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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.

Network164.0.0.0/6
Usable hosts67,108,862
Subnet mask252.0.0.0
Addresses67,108,864
Network address
164.0.0.0
Broadcast address
167.255.255.255
First usable
164.0.0.1
Last usable
167.255.255.254
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
B (default /16)
As numbers
Hex A4000000 · Integer 2751463424 to 2818572287
Reverse DNS zones
164.in-addr.arpa
165.in-addr.arpa
166.in-addr.arpa
167.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
Address10100100.00000000.00000000.00000000164.0.0.0
Subnet mask11111100.00000000.00000000.00000000252.0.0.0
Network10100100.00000000.00000000.00000000164.0.0.0
Broadcast10100111.11111111.11111111.11111111167.255.255.255
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)

164.0.0.0/6 makes 2,048 subnets of /17; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1164.0.0.0/17164.0.0.1 to 164.0.127.254164.0.127.25532,766
2164.0.128.0/17164.0.128.1 to 164.0.255.254164.0.255.25532,766
3164.1.0.0/17164.1.0.1 to 164.1.127.254164.1.127.25532,766
4164.1.128.0/17164.1.128.1 to 164.1.255.254164.1.255.25532,766
5164.2.0.0/17164.2.0.1 to 164.2.127.254164.2.127.25532,766
6164.2.128.0/17164.2.128.1 to 164.2.255.254164.2.255.25532,766
7164.3.0.0/17164.3.0.1 to 164.3.127.254164.3.127.25532,766
8164.3.128.0/17164.3.128.1 to 164.3.255.254164.3.255.25532,766
9164.4.0.0/17164.4.0.1 to 164.4.127.254164.4.127.25532,766
10164.4.128.0/17164.4.128.1 to 164.4.255.254164.4.255.25532,766
11164.5.0.0/17164.5.0.1 to 164.5.127.254164.5.127.25532,766
12164.5.128.0/17164.5.128.1 to 164.5.255.254164.5.255.25532,766
13164.6.0.0/17164.6.0.1 to 164.6.127.254164.6.127.25532,766
14164.6.128.0/17164.6.128.1 to 164.6.255.254164.6.255.25532,766
15164.7.0.0/17164.7.0.1 to 164.7.127.254164.7.127.25532,766
16164.7.128.0/17164.7.128.1 to 164.7.255.254164.7.255.25532,766
17164.8.0.0/17164.8.0.1 to 164.8.127.254164.8.127.25532,766
18164.8.128.0/17164.8.128.1 to 164.8.255.254164.8.255.25532,766
19164.9.0.0/17164.9.0.1 to 164.9.127.254164.9.127.25532,766
20164.9.128.0/17164.9.128.1 to 164.9.255.254164.9.255.25532,766
21164.10.0.0/17164.10.0.1 to 164.10.127.254164.10.127.25532,766
22164.10.128.0/17164.10.128.1 to 164.10.255.254164.10.255.25532,766
23164.11.0.0/17164.11.0.1 to 164.11.127.254164.11.127.25532,766
24164.11.128.0/17164.11.128.1 to 164.11.255.254164.11.255.25532,766
25164.12.0.0/17164.12.0.1 to 164.12.127.254164.12.127.25532,766
26164.12.128.0/17164.12.128.1 to 164.12.255.254164.12.255.25532,766
27164.13.0.0/17164.13.0.1 to 164.13.127.254164.13.127.25532,766
28164.13.128.0/17164.13.128.1 to 164.13.255.254164.13.255.25532,766
29164.14.0.0/17164.14.0.1 to 164.14.127.254164.14.127.25532,766
30164.14.128.0/17164.14.128.1 to 164.14.255.254164.14.255.25532,766
31164.15.0.0/17164.15.0.1 to 164.15.127.254164.15.127.25532,766
32164.15.128.0/17164.15.128.1 to 164.15.255.254164.15.255.25532,766
33164.16.0.0/17164.16.0.1 to 164.16.127.254164.16.127.25532,766
