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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.

Network199.8.0.0/16
Usable hosts65,534
Subnet mask255.255.0.0
Addresses65,536
Network address
199.8.0.0
Broadcast address
199.8.255.255
First usable
199.8.0.1
Last usable
199.8.255.254
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
C (default /24)
As numbers
Hex C7080000 · Integer 3339190272 to 3339255807
Reverse DNS zone
8.199.in-addr.arpa
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11000111.00001000..00000000.00000000199.8.0.0
Subnet mask11111111.11111111..00000000.00000000255.255.0.0
Network11000111.00001000..00000000.00000000199.8.0.0
Broadcast11000111.00001000..11111111.11111111199.8.255.255
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)

199.8.0.0/16 makes 512 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1199.8.0.0/25199.8.0.1 to 199.8.0.126199.8.0.127126
2199.8.0.128/25199.8.0.129 to 199.8.0.254199.8.0.255126
3199.8.1.0/25199.8.1.1 to 199.8.1.126199.8.1.127126
4199.8.1.128/25199.8.1.129 to 199.8.1.254199.8.1.255126
5199.8.2.0/25199.8.2.1 to 199.8.2.126199.8.2.127126
6199.8.2.128/25199.8.2.129 to 199.8.2.254199.8.2.255126
7199.8.3.0/25199.8.3.1 to 199.8.3.126199.8.3.127126
8199.8.3.128/25199.8.3.129 to 199.8.3.254199.8.3.255126
9199.8.4.0/25199.8.4.1 to 199.8.4.126199.8.4.127126
10199.8.4.128/25199.8.4.129 to 199.8.4.254199.8.4.255126
11199.8.5.0/25199.8.5.1 to 199.8.5.126199.8.5.127126
12199.8.5.128/25199.8.5.129 to 199.8.5.254199.8.5.255126
13199.8.6.0/25199.8.6.1 to 199.8.6.126199.8.6.127126
14199.8.6.128/25199.8.6.129 to 199.8.6.254199.8.6.255126
15199.8.7.0/25199.8.7.1 to 199.8.7.126199.8.7.127126
16199.8.7.128/25199.8.7.129 to 199.8.7.254199.8.7.255126
17199.8.8.0/25199.8.8.1 to 199.8.8.126199.8.8.127126
18199.8.8.128/25199.8.8.129 to 199.8.8.254199.8.8.255126
19199.8.9.0/25199.8.9.1 to 199.8.9.126199.8.9.127126
20199.8.9.128/25199.8.9.129 to 199.8.9.254199.8.9.255126
21199.8.10.0/25199.8.10.1 to 199.8.10.126199.8.10.127126
22199.8.10.128/25199.8.10.129 to 199.8.10.254199.8.10.255126
23199.8.11.0/25199.8.11.1 to 199.8.11.126199.8.11.127126
24199.8.11.128/25199.8.11.129 to 199.8.11.254199.8.11.255126
25199.8.12.0/25199.8.12.1 to 199.8.12.126199.8.12.127126
26199.8.12.128/25199.8.12.129 to 199.8.12.254199.8.12.255126
27199.8.13.0/25199.8.13.1 to 199.8.13.126199.8.13.127126
28199.8.13.128/25199.8.13.129 to 199.8.13.254199.8.13.255126
29199.8.14.0/25199.8.14.1 to 199.8.14.126199.8.14.127126
30199.8.14.128/25199.8.14.129 to 199.8.14.254199.8.14.255126
31199.8.15.0/25199.8.15.1 to 199.8.15.126199.8.15.127126
32199.8.15.128/25199.8.15.129 to 199.8.15.254199.8.15.255126
33199.8.16.0/25199.8.16.1 to 199.8.16.126199.8.16.127126
34199.8.16.128/25199.8.16.129 to 199.8.16.254199.8.16.255126
35199.8.17.0/25199.8.17.1 to 199.8.17.126199.8.17.127126
36199.8.17.128/25199.8.17.129 to 199.8.17.254199.8.17.255126
