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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.

Network149.24.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
149.24.0.0
Broadcast address
149.25.255.255
First usable
149.24.0.1
Last usable
149.25.255.254
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 95180000 · Integer 2501378048 to 2501509119
Reverse DNS zones
24.149.in-addr.arpa
25.149.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
Address10010101.00011000.00000000.00000000149.24.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10010101.00011000.00000000.00000000149.24.0.0
Broadcast10010101.00011001.11111111.11111111149.25.255.255
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)

149.24.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1149.24.0.0/25149.24.0.1 to 149.24.0.126149.24.0.127126
2149.24.0.128/25149.24.0.129 to 149.24.0.254149.24.0.255126
3149.24.1.0/25149.24.1.1 to 149.24.1.126149.24.1.127126
4149.24.1.128/25149.24.1.129 to 149.24.1.254149.24.1.255126
5149.24.2.0/25149.24.2.1 to 149.24.2.126149.24.2.127126
6149.24.2.128/25149.24.2.129 to 149.24.2.254149.24.2.255126
7149.24.3.0/25149.24.3.1 to 149.24.3.126149.24.3.127126
8149.24.3.128/25149.24.3.129 to 149.24.3.254149.24.3.255126
9149.24.4.0/25149.24.4.1 to 149.24.4.126149.24.4.127126
10149.24.4.128/25149.24.4.129 to 149.24.4.254149.24.4.255126
11149.24.5.0/25149.24.5.1 to 149.24.5.126149.24.5.127126
12149.24.5.128/25149.24.5.129 to 149.24.5.254149.24.5.255126
13149.24.6.0/25149.24.6.1 to 149.24.6.126149.24.6.127126
14149.24.6.128/25149.24.6.129 to 149.24.6.254149.24.6.255126
15149.24.7.0/25149.24.7.1 to 149.24.7.126149.24.7.127126
16149.24.7.128/25149.24.7.129 to 149.24.7.254149.24.7.255126
17149.24.8.0/25149.24.8.1 to 149.24.8.126149.24.8.127126
18149.24.8.128/25149.24.8.129 to 149.24.8.254149.24.8.255126
19149.24.9.0/25149.24.9.1 to 149.24.9.126149.24.9.127126
20149.24.9.128/25149.24.9.129 to 149.24.9.254149.24.9.255126
21149.24.10.0/25149.24.10.1 to 149.24.10.126149.24.10.127126
22149.24.10.128/25149.24.10.129 to 149.24.10.254149.24.10.255126
23149.24.11.0/25149.24.11.1 to 149.24.11.126149.24.11.127126
24149.24.11.128/25149.24.11.129 to 149.24.11.254149.24.11.255126
25149.24.12.0/25149.24.12.1 to 149.24.12.126149.24.12.127126
26149.24.12.128/25149.24.12.129 to 149.24.12.254149.24.12.255126
27149.24.13.0/25149.24.13.1 to 149.24.13.126149.24.13.127126
28149.24.13.128/25149.24.13.129 to 149.24.13.254149.24.13.255126
29149.24.14.0/25149.24.14.1 to 149.24.14.126149.24.14.127126
30149.24.14.128/25149.24.14.129 to 149.24.14.254149.24.14.255126
31149.24.15.0/25149.24.15.1 to 149.24.15.126149.24.15.127126
32149.24.15.128/25149.24.15.129 to 149.24.15.254149.24.15.255126
33149.24.16.0/25149.24.16.1 to 149.24.16.126149.24.16.127126
34149.24.16.128/25149.24.16.129 to 149.24.16.254149.24.16.255126
35149.24.17.0/25149.24.17.1 to 149.24.17.126149.24.17.127126