34164.16.128.0/17164.16.128.1 to 164.16.255.254164.16.255.25532,766
35164.17.0.0/17164.17.0.1 to 164.17.127.254164.17.127.25532,766
36164.17.128.0/17164.17.128.1 to 164.17.255.254164.17.255.25532,766
37164.18.0.0/17164.18.0.1 to 164.18.127.254164.18.127.25532,766
38164.18.128.0/17164.18.128.1 to 164.18.255.254164.18.255.25532,766
39164.19.0.0/17164.19.0.1 to 164.19.127.254164.19.127.25532,766
40164.19.128.0/17164.19.128.1 to 164.19.255.254164.19.255.25532,766
41164.20.0.0/17164.20.0.1 to 164.20.127.254164.20.127.25532,766
42164.20.128.0/17164.20.128.1 to 164.20.255.254164.20.255.25532,766
43164.21.0.0/17164.21.0.1 to 164.21.127.254164.21.127.25532,766
44164.21.128.0/17164.21.128.1 to 164.21.255.254164.21.255.25532,766
45164.22.0.0/17164.22.0.1 to 164.22.127.254164.22.127.25532,766
46164.22.128.0/17164.22.128.1 to 164.22.255.254164.22.255.25532,766
47164.23.0.0/17164.23.0.1 to 164.23.127.254164.23.127.25532,766
48164.23.128.0/17164.23.128.1 to 164.23.255.254164.23.255.25532,766
49164.24.0.0/17164.24.0.1 to 164.24.127.254164.24.127.25532,766
50164.24.128.0/17164.24.128.1 to 164.24.255.254164.24.255.25532,766
51164.25.0.0/17164.25.0.1 to 164.25.127.254164.25.127.25532,766
52164.25.128.0/17164.25.128.1 to 164.25.255.254164.25.255.25532,766
53164.26.0.0/17164.26.0.1 to 164.26.127.254164.26.127.25532,766
54164.26.128.0/17164.26.128.1 to 164.26.255.254164.26.255.25532,766
55164.27.0.0/17164.27.0.1 to 164.27.127.254164.27.127.25532,766
56164.27.128.0/17164.27.128.1 to 164.27.255.254164.27.255.25532,766
57164.28.0.0/17164.28.0.1 to 164.28.127.254164.28.127.25532,766
58164.28.128.0/17164.28.128.1 to 164.28.255.254164.28.255.25532,766
59164.29.0.0/17164.29.0.1 to 164.29.127.254164.29.127.25532,766
60164.29.128.0/17164.29.128.1 to 164.29.255.254164.29.255.25532,766
61164.30.0.0/17164.30.0.1 to 164.30.127.254164.30.127.25532,766
62164.30.128.0/17164.30.128.1 to 164.30.255.254164.30.255.25532,766
63164.31.0.0/17164.31.0.1 to 164.31.127.254164.31.127.25532,766
64164.31.128.0/17164.31.128.1 to 164.31.255.254164.31.255.25532,766
65164.32.0.0/17164.32.0.1 to 164.32.127.254164.32.127.25532,766
66164.32.128.0/17164.32.128.1 to 164.32.255.254164.32.255.25532,766
67164.33.0.0/17164.33.0.1 to 164.33.127.254164.33.127.25532,766
68164.33.128.0/17164.33.128.1 to 164.33.255.254164.33.255.25532,766
69164.34.0.0/17164.34.0.1 to 164.34.127.254164.34.127.25532,766
70164.34.128.0/17164.34.128.1 to 164.34.255.254164.34.255.25532,766
71164.35.0.0/17164.35.0.1 to 164.35.127.254164.35.127.25532,766
72164.35.128.0/17164.35.128.1 to 164.35.255.254164.35.255.25532,766
73164.36.0.0/17164.36.0.1 to 164.36.127.254164.36.127.25532,766
74164.36.128.0/17164.36.128.1 to 164.36.255.254164.36.255.25532,766
75164.37.0.0/17164.37.0.1 to 164.37.127.254164.37.127.25532,766
76164.37.128.0/17164.37.128.1 to 164.37.255.254164.37.255.25532,766
77164.38.0.0/17164.38.0.1 to 164.38.127.254164.38.127.25532,766
78164.38.128.0/17164.38.128.1 to 164.38.255.254164.38.255.25532,766
79164.39.0.0/17164.39.0.1 to 164.39.127.254164.39.127.25532,766
