.254108.6.255.25532,766
15108.7.0.0/17108.7.0.1 to 108.7.127.254108.7.127.25532,766
16108.7.128.0/17108.7.128.1 to 108.7.255.254108.7.255.25532,766
17108.8.0.0/17108.8.0.1 to 108.8.127.254108.8.127.25532,766
18108.8.128.0/17108.8.128.1 to 108.8.255.254108.8.255.25532,766
19108.9.0.0/17108.9.0.1 to 108.9.127.254108.9.127.25532,766
20108.9.128.0/17108.9.128.1 to 108.9.255.254108.9.255.25532,766
21108.10.0.0/17108.10.0.1 to 108.10.127.254108.10.127.25532,766
22108.10.128.0/17108.10.128.1 to 108.10.255.254108.10.255.25532,766
23108.11.0.0/17108.11.0.1 to 108.11.127.254108.11.127.25532,766
24108.11.128.0/17108.11.128.1 to 108.11.255.254108.11.255.25532,766
25108.12.0.0/17108.12.0.1 to 108.12.127.254108.12.127.25532,766
26108.12.128.0/17108.12.128.1 to 108.12.255.254108.12.255.25532,766
27108.13.0.0/17108.13.0.1 to 108.13.127.254108.13.127.25532,766
28108.13.128.0/17108.13.128.1 to 108.13.255.254108.13.255.25532,766
29108.14.0.0/17108.14.0.1 to 108.14.127.254108.14.127.25532,766
30108.14.128.0/17108.14.128.1 to 108.14.255.254108.14.255.25532,766
31108.15.0.0/17108.15.0.1 to 108.15.127.254108.15.127.25532,766
32108.15.128.0/17108.15.128.1 to 108.15.255.254108.15.255.25532,766
33108.16.0.0/17108.16.0.1 to 108.16.127.254108.16.127.25532,766
34108.16.128.0/17108.16.128.1 to 108.16.255.254108.16.255.25532,766
35108.17.0.0/17108.17.0.1 to 108.17.127.254108.17.127.25532,766
36108.17.128.0/17108.17.128.1 to 108.17.255.254108.17.255.25532,766
37108.18.0.0/17108.18.0.1 to 108.18.127.254108.18.127.25532,766
38108.18.128.0/17108.18.128.1 to 108.18.255.254108.18.255.25532,766
39108.19.0.0/17108.19.0.1 to 108.19.127.254108.19.127.25532,766
40108.19.128.0/17108.19.128.1 to 108.19.255.254108.19.255.25532,766
41108.20.0.0/17108.20.0.1 to 108.20.127.254108.20.127.25532,766
42108.20.128.0/17108.20.128.1 to 108.20.255.254108.20.255.25532,766
43108.21.0.0/17108.21.0.1 to 108.21.127.254108.21.127.25532,766
44108.21.128.0/17108.21.128.1 to 108.21.255.254108.21.255.25532,766
45108.22.0.0/17108.22.0.1 to 108.22.127.254108.22.127.25532,766
46108.22.128.0/17108.22.128.1 to 108.22.255.254108.22.255.25532,766
47108.23.0.0/17108.23.0.1 to 108.23.127.254108.23.127.25532,766
48108.23.128.0/17108.23.128.1 to 108.23.255.254108.23.255.25532,766
49108.24.0.0/17108.24.0.1 to 108.24.127.254108.24.127.25532,766
50108.24.128.0/17108.24.128.1 to 108.24.255.254108.24.255.25532,766
51108.25.0.0/17108.25.0.1 to 108.25.127.254108.25.127.25532,766
52108.25.128.0/17108.25.128.1 to 108.25.255.254108.25.255.25532,766
53108.26.0.0/17108.26.0.1 to 108.26.127.254108.26.127.25532,766
54108.26.128.0/17108.26.128.1 to 108.26.255.254108.26.255.25532,766
55108.27.0.0/17108.27.0.1 to 108.27.127.254108.27.127.25532,766
56108.27.128.0/17108.27.128.1 to 108.27.255.254108.27.255.25532,766
57108.28.0.0/17108.28.0.1 to 108.28.127.254108.28.127.25532,766
58108.28.128.0/17108.28.128.1 to 108.28.255.254108.28.255.25532,766
59108.29.0.0/17108.29.0.1 to 108.29.127.254108.29.127.25532,766
60108.29.128.0/17108.29.128.1 to 108.29.255.254108.29.255.25532,766
61108.30.0.0/17108.30.0.1 to 108.30.127.254108.30.127.25532,766
62108.30.128.0/17108.30.128.1 to 108.30.255.254108.30.255.25532,766
63108.31.0.0/17108.31.0.1 to 108.31.127.254108.31.127.25532,766
64108.31.128.0/17108.31.128.1 to 108.31.255.254108.31.255.25532,766