36149.24.17.128/25149.24.17.129 to 149.24.17.254149.24.17.255126
37149.24.18.0/25149.24.18.1 to 149.24.18.126149.24.18.127126
38149.24.18.128/25149.24.18.129 to 149.24.18.254149.24.18.255126
39149.24.19.0/25149.24.19.1 to 149.24.19.126149.24.19.127126
40149.24.19.128/25149.24.19.129 to 149.24.19.254149.24.19.255126
41149.24.20.0/25149.24.20.1 to 149.24.20.126149.24.20.127126
42149.24.20.128/25149.24.20.129 to 149.24.20.254149.24.20.255126
43149.24.21.0/25149.24.21.1 to 149.24.21.126149.24.21.127126
44149.24.21.128/25149.24.21.129 to 149.24.21.254149.24.21.255126
45149.24.22.0/25149.24.22.1 to 149.24.22.126149.24.22.127126
46149.24.22.128/25149.24.22.129 to 149.24.22.254149.24.22.255126
47149.24.23.0/25149.24.23.1 to 149.24.23.126149.24.23.127126
48149.24.23.128/25149.24.23.129 to 149.24.23.254149.24.23.255126
49149.24.24.0/25149.24.24.1 to 149.24.24.126149.24.24.127126
50149.24.24.128/25149.24.24.129 to 149.24.24.254149.24.24.255126
51149.24.25.0/25149.24.25.1 to 149.24.25.126149.24.25.127126
52149.24.25.128/25149.24.25.129 to 149.24.25.254149.24.25.255126
53149.24.26.0/25149.24.26.1 to 149.24.26.126149.24.26.127126
54149.24.26.128/25149.24.26.129 to 149.24.26.254149.24.26.255126
55149.24.27.0/25149.24.27.1 to 149.24.27.126149.24.27.127126
56149.24.27.128/25149.24.27.129 to 149.24.27.254149.24.27.255126
57149.24.28.0/25149.24.28.1 to 149.24.28.126149.24.28.127126
58149.24.28.128/25149.24.28.129 to 149.24.28.254149.24.28.255126
59149.24.29.0/25149.24.29.1 to 149.24.29.126149.24.29.127126
60149.24.29.128/25149.24.29.129 to 149.24.29.254149.24.29.255126
61149.24.30.0/25149.24.30.1 to 149.24.30.126149.24.30.127126
62149.24.30.128/25149.24.30.129 to 149.24.30.254149.24.30.255126
63149.24.31.0/25149.24.31.1 to 149.24.31.126149.24.31.127126
64149.24.31.128/25149.24.31.129 to 149.24.31.254149.24.31.255126
65149.24.32.0/25149.24.32.1 to 149.24.32.126149.24.32.127126
66149.24.32.128/25149.24.32.129 to 149.24.32.254149.24.32.255126
67149.24.33.0/25149.24.33.1 to 149.24.33.126149.24.33.127126
68149.24.33.128/25149.24.33.129 to 149.24.33.254149.24.33.255126
69149.24.34.0/25149.24.34.1 to 149.24.34.126149.24.34.127126
70149.24.34.128/25149.24.34.129 to 149.24.34.254149.24.34.255126
71149.24.35.0/25149.24.35.1 to 149.24.35.126149.24.35.127126
72149.24.35.128/25149.24.35.129 to 149.24.35.254149.24.35.255126
73149.24.36.0/25149.24.36.1 to 149.24.36.126149.24.36.127126
74149.24.36.128/25149.24.36.129 to 149.24.36.254149.24.36.255126
75149.24.37.0/25149.24.37.1 to 149.24.37.126149.24.37.127126
76149.24.37.128/25149.24.37.129 to 149.24.37.254149.24.37.255126
77149.24.38.0/25149.24.38.1 to 149.24.38.126149.24.38.127126
78149.24.38.128/25149.24.38.129 to 149.24.38.254149.24.38.255126
79149.24.39.0/25149.24.39.1 to 149.24.39.126149.24.39.127126
80149.24.39.128/25149.24.39.129 to 149.24.39.254149.24.39.255126