80164.39.128.0/17164.39.128.1 to 164.39.255.254164.39.255.25532,766
81164.40.0.0/17164.40.0.1 to 164.40.127.254164.40.127.25532,766
82164.40.128.0/17164.40.128.1 to 164.40.255.254164.40.255.25532,766
83164.41.0.0/17164.41.0.1 to 164.41.127.254164.41.127.25532,766
84164.41.128.0/17164.41.128.1 to 164.41.255.254164.41.255.25532,766
85164.42.0.0/17164.42.0.1 to 164.42.127.254164.42.127.25532,766
86164.42.128.0/17164.42.128.1 to 164.42.255.254164.42.255.25532,766
87164.43.0.0/17164.43.0.1 to 164.43.127.254164.43.127.25532,766
88164.43.128.0/17164.43.128.1 to 164.43.255.254164.43.255.25532,766
89164.44.0.0/17164.44.0.1 to 164.44.127.254164.44.127.25532,766
90164.44.128.0/17164.44.128.1 to 164.44.255.254164.44.255.25532,766
91164.45.0.0/17164.45.0.1 to 164.45.127.254164.45.127.25532,766
92164.45.128.0/17164.45.128.1 to 164.45.255.254164.45.255.25532,766
93164.46.0.0/17164.46.0.1 to 164.46.127.254164.46.127.25532,766
94164.46.128.0/17164.46.128.1 to 164.46.255.254164.46.255.25532,766
95164.47.0.0/17164.47.0.1 to 164.47.127.254164.47.127.25532,766
96164.47.128.0/17164.47.128.1 to 164.47.255.254164.47.255.25532,766
97164.48.0.0/17164.48.0.1 to 164.48.127.254164.48.127.25532,766
98164.48.128.0/17164.48.128.1 to 164.48.255.254164.48.255.25532,766
99164.49.0.0/17164.49.0.1 to 164.49.127.254164.49.127.25532,766
100164.49.128.0/17164.49.128.1 to 164.49.255.254164.49.255.25532,766
101164.50.0.0/17164.50.0.1 to 164.50.127.254164.50.127.25532,766
102164.50.128.0/17164.50.128.1 to 164.50.255.254164.50.255.25532,766
103164.51.0.0/17164.51.0.1 to 164.51.127.254164.51.127.25532,766
104164.51.128.0/17164.51.128.1 to 164.51.255.254164.51.255.25532,766
105164.52.0.0/17164.52.0.1 to 164.52.127.254164.52.127.25532,766
106164.52.128.0/17164.52.128.1 to 164.52.255.254164.52.255.25532,766
107164.53.0.0/17164.53.0.1 to 164.53.127.254164.53.127.25532,766
108164.53.128.0/17164.53.128.1 to 164.53.255.254164.53.255.25532,766
109164.54.0.0/17164.54.0.1 to 164.54.127.254164.54.127.25532,766
110164.54.128.0/17164.54.128.1 to 164.54.255.254164.54.255.25532,766
111164.55.0.0/17164.55.0.1 to 164.55.127.254164.55.127.25532,766
112164.55.128.0/17164.55.128.1 to 164.55.255.254164.55.255.25532,766
113164.56.0.0/17164.56.0.1 to 164.56.127.254164.56.127.25532,766
114164.56.128.0/17164.56.128.1 to 164.56.255.254164.56.255.25532,766
115164.57.0.0/17164.57.0.1 to 164.57.127.254164.57.127.25532,766
116164.57.128.0/17164.57.128.1 to 164.57.255.254164.57.255.25532,766
117164.58.0.0/17164.58.0.1 to 164.58.127.254164.58.127.25532,766
118164.58.128.0/17164.58.128.1 to 164.58.255.254164.58.255.25532,766
119164.59.0.0/17164.59.0.1 to 164.59.127.254164.59.127.25532,766
120164.59.128.0/17164.59.128.1 to 164.59.255.254164.59.255.25532,766
121164.60.0.0/17164.60.0.1 to 164.60.127.254164.60.127.25532,766
122164.60.128.0/17164.60.128.1 to 164.60.255.254164.60.255.25532,766
123164.61.0.0/17164.61.0.1 to 164.61.127.254164.61.127.25532,766
124164.61.128.0/17164.61.128.1 to 164.61.255.254164.61.255.25532,766
125164.62.0.0/17164.62.0.1 to 164.62.127.254164.62.127.25532,766