65108.32.0.0/17108.32.0.1 to 108.32.127.254108.32.127.25532,766
66108.32.128.0/17108.32.128.1 to 108.32.255.254108.32.255.25532,766
67108.33.0.0/17108.33.0.1 to 108.33.127.254108.33.127.25532,766
68108.33.128.0/17108.33.128.1 to 108.33.255.254108.33.255.25532,766
69108.34.0.0/17108.34.0.1 to 108.34.127.254108.34.127.25532,766
70108.34.128.0/17108.34.128.1 to 108.34.255.254108.34.255.25532,766
71108.35.0.0/17108.35.0.1 to 108.35.127.254108.35.127.25532,766
72108.35.128.0/17108.35.128.1 to 108.35.255.254108.35.255.25532,766
73108.36.0.0/17108.36.0.1 to 108.36.127.254108.36.127.25532,766
74108.36.128.0/17108.36.128.1 to 108.36.255.254108.36.255.25532,766
75108.37.0.0/17108.37.0.1 to 108.37.127.254108.37.127.25532,766
76108.37.128.0/17108.37.128.1 to 108.37.255.254108.37.255.25532,766
77108.38.0.0/17108.38.0.1 to 108.38.127.254108.38.127.25532,766
78108.38.128.0/17108.38.128.1 to 108.38.255.254108.38.255.25532,766
79108.39.0.0/17108.39.0.1 to 108.39.127.254108.39.127.25532,766
80108.39.128.0/17108.39.128.1 to 108.39.255.254108.39.255.25532,766
81108.40.0.0/17108.40.0.1 to 108.40.127.254108.40.127.25532,766
82108.40.128.0/17108.40.128.1 to 108.40.255.254108.40.255.25532,766
83108.41.0.0/17108.41.0.1 to 108.41.127.254108.41.127.25532,766
84108.41.128.0/17108.41.128.1 to 108.41.255.254108.41.255.25532,766
85108.42.0.0/17108.42.0.1 to 108.42.127.254108.42.127.25532,766
86108.42.128.0/17108.42.128.1 to 108.42.255.254108.42.255.25532,766
87108.43.0.0/17108.43.0.1 to 108.43.127.254108.43.127.25532,766
88108.43.128.0/17108.43.128.1 to 108.43.255.254108.43.255.25532,766
89108.44.0.0/17108.44.0.1 to 108.44.127.254108.44.127.25532,766
90108.44.128.0/17108.44.128.1 to 108.44.255.254108.44.255.25532,766
91108.45.0.0/17108.45.0.1 to 108.45.127.254108.45.127.25532,766
92108.45.128.0/17108.45.128.1 to 108.45.255.254108.45.255.25532,766
93108.46.0.0/17108.46.0.1 to 108.46.127.254108.46.127.25532,766
94108.46.128.0/17108.46.128.1 to 108.46.255.254108.46.255.25532,766
95108.47.0.0/17108.47.0.1 to 108.47.127.254108.47.127.25532,766
96108.47.128.0/17108.47.128.1 to 108.47.255.254108.47.255.25532,766
97108.48.0.0/17108.48.0.1 to 108.48.127.254108.48.127.25532,766
98108.48.128.0/17108.48.128.1 to 108.48.255.254108.48.255.25532,766
99108.49.0.0/17108.49.0.1 to 108.49.127.254108.49.127.25532,766
100108.49.128.0/17108.49.128.1 to 108.49.255.254108.49.255.25532,766
101108.50.0.0/17108.50.0.1 to 108.50.127.254108.50.127.25532,766
102108.50.128.0/17108.50.128.1 to 108.50.255.254108.50.255.25532,766
103108.51.0.0/17108.51.0.1 to 108.51.127.254108.51.127.25532,766
104108.51.128.0/17108.51.128.1 to 108.51.255.254108.51.255.25532,766
105108.52.0.0/17108.52.0.1 to 108.52.127.254108.52.127.25532,766
106108.52.128.0/17108.52.128.1 to 108.52.255.254108.52.255.25532,766
107108.53.0.0/17108.53.0.1 to 108.53.127.254108.53.127.25532,766
108108.53.128.0/17108.53.128.1 to 108.53.255.254108.53.255.25532,766
109108.54.0.0/17108.54.0.1 to 108.54.127.254108.54.127.25532,766
110108.54.128.0/17108.54.128.1 to 108.54.255.254108.54.255.25532,766
111108.55.0.0/17108.55.0.1 to 108.55.127.254108.55.127.25532,766
112108.55.128.0/17108.55.128.1 to 108.55.255.254108.55.255.25532,766
113108.56.0.0/17108.56.0.1 to 108.56.127.254108.56.127.25532,766