81149.24.40.0/25149.24.40.1 to 149.24.40.126149.24.40.127126
82149.24.40.128/25149.24.40.129 to 149.24.40.254149.24.40.255126
83149.24.41.0/25149.24.41.1 to 149.24.41.126149.24.41.127126
84149.24.41.128/25149.24.41.129 to 149.24.41.254149.24.41.255126
85149.24.42.0/25149.24.42.1 to 149.24.42.126149.24.42.127126
86149.24.42.128/25149.24.42.129 to 149.24.42.254149.24.42.255126
87149.24.43.0/25149.24.43.1 to 149.24.43.126149.24.43.127126
88149.24.43.128/25149.24.43.129 to 149.24.43.254149.24.43.255126
89149.24.44.0/25149.24.44.1 to 149.24.44.126149.24.44.127126
90149.24.44.128/25149.24.44.129 to 149.24.44.254149.24.44.255126
91149.24.45.0/25149.24.45.1 to 149.24.45.126149.24.45.127126
92149.24.45.128/25149.24.45.129 to 149.24.45.254149.24.45.255126
93149.24.46.0/25149.24.46.1 to 149.24.46.126149.24.46.127126
94149.24.46.128/25149.24.46.129 to 149.24.46.254149.24.46.255126
95149.24.47.0/25149.24.47.1 to 149.24.47.126149.24.47.127126
96149.24.47.128/25149.24.47.129 to 149.24.47.254149.24.47.255126
97149.24.48.0/25149.24.48.1 to 149.24.48.126149.24.48.127126
98149.24.48.128/25149.24.48.129 to 149.24.48.254149.24.48.255126
99149.24.49.0/25149.24.49.1 to 149.24.49.126149.24.49.127126
100149.24.49.128/25149.24.49.129 to 149.24.49.254149.24.49.255126
101149.24.50.0/25149.24.50.1 to 149.24.50.126149.24.50.127126
102149.24.50.128/25149.24.50.129 to 149.24.50.254149.24.50.255126
103149.24.51.0/25149.24.51.1 to 149.24.51.126149.24.51.127126
104149.24.51.128/25149.24.51.129 to 149.24.51.254149.24.51.255126
105149.24.52.0/25149.24.52.1 to 149.24.52.126149.24.52.127126
106149.24.52.128/25149.24.52.129 to 149.24.52.254149.24.52.255126
107149.24.53.0/25149.24.53.1 to 149.24.53.126149.24.53.127126
108149.24.53.128/25149.24.53.129 to 149.24.53.254149.24.53.255126
109149.24.54.0/25149.24.54.1 to 149.24.54.126149.24.54.127126
110149.24.54.128/25149.24.54.129 to 149.24.54.254149.24.54.255126
111149.24.55.0/25149.24.55.1 to 149.24.55.126149.24.55.127126
112149.24.55.128/25149.24.55.129 to 149.24.55.254149.24.55.255126
113149.24.56.0/25149.24.56.1 to 149.24.56.126149.24.56.127126
114149.24.56.128/25149.24.56.129 to 149.24.56.254149.24.56.255126
115149.24.57.0/25149.24.57.1 to 149.24.57.126149.24.57.127126
116149.24.57.128/25149.24.57.129 to 149.24.57.254149.24.57.255126
117149.24.58.0/25149.24.58.1 to 149.24.58.126149.24.58.127126
118149.24.58.128/25149.24.58.129 to 149.24.58.254149.24.58.255126
119149.24.59.0/25149.24.59.1 to 149.24.59.126149.24.59.127126
120149.24.59.128/25149.24.59.129 to 149.24.59.254149.24.59.255126
121149.24.60.0/25149.24.60.1 to 149.24.60.126149.24.60.127126
122149.24.60.128/25149.24.60.129 to 149.24.60.254149.24.60.255126
123149.24.61.0/25149.24.61.1 to 149.24.61.126149.24.61.127126
124149.24.61.128/25149.24.61.129 to 149.24.61.254149.24.61.255126
125149.24.62.0/25149.24.62.1 to 149.24.62.126149.24.62.127126