126164.62.128.0/17164.62.128.1 to 164.62.255.254164.62.255.25532,766
127164.63.0.0/17164.63.0.1 to 164.63.127.254164.63.127.25532,766
128164.63.128.0/17164.63.128.1 to 164.63.255.254164.63.255.25532,766
129164.64.0.0/17164.64.0.1 to 164.64.127.254164.64.127.25532,766
130164.64.128.0/17164.64.128.1 to 164.64.255.254164.64.255.25532,766
131164.65.0.0/17164.65.0.1 to 164.65.127.254164.65.127.25532,766
132164.65.128.0/17164.65.128.1 to 164.65.255.254164.65.255.25532,766
133164.66.0.0/17164.66.0.1 to 164.66.127.254164.66.127.25532,766
134164.66.128.0/17164.66.128.1 to 164.66.255.254164.66.255.25532,766
135164.67.0.0/17164.67.0.1 to 164.67.127.254164.67.127.25532,766
136164.67.128.0/17164.67.128.1 to 164.67.255.254164.67.255.25532,766
137164.68.0.0/17164.68.0.1 to 164.68.127.254164.68.127.25532,766
138164.68.128.0/17164.68.128.1 to 164.68.255.254164.68.255.25532,766
139164.69.0.0/17164.69.0.1 to 164.69.127.254164.69.127.25532,766
140164.69.128.0/17164.69.128.1 to 164.69.255.254164.69.255.25532,766
141164.70.0.0/17164.70.0.1 to 164.70.127.254164.70.127.25532,766
142164.70.128.0/17164.70.128.1 to 164.70.255.254164.70.255.25532,766
143164.71.0.0/17164.71.0.1 to 164.71.127.254164.71.127.25532,766
144164.71.128.0/17164.71.128.1 to 164.71.255.254164.71.255.25532,766
145164.72.0.0/17164.72.0.1 to 164.72.127.254164.72.127.25532,766
146164.72.128.0/17164.72.128.1 to 164.72.255.254164.72.255.25532,766
147164.73.0.0/17164.73.0.1 to 164.73.127.254164.73.127.25532,766
148164.73.128.0/17164.73.128.1 to 164.73.255.254164.73.255.25532,766
149164.74.0.0/17164.74.0.1 to 164.74.127.254164.74.127.25532,766
150164.74.128.0/17164.74.128.1 to 164.74.255.254164.74.255.25532,766
151164.75.0.0/17164.75.0.1 to 164.75.127.254164.75.127.25532,766
152164.75.128.0/17164.75.128.1 to 164.75.255.254164.75.255.25532,766
153164.76.0.0/17164.76.0.1 to 164.76.127.254164.76.127.25532,766
154164.76.128.0/17164.76.128.1 to 164.76.255.254164.76.255.25532,766
155164.77.0.0/17164.77.0.1 to 164.77.127.254164.77.127.25532,766
156164.77.128.0/17164.77.128.1 to 164.77.255.254164.77.255.25532,766
157164.78.0.0/17164.78.0.1 to 164.78.127.254164.78.127.25532,766
158164.78.128.0/17164.78.128.1 to 164.78.255.254164.78.255.25532,766
159164.79.0.0/17164.79.0.1 to 164.79.127.254164.79.127.25532,766
160164.79.128.0/17164.79.128.1 to 164.79.255.254164.79.255.25532,766
161164.80.0.0/17164.80.0.1 to 164.80.127.254164.80.127.25532,766
162164.80.128.0/17164.80.128.1 to 164.80.255.254164.80.255.25532,766
163164.81.0.0/17164.81.0.1 to 164.81.127.254164.81.127.25532,766
164164.81.128.0/17164.81.128.1 to 164.81.255.254164.81.255.25532,766
165164.82.0.0/17164.82.0.1 to 164.82.127.254164.82.127.25532,766
166164.82.128.0/17164.82.128.1 to 164.82.255.254164.82.255.25532,766
167164.83.0.0/17164.83.0.1 to 164.83.127.254164.83.127.25532,766
168164.83.128.0/17164.83.128.1 to 164.83.255.254164.83.255.25532,766
169164.84.0.0/17164.84.0.1 to 164.84.127.254164.84.127.25532,766
170164.84.128.0/17164.84.128.1 to 164.84.255.254164.84.255.25532,766
