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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.

Network124.8.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
124.8.0.0
Broadcast address
124.8.255.255
First usable
124.8.0.1
Last usable
124.8.255.254
Usable hosts
65,534 (65,536 less the network and broadcast addresses)
Subnet mask
255.255.0.0
Wildcard mask
0.0.255.255 (Cisco ACLs, OSPF)
Prefix length
/16
Type
Public public
Old class
A (default /8)
As numbers
Hex 7C080000 · Integer 2080899072 to 2080964607
Reverse DNS zone
8.124.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address01111100.00001000..00000000.00000000124.8.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network01111100.00001000..00000000.00000000124.8.0.0
Broadcast01111100.00001000..11111111.11111111124.8.255.255
Split into smaller subnets/25
/17 (2)/18 (4)/19 (8)/20 (16)/21 (32)/22 (64)/23 (128)/24 (256)/25 (512)/26 (1,024)/27 (2,048)/28 (4,096)

124.8.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1124.8.0.0/25124.8.0.1 to 124.8.0.126124.8.0.127126
2124.8.0.128/25124.8.0.129 to 124.8.0.254124.8.0.255126
3124.8.1.0/25124.8.1.1 to 124.8.1.126124.8.1.127126
4124.8.1.128/25124.8.1.129 to 124.8.1.254124.8.1.255126
5124.8.2.0/25124.8.2.1 to 124.8.2.126124.8.2.127126
6124.8.2.128/25124.8.2.129 to 124.8.2.254124.8.2.255126
7124.8.3.0/25124.8.3.1 to 124.8.3.126124.8.3.127126
8124.8.3.128/25124.8.3.129 to 124.8.3.254124.8.3.255126
9124.8.4.0/25124.8.4.1 to 124.8.4.126124.8.4.127126
10124.8.4.128/25124.8.4.129 to 124.8.4.254124.8.4.255126
11124.8.5.0/25124.8.5.1 to 124.8.5.126124.8.5.127126
12124.8.5.128/25124.8.5.129 to 124.8.5.254124.8.5.255126
13124.8.6.0/25124.8.6.1 to 124.8.6.126124.8.6.127126
14124.8.6.128/25124.8.6.129 to 124.8.6.254124.8.6.255126
15124.8.7.0/25124.8.7.1 to 124.8.7.126124.8.7.127126
16124.8.7.128/25124.8.7.129 to 124.8.7.254124.8.7.255126
17124.8.8.0/25124.8.8.1 to 124.8.8.126124.8.8.127126
18124.8.8.128/25124.8.8.129 to 124.8.8.254124.8.8.255126
19124.8.9.0/25124.8.9.1 to 124.8.9.126124.8.9.127126
20124.8.9.128/25124.8.9.129 to 124.8.9.254124.8.9.255126
21124.8.10.0/25124.8.10.1 to 124.8.10.126124.8.10.127126
22124.8.10.128/25124.8.10.129 to 124.8.10.254124.8.10.255126
23124.8.11.0/25124.8.11.1 to 124.8.11.126124.8.11.127126
24124.8.11.128/25124.8.11.129 to 124.8.11.254124.8.11.255126
25124.8.12.0/25124.8.12.1 to 124.8.12.126124.8.12.127126
26124.8.12.128/25124.8.12.129 to 124.8.12.254124.8.12.255126
27124.8.13.0/25124.8.13.1 to 124.8.13.126124.8.13.127126
28124.8.13.128/25124.8.13.129 to 124.8.13.254124.8.13.255126
29124.8.14.0/25124.8.14.1 to 124.8.14.126124.8.14.127126
30124.8.14.128/25124.8.14.129 to 124.8.14.254124.8.14.255126
31124.8.15.0/25124.8.15.1 to 124.8.15.126124.8.15.127126