126149.24.62.128/25149.24.62.129 to 149.24.62.254149.24.62.255126
127149.24.63.0/25149.24.63.1 to 149.24.63.126149.24.63.127126
128149.24.63.128/25149.24.63.129 to 149.24.63.254149.24.63.255126
129149.24.64.0/25149.24.64.1 to 149.24.64.126149.24.64.127126
130149.24.64.128/25149.24.64.129 to 149.24.64.254149.24.64.255126
131149.24.65.0/25149.24.65.1 to 149.24.65.126149.24.65.127126
132149.24.65.128/25149.24.65.129 to 149.24.65.254149.24.65.255126
133149.24.66.0/25149.24.66.1 to 149.24.66.126149.24.66.127126
134149.24.66.128/25149.24.66.129 to 149.24.66.254149.24.66.255126
135149.24.67.0/25149.24.67.1 to 149.24.67.126149.24.67.127126
136149.24.67.128/25149.24.67.129 to 149.24.67.254149.24.67.255126
137149.24.68.0/25149.24.68.1 to 149.24.68.126149.24.68.127126
138149.24.68.128/25149.24.68.129 to 149.24.68.254149.24.68.255126
139149.24.69.0/25149.24.69.1 to 149.24.69.126149.24.69.127126
140149.24.69.128/25149.24.69.129 to 149.24.69.254149.24.69.255126
141149.24.70.0/25149.24.70.1 to 149.24.70.126149.24.70.127126
142149.24.70.128/25149.24.70.129 to 149.24.70.254149.24.70.255126
143149.24.71.0/25149.24.71.1 to 149.24.71.126149.24.71.127126
144149.24.71.128/25149.24.71.129 to 149.24.71.254149.24.71.255126
145149.24.72.0/25149.24.72.1 to 149.24.72.126149.24.72.127126
146149.24.72.128/25149.24.72.129 to 149.24.72.254149.24.72.255126
147149.24.73.0/25149.24.73.1 to 149.24.73.126149.24.73.127126
148149.24.73.128/25149.24.73.129 to 149.24.73.254149.24.73.255126
149149.24.74.0/25149.24.74.1 to 149.24.74.126149.24.74.127126
150149.24.74.128/25149.24.74.129 to 149.24.74.254149.24.74.255126
151149.24.75.0/25149.24.75.1 to 149.24.75.126149.24.75.127126
152149.24.75.128/25149.24.75.129 to 149.24.75.254149.24.75.255126
153149.24.76.0/25149.24.76.1 to 149.24.76.126149.24.76.127126
154149.24.76.128/25149.24.76.129 to 149.24.76.254149.24.76.255126
155149.24.77.0/25149.24.77.1 to 149.24.77.126149.24.77.127126
156149.24.77.128/25149.24.77.129 to 149.24.77.254149.24.77.255126
157149.24.78.0/25149.24.78.1 to 149.24.78.126149.24.78.127126
158149.24.78.128/25149.24.78.129 to 149.24.78.254149.24.78.255126
159149.24.79.0/25149.24.79.1 to 149.24.79.126149.24.79.127126
160149.24.79.128/25149.24.79.129 to 149.24.79.254149.24.79.255126
161149.24.80.0/25149.24.80.1 to 149.24.80.126149.24.80.127126
162149.24.80.128/25149.24.80.129 to 149.24.80.254149.24.80.255126
163149.24.81.0/25149.24.81.1 to 149.24.81.126149.24.81.127126
164149.24.81.128/25149.24.81.129 to 149.24.81.254149.24.81.255126
165149.24.82.0/25149.24.82.1 to 149.24.82.126149.24.82.127126
166149.24.82.128/25149.24.82.129 to 149.24.82.254149.24.82.255126
167149.24.83.0/25149.24.83.1 to 149.24.83.126149.24.83.127126
168149.24.83.128/25149.24.83.129 to 149.24.83.254149.24.83.255126
169149.24.84.0/25149.24.84.1 to 149.24.84.126149.24.84.127126
170149.24.84.128/25149.24.84.129 to 149.24.84.254149.24.84.255126