171164.85.0.0/17164.85.0.1 to 164.85.127.254164.85.127.25532,766
172164.85.128.0/17164.85.128.1 to 164.85.255.254164.85.255.25532,766
173164.86.0.0/17164.86.0.1 to 164.86.127.254164.86.127.25532,766
174164.86.128.0/17164.86.128.1 to 164.86.255.254164.86.255.25532,766
175164.87.0.0/17164.87.0.1 to 164.87.127.254164.87.127.25532,766
176164.87.128.0/17164.87.128.1 to 164.87.255.254164.87.255.25532,766
177164.88.0.0/17164.88.0.1 to 164.88.127.254164.88.127.25532,766
178164.88.128.0/17164.88.128.1 to 164.88.255.254164.88.255.25532,766
179164.89.0.0/17164.89.0.1 to 164.89.127.254164.89.127.25532,766
180164.89.128.0/17164.89.128.1 to 164.89.255.254164.89.255.25532,766
181164.90.0.0/17164.90.0.1 to 164.90.127.254164.90.127.25532,766
182164.90.128.0/17164.90.128.1 to 164.90.255.254164.90.255.25532,766
183164.91.0.0/17164.91.0.1 to 164.91.127.254164.91.127.25532,766
184164.91.128.0/17164.91.128.1 to 164.91.255.254164.91.255.25532,766
185164.92.0.0/17164.92.0.1 to 164.92.127.254164.92.127.25532,766
186164.92.128.0/17164.92.128.1 to 164.92.255.254164.92.255.25532,766
187164.93.0.0/17164.93.0.1 to 164.93.127.254164.93.127.25532,766
188164.93.128.0/17164.93.128.1 to 164.93.255.254164.93.255.25532,766
189164.94.0.0/17164.94.0.1 to 164.94.127.254164.94.127.25532,766
190164.94.128.0/17164.94.128.1 to 164.94.255.254164.94.255.25532,766
191164.95.0.0/17164.95.0.1 to 164.95.127.254164.95.127.25532,766
192164.95.128.0/17164.95.128.1 to 164.95.255.254164.95.255.25532,766
193164.96.0.0/17164.96.0.1 to 164.96.127.254164.96.127.25532,766
194164.96.128.0/17164.96.128.1 to 164.96.255.254164.96.255.25532,766
195164.97.0.0/17164.97.0.1 to 164.97.127.254164.97.127.25532,766
196164.97.128.0/17164.97.128.1 to 164.97.255.254164.97.255.25532,766
197164.98.0.0/17164.98.0.1 to 164.98.127.254164.98.127.25532,766
198164.98.128.0/17164.98.128.1 to 164.98.255.254164.98.255.25532,766
199164.99.0.0/17164.99.0.1 to 164.99.127.254164.99.127.25532,766
200164.99.128.0/17164.99.128.1 to 164.99.255.254164.99.255.25532,766
201164.100.0.0/17164.100.0.1 to 164.100.127.254164.100.127.25532,766
202164.100.128.0/17164.100.128.1 to 164.100.255.254164.100.255.25532,766
203164.101.0.0/17164.101.0.1 to 164.101.127.254164.101.127.25532,766
204164.101.128.0/17164.101.128.1 to 164.101.255.254164.101.255.25532,766
205164.102.0.0/17164.102.0.1 to 164.102.127.254164.102.127.25532,766
206164.102.128.0/17164.102.128.1 to 164.102.255.254164.102.255.25532,766
207164.103.0.0/17164.103.0.1 to 164.103.127.254164.103.127.25532,766
208164.103.128.0/17164.103.128.1 to 164.103.255.254164.103.255.25532,766
209164.104.0.0/17164.104.0.1 to 164.104.127.254164.104.127.25532,766
210164.104.128.0/17164.104.128.1 to 164.104.255.254164.104.255.25532,766
211164.105.0.0/17164.105.0.1 to 164.105.127.254164.105.127.25532,766
212164.105.128.0/17164.105.128.1 to 164.105.255.254164.105.255.25532,766
213164.106.0.0/17164.106.0.1 to 164.106.127.254164.106.127.25532,766
214164.106.128.0/17164.106.128.1 to 164.106.255.254164.106.255.25532,766