32124.8.15.128/25124.8.15.129 to 124.8.15.254124.8.15.255126
33124.8.16.0/25124.8.16.1 to 124.8.16.126124.8.16.127126
34124.8.16.128/25124.8.16.129 to 124.8.16.254124.8.16.255126
35124.8.17.0/25124.8.17.1 to 124.8.17.126124.8.17.127126
36124.8.17.128/25124.8.17.129 to 124.8.17.254124.8.17.255126
37124.8.18.0/25124.8.18.1 to 124.8.18.126124.8.18.127126
38124.8.18.128/25124.8.18.129 to 124.8.18.254124.8.18.255126
39124.8.19.0/25124.8.19.1 to 124.8.19.126124.8.19.127126
40124.8.19.128/25124.8.19.129 to 124.8.19.254124.8.19.255126
41124.8.20.0/25124.8.20.1 to 124.8.20.126124.8.20.127126
42124.8.20.128/25124.8.20.129 to 124.8.20.254124.8.20.255126
43124.8.21.0/25124.8.21.1 to 124.8.21.126124.8.21.127126
44124.8.21.128/25124.8.21.129 to 124.8.21.254124.8.21.255126
45124.8.22.0/25124.8.22.1 to 124.8.22.126124.8.22.127126
46124.8.22.128/25124.8.22.129 to 124.8.22.254124.8.22.255126
47124.8.23.0/25124.8.23.1 to 124.8.23.126124.8.23.127126
48124.8.23.128/25124.8.23.129 to 124.8.23.254124.8.23.255126
49124.8.24.0/25124.8.24.1 to 124.8.24.126124.8.24.127126
50124.8.24.128/25124.8.24.129 to 124.8.24.254124.8.24.255126
51124.8.25.0/25124.8.25.1 to 124.8.25.126124.8.25.127126
52124.8.25.128/25124.8.25.129 to 124.8.25.254124.8.25.255126
53124.8.26.0/25124.8.26.1 to 124.8.26.126124.8.26.127126
54124.8.26.128/25124.8.26.129 to 124.8.26.254124.8.26.255126
55124.8.27.0/25124.8.27.1 to 124.8.27.126124.8.27.127126
56124.8.27.128/25124.8.27.129 to 124.8.27.254124.8.27.255126
57124.8.28.0/25124.8.28.1 to 124.8.28.126124.8.28.127126
58124.8.28.128/25124.8.28.129 to 124.8.28.254124.8.28.255126
59124.8.29.0/25124.8.29.1 to 124.8.29.126124.8.29.127126
60124.8.29.128/25124.8.29.129 to 124.8.29.254124.8.29.255126
61124.8.30.0/25124.8.30.1 to 124.8.30.126124.8.30.127126
62124.8.30.128/25124.8.30.129 to 124.8.30.254124.8.30.255126
63124.8.31.0/25124.8.31.1 to 124.8.31.126124.8.31.127126
64124.8.31.128/25124.8.31.129 to 124.8.31.254124.8.31.255126
65124.8.32.0/25124.8.32.1 to 124.8.32.126124.8.32.127126
66124.8.32.128/25124.8.32.129 to 124.8.32.254124.8.32.255126
67124.8.33.0/25124.8.33.1 to 124.8.33.126124.8.33.127126
68124.8.33.128/25124.8.33.129 to 124.8.33.254124.8.33.255126
69124.8.34.0/25124.8.34.1 to 124.8.34.126124.8.34.127126
70124.8.34.128/25124.8.34.129 to 124.8.34.254124.8.34.255126
71124.8.35.0/25124.8.35.1 to 124.8.35.126124.8.35.127126
72124.8.35.128/25124.8.35.129 to 124.8.35.254124.8.35.255126
73124.8.36.0/25124.8.36.1 to 124.8.36.126124.8.36.127126
74124.8.36.128/25124.8.36.129 to 124.8.36.254124.8.36.255126
75124.8.37.0/25124.8.37.1 to 124.8.37.126124.8.37.127126
76124.8.37.128/25124.8.37.129 to 124.8.37.254124.8.37.255126
77124.8.38.0/25124.8.38.1 to 124.8.38.126124.8.38.127126