171149.24.85.0/25149.24.85.1 to 149.24.85.126149.24.85.127126
172149.24.85.128/25149.24.85.129 to 149.24.85.254149.24.85.255126
173149.24.86.0/25149.24.86.1 to 149.24.86.126149.24.86.127126
174149.24.86.128/25149.24.86.129 to 149.24.86.254149.24.86.255126
175149.24.87.0/25149.24.87.1 to 149.24.87.126149.24.87.127126
176149.24.87.128/25149.24.87.129 to 149.24.87.254149.24.87.255126
177149.24.88.0/25149.24.88.1 to 149.24.88.126149.24.88.127126
178149.24.88.128/25149.24.88.129 to 149.24.88.254149.24.88.255126
179149.24.89.0/25149.24.89.1 to 149.24.89.126149.24.89.127126
180149.24.89.128/25149.24.89.129 to 149.24.89.254149.24.89.255126
181149.24.90.0/25149.24.90.1 to 149.24.90.126149.24.90.127126
182149.24.90.128/25149.24.90.129 to 149.24.90.254149.24.90.255126
183149.24.91.0/25149.24.91.1 to 149.24.91.126149.24.91.127126
184149.24.91.128/25149.24.91.129 to 149.24.91.254149.24.91.255126
185149.24.92.0/25149.24.92.1 to 149.24.92.126149.24.92.127126
186149.24.92.128/25149.24.92.129 to 149.24.92.254149.24.92.255126
187149.24.93.0/25149.24.93.1 to 149.24.93.126149.24.93.127126
188149.24.93.128/25149.24.93.129 to 149.24.93.254149.24.93.255126
189149.24.94.0/25149.24.94.1 to 149.24.94.126149.24.94.127126
190149.24.94.128/25149.24.94.129 to 149.24.94.254149.24.94.255126
191149.24.95.0/25149.24.95.1 to 149.24.95.126149.24.95.127126
192149.24.95.128/25149.24.95.129 to 149.24.95.254149.24.95.255126
193149.24.96.0/25149.24.96.1 to 149.24.96.126149.24.96.127126
194149.24.96.128/25149.24.96.129 to 149.24.96.254149.24.96.255126
195149.24.97.0/25149.24.97.1 to 149.24.97.126149.24.97.127126
196149.24.97.128/25149.24.97.129 to 149.24.97.254149.24.97.255126
197149.24.98.0/25149.24.98.1 to 149.24.98.126149.24.98.127126
198149.24.98.128/25149.24.98.129 to 149.24.98.254149.24.98.255126
199149.24.99.0/25149.24.99.1 to 149.24.99.126149.24.99.127126
200149.24.99.128/25149.24.99.129 to 149.24.99.254149.24.99.255126
201149.24.100.0/25149.24.100.1 to 149.24.100.126149.24.100.127126
202149.24.100.128/25149.24.100.129 to 149.24.100.254149.24.100.255126
203149.24.101.0/25149.24.101.1 to 149.24.101.126149.24.101.127126
204149.24.101.128/25149.24.101.129 to 149.24.101.254149.24.101.255126
205149.24.102.0/25149.24.102.1 to 149.24.102.126149.24.102.127126
206149.24.102.128/25149.24.102.129 to 149.24.102.254149.24.102.255126
207149.24.103.0/25149.24.103.1 to 149.24.103.126149.24.103.127126
208149.24.103.128/25149.24.103.129 to 149.24.103.254149.24.103.255126
209149.24.104.0/25149.24.104.1 to 149.24.104.126149.24.104.127126
210149.24.104.128/25149.24.104.129 to 149.24.104.254149.24.104.255126
211149.24.105.0/25149.24.105.1 to 149.24.105.126149.24.105.127126
212149.24.105.128/25149.24.105.129 to 149.24.105.254149.24.105.255126
213149.24.106.0/25149.24.106.1 to 149.24.106.126149.24.106.127126
214149.24.106.128/25149.24.106.129 to 149.24.106.254149.24.106.255126
215149.24.107.0/25149.24.107.1 to 149.24.107.126149.24.107.127126