114108.56.128.0/17108.56.128.1 to 108.56.255.254108.56.255.25532,766
115108.57.0.0/17108.57.0.1 to 108.57.127.254108.57.127.25532,766
116108.57.128.0/17108.57.128.1 to 108.57.255.254108.57.255.25532,766
117108.58.0.0/17108.58.0.1 to 108.58.127.254108.58.127.25532,766
118108.58.128.0/17108.58.128.1 to 108.58.255.254108.58.255.25532,766
119108.59.0.0/17108.59.0.1 to 108.59.127.254108.59.127.25532,766
120108.59.128.0/17108.59.128.1 to 108.59.255.254108.59.255.25532,766
121108.60.0.0/17108.60.0.1 to 108.60.127.254108.60.127.25532,766
122108.60.128.0/17108.60.128.1 to 108.60.255.254108.60.255.25532,766
123108.61.0.0/17108.61.0.1 to 108.61.127.254108.61.127.25532,766
124108.61.128.0/17108.61.128.1 to 108.61.255.254108.61.255.25532,766
125108.62.0.0/17108.62.0.1 to 108.62.127.254108.62.127.25532,766
126108.62.128.0/17108.62.128.1 to 108.62.255.254108.62.255.25532,766
127108.63.0.0/17108.63.0.1 to 108.63.127.254108.63.127.25532,766
128108.63.128.0/17108.63.128.1 to 108.63.255.254108.63.255.25532,766
129108.64.0.0/17108.64.0.1 to 108.64.127.254108.64.127.25532,766
130108.64.128.0/17108.64.128.1 to 108.64.255.254108.64.255.25532,766
131108.65.0.0/17108.65.0.1 to 108.65.127.254108.65.127.25532,766
132108.65.128.0/17108.65.128.1 to 108.65.255.254108.65.255.25532,766
133108.66.0.0/17108.66.0.1 to 108.66.127.254108.66.127.25532,766
134108.66.128.0/17108.66.128.1 to 108.66.255.254108.66.255.25532,766
135108.67.0.0/17108.67.0.1 to 108.67.127.254108.67.127.25532,766
136108.67.128.0/17108.67.128.1 to 108.67.255.254108.67.255.25532,766
137108.68.0.0/17108.68.0.1 to 108.68.127.254108.68.127.25532,766
138108.68.128.0/17108.68.128.1 to 108.68.255.254108.68.255.25532,766
139108.69.0.0/17108.69.0.1 to 108.69.127.254108.69.127.25532,766
140108.69.128.0/17108.69.128.1 to 108.69.255.254108.69.255.25532,766
141108.70.0.0/17108.70.0.1 to 108.70.127.254108.70.127.25532,766
142108.70.128.0/17108.70.128.1 to 108.70.255.254108.70.255.25532,766
143108.71.0.0/17108.71.0.1 to 108.71.127.254108.71.127.25532,766
144108.71.128.0/17108.71.128.1 to 108.71.255.254108.71.255.25532,766
145108.72.0.0/17108.72.0.1 to 108.72.127.254108.72.127.25532,766
146108.72.128.0/17108.72.128.1 to 108.72.255.254108.72.255.25532,766
147108.73.0.0/17108.73.0.1 to 108.73.127.254108.73.127.25532,766
148108.73.128.0/17108.73.128.1 to 108.73.255.254108.73.255.25532,766
149108.74.0.0/17108.74.0.1 to 108.74.127.254108.74.127.25532,766
150108.74.128.0/17108.74.128.1 to 108.74.255.254108.74.255.25532,766
151108.75.0.0/17108.75.0.1 to 108.75.127.254108.75.127.25532,766
152108.75.128.0/17108.75.128.1 to 108.75.255.254108.75.255.25532,766
153108.76.0.0/17108.76.0.1 to 108.76.127.254108.76.127.25532,766
154108.76.128.0/17108.76.128.1 to 108.76.255.254108.76.255.25532,766
155108.77.0.0/17108.77.0.1 to 108.77.127.254108.77.127.25532,766
156108.77.128.0/17108.77.128.1 to 108.77.255.254108.77.255.25532,766
157108.78.0.0/17108.78.0.1 to 108.78.127.254108.78.127.25532,766
158108.78.128.0/17108.78.128.1 to 108.78.255.254108.78.255.25532,766
159108.79.0.0/17108.79.0.1 to 108.79.127.254108.79.127.25532,766
160108.79.128.0/17108.79.128.1 to 108.79.255.254108.79.255.25532,766
161108.80.0.0/17108.80.0.1 to 108.80.127.254108.80.127.25532,766
162108.80.128.0/17108.80.128.1 to 108.80.255.254108.80.255.25532,766