78124.8.38.128/25124.8.38.129 to 124.8.38.254124.8.38.255126
79124.8.39.0/25124.8.39.1 to 124.8.39.126124.8.39.127126
80124.8.39.128/25124.8.39.129 to 124.8.39.254124.8.39.255126
81124.8.40.0/25124.8.40.1 to 124.8.40.126124.8.40.127126
82124.8.40.128/25124.8.40.129 to 124.8.40.254124.8.40.255126
83124.8.41.0/25124.8.41.1 to 124.8.41.126124.8.41.127126
84124.8.41.128/25124.8.41.129 to 124.8.41.254124.8.41.255126
85124.8.42.0/25124.8.42.1 to 124.8.42.126124.8.42.127126
86124.8.42.128/25124.8.42.129 to 124.8.42.254124.8.42.255126
87124.8.43.0/25124.8.43.1 to 124.8.43.126124.8.43.127126
88124.8.43.128/25124.8.43.129 to 124.8.43.254124.8.43.255126
89124.8.44.0/25124.8.44.1 to 124.8.44.126124.8.44.127126
90124.8.44.128/25124.8.44.129 to 124.8.44.254124.8.44.255126
91124.8.45.0/25124.8.45.1 to 124.8.45.126124.8.45.127126
92124.8.45.128/25124.8.45.129 to 124.8.45.254124.8.45.255126
93124.8.46.0/25124.8.46.1 to 124.8.46.126124.8.46.127126
94124.8.46.128/25124.8.46.129 to 124.8.46.254124.8.46.255126
95124.8.47.0/25124.8.47.1 to 124.8.47.126124.8.47.127126
96124.8.47.128/25124.8.47.129 to 124.8.47.254124.8.47.255126
97124.8.48.0/25124.8.48.1 to 124.8.48.126124.8.48.127126
98124.8.48.128/25124.8.48.129 to 124.8.48.254124.8.48.255126
99124.8.49.0/25124.8.49.1 to 124.8.49.126124.8.49.127126
100124.8.49.128/25124.8.49.129 to 124.8.49.254124.8.49.255126
101124.8.50.0/25124.8.50.1 to 124.8.50.126124.8.50.127126
102124.8.50.128/25124.8.50.129 to 124.8.50.254124.8.50.255126
103124.8.51.0/25124.8.51.1 to 124.8.51.126124.8.51.127126
104124.8.51.128/25124.8.51.129 to 124.8.51.254124.8.51.255126
105124.8.52.0/25124.8.52.1 to 124.8.52.126124.8.52.127126
106124.8.52.128/25124.8.52.129 to 124.8.52.254124.8.52.255126
107124.8.53.0/25124.8.53.1 to 124.8.53.126124.8.53.127126
108124.8.53.128/25124.8.53.129 to 124.8.53.254124.8.53.255126
109124.8.54.0/25124.8.54.1 to 124.8.54.126124.8.54.127126
110124.8.54.128/25124.8.54.129 to 124.8.54.254124.8.54.255126
111124.8.55.0/25124.8.55.1 to 124.8.55.126124.8.55.127126
112124.8.55.128/25124.8.55.129 to 124.8.55.254124.8.55.255126
113124.8.56.0/25124.8.56.1 to 124.8.56.126124.8.56.127126
114124.8.56.128/25124.8.56.129 to 124.8.56.254124.8.56.255126
115124.8.57.0/25124.8.57.1 to 124.8.57.126124.8.57.127126
116124.8.57.128/25124.8.57.129 to 124.8.57.254124.8.57.255126
117124.8.58.0/25124.8.58.1 to 124.8.58.126124.8.58.127126
118124.8.58.128/25124.8.58.129 to 124.8.58.254124.8.58.255126
119124.8.59.0/25124.8.59.1 to 124.8.59.126124.8.59.127126
120124.8.59.128/25124.8.59.129 to 124.8.59.254124.8.59.255126
121124.8.60.0/25124.8.60.1 to 124.8.60.126124.8.60.127126
122124.8.60.128/25124.8.60.129 to 124.8.60.254124.8.60.255126
123124.8.61.0/25124.8.61.1 to 124.8.61.126124.8.61.127126
