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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.

Network176.2.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
176.2.0.0
Broadcast address
176.3.255.255
First usable
176.2.0.1
Last usable
176.3.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex B0020000 · Integer 2952921088 to 2953052159
Reverse DNS zones
2.176.in-addr.arpa
3.176.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110000.00000010.00000000.00000000176.2.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10110000.00000010.00000000.00000000176.2.0.0
Broadcast10110000.00000011.11111111.11111111176.3.255.255
Split into smaller subnets/25
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

176.2.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1176.2.0.0/25176.2.0.1 to 176.2.0.126176.2.0.127126
2176.2.0.128/25176.2.0.129 to 176.2.0.254176.2.0.255126
3176.2.1.0/25176.2.1.1 to 176.2.1.126176.2.1.127126
4176.2.1.128/25176.2.1.129 to 176.2.1.254176.2.1.255126
5176.2.2.0/25176.2.2.1 to 176.2.2.126176.2.2.127126
6176.2.2.128/25176.2.2.129 to 176.2.2.254176.2.2.255126
7176.2.3.0/25176.2.3.1 to 176.2.3.126176.2.3.127126
8176.2.3.128/25176.2.3.129 to 176.2.3.254176.2.3.255126
9176.2.4.0/25176.2.4.1 to 176.2.4.126176.2.4.127126
10176.2.4.128/25176.2.4.129 to 176.2.4.254176.2.4.255126
11176.2.5.0/25176.2.5.1 to 176.2.5.126176.2.5.127126
12176.2.5.128/25176.2.5.129 to 176.2.5.254176.2.5.255126
13176.2.6.0/25176.2.6.1 to 176.2.6.126176.2.6.127126
14176.2.6.128/25176.2.6.129 to 176.2.6.254176.2.6.255126
15176.2.7.0/25176.2.7.1 to 176.2.7.126176.2.7.127126
16176.2.7.128/25176.2.7.129 to 176.2.7.254176.2.7.255126
17176.2.8.0/25176.2.8.1 to 176.2.8.126176.2.8.127126
18176.2.8.128/25176.2.8.129 to 176.2.8.254176.2.8.255126
19176.2.9.0/25176.2.9.1 to 176.2.9.126176.2.9.127126
20176.2.9.128/25176.2.9.129 to 176.2.9.254176.2.9.255126
21176.2.10.0/25176.2.10.1 to 176.2.10.126176.2.10.127126
22176.2.10.128/25176.2.10.129 to 176.2.10.254176.2.10.255126
23176.2.11.0/25176.2.11.1 to 176.2.11.126176.2.11.127126
24176.2.11.128/25176.2.11.129 to 176.2.11.254176.2.11.255126
25176.2.12.0/25176.2.12.1 to 176.2.12.126176.2.12.127126
26176.2.12.128/25176.2.12.129 to 176.2.12.254176.2.12.255126
27176.2.13.0/25176.2.13.1 to 176.2.13.126176.2.13.127126
28176.2.13.128/25176.2.13.129 to 176.2.13.254176.2.13.255126
29176.2.14.0/25176.2.14.1 to 176.2.14.126176.2.14.127126
30176.2.14.128/25176.2.14.129 to 176.2.14.254176.2.14.255126
31176.2.15.0/25176.2.15.1 to 176.2.15.126176.2.15.127126
32176.2.15.128/25176.2.15.129 to 176.2.15.254176.2.15.255126
33176.2.16.0/25176.2.16.1 to 176.2.16.126176.2.16.127126
34176.2.16.128/25176.2.16.129 to 176.2.16.254176.2.16.255126