163108.81.0.0/17108.81.0.1 to 108.81.127.254108.81.127.25532,766
164108.81.128.0/17108.81.128.1 to 108.81.255.254108.81.255.25532,766
165108.82.0.0/17108.82.0.1 to 108.82.127.254108.82.127.25532,766
166108.82.128.0/17108.82.128.1 to 108.82.255.254108.82.255.25532,766
167108.83.0.0/17108.83.0.1 to 108.83.127.254108.83.127.25532,766
168108.83.128.0/17108.83.128.1 to 108.83.255.254108.83.255.25532,766
169108.84.0.0/17108.84.0.1 to 108.84.127.254108.84.127.25532,766
170108.84.128.0/17108.84.128.1 to 108.84.255.254108.84.255.25532,766
171108.85.0.0/17108.85.0.1 to 108.85.127.254108.85.127.25532,766
172108.85.128.0/17108.85.128.1 to 108.85.255.254108.85.255.25532,766
173108.86.0.0/17108.86.0.1 to 108.86.127.254108.86.127.25532,766
174108.86.128.0/17108.86.128.1 to 108.86.255.254108.86.255.25532,766
175108.87.0.0/17108.87.0.1 to 108.87.127.254108.87.127.25532,766
176108.87.128.0/17108.87.128.1 to 108.87.255.254108.87.255.25532,766
177108.88.0.0/17108.88.0.1 to 108.88.127.254108.88.127.25532,766
178108.88.128.0/17108.88.128.1 to 108.88.255.254108.88.255.25532,766
179108.89.0.0/17108.89.0.1 to 108.89.127.254108.89.127.25532,766
180108.89.128.0/17108.89.128.1 to 108.89.255.254108.89.255.25532,766
181108.90.0.0/17108.90.0.1 to 108.90.127.254108.90.127.25532,766
182108.90.128.0/17108.90.128.1 to 108.90.255.254108.90.255.25532,766
183108.91.0.0/17108.91.0.1 to 108.91.127.254108.91.127.25532,766
184108.91.128.0/17108.91.128.1 to 108.91.255.254108.91.255.25532,766
185108.92.0.0/17108.92.0.1 to 108.92.127.254108.92.127.25532,766
186108.92.128.0/17108.92.128.1 to 108.92.255.254108.92.255.25532,766
187108.93.0.0/17108.93.0.1 to 108.93.127.254108.93.127.25532,766
188108.93.128.0/17108.93.128.1 to 108.93.255.254108.93.255.25532,766
189108.94.0.0/17108.94.0.1 to 108.94.127.254108.94.127.25532,766
190108.94.128.0/17108.94.128.1 to 108.94.255.254108.94.255.25532,766
191108.95.0.0/17108.95.0.1 to 108.95.127.254108.95.127.25532,766
192108.95.128.0/17108.95.128.1 to 108.95.255.254108.95.255.25532,766
193108.96.0.0/17108.96.0.1 to 108.96.127.254108.96.127.25532,766
194108.96.128.0/17108.96.128.1 to 108.96.255.254108.96.255.25532,766
195108.97.0.0/17108.97.0.1 to 108.97.127.254108.97.127.25532,766
196108.97.128.0/17108.97.128.1 to 108.97.255.254108.97.255.25532,766
197108.98.0.0/17108.98.0.1 to 108.98.127.254108.98.127.25532,766
198108.98.128.0/17108.98.128.1 to 108.98.255.254108.98.255.25532,766
199108.99.0.0/17108.99.0.1 to 108.99.127.254108.99.127.25532,766
200108.99.128.0/17108.99.128.1 to 108.99.255.254108.99.255.25532,766
201108.100.0.0/17108.100.0.1 to 108.100.127.254108.100.127.25532,766
202108.100.128.0/17108.100.128.1 to 108.100.255.254108.100.255.25532,766
203108.101.0.0/17108.101.0.1 to 108.101.127.254108.101.127.25532,766
204108.101.128.0/17108.101.128.1 to 108.101.255.254108.101.255.25532,766
205108.102.0.0/17108.102.0.1 to 108.102.127.254108.102.127.25532,766
206108.102.128.0/17108.102.128.1 to 108.102.255.254108.102.255.25532,766
207108.103.0.0/17108.103.0.1 to 108.103.127.254108.103.127.25532,766
208108.103.128.0/17108.103.128.1 to 108.103.255.254108.103.255.25532,766
209108.104.0.0/17108.104.0.1 to 108.104.127.254108.104.127.25532,766
210108.104.128.0/17108.104.128.1 to 108.104.255.254108.104.255.25532,766
211108.105.0.0/17108.105.0.1 to 108.105.127.254108.105.127.25532,766