124124.8.61.128/25124.8.61.129 to 124.8.61.254124.8.61.255126
125124.8.62.0/25124.8.62.1 to 124.8.62.126124.8.62.127126
126124.8.62.128/25124.8.62.129 to 124.8.62.254124.8.62.255126
127124.8.63.0/25124.8.63.1 to 124.8.63.126124.8.63.127126
128124.8.63.128/25124.8.63.129 to 124.8.63.254124.8.63.255126
129124.8.64.0/25124.8.64.1 to 124.8.64.126124.8.64.127126
130124.8.64.128/25124.8.64.129 to 124.8.64.254124.8.64.255126
131124.8.65.0/25124.8.65.1 to 124.8.65.126124.8.65.127126
132124.8.65.128/25124.8.65.129 to 124.8.65.254124.8.65.255126
133124.8.66.0/25124.8.66.1 to 124.8.66.126124.8.66.127126
134124.8.66.128/25124.8.66.129 to 124.8.66.254124.8.66.255126
135124.8.67.0/25124.8.67.1 to 124.8.67.126124.8.67.127126
136124.8.67.128/25124.8.67.129 to 124.8.67.254124.8.67.255126
137124.8.68.0/25124.8.68.1 to 124.8.68.126124.8.68.127126
138124.8.68.128/25124.8.68.129 to 124.8.68.254124.8.68.255126
139124.8.69.0/25124.8.69.1 to 124.8.69.126124.8.69.127126
140124.8.69.128/25124.8.69.129 to 124.8.69.254124.8.69.255126
141124.8.70.0/25124.8.70.1 to 124.8.70.126124.8.70.127126
142124.8.70.128/25124.8.70.129 to 124.8.70.254124.8.70.255126
143124.8.71.0/25124.8.71.1 to 124.8.71.126124.8.71.127126
144124.8.71.128/25124.8.71.129 to 124.8.71.254124.8.71.255126
145124.8.72.0/25124.8.72.1 to 124.8.72.126124.8.72.127126
146124.8.72.128/25124.8.72.129 to 124.8.72.254124.8.72.255126
147124.8.73.0/25124.8.73.1 to 124.8.73.126124.8.73.127126
148124.8.73.128/25124.8.73.129 to 124.8.73.254124.8.73.255126
149124.8.74.0/25124.8.74.1 to 124.8.74.126124.8.74.127126
150124.8.74.128/25124.8.74.129 to 124.8.74.254124.8.74.255126
151124.8.75.0/25124.8.75.1 to 124.8.75.126124.8.75.127126
152124.8.75.128/25124.8.75.129 to 124.8.75.254124.8.75.255126
153124.8.76.0/25124.8.76.1 to 124.8.76.126124.8.76.127126
154124.8.76.128/25124.8.76.129 to 124.8.76.254124.8.76.255126
155124.8.77.0/25124.8.77.1 to 124.8.77.126124.8.77.127126
156124.8.77.128/25124.8.77.129 to 124.8.77.254124.8.77.255126
157124.8.78.0/25124.8.78.1 to 124.8.78.126124.8.78.127126
158124.8.78.128/25124.8.78.129 to 124.8.78.254124.8.78.255126
159124.8.79.0/25124.8.79.1 to 124.8.79.126124.8.79.127126
160124.8.79.128/25124.8.79.129 to 124.8.79.254124.8.79.255126
161124.8.80.0/25124.8.80.1 to 124.8.80.126124.8.80.127126
162124.8.80.128/25124.8.80.129 to 124.8.80.254124.8.80.255126
163124.8.81.0/25124.8.81.1 to 124.8.81.126124.8.81.127126
164124.8.81.128/25124.8.81.129 to 124.8.81.254124.8.81.255126
165124.8.82.0/25124.8.82.1 to 124.8.82.126124.8.82.127126
166124.8.82.128/25124.8.82.129 to 124.8.82.254124.8.82.255126
167124.8.83.0/25124.8.83.1 to 124.8.83.126124.8.83.127126
168124.8.83.128/25124.8.83.129 to 124.8.83.254124.8.83.255126
169124.8.84.0/25124.8.84.1 to 124.8.84.126124.8.84.127126