35176.2.17.0/25176.2.17.1 to 176.2.17.126176.2.17.127126
36176.2.17.128/25176.2.17.129 to 176.2.17.254176.2.17.255126
37176.2.18.0/25176.2.18.1 to 176.2.18.126176.2.18.127126
38176.2.18.128/25176.2.18.129 to 176.2.18.254176.2.18.255126
39176.2.19.0/25176.2.19.1 to 176.2.19.126176.2.19.127126
40176.2.19.128/25176.2.19.129 to 176.2.19.254176.2.19.255126
41176.2.20.0/25176.2.20.1 to 176.2.20.126176.2.20.127126
42176.2.20.128/25176.2.20.129 to 176.2.20.254176.2.20.255126
43176.2.21.0/25176.2.21.1 to 176.2.21.126176.2.21.127126
44176.2.21.128/25176.2.21.129 to 176.2.21.254176.2.21.255126
45176.2.22.0/25176.2.22.1 to 176.2.22.126176.2.22.127126
46176.2.22.128/25176.2.22.129 to 176.2.22.254176.2.22.255126
47176.2.23.0/25176.2.23.1 to 176.2.23.126176.2.23.127126
48176.2.23.128/25176.2.23.129 to 176.2.23.254176.2.23.255126
49176.2.24.0/25176.2.24.1 to 176.2.24.126176.2.24.127126
50176.2.24.128/25176.2.24.129 to 176.2.24.254176.2.24.255126
51176.2.25.0/25176.2.25.1 to 176.2.25.126176.2.25.127126
52176.2.25.128/25176.2.25.129 to 176.2.25.254176.2.25.255126
53176.2.26.0/25176.2.26.1 to 176.2.26.126176.2.26.127126
54176.2.26.128/25176.2.26.129 to 176.2.26.254176.2.26.255126
55176.2.27.0/25176.2.27.1 to 176.2.27.126176.2.27.127126
56176.2.27.128/25176.2.27.129 to 176.2.27.254176.2.27.255126
57176.2.28.0/25176.2.28.1 to 176.2.28.126176.2.28.127126
58176.2.28.128/25176.2.28.129 to 176.2.28.254176.2.28.255126
59176.2.29.0/25176.2.29.1 to 176.2.29.126176.2.29.127126
60176.2.29.128/25176.2.29.129 to 176.2.29.254176.2.29.255126
61176.2.30.0/25176.2.30.1 to 176.2.30.126176.2.30.127126
62176.2.30.128/25176.2.30.129 to 176.2.30.254176.2.30.255126
63176.2.31.0/25176.2.31.1 to 176.2.31.126176.2.31.127126
64176.2.31.128/25176.2.31.129 to 176.2.31.254176.2.31.255126
65176.2.32.0/25176.2.32.1 to 176.2.32.126176.2.32.127126
66176.2.32.128/25176.2.32.129 to 176.2.32.254176.2.32.255126
67176.2.33.0/25176.2.33.1 to 176.2.33.126176.2.33.127126
68176.2.33.128/25176.2.33.129 to 176.2.33.254176.2.33.255126
69176.2.34.0/25176.2.34.1 to 176.2.34.126176.2.34.127126
70176.2.34.128/25176.2.34.129 to 176.2.34.254176.2.34.255126
71176.2.35.0/25176.2.35.1 to 176.2.35.126176.2.35.127126
72176.2.35.128/25176.2.35.129 to 176.2.35.254176.2.35.255126
73176.2.36.0/25176.2.36.1 to 176.2.36.126176.2.36.127126
74176.2.36.128/25176.2.36.129 to 176.2.36.254176.2.36.255126
75176.2.37.0/25176.2.37.1 to 176.2.37.126176.2.37.127126
76176.2.37.128/25176.2.37.129 to 176.2.37.254176.2.37.255126
77176.2.38.0/25176.2.38.1 to 176.2.38.126176.2.38.127126
78176.2.38.128/25176.2.38.129 to 176.2.38.254176.2.38.255126
79176.2.39.0/25176.2.39.1 to 176.2.39.126176.2.39.127126
80176.2.39.128/25176.2.39.129 to 176.2.39.254176.2.39.255126
