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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.

Network165.158.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
165.158.0.0
Broadcast address
165.159.255.255
First usable
165.158.0.1
Last usable
165.159.255.254
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 A59E0000 · Integer 2778595328 to 2778726399
Reverse DNS zones
158.165.in-addr.arpa
159.165.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
Address10100101.10011110.00000000.00000000165.158.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10100101.10011110.00000000.00000000165.158.0.0
Broadcast10100101.10011111.11111111.11111111165.159.255.255
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)

165.158.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1165.158.0.0/25165.158.0.1 to 165.158.0.126165.158.0.127126
2165.158.0.128/25165.158.0.129 to 165.158.0.254165.158.0.255126
3165.158.1.0/25165.158.1.1 to 165.158.1.126165.158.1.127126
4165.158.1.128/25165.158.1.129 to 165.158.1.254165.158.1.255126
5165.158.2.0/25165.158.2.1 to 165.158.2.126165.158.2.127126
6165.158.2.128/25165.158.2.129 to 165.158.2.254165.158.2.255126
7165.158.3.0/25165.158.3.1 to 165.158.3.126165.158.3.127126
8165.158.3.128/25165.158.3.129 to 165.158.3.254165.158.3.255126
9165.158.4.0/25165.158.4.1 to 165.158.4.126165.158.4.127126
10165.158.4.128/25165.158.4.129 to 165.158.4.254165.158.4.255126
11165.158.5.0/25165.158.5.1 to 165.158.5.126165.158.5.127126
12165.158.5.128/25165.158.5.129 to 165.158.5.254165.158.5.255126
13165.158.6.0/25165.158.6.1 to 165.158.6.126165.158.6.127126
14165.158.6.128/25165.158.6.129 to 165.158.6.254165.158.6.255126
15165.158.7.0/25165.158.7.1 to 165.158.7.126165.158.7.127126
16165.158.7.128/25165.158.7.129 to 165.158.7.254165.158.7.255126
17165.158.8.0/25165.158.8.1 to 165.158.8.126165.158.8.127126
18165.158.8.128/25165.158.8.129 to 165.158.8.254165.158.8.255126
19165.158.9.0/25165.158.9.1 to 165.158.9.126165.158.9.127126
20165.158.9.128/25165.158.9.129 to 165.158.9.254165.158.9.255126
21165.158.10.0/25165.158.10.1 to 165.158.10.126165.158.10.127126
22165.158.10.128/25165.158.10.129 to 165.158.10.254165.158.10.255126
23165.158.11.0/25165.158.11.1 to 165.158.11.126165.158.11.127126
24165.158.11.128/25165.158.11.129 to 165.158.11.254165.158.11.255126
25165.158.12.0/25165.158.12.1 to 165.158.12.126165.158.12.127126
26165.158.12.128/25165.158.12.129 to 165.158.12.254165.158.12.255126
27165.158.13.0/25165.158.13.1 to 165.158.13.126165.158.13.127126
28165.158.13.128/25165.158.13.129 to 165.158.13.254165.158.13.255126
29165.158.14.0/25165.158.14.1 to 165.158.14.126165.158.14.127126
30165.158.14.128/25165.158.14.129 to 165.158.14.254165.158.14.255126
31165.158.15.0/25165.158.15.1 to 165.158.15.126165.158.15.127126
32165.158.15.128/25165.158.15.129 to 165.158.15.254165.158.15.255126
33165.158.16.0/25165.158.16.1 to 165.158.16.126165.158.16.127126
34165.158.16.128/25165.158.16.129 to 165.158.16.254165.158.16.255126
35165.158.17.0/25165.158.17.1 to 165.158.17.126165.158.17.127126