170124.8.84.128/25124.8.84.129 to 124.8.84.254124.8.84.255126
171124.8.85.0/25124.8.85.1 to 124.8.85.126124.8.85.127126
172124.8.85.128/25124.8.85.129 to 124.8.85.254124.8.85.255126
173124.8.86.0/25124.8.86.1 to 124.8.86.126124.8.86.127126
174124.8.86.128/25124.8.86.129 to 124.8.86.254124.8.86.255126
175124.8.87.0/25124.8.87.1 to 124.8.87.126124.8.87.127126
176124.8.87.128/25124.8.87.129 to 124.8.87.254124.8.87.255126
177124.8.88.0/25124.8.88.1 to 124.8.88.126124.8.88.127126
178124.8.88.128/25124.8.88.129 to 124.8.88.254124.8.88.255126
179124.8.89.0/25124.8.89.1 to 124.8.89.126124.8.89.127126
180124.8.89.128/25124.8.89.129 to 124.8.89.254124.8.89.255126
181124.8.90.0/25124.8.90.1 to 124.8.90.126124.8.90.127126
182124.8.90.128/25124.8.90.129 to 124.8.90.254124.8.90.255126
183124.8.91.0/25124.8.91.1 to 124.8.91.126124.8.91.127126
184124.8.91.128/25124.8.91.129 to 124.8.91.254124.8.91.255126
185124.8.92.0/25124.8.92.1 to 124.8.92.126124.8.92.127126
186124.8.92.128/25124.8.92.129 to 124.8.92.254124.8.92.255126
187124.8.93.0/25124.8.93.1 to 124.8.93.126124.8.93.127126
188124.8.93.128/25124.8.93.129 to 124.8.93.254124.8.93.255126
189124.8.94.0/25124.8.94.1 to 124.8.94.126124.8.94.127126
190124.8.94.128/25124.8.94.129 to 124.8.94.254124.8.94.255126
191124.8.95.0/25124.8.95.1 to 124.8.95.126124.8.95.127126
192124.8.95.128/25124.8.95.129 to 124.8.95.254124.8.95.255126
193124.8.96.0/25124.8.96.1 to 124.8.96.126124.8.96.127126
194124.8.96.128/25124.8.96.129 to 124.8.96.254124.8.96.255126
195124.8.97.0/25124.8.97.1 to 124.8.97.126124.8.97.127126
196124.8.97.128/25124.8.97.129 to 124.8.97.254124.8.97.255126
197124.8.98.0/25124.8.98.1 to 124.8.98.126124.8.98.127126
198124.8.98.128/25124.8.98.129 to 124.8.98.254124.8.98.255126
199124.8.99.0/25124.8.99.1 to 124.8.99.126124.8.99.127126
200124.8.99.128/25124.8.99.129 to 124.8.99.254124.8.99.255126
201124.8.100.0/25124.8.100.1 to 124.8.100.126124.8.100.127126
202124.8.100.128/25124.8.100.129 to 124.8.100.254124.8.100.255126
203124.8.101.0/25124.8.101.1 to 124.8.101.126124.8.101.127126
204124.8.101.128/25124.8.101.129 to 124.8.101.254124.8.101.255126
205124.8.102.0/25124.8.102.1 to 124.8.102.126124.8.102.127126
206124.8.102.128/25124.8.102.129 to 124.8.102.254124.8.102.255126
207124.8.103.0/25124.8.103.1 to 124.8.103.126124.8.103.127126
208124.8.103.128/25124.8.103.129 to 124.8.103.254124.8.103.255126
209124.8.104.0/25124.8.104.1 to 124.8.104.126124.8.104.127126
210124.8.104.128/25124.8.104.129 to 124.8.104.254124.8.104.255126
211124.8.105.0/25124.8.105.1 to 124.8.105.126124.8.105.127126
212124.8.105.128/25124.8.105.129 to 124.8.105.254124.8.105.255126
213124.8.106.0/25124.8.106.1 to 124.8.106.126124.8.106.127126
214124.8.106.128/25124.8.106.129 to 124.8.106.254124.8.106.255126