37199.8.18.0/25199.8.18.1 to 199.8.18.126199.8.18.127126
38199.8.18.128/25199.8.18.129 to 199.8.18.254199.8.18.255126
39199.8.19.0/25199.8.19.1 to 199.8.19.126199.8.19.127126
40199.8.19.128/25199.8.19.129 to 199.8.19.254199.8.19.255126
41199.8.20.0/25199.8.20.1 to 199.8.20.126199.8.20.127126
42199.8.20.128/25199.8.20.129 to 199.8.20.254199.8.20.255126
43199.8.21.0/25199.8.21.1 to 199.8.21.126199.8.21.127126
44199.8.21.128/25199.8.21.129 to 199.8.21.254199.8.21.255126
45199.8.22.0/25199.8.22.1 to 199.8.22.126199.8.22.127126
46199.8.22.128/25199.8.22.129 to 199.8.22.254199.8.22.255126
47199.8.23.0/25199.8.23.1 to 199.8.23.126199.8.23.127126
48199.8.23.128/25199.8.23.129 to 199.8.23.254199.8.23.255126
49199.8.24.0/25199.8.24.1 to 199.8.24.126199.8.24.127126
50199.8.24.128/25199.8.24.129 to 199.8.24.254199.8.24.255126
51199.8.25.0/25199.8.25.1 to 199.8.25.126199.8.25.127126
52199.8.25.128/25199.8.25.129 to 199.8.25.254199.8.25.255126
53199.8.26.0/25199.8.26.1 to 199.8.26.126199.8.26.127126
54199.8.26.128/25199.8.26.129 to 199.8.26.254199.8.26.255126
55199.8.27.0/25199.8.27.1 to 199.8.27.126199.8.27.127126
56199.8.27.128/25199.8.27.129 to 199.8.27.254199.8.27.255126
57199.8.28.0/25199.8.28.1 to 199.8.28.126199.8.28.127126
58199.8.28.128/25199.8.28.129 to 199.8.28.254199.8.28.255126
59199.8.29.0/25199.8.29.1 to 199.8.29.126199.8.29.127126
60199.8.29.128/25199.8.29.129 to 199.8.29.254199.8.29.255126
61199.8.30.0/25199.8.30.1 to 199.8.30.126199.8.30.127126
62199.8.30.128/25199.8.30.129 to 199.8.30.254199.8.30.255126
63199.8.31.0/25199.8.31.1 to 199.8.31.126199.8.31.127126
64199.8.31.128/25199.8.31.129 to 199.8.31.254199.8.31.255126
65199.8.32.0/25199.8.32.1 to 199.8.32.126199.8.32.127126
66199.8.32.128/25199.8.32.129 to 199.8.32.254199.8.32.255126
67199.8.33.0/25199.8.33.1 to 199.8.33.126199.8.33.127126
68199.8.33.128/25199.8.33.129 to 199.8.33.254199.8.33.255126
69199.8.34.0/25199.8.34.1 to 199.8.34.126199.8.34.127126
70199.8.34.128/25199.8.34.129 to 199.8.34.254199.8.34.255126
71199.8.35.0/25199.8.35.1 to 199.8.35.126199.8.35.127126
72199.8.35.128/25199.8.35.129 to 199.8.35.254199.8.35.255126
73199.8.36.0/25199.8.36.1 to 199.8.36.126199.8.36.127126
74199.8.36.128/25199.8.36.129 to 199.8.36.254199.8.36.255126
75199.8.37.0/25199.8.37.1 to 199.8.37.126199.8.37.127126
76199.8.37.128/25199.8.37.129 to 199.8.37.254199.8.37.255126
77199.8.38.0/25199.8.38.1 to 199.8.38.126199.8.38.127126
78199.8.38.128/25199.8.38.129 to 199.8.38.254199.8.38.255126
79199.8.39.0/25199.8.39.1 to 199.8.39.126199.8.39.127126
80199.8.39.128/25199.8.39.129 to 199.8.39.254199.8.39.255126
81199.8.40.0/25199.8.40.1 to 199.8.40.126199.8.40.127126
82199.8.40.128/25199.8.40.129 to 199.8.40.254199.8.40.255126
83199.8.41.0/25199.8.41.1 to 199.8.41.126199.8.41.127126
84199.8.41.128/25199.8.41.129 to 199.8.41.254199.8.41.255126