36165.158.17.128/25165.158.17.129 to 165.158.17.254165.158.17.255126
37165.158.18.0/25165.158.18.1 to 165.158.18.126165.158.18.127126
38165.158.18.128/25165.158.18.129 to 165.158.18.254165.158.18.255126
39165.158.19.0/25165.158.19.1 to 165.158.19.126165.158.19.127126
40165.158.19.128/25165.158.19.129 to 165.158.19.254165.158.19.255126
41165.158.20.0/25165.158.20.1 to 165.158.20.126165.158.20.127126
42165.158.20.128/25165.158.20.129 to 165.158.20.254165.158.20.255126
43165.158.21.0/25165.158.21.1 to 165.158.21.126165.158.21.127126
44165.158.21.128/25165.158.21.129 to 165.158.21.254165.158.21.255126
45165.158.22.0/25165.158.22.1 to 165.158.22.126165.158.22.127126
46165.158.22.128/25165.158.22.129 to 165.158.22.254165.158.22.255126
47165.158.23.0/25165.158.23.1 to 165.158.23.126165.158.23.127126
48165.158.23.128/25165.158.23.129 to 165.158.23.254165.158.23.255126
49165.158.24.0/25165.158.24.1 to 165.158.24.126165.158.24.127126
50165.158.24.128/25165.158.24.129 to 165.158.24.254165.158.24.255126
51165.158.25.0/25165.158.25.1 to 165.158.25.126165.158.25.127126
52165.158.25.128/25165.158.25.129 to 165.158.25.254165.158.25.255126
53165.158.26.0/25165.158.26.1 to 165.158.26.126165.158.26.127126
54165.158.26.128/25165.158.26.129 to 165.158.26.254165.158.26.255126
55165.158.27.0/25165.158.27.1 to 165.158.27.126165.158.27.127126
56165.158.27.128/25165.158.27.129 to 165.158.27.254165.158.27.255126
57165.158.28.0/25165.158.28.1 to 165.158.28.126165.158.28.127126
58165.158.28.128/25165.158.28.129 to 165.158.28.254165.158.28.255126
59165.158.29.0/25165.158.29.1 to 165.158.29.126165.158.29.127126
60165.158.29.128/25165.158.29.129 to 165.158.29.254165.158.29.255126
61165.158.30.0/25165.158.30.1 to 165.158.30.126165.158.30.127126
62165.158.30.128/25165.158.30.129 to 165.158.30.254165.158.30.255126
63165.158.31.0/25165.158.31.1 to 165.158.31.126165.158.31.127126
64165.158.31.128/25165.158.31.129 to 165.158.31.254165.158.31.255126
65165.158.32.0/25165.158.32.1 to 165.158.32.126165.158.32.127126
66165.158.32.128/25165.158.32.129 to 165.158.32.254165.158.32.255126
67165.158.33.0/25165.158.33.1 to 165.158.33.126165.158.33.127126
68165.158.33.128/25165.158.33.129 to 165.158.33.254165.158.33.255126
69165.158.34.0/25165.158.34.1 to 165.158.34.126165.158.34.127126
70165.158.34.128/25165.158.34.129 to 165.158.34.254165.158.34.255126
71165.158.35.0/25165.158.35.1 to 165.158.35.126165.158.35.127126
72165.158.35.128/25165.158.35.129 to 165.158.35.254165.158.35.255126
73165.158.36.0/25165.158.36.1 to 165.158.36.126165.158.36.127126
74165.158.36.128/25165.158.36.129 to 165.158.36.254165.158.36.255126
75165.158.37.0/25165.158.37.1 to 165.158.37.126165.158.37.127126
76165.158.37.128/25165.158.37.129 to 165.158.37.254165.158.37.255126
77165.158.38.0/25165.158.38.1 to 165.158.38.126165.158.38.127126
78165.158.38.128/25165.158.38.129 to 165.158.38.254165.158.38.255126
79165.158.39.0/25165.158.39.1 to 165.158.39.126165.158.39.127126
80165.158.39.128/25165.158.39.129 to 165.158.39.254165.158.39.255126