81176.2.40.0/25176.2.40.1 to 176.2.40.126176.2.40.127126
82176.2.40.128/25176.2.40.129 to 176.2.40.254176.2.40.255126
83176.2.41.0/25176.2.41.1 to 176.2.41.126176.2.41.127126
84176.2.41.128/25176.2.41.129 to 176.2.41.254176.2.41.255126
85176.2.42.0/25176.2.42.1 to 176.2.42.126176.2.42.127126
86176.2.42.128/25176.2.42.129 to 176.2.42.254176.2.42.255126
87176.2.43.0/25176.2.43.1 to 176.2.43.126176.2.43.127126
88176.2.43.128/25176.2.43.129 to 176.2.43.254176.2.43.255126
89176.2.44.0/25176.2.44.1 to 176.2.44.126176.2.44.127126
90176.2.44.128/25176.2.44.129 to 176.2.44.254176.2.44.255126
91176.2.45.0/25176.2.45.1 to 176.2.45.126176.2.45.127126
92176.2.45.128/25176.2.45.129 to 176.2.45.254176.2.45.255126
93176.2.46.0/25176.2.46.1 to 176.2.46.126176.2.46.127126
94176.2.46.128/25176.2.46.129 to 176.2.46.254176.2.46.255126
95176.2.47.0/25176.2.47.1 to 176.2.47.126176.2.47.127126
96176.2.47.128/25176.2.47.129 to 176.2.47.254176.2.47.255126
97176.2.48.0/25176.2.48.1 to 176.2.48.126176.2.48.127126
98176.2.48.128/25176.2.48.129 to 176.2.48.254176.2.48.255126
99176.2.49.0/25176.2.49.1 to 176.2.49.126176.2.49.127126
100176.2.49.128/25176.2.49.129 to 176.2.49.254176.2.49.255126
101176.2.50.0/25176.2.50.1 to 176.2.50.126176.2.50.127126
102176.2.50.128/25176.2.50.129 to 176.2.50.254176.2.50.255126
103176.2.51.0/25176.2.51.1 to 176.2.51.126176.2.51.127126
104176.2.51.128/25176.2.51.129 to 176.2.51.254176.2.51.255126
105176.2.52.0/25176.2.52.1 to 176.2.52.126176.2.52.127126
106176.2.52.128/25176.2.52.129 to 176.2.52.254176.2.52.255126
107176.2.53.0/25176.2.53.1 to 176.2.53.126176.2.53.127126
108176.2.53.128/25176.2.53.129 to 176.2.53.254176.2.53.255126
109176.2.54.0/25176.2.54.1 to 176.2.54.126176.2.54.127126
110176.2.54.128/25176.2.54.129 to 176.2.54.254176.2.54.255126
111176.2.55.0/25176.2.55.1 to 176.2.55.126176.2.55.127126
112176.2.55.128/25176.2.55.129 to 176.2.55.254176.2.55.255126
113176.2.56.0/25176.2.56.1 to 176.2.56.126176.2.56.127126
114176.2.56.128/25176.2.56.129 to 176.2.56.254176.2.56.255126
115176.2.57.0/25176.2.57.1 to 176.2.57.126176.2.57.127126
116176.2.57.128/25176.2.57.129 to 176.2.57.254176.2.57.255126
117176.2.58.0/25176.2.58.1 to 176.2.58.126176.2.58.127126
118176.2.58.128/25176.2.58.129 to 176.2.58.254176.2.58.255126
119176.2.59.0/25176.2.59.1 to 176.2.59.126176.2.59.127126
120176.2.59.128/25176.2.59.129 to 176.2.59.254176.2.59.255126
121176.2.60.0/25176.2.60.1 to 176.2.60.126176.2.60.127126
122176.2.60.128/25176.2.60.129 to 176.2.60.254176.2.60.255126
123176.2.61.0/25176.2.61.1 to 176.2.61.126176.2.61.127126
124176.2.61.128/25176.2.61.129 to 176.2.61.254176.2.61.255126
125176.2.62.0/25176.2.62.1 to 176.2.62.126176.2.62.127126