215124.8.107.0/25124.8.107.1 to 124.8.107.126124.8.107.127126
216124.8.107.128/25124.8.107.129 to 124.8.107.254124.8.107.255126
217124.8.108.0/25124.8.108.1 to 124.8.108.126124.8.108.127126
218124.8.108.128/25124.8.108.129 to 124.8.108.254124.8.108.255126
219124.8.109.0/25124.8.109.1 to 124.8.109.126124.8.109.127126
220124.8.109.128/25124.8.109.129 to 124.8.109.254124.8.109.255126
221124.8.110.0/25124.8.110.1 to 124.8.110.126124.8.110.127126
222124.8.110.128/25124.8.110.129 to 124.8.110.254124.8.110.255126
223124.8.111.0/25124.8.111.1 to 124.8.111.126124.8.111.127126
224124.8.111.128/25124.8.111.129 to 124.8.111.254124.8.111.255126
225124.8.112.0/25124.8.112.1 to 124.8.112.126124.8.112.127126
226124.8.112.128/25124.8.112.129 to 124.8.112.254124.8.112.255126
227124.8.113.0/25124.8.113.1 to 124.8.113.126124.8.113.127126
228124.8.113.128/25124.8.113.129 to 124.8.113.254124.8.113.255126
229124.8.114.0/25124.8.114.1 to 124.8.114.126124.8.114.127126
230124.8.114.128/25124.8.114.129 to 124.8.114.254124.8.114.255126
231124.8.115.0/25124.8.115.1 to 124.8.115.126124.8.115.127126
232124.8.115.128/25124.8.115.129 to 124.8.115.254124.8.115.255126
233124.8.116.0/25124.8.116.1 to 124.8.116.126124.8.116.127126
234124.8.116.128/25124.8.116.129 to 124.8.116.254124.8.116.255126
235124.8.117.0/25124.8.117.1 to 124.8.117.126124.8.117.127126
236124.8.117.128/25124.8.117.129 to 124.8.117.254124.8.117.255126
237124.8.118.0/25124.8.118.1 to 124.8.118.126124.8.118.127126
238124.8.118.128/25124.8.118.129 to 124.8.118.254124.8.118.255126
239124.8.119.0/25124.8.119.1 to 124.8.119.126124.8.119.127126
240124.8.119.128/25124.8.119.129 to 124.8.119.254124.8.119.255126
241124.8.120.0/25124.8.120.1 to 124.8.120.126124.8.120.127126
242124.8.120.128/25124.8.120.129 to 124.8.120.254124.8.120.255126
243124.8.121.0/25124.8.121.1 to 124.8.121.126124.8.121.127126
244124.8.121.128/25124.8.121.129 to 124.8.121.254124.8.121.255126
245124.8.122.0/25124.8.122.1 to 124.8.122.126124.8.122.127126
246124.8.122.128/25124.8.122.129 to 124.8.122.254124.8.122.255126
247124.8.123.0/25124.8.123.1 to 124.8.123.126124.8.123.127126
248124.8.123.128/25124.8.123.129 to 124.8.123.254124.8.123.255126
249124.8.124.0/25124.8.124.1 to 124.8.124.126124.8.124.127126
250124.8.124.128/25124.8.124.129 to 124.8.124.254124.8.124.255126
251124.8.125.0/25124.8.125.1 to 124.8.125.126124.8.125.127126
252124.8.125.128/25124.8.125.129 to 124.8.125.254124.8.125.255126
253124.8.126.0/25124.8.126.1 to 124.8.126.126124.8.126.127126
254124.8.126.128/25124.8.126.129 to 124.8.126.254124.8.126.255126
255124.8.127.0/25124.8.127.1 to 124.8.127.126124.8.127.127126
256124.8.127.128/25124.8.127.129 to 124.8.127.254124.8.127.255126

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.