81165.158.40.0/25165.158.40.1 to 165.158.40.126165.158.40.127126
82165.158.40.128/25165.158.40.129 to 165.158.40.254165.158.40.255126
83165.158.41.0/25165.158.41.1 to 165.158.41.126165.158.41.127126
84165.158.41.128/25165.158.41.129 to 165.158.41.254165.158.41.255126
85165.158.42.0/25165.158.42.1 to 165.158.42.126165.158.42.127126
86165.158.42.128/25165.158.42.129 to 165.158.42.254165.158.42.255126
87165.158.43.0/25165.158.43.1 to 165.158.43.126165.158.43.127126
88165.158.43.128/25165.158.43.129 to 165.158.43.254165.158.43.255126
89165.158.44.0/25165.158.44.1 to 165.158.44.126165.158.44.127126
90165.158.44.128/25165.158.44.129 to 165.158.44.254165.158.44.255126
91165.158.45.0/25165.158.45.1 to 165.158.45.126165.158.45.127126
92165.158.45.128/25165.158.45.129 to 165.158.45.254165.158.45.255126
93165.158.46.0/25165.158.46.1 to 165.158.46.126165.158.46.127126
94165.158.46.128/25165.158.46.129 to 165.158.46.254165.158.46.255126
95165.158.47.0/25165.158.47.1 to 165.158.47.126165.158.47.127126
96165.158.47.128/25165.158.47.129 to 165.158.47.254165.158.47.255126
97165.158.48.0/25165.158.48.1 to 165.158.48.126165.158.48.127126
98165.158.48.128/25165.158.48.129 to 165.158.48.254165.158.48.255126
99165.158.49.0/25165.158.49.1 to 165.158.49.126165.158.49.127126
100165.158.49.128/25165.158.49.129 to 165.158.49.254165.158.49.255126
101165.158.50.0/25165.158.50.1 to 165.158.50.126165.158.50.127126
102165.158.50.128/25165.158.50.129 to 165.158.50.254165.158.50.255126
103165.158.51.0/25165.158.51.1 to 165.158.51.126165.158.51.127126
104165.158.51.128/25165.158.51.129 to 165.158.51.254165.158.51.255126
105165.158.52.0/25165.158.52.1 to 165.158.52.126165.158.52.127126
106165.158.52.128/25165.158.52.129 to 165.158.52.254165.158.52.255126
107165.158.53.0/25165.158.53.1 to 165.158.53.126165.158.53.127126
108165.158.53.128/25165.158.53.129 to 165.158.53.254165.158.53.255126
109165.158.54.0/25165.158.54.1 to 165.158.54.126165.158.54.127126
110165.158.54.128/25165.158.54.129 to 165.158.54.254165.158.54.255126
111165.158.55.0/25165.158.55.1 to 165.158.55.126165.158.55.127126
112165.158.55.128/25165.158.55.129 to 165.158.55.254165.158.55.255126
113165.158.56.0/25165.158.56.1 to 165.158.56.126165.158.56.127126
114165.158.56.128/25165.158.56.129 to 165.158.56.254165.158.56.255126
115165.158.57.0/25165.158.57.1 to 165.158.57.126165.158.57.127126
116165.158.57.128/25165.158.57.129 to 165.158.57.254165.158.57.255126
117165.158.58.0/25165.158.58.1 to 165.158.58.126165.158.58.127126
118165.158.58.128/25165.158.58.129 to 165.158.58.254165.158.58.255126
119165.158.59.0/25165.158.59.1 to 165.158.59.126165.158.59.127126
120165.158.59.128/25165.158.59.129 to 165.158.59.254165.158.59.255126
121165.158.60.0/25165.158.60.1 to 165.158.60.126165.158.60.127126
122165.158.60.128/25165.158.60.129 to 165.158.60.254165.158.60.255126
123165.158.61.0/25165.158.61.1 to 165.158.61.126165.158.61.127126
124165.158.61.128/25165.158.61.129 to 165.158.61.254165.158.61.255126
125165.158.62.0/25165.158.62.1 to 165.158.62.126165.158.62.127126
126165.158.62.128/25165.158.62.129 to 165.158.62.254165.158.62.255126