126176.2.62.128/25176.2.62.129 to 176.2.62.254176.2.62.255126
127176.2.63.0/25176.2.63.1 to 176.2.63.126176.2.63.127126
128176.2.63.128/25176.2.63.129 to 176.2.63.254176.2.63.255126
129176.2.64.0/25176.2.64.1 to 176.2.64.126176.2.64.127126
130176.2.64.128/25176.2.64.129 to 176.2.64.254176.2.64.255126
131176.2.65.0/25176.2.65.1 to 176.2.65.126176.2.65.127126
132176.2.65.128/25176.2.65.129 to 176.2.65.254176.2.65.255126
133176.2.66.0/25176.2.66.1 to 176.2.66.126176.2.66.127126
134176.2.66.128/25176.2.66.129 to 176.2.66.254176.2.66.255126
135176.2.67.0/25176.2.67.1 to 176.2.67.126176.2.67.127126
136176.2.67.128/25176.2.67.129 to 176.2.67.254176.2.67.255126
137176.2.68.0/25176.2.68.1 to 176.2.68.126176.2.68.127126
138176.2.68.128/25176.2.68.129 to 176.2.68.254176.2.68.255126
139176.2.69.0/25176.2.69.1 to 176.2.69.126176.2.69.127126
140176.2.69.128/25176.2.69.129 to 176.2.69.254176.2.69.255126
141176.2.70.0/25176.2.70.1 to 176.2.70.126176.2.70.127126
142176.2.70.128/25176.2.70.129 to 176.2.70.254176.2.70.255126
143176.2.71.0/25176.2.71.1 to 176.2.71.126176.2.71.127126
144176.2.71.128/25176.2.71.129 to 176.2.71.254176.2.71.255126
145176.2.72.0/25176.2.72.1 to 176.2.72.126176.2.72.127126
146176.2.72.128/25176.2.72.129 to 176.2.72.254176.2.72.255126
147176.2.73.0/25176.2.73.1 to 176.2.73.126176.2.73.127126
148176.2.73.128/25176.2.73.129 to 176.2.73.254176.2.73.255126
149176.2.74.0/25176.2.74.1 to 176.2.74.126176.2.74.127126
150176.2.74.128/25176.2.74.129 to 176.2.74.254176.2.74.255126
151176.2.75.0/25176.2.75.1 to 176.2.75.126176.2.75.127126
152176.2.75.128/25176.2.75.129 to 176.2.75.254176.2.75.255126
153176.2.76.0/25176.2.76.1 to 176.2.76.126176.2.76.127126
154176.2.76.128/25176.2.76.129 to 176.2.76.254176.2.76.255126
155176.2.77.0/25176.2.77.1 to 176.2.77.126176.2.77.127126
156176.2.77.128/25176.2.77.129 to 176.2.77.254176.2.77.255126
157176.2.78.0/25176.2.78.1 to 176.2.78.126176.2.78.127126
158176.2.78.128/25176.2.78.129 to 176.2.78.254176.2.78.255126
159176.2.79.0/25176.2.79.1 to 176.2.79.126176.2.79.127126
160176.2.79.128/25176.2.79.129 to 176.2.79.254176.2.79.255126
161176.2.80.0/25176.2.80.1 to 176.2.80.126176.2.80.127126
162176.2.80.128/25176.2.80.129 to 176.2.80.254176.2.80.255126
163176.2.81.0/25176.2.81.1 to 176.2.81.126176.2.81.127126
164176.2.81.128/25176.2.81.129 to 176.2.81.254176.2.81.255126
165176.2.82.0/25176.2.82.1 to 176.2.82.126176.2.82.127126
166176.2.82.128/25176.2.82.129 to 176.2.82.254176.2.82.255126
167176.2.83.0/25176.2.83.1 to 176.2.83.126176.2.83.127126
168176.2.83.128/25176.2.83.129 to 176.2.83.254176.2.83.255126
169176.2.84.0/25176.2.84.1 to 176.2.84.126176.2.84.127126
170176.2.84.128/25176.2.84.129 to 176.2.84.254176.2.84.255126