212108.105.128.0/17108.105.128.1 to 108.105.255.254108.105.255.25532,766
213108.106.0.0/17108.106.0.1 to 108.106.127.254108.106.127.25532,766
214108.106.128.0/17108.106.128.1 to 108.106.255.254108.106.255.25532,766
215108.107.0.0/17108.107.0.1 to 108.107.127.254108.107.127.25532,766
216108.107.128.0/17108.107.128.1 to 108.107.255.254108.107.255.25532,766
217108.108.0.0/17108.108.0.1 to 108.108.127.254108.108.127.25532,766
218108.108.128.0/17108.108.128.1 to 108.108.255.254108.108.255.25532,766
219108.109.0.0/17108.109.0.1 to 108.109.127.254108.109.127.25532,766
220108.109.128.0/17108.109.128.1 to 108.109.255.254108.109.255.25532,766
221108.110.0.0/17108.110.0.1 to 108.110.127.254108.110.127.25532,766
222108.110.128.0/17108.110.128.1 to 108.110.255.254108.110.255.25532,766
223108.111.0.0/17108.111.0.1 to 108.111.127.254108.111.127.25532,766
224108.111.128.0/17108.111.128.1 to 108.111.255.254108.111.255.25532,766
225108.112.0.0/17108.112.0.1 to 108.112.127.254108.112.127.25532,766
226108.112.128.0/17108.112.128.1 to 108.112.255.254108.112.255.25532,766
227108.113.0.0/17108.113.0.1 to 108.113.127.254108.113.127.25532,766
228108.113.128.0/17108.113.128.1 to 108.113.255.254108.113.255.25532,766
229108.114.0.0/17108.114.0.1 to 108.114.127.254108.114.127.25532,766
230108.114.128.0/17108.114.128.1 to 108.114.255.254108.114.255.25532,766
231108.115.0.0/17108.115.0.1 to 108.115.127.254108.115.127.25532,766
232108.115.128.0/17108.115.128.1 to 108.115.255.254108.115.255.25532,766
233108.116.0.0/17108.116.0.1 to 108.116.127.254108.116.127.25532,766
234108.116.128.0/17108.116.128.1 to 108.116.255.254108.116.255.25532,766
235108.117.0.0/17108.117.0.1 to 108.117.127.254108.117.127.25532,766
236108.117.128.0/17108.117.128.1 to 108.117.255.254108.117.255.25532,766
237108.118.0.0/17108.118.0.1 to 108.118.127.254108.118.127.25532,766
238108.118.128.0/17108.118.128.1 to 108.118.255.254108.118.255.25532,766
239108.119.0.0/17108.119.0.1 to 108.119.127.254108.119.127.25532,766
240108.119.128.0/17108.119.128.1 to 108.119.255.254108.119.255.25532,766
241108.120.0.0/17108.120.0.1 to 108.120.127.254108.120.127.25532,766
242108.120.128.0/17108.120.128.1 to 108.120.255.254108.120.255.25532,766
243108.121.0.0/17108.121.0.1 to 108.121.127.254108.121.127.25532,766
244108.121.128.0/17108.121.128.1 to 108.121.255.254108.121.255.25532,766
245108.122.0.0/17108.122.0.1 to 108.122.127.254108.122.127.25532,766
246108.122.128.0/17108.122.128.1 to 108.122.255.254108.122.255.25532,766
247108.123.0.0/17108.123.0.1 to 108.123.127.254108.123.127.25532,766
248108.123.128.0/17108.123.128.1 to 108.123.255.254108.123.255.25532,766
249108.124.0.0/17108.124.0.1 to 108.124.127.254108.124.127.25532,766
250108.124.128.0/17108.124.128.1 to 108.124.255.254108.124.255.25532,766
251108.125.0.0/17108.125.0.1 to 108.125.127.254108.125.127.25532,766
252108.125.128.0/17108.125.128.1 to 108.125.255.254108.125.255.25532,766
253108.126.0.0/17108.126.0.1 to 108.126.127.254108.126.127.25532,766
254108.126.128.0/17108.126.128.1 to 108.126.255.254108.126.255.25532,766
255108.127.0.0/17108.127.0.1 to 108.127.127.254108.127.127.25532,766
256108.127.128.0/17108.127.128.1 to 108.127.255.254108.127.255.25532,766

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.