127165.158.63.0/25165.158.63.1 to 165.158.63.126165.158.63.127126
128165.158.63.128/25165.158.63.129 to 165.158.63.254165.158.63.255126
129165.158.64.0/25165.158.64.1 to 165.158.64.126165.158.64.127126
130165.158.64.128/25165.158.64.129 to 165.158.64.254165.158.64.255126
131165.158.65.0/25165.158.65.1 to 165.158.65.126165.158.65.127126
132165.158.65.128/25165.158.65.129 to 165.158.65.254165.158.65.255126
133165.158.66.0/25165.158.66.1 to 165.158.66.126165.158.66.127126
134165.158.66.128/25165.158.66.129 to 165.158.66.254165.158.66.255126
135165.158.67.0/25165.158.67.1 to 165.158.67.126165.158.67.127126
136165.158.67.128/25165.158.67.129 to 165.158.67.254165.158.67.255126
137165.158.68.0/25165.158.68.1 to 165.158.68.126165.158.68.127126
138165.158.68.128/25165.158.68.129 to 165.158.68.254165.158.68.255126
139165.158.69.0/25165.158.69.1 to 165.158.69.126165.158.69.127126
140165.158.69.128/25165.158.69.129 to 165.158.69.254165.158.69.255126
141165.158.70.0/25165.158.70.1 to 165.158.70.126165.158.70.127126
142165.158.70.128/25165.158.70.129 to 165.158.70.254165.158.70.255126
143165.158.71.0/25165.158.71.1 to 165.158.71.126165.158.71.127126
144165.158.71.128/25165.158.71.129 to 165.158.71.254165.158.71.255126
145165.158.72.0/25165.158.72.1 to 165.158.72.126165.158.72.127126
146165.158.72.128/25165.158.72.129 to 165.158.72.254165.158.72.255126
147165.158.73.0/25165.158.73.1 to 165.158.73.126165.158.73.127126
148165.158.73.128/25165.158.73.129 to 165.158.73.254165.158.73.255126
149165.158.74.0/25165.158.74.1 to 165.158.74.126165.158.74.127126
150165.158.74.128/25165.158.74.129 to 165.158.74.254165.158.74.255126
151165.158.75.0/25165.158.75.1 to 165.158.75.126165.158.75.127126
152165.158.75.128/25165.158.75.129 to 165.158.75.254165.158.75.255126
153165.158.76.0/25165.158.76.1 to 165.158.76.126165.158.76.127126
154165.158.76.128/25165.158.76.129 to 165.158.76.254165.158.76.255126
155165.158.77.0/25165.158.77.1 to 165.158.77.126165.158.77.127126
156165.158.77.128/25165.158.77.129 to 165.158.77.254165.158.77.255126
157165.158.78.0/25165.158.78.1 to 165.158.78.126165.158.78.127126
158165.158.78.128/25165.158.78.129 to 165.158.78.254165.158.78.255126
159165.158.79.0/25165.158.79.1 to 165.158.79.126165.158.79.127126
160165.158.79.128/25165.158.79.129 to 165.158.79.254165.158.79.255126
161165.158.80.0/25165.158.80.1 to 165.158.80.126165.158.80.127126
162165.158.80.128/25165.158.80.129 to 165.158.80.254165.158.80.255126
163165.158.81.0/25165.158.81.1 to 165.158.81.126165.158.81.127126
164165.158.81.128/25165.158.81.129 to 165.158.81.254165.158.81.255126
165165.158.82.0/25165.158.82.1 to 165.158.82.126165.158.82.127126
166165.158.82.128/25165.158.82.129 to 165.158.82.254165.158.82.255126
167165.158.83.0/25165.158.83.1 to 165.158.83.126165.158.83.127126
168165.158.83.128/25165.158.83.129 to 165.158.83.254165.158.83.255126
169165.158.84.0/25165.158.84.1 to 165.158.84.126165.158.84.127126
170165.158.84.128/25165.158.84.129 to 165.158.84.254165.158.84.255126