85199.8.42.0/25199.8.42.1 to 199.8.42.126199.8.42.127126
86199.8.42.128/25199.8.42.129 to 199.8.42.254199.8.42.255126
87199.8.43.0/25199.8.43.1 to 199.8.43.126199.8.43.127126
88199.8.43.128/25199.8.43.129 to 199.8.43.254199.8.43.255126
89199.8.44.0/25199.8.44.1 to 199.8.44.126199.8.44.127126
90199.8.44.128/25199.8.44.129 to 199.8.44.254199.8.44.255126
91199.8.45.0/25199.8.45.1 to 199.8.45.126199.8.45.127126
92199.8.45.128/25199.8.45.129 to 199.8.45.254199.8.45.255126
93199.8.46.0/25199.8.46.1 to 199.8.46.126199.8.46.127126
94199.8.46.128/25199.8.46.129 to 199.8.46.254199.8.46.255126
95199.8.47.0/25199.8.47.1 to 199.8.47.126199.8.47.127126
96199.8.47.128/25199.8.47.129 to 199.8.47.254199.8.47.255126
97199.8.48.0/25199.8.48.1 to 199.8.48.126199.8.48.127126
98199.8.48.128/25199.8.48.129 to 199.8.48.254199.8.48.255126
99199.8.49.0/25199.8.49.1 to 199.8.49.126199.8.49.127126
100199.8.49.128/25199.8.49.129 to 199.8.49.254199.8.49.255126
101199.8.50.0/25199.8.50.1 to 199.8.50.126199.8.50.127126
102199.8.50.128/25199.8.50.129 to 199.8.50.254199.8.50.255126
103199.8.51.0/25199.8.51.1 to 199.8.51.126199.8.51.127126
104199.8.51.128/25199.8.51.129 to 199.8.51.254199.8.51.255126
105199.8.52.0/25199.8.52.1 to 199.8.52.126199.8.52.127126
106199.8.52.128/25199.8.52.129 to 199.8.52.254199.8.52.255126
107199.8.53.0/25199.8.53.1 to 199.8.53.126199.8.53.127126
108199.8.53.128/25199.8.53.129 to 199.8.53.254199.8.53.255126
109199.8.54.0/25199.8.54.1 to 199.8.54.126199.8.54.127126
110199.8.54.128/25199.8.54.129 to 199.8.54.254199.8.54.255126
111199.8.55.0/25199.8.55.1 to 199.8.55.126199.8.55.127126
112199.8.55.128/25199.8.55.129 to 199.8.55.254199.8.55.255126
113199.8.56.0/25199.8.56.1 to 199.8.56.126199.8.56.127126
114199.8.56.128/25199.8.56.129 to 199.8.56.254199.8.56.255126
115199.8.57.0/25199.8.57.1 to 199.8.57.126199.8.57.127126
116199.8.57.128/25199.8.57.129 to 199.8.57.254199.8.57.255126
117199.8.58.0/25199.8.58.1 to 199.8.58.126199.8.58.127126
118199.8.58.128/25199.8.58.129 to 199.8.58.254199.8.58.255126
119199.8.59.0/25199.8.59.1 to 199.8.59.126199.8.59.127126
120199.8.59.128/25199.8.59.129 to 199.8.59.254199.8.59.255126
121199.8.60.0/25199.8.60.1 to 199.8.60.126199.8.60.127126
122199.8.60.128/25199.8.60.129 to 199.8.60.254199.8.60.255126
123199.8.61.0/25199.8.61.1 to 199.8.61.126199.8.61.127126
124199.8.61.128/25199.8.61.129 to 199.8.61.254199.8.61.255126
125199.8.62.0/25199.8.62.1 to 199.8.62.126199.8.62.127126
126199.8.62.128/25199.8.62.129 to 199.8.62.254199.8.62.255126
127199.8.63.0/25199.8.63.1 to 199.8.63.126199.8.63.127126
128199.8.63.128/25199.8.63.129 to 199.8.63.254199.8.63.255126
129199.8.64.0/25199.8.64.1 to 199.8.64.126199.8.64.127126
130199.8.64.128/25199.8.64.129 to 199.8.64.254199.8.64.255126
131199.8.65.0/25199.8.65.1 to 199.8.65.126199.8.65.127126
132199.8.65.128/25199.8.65.129 to 199.8.65.254199.8.65.255126
133199.8.66.0/25199.8.66.1 to 199.8.66.126199.8.66.127126