216149.24.107.128/25149.24.107.129 to 149.24.107.254149.24.107.255126
217149.24.108.0/25149.24.108.1 to 149.24.108.126149.24.108.127126
218149.24.108.128/25149.24.108.129 to 149.24.108.254149.24.108.255126
219149.24.109.0/25149.24.109.1 to 149.24.109.126149.24.109.127126
220149.24.109.128/25149.24.109.129 to 149.24.109.254149.24.109.255126
221149.24.110.0/25149.24.110.1 to 149.24.110.126149.24.110.127126
222149.24.110.128/25149.24.110.129 to 149.24.110.254149.24.110.255126
223149.24.111.0/25149.24.111.1 to 149.24.111.126149.24.111.127126
224149.24.111.128/25149.24.111.129 to 149.24.111.254149.24.111.255126
225149.24.112.0/25149.24.112.1 to 149.24.112.126149.24.112.127126
226149.24.112.128/25149.24.112.129 to 149.24.112.254149.24.112.255126
227149.24.113.0/25149.24.113.1 to 149.24.113.126149.24.113.127126
228149.24.113.128/25149.24.113.129 to 149.24.113.254149.24.113.255126
229149.24.114.0/25149.24.114.1 to 149.24.114.126149.24.114.127126
230149.24.114.128/25149.24.114.129 to 149.24.114.254149.24.114.255126
231149.24.115.0/25149.24.115.1 to 149.24.115.126149.24.115.127126
232149.24.115.128/25149.24.115.129 to 149.24.115.254149.24.115.255126
233149.24.116.0/25149.24.116.1 to 149.24.116.126149.24.116.127126
234149.24.116.128/25149.24.116.129 to 149.24.116.254149.24.116.255126
235149.24.117.0/25149.24.117.1 to 149.24.117.126149.24.117.127126
236149.24.117.128/25149.24.117.129 to 149.24.117.254149.24.117.255126
237149.24.118.0/25149.24.118.1 to 149.24.118.126149.24.118.127126
238149.24.118.128/25149.24.118.129 to 149.24.118.254149.24.118.255126
239149.24.119.0/25149.24.119.1 to 149.24.119.126149.24.119.127126
240149.24.119.128/25149.24.119.129 to 149.24.119.254149.24.119.255126
241149.24.120.0/25149.24.120.1 to 149.24.120.126149.24.120.127126
242149.24.120.128/25149.24.120.129 to 149.24.120.254149.24.120.255126
243149.24.121.0/25149.24.121.1 to 149.24.121.126149.24.121.127126
244149.24.121.128/25149.24.121.129 to 149.24.121.254149.24.121.255126
245149.24.122.0/25149.24.122.1 to 149.24.122.126149.24.122.127126
246149.24.122.128/25149.24.122.129 to 149.24.122.254149.24.122.255126
247149.24.123.0/25149.24.123.1 to 149.24.123.126149.24.123.127126
248149.24.123.128/25149.24.123.129 to 149.24.123.254149.24.123.255126
249149.24.124.0/25149.24.124.1 to 149.24.124.126149.24.124.127126
250149.24.124.128/25149.24.124.129 to 149.24.124.254149.24.124.255126
251149.24.125.0/25149.24.125.1 to 149.24.125.126149.24.125.127126
252149.24.125.128/25149.24.125.129 to 149.24.125.254149.24.125.255126
253149.24.126.0/25149.24.126.1 to 149.24.126.126149.24.126.127126
254149.24.126.128/25149.24.126.129 to 149.24.126.254149.24.126.255126
255149.24.127.0/25149.24.127.1 to 149.24.127.126149.24.127.127126
256149.24.127.128/25149.24.127.129 to 149.24.127.254149.24.127.255126

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.