171165.158.85.0/25165.158.85.1 to 165.158.85.126165.158.85.127126
172165.158.85.128/25165.158.85.129 to 165.158.85.254165.158.85.255126
173165.158.86.0/25165.158.86.1 to 165.158.86.126165.158.86.127126
174165.158.86.128/25165.158.86.129 to 165.158.86.254165.158.86.255126
175165.158.87.0/25165.158.87.1 to 165.158.87.126165.158.87.127126
176165.158.87.128/25165.158.87.129 to 165.158.87.254165.158.87.255126
177165.158.88.0/25165.158.88.1 to 165.158.88.126165.158.88.127126
178165.158.88.128/25165.158.88.129 to 165.158.88.254165.158.88.255126
179165.158.89.0/25165.158.89.1 to 165.158.89.126165.158.89.127126
180165.158.89.128/25165.158.89.129 to 165.158.89.254165.158.89.255126
181165.158.90.0/25165.158.90.1 to 165.158.90.126165.158.90.127126
182165.158.90.128/25165.158.90.129 to 165.158.90.254165.158.90.255126
183165.158.91.0/25165.158.91.1 to 165.158.91.126165.158.91.127126
184165.158.91.128/25165.158.91.129 to 165.158.91.254165.158.91.255126
185165.158.92.0/25165.158.92.1 to 165.158.92.126165.158.92.127126
186165.158.92.128/25165.158.92.129 to 165.158.92.254165.158.92.255126
187165.158.93.0/25165.158.93.1 to 165.158.93.126165.158.93.127126
188165.158.93.128/25165.158.93.129 to 165.158.93.254165.158.93.255126
189165.158.94.0/25165.158.94.1 to 165.158.94.126165.158.94.127126
190165.158.94.128/25165.158.94.129 to 165.158.94.254165.158.94.255126
191165.158.95.0/25165.158.95.1 to 165.158.95.126165.158.95.127126
192165.158.95.128/25165.158.95.129 to 165.158.95.254165.158.95.255126
193165.158.96.0/25165.158.96.1 to 165.158.96.126165.158.96.127126
194165.158.96.128/25165.158.96.129 to 165.158.96.254165.158.96.255126
195165.158.97.0/25165.158.97.1 to 165.158.97.126165.158.97.127126
196165.158.97.128/25165.158.97.129 to 165.158.97.254165.158.97.255126
197165.158.98.0/25165.158.98.1 to 165.158.98.126165.158.98.127126
198165.158.98.128/25165.158.98.129 to 165.158.98.254165.158.98.255126
199165.158.99.0/25165.158.99.1 to 165.158.99.126165.158.99.127126
200165.158.99.128/25165.158.99.129 to 165.158.99.254165.158.99.255126
201165.158.100.0/25165.158.100.1 to 165.158.100.126165.158.100.127126
202165.158.100.128/25165.158.100.129 to 165.158.100.254165.158.100.255126
203165.158.101.0/25165.158.101.1 to 165.158.101.126165.158.101.127126
204165.158.101.128/25165.158.101.129 to 165.158.101.254165.158.101.255126
205165.158.102.0/25165.158.102.1 to 165.158.102.126165.158.102.127126
206165.158.102.128/25165.158.102.129 to 165.158.102.254165.158.102.255126
207165.158.103.0/25165.158.103.1 to 165.158.103.126165.158.103.127126
208165.158.103.128/25165.158.103.129 to 165.158.103.254165.158.103.255126
209165.158.104.0/25165.158.104.1 to 165.158.104.126165.158.104.127126
210165.158.104.128/25165.158.104.129 to 165.158.104.254165.158.104.255126
211165.158.105.0/25165.158.105.1 to 165.158.105.126165.158.105.127126
212165.158.105.128/25165.158.105.129 to 165.158.105.254165.158.105.255126
213165.158.106.0/25165.158.106.1 to 165.158.106.126165.158.106.127126
214165.158.106.128/25165.158.106.129 to 165.158.106.254165.158.106.255126