134199.8.66.128/25199.8.66.129 to 199.8.66.254199.8.66.255126
135199.8.67.0/25199.8.67.1 to 199.8.67.126199.8.67.127126
136199.8.67.128/25199.8.67.129 to 199.8.67.254199.8.67.255126
137199.8.68.0/25199.8.68.1 to 199.8.68.126199.8.68.127126
138199.8.68.128/25199.8.68.129 to 199.8.68.254199.8.68.255126
139199.8.69.0/25199.8.69.1 to 199.8.69.126199.8.69.127126
140199.8.69.128/25199.8.69.129 to 199.8.69.254199.8.69.255126
141199.8.70.0/25199.8.70.1 to 199.8.70.126199.8.70.127126
142199.8.70.128/25199.8.70.129 to 199.8.70.254199.8.70.255126
143199.8.71.0/25199.8.71.1 to 199.8.71.126199.8.71.127126
144199.8.71.128/25199.8.71.129 to 199.8.71.254199.8.71.255126
145199.8.72.0/25199.8.72.1 to 199.8.72.126199.8.72.127126
146199.8.72.128/25199.8.72.129 to 199.8.72.254199.8.72.255126
147199.8.73.0/25199.8.73.1 to 199.8.73.126199.8.73.127126
148199.8.73.128/25199.8.73.129 to 199.8.73.254199.8.73.255126
149199.8.74.0/25199.8.74.1 to 199.8.74.126199.8.74.127126
150199.8.74.128/25199.8.74.129 to 199.8.74.254199.8.74.255126
151199.8.75.0/25199.8.75.1 to 199.8.75.126199.8.75.127126
152199.8.75.128/25199.8.75.129 to 199.8.75.254199.8.75.255126
153199.8.76.0/25199.8.76.1 to 199.8.76.126199.8.76.127126
154199.8.76.128/25199.8.76.129 to 199.8.76.254199.8.76.255126
155199.8.77.0/25199.8.77.1 to 199.8.77.126199.8.77.127126
156199.8.77.128/25199.8.77.129 to 199.8.77.254199.8.77.255126
157199.8.78.0/25199.8.78.1 to 199.8.78.126199.8.78.127126
158199.8.78.128/25199.8.78.129 to 199.8.78.254199.8.78.255126
159199.8.79.0/25199.8.79.1 to 199.8.79.126199.8.79.127126
160199.8.79.128/25199.8.79.129 to 199.8.79.254199.8.79.255126
161199.8.80.0/25199.8.80.1 to 199.8.80.126199.8.80.127126
162199.8.80.128/25199.8.80.129 to 199.8.80.254199.8.80.255126
163199.8.81.0/25199.8.81.1 to 199.8.81.126199.8.81.127126
164199.8.81.128/25199.8.81.129 to 199.8.81.254199.8.81.255126
165199.8.82.0/25199.8.82.1 to 199.8.82.126199.8.82.127126
166199.8.82.128/25199.8.82.129 to 199.8.82.254199.8.82.255126
167199.8.83.0/25199.8.83.1 to 199.8.83.126199.8.83.127126
168199.8.83.128/25199.8.83.129 to 199.8.83.254199.8.83.255126
169199.8.84.0/25199.8.84.1 to 199.8.84.126199.8.84.127126
170199.8.84.128/25199.8.84.129 to 199.8.84.254199.8.84.255126
171199.8.85.0/25199.8.85.1 to 199.8.85.126199.8.85.127126
172199.8.85.128/25199.8.85.129 to 199.8.85.254199.8.85.255126
173199.8.86.0/25199.8.86.1 to 199.8.86.126199.8.86.127126
174199.8.86.128/25199.8.86.129 to 199.8.86.254199.8.86.255126
175199.8.87.0/25199.8.87.1 to 199.8.87.126199.8.87.127126
176199.8.87.128/25199.8.87.129 to 199.8.87.254199.8.87.255126
177199.8.88.0/25199.8.88.1 to 199.8.88.126199.8.88.127126
178199.8.88.128/25199.8.88.129 to 199.8.88.254199.8.88.255126
179199.8.89.0/25199.8.89.1 to 199.8.89.126199.8.89.127126
180199.8.89.128/25199.8.89.129 to 199.8.89.254199.8.89.255126
181199.8.90.0/25199.8.90.1 to 199.8.90.126199.8.90.127126