171176.2.85.0/25176.2.85.1 to 176.2.85.126176.2.85.127126
172176.2.85.128/25176.2.85.129 to 176.2.85.254176.2.85.255126
173176.2.86.0/25176.2.86.1 to 176.2.86.126176.2.86.127126
174176.2.86.128/25176.2.86.129 to 176.2.86.254176.2.86.255126
175176.2.87.0/25176.2.87.1 to 176.2.87.126176.2.87.127126
176176.2.87.128/25176.2.87.129 to 176.2.87.254176.2.87.255126
177176.2.88.0/25176.2.88.1 to 176.2.88.126176.2.88.127126
178176.2.88.128/25176.2.88.129 to 176.2.88.254176.2.88.255126
179176.2.89.0/25176.2.89.1 to 176.2.89.126176.2.89.127126
180176.2.89.128/25176.2.89.129 to 176.2.89.254176.2.89.255126
181176.2.90.0/25176.2.90.1 to 176.2.90.126176.2.90.127126
182176.2.90.128/25176.2.90.129 to 176.2.90.254176.2.90.255126
183176.2.91.0/25176.2.91.1 to 176.2.91.126176.2.91.127126
184176.2.91.128/25176.2.91.129 to 176.2.91.254176.2.91.255126
185176.2.92.0/25176.2.92.1 to 176.2.92.126176.2.92.127126
186176.2.92.128/25176.2.92.129 to 176.2.92.254176.2.92.255126
187176.2.93.0/25176.2.93.1 to 176.2.93.126176.2.93.127126
188176.2.93.128/25176.2.93.129 to 176.2.93.254176.2.93.255126
189176.2.94.0/25176.2.94.1 to 176.2.94.126176.2.94.127126
190176.2.94.128/25176.2.94.129 to 176.2.94.254176.2.94.255126
191176.2.95.0/25176.2.95.1 to 176.2.95.126176.2.95.127126
192176.2.95.128/25176.2.95.129 to 176.2.95.254176.2.95.255126
193176.2.96.0/25176.2.96.1 to 176.2.96.126176.2.96.127126
194176.2.96.128/25176.2.96.129 to 176.2.96.254176.2.96.255126
195176.2.97.0/25176.2.97.1 to 176.2.97.126176.2.97.127126
196176.2.97.128/25176.2.97.129 to 176.2.97.254176.2.97.255126
197176.2.98.0/25176.2.98.1 to 176.2.98.126176.2.98.127126
198176.2.98.128/25176.2.98.129 to 176.2.98.254176.2.98.255126
199176.2.99.0/25176.2.99.1 to 176.2.99.126176.2.99.127126
200176.2.99.128/25176.2.99.129 to 176.2.99.254176.2.99.255126
201176.2.100.0/25176.2.100.1 to 176.2.100.126176.2.100.127126
202176.2.100.128/25176.2.100.129 to 176.2.100.254176.2.100.255126
203176.2.101.0/25176.2.101.1 to 176.2.101.126176.2.101.127126
204176.2.101.128/25176.2.101.129 to 176.2.101.254176.2.101.255126
205176.2.102.0/25176.2.102.1 to 176.2.102.126176.2.102.127126
206176.2.102.128/25176.2.102.129 to 176.2.102.254176.2.102.255126
207176.2.103.0/25176.2.103.1 to 176.2.103.126176.2.103.127126
208176.2.103.128/25176.2.103.129 to 176.2.103.254176.2.103.255126
209176.2.104.0/25176.2.104.1 to 176.2.104.126176.2.104.127126
210176.2.104.128/25176.2.104.129 to 176.2.104.254176.2.104.255126
211176.2.105.0/25176.2.105.1 to 176.2.105.126176.2.105.127126
212176.2.105.128/25176.2.105.129 to 176.2.105.254176.2.105.255126
213176.2.106.0/25176.2.106.1 to 176.2.106.126176.2.106.127126
214176.2.106.128/25176.2.106.129 to 176.2.106.254176.2.106.255126
215176.2.107.0/25176.2.107.1 to 176.2.107.126176.2.107.127126