215164.107.0.0/17164.107.0.1 to 164.107.127.254164.107.127.25532,766
216164.107.128.0/17164.107.128.1 to 164.107.255.254164.107.255.25532,766
217164.108.0.0/17164.108.0.1 to 164.108.127.254164.108.127.25532,766
218164.108.128.0/17164.108.128.1 to 164.108.255.254164.108.255.25532,766
219164.109.0.0/17164.109.0.1 to 164.109.127.254164.109.127.25532,766
220164.109.128.0/17164.109.128.1 to 164.109.255.254164.109.255.25532,766
221164.110.0.0/17164.110.0.1 to 164.110.127.254164.110.127.25532,766
222164.110.128.0/17164.110.128.1 to 164.110.255.254164.110.255.25532,766
223164.111.0.0/17164.111.0.1 to 164.111.127.254164.111.127.25532,766
224164.111.128.0/17164.111.128.1 to 164.111.255.254164.111.255.25532,766
225164.112.0.0/17164.112.0.1 to 164.112.127.254164.112.127.25532,766
226164.112.128.0/17164.112.128.1 to 164.112.255.254164.112.255.25532,766
227164.113.0.0/17164.113.0.1 to 164.113.127.254164.113.127.25532,766
228164.113.128.0/17164.113.128.1 to 164.113.255.254164.113.255.25532,766
229164.114.0.0/17164.114.0.1 to 164.114.127.254164.114.127.25532,766
230164.114.128.0/17164.114.128.1 to 164.114.255.254164.114.255.25532,766
231164.115.0.0/17164.115.0.1 to 164.115.127.254164.115.127.25532,766
232164.115.128.0/17164.115.128.1 to 164.115.255.254164.115.255.25532,766
233164.116.0.0/17164.116.0.1 to 164.116.127.254164.116.127.25532,766
234164.116.128.0/17164.116.128.1 to 164.116.255.254164.116.255.25532,766
235164.117.0.0/17164.117.0.1 to 164.117.127.254164.117.127.25532,766
236164.117.128.0/17164.117.128.1 to 164.117.255.254164.117.255.25532,766
237164.118.0.0/17164.118.0.1 to 164.118.127.254164.118.127.25532,766
238164.118.128.0/17164.118.128.1 to 164.118.255.254164.118.255.25532,766
239164.119.0.0/17164.119.0.1 to 164.119.127.254164.119.127.25532,766
240164.119.128.0/17164.119.128.1 to 164.119.255.254164.119.255.25532,766
241164.120.0.0/17164.120.0.1 to 164.120.127.254164.120.127.25532,766
242164.120.128.0/17164.120.128.1 to 164.120.255.254164.120.255.25532,766
243164.121.0.0/17164.121.0.1 to 164.121.127.254164.121.127.25532,766
244164.121.128.0/17164.121.128.1 to 164.121.255.254164.121.255.25532,766
245164.122.0.0/17164.122.0.1 to 164.122.127.254164.122.127.25532,766
246164.122.128.0/17164.122.128.1 to 164.122.255.254164.122.255.25532,766
247164.123.0.0/17164.123.0.1 to 164.123.127.254164.123.127.25532,766
248164.123.128.0/17164.123.128.1 to 164.123.255.254164.123.255.25532,766
249164.124.0.0/17164.124.0.1 to 164.124.127.254164.124.127.25532,766
250164.124.128.0/17164.124.128.1 to 164.124.255.254164.124.255.25532,766
251164.125.0.0/17164.125.0.1 to 164.125.127.254164.125.127.25532,766
252164.125.128.0/17164.125.128.1 to 164.125.255.254164.125.255.25532,766
253164.126.0.0/17164.126.0.1 to 164.126.127.254164.126.127.25532,766
254164.126.128.0/17164.126.128.1 to 164.126.255.254164.126.255.25532,766
255164.127.0.0/17164.127.0.1 to 164.127.127.254164.127.127.25532,766
256164.127.128.0/17164.127.128.1 to 164.127.255.254164.127.255.25532,766

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.