215165.158.107.0/25165.158.107.1 to 165.158.107.126165.158.107.127126
216165.158.107.128/25165.158.107.129 to 165.158.107.254165.158.107.255126
217165.158.108.0/25165.158.108.1 to 165.158.108.126165.158.108.127126
218165.158.108.128/25165.158.108.129 to 165.158.108.254165.158.108.255126
219165.158.109.0/25165.158.109.1 to 165.158.109.126165.158.109.127126
220165.158.109.128/25165.158.109.129 to 165.158.109.254165.158.109.255126
221165.158.110.0/25165.158.110.1 to 165.158.110.126165.158.110.127126
222165.158.110.128/25165.158.110.129 to 165.158.110.254165.158.110.255126
223165.158.111.0/25165.158.111.1 to 165.158.111.126165.158.111.127126
224165.158.111.128/25165.158.111.129 to 165.158.111.254165.158.111.255126
225165.158.112.0/25165.158.112.1 to 165.158.112.126165.158.112.127126
226165.158.112.128/25165.158.112.129 to 165.158.112.254165.158.112.255126
227165.158.113.0/25165.158.113.1 to 165.158.113.126165.158.113.127126
228165.158.113.128/25165.158.113.129 to 165.158.113.254165.158.113.255126
229165.158.114.0/25165.158.114.1 to 165.158.114.126165.158.114.127126
230165.158.114.128/25165.158.114.129 to 165.158.114.254165.158.114.255126
231165.158.115.0/25165.158.115.1 to 165.158.115.126165.158.115.127126
232165.158.115.128/25165.158.115.129 to 165.158.115.254165.158.115.255126
233165.158.116.0/25165.158.116.1 to 165.158.116.126165.158.116.127126
234165.158.116.128/25165.158.116.129 to 165.158.116.254165.158.116.255126
235165.158.117.0/25165.158.117.1 to 165.158.117.126165.158.117.127126
236165.158.117.128/25165.158.117.129 to 165.158.117.254165.158.117.255126
237165.158.118.0/25165.158.118.1 to 165.158.118.126165.158.118.127126
238165.158.118.128/25165.158.118.129 to 165.158.118.254165.158.118.255126
239165.158.119.0/25165.158.119.1 to 165.158.119.126165.158.119.127126
240165.158.119.128/25165.158.119.129 to 165.158.119.254165.158.119.255126
241165.158.120.0/25165.158.120.1 to 165.158.120.126165.158.120.127126
242165.158.120.128/25165.158.120.129 to 165.158.120.254165.158.120.255126
243165.158.121.0/25165.158.121.1 to 165.158.121.126165.158.121.127126
244165.158.121.128/25165.158.121.129 to 165.158.121.254165.158.121.255126
245165.158.122.0/25165.158.122.1 to 165.158.122.126165.158.122.127126
246165.158.122.128/25165.158.122.129 to 165.158.122.254165.158.122.255126
247165.158.123.0/25165.158.123.1 to 165.158.123.126165.158.123.127126
248165.158.123.128/25165.158.123.129 to 165.158.123.254165.158.123.255126
249165.158.124.0/25165.158.124.1 to 165.158.124.126165.158.124.127126
250165.158.124.128/25165.158.124.129 to 165.158.124.254165.158.124.255126
251165.158.125.0/25165.158.125.1 to 165.158.125.126165.158.125.127126
252165.158.125.128/25165.158.125.129 to 165.158.125.254165.158.125.255126
253165.158.126.0/25165.158.126.1 to 165.158.126.126165.158.126.127126
254165.158.126.128/25165.158.126.129 to 165.158.126.254165.158.126.255126
255165.158.127.0/25165.158.127.1 to 165.158.127.126165.158.127.127126
256165.158.127.128/25165.158.127.129 to 165.158.127.254165.158.127.255126

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.