216176.2.107.128/25176.2.107.129 to 176.2.107.254176.2.107.255126
217176.2.108.0/25176.2.108.1 to 176.2.108.126176.2.108.127126
218176.2.108.128/25176.2.108.129 to 176.2.108.254176.2.108.255126
219176.2.109.0/25176.2.109.1 to 176.2.109.126176.2.109.127126
220176.2.109.128/25176.2.109.129 to 176.2.109.254176.2.109.255126
221176.2.110.0/25176.2.110.1 to 176.2.110.126176.2.110.127126
222176.2.110.128/25176.2.110.129 to 176.2.110.254176.2.110.255126
223176.2.111.0/25176.2.111.1 to 176.2.111.126176.2.111.127126
224176.2.111.128/25176.2.111.129 to 176.2.111.254176.2.111.255126
225176.2.112.0/25176.2.112.1 to 176.2.112.126176.2.112.127126
226176.2.112.128/25176.2.112.129 to 176.2.112.254176.2.112.255126
227176.2.113.0/25176.2.113.1 to 176.2.113.126176.2.113.127126
228176.2.113.128/25176.2.113.129 to 176.2.113.254176.2.113.255126
229176.2.114.0/25176.2.114.1 to 176.2.114.126176.2.114.127126
230176.2.114.128/25176.2.114.129 to 176.2.114.254176.2.114.255126
231176.2.115.0/25176.2.115.1 to 176.2.115.126176.2.115.127126
232176.2.115.128/25176.2.115.129 to 176.2.115.254176.2.115.255126
233176.2.116.0/25176.2.116.1 to 176.2.116.126176.2.116.127126
234176.2.116.128/25176.2.116.129 to 176.2.116.254176.2.116.255126
235176.2.117.0/25176.2.117.1 to 176.2.117.126176.2.117.127126
236176.2.117.128/25176.2.117.129 to 176.2.117.254176.2.117.255126
237176.2.118.0/25176.2.118.1 to 176.2.118.126176.2.118.127126
238176.2.118.128/25176.2.118.129 to 176.2.118.254176.2.118.255126
239176.2.119.0/25176.2.119.1 to 176.2.119.126176.2.119.127126
240176.2.119.128/25176.2.119.129 to 176.2.119.254176.2.119.255126
241176.2.120.0/25176.2.120.1 to 176.2.120.126176.2.120.127126
242176.2.120.128/25176.2.120.129 to 176.2.120.254176.2.120.255126
243176.2.121.0/25176.2.121.1 to 176.2.121.126176.2.121.127126
244176.2.121.128/25176.2.121.129 to 176.2.121.254176.2.121.255126
245176.2.122.0/25176.2.122.1 to 176.2.122.126176.2.122.127126
246176.2.122.128/25176.2.122.129 to 176.2.122.254176.2.122.255126
247176.2.123.0/25176.2.123.1 to 176.2.123.126176.2.123.127126
248176.2.123.128/25176.2.123.129 to 176.2.123.254176.2.123.255126
249176.2.124.0/25176.2.124.1 to 176.2.124.126176.2.124.127126
250176.2.124.128/25176.2.124.129 to 176.2.124.254176.2.124.255126
251176.2.125.0/25176.2.125.1 to 176.2.125.126176.2.125.127126
252176.2.125.128/25176.2.125.129 to 176.2.125.254176.2.125.255126
253176.2.126.0/25176.2.126.1 to 176.2.126.126176.2.126.127126
254176.2.126.128/25176.2.126.129 to 176.2.126.254176.2.126.255126
255176.2.127.0/25176.2.127.1 to 176.2.127.126176.2.127.127126
256176.2.127.128/25176.2.127.129 to 176.2.127.254176.2.127.255126

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.