182199.8.90.128/25199.8.90.129 to 199.8.90.254199.8.90.255126
183199.8.91.0/25199.8.91.1 to 199.8.91.126199.8.91.127126
184199.8.91.128/25199.8.91.129 to 199.8.91.254199.8.91.255126
185199.8.92.0/25199.8.92.1 to 199.8.92.126199.8.92.127126
186199.8.92.128/25199.8.92.129 to 199.8.92.254199.8.92.255126
187199.8.93.0/25199.8.93.1 to 199.8.93.126199.8.93.127126
188199.8.93.128/25199.8.93.129 to 199.8.93.254199.8.93.255126
189199.8.94.0/25199.8.94.1 to 199.8.94.126199.8.94.127126
190199.8.94.128/25199.8.94.129 to 199.8.94.254199.8.94.255126
191199.8.95.0/25199.8.95.1 to 199.8.95.126199.8.95.127126
192199.8.95.128/25199.8.95.129 to 199.8.95.254199.8.95.255126
193199.8.96.0/25199.8.96.1 to 199.8.96.126199.8.96.127126
194199.8.96.128/25199.8.96.129 to 199.8.96.254199.8.96.255126
195199.8.97.0/25199.8.97.1 to 199.8.97.126199.8.97.127126
196199.8.97.128/25199.8.97.129 to 199.8.97.254199.8.97.255126
197199.8.98.0/25199.8.98.1 to 199.8.98.126199.8.98.127126
198199.8.98.128/25199.8.98.129 to 199.8.98.254199.8.98.255126
199199.8.99.0/25199.8.99.1 to 199.8.99.126199.8.99.127126
200199.8.99.128/25199.8.99.129 to 199.8.99.254199.8.99.255126
201199.8.100.0/25199.8.100.1 to 199.8.100.126199.8.100.127126
202199.8.100.128/25199.8.100.129 to 199.8.100.254199.8.100.255126
203199.8.101.0/25199.8.101.1 to 199.8.101.126199.8.101.127126
204199.8.101.128/25199.8.101.129 to 199.8.101.254199.8.101.255126
205199.8.102.0/25199.8.102.1 to 199.8.102.126199.8.102.127126
206199.8.102.128/25199.8.102.129 to 199.8.102.254199.8.102.255126
207199.8.103.0/25199.8.103.1 to 199.8.103.126199.8.103.127126
208199.8.103.128/25199.8.103.129 to 199.8.103.254199.8.103.255126
209199.8.104.0/25199.8.104.1 to 199.8.104.126199.8.104.127126
210199.8.104.128/25199.8.104.129 to 199.8.104.254199.8.104.255126
211199.8.105.0/25199.8.105.1 to 199.8.105.126199.8.105.127126
212199.8.105.128/25199.8.105.129 to 199.8.105.254199.8.105.255126
213199.8.106.0/25199.8.106.1 to 199.8.106.126199.8.106.127126
214199.8.106.128/25199.8.106.129 to 199.8.106.254199.8.106.255126
215199.8.107.0/25199.8.107.1 to 199.8.107.126199.8.107.127126
216199.8.107.128/25199.8.107.129 to 199.8.107.254199.8.107.255126
217199.8.108.0/25199.8.108.1 to 199.8.108.126199.8.108.127126
218199.8.108.128/25199.8.108.129 to 199.8.108.254199.8.108.255126
219199.8.109.0/25199.8.109.1 to 199.8.109.126199.8.109.127126
220199.8.109.128/25199.8.109.129 to 199.8.109.254199.8.109.255126
221199.8.110.0/25199.8.110.1 to 199.8.110.126199.8.110.127126
222199.8.110.128/25199.8.110.129 to 199.8.110.254199.8.110.255126
223199.8.111.0/25199.8.111.1 to 199.8.111.126199.8.111.127126
224199.8.111.128/25199.8.111.129 to 199.8.111.254199.8.111.255126
225199.8.112.0/25199.8.112.1 to 199.8.112.126199.8.112.127126
226199.8.112.128/25199.8.112.129 to 199.8.112.254199.8.112.255126
227199.8.113.0/25199.8.113.1 to 199.8.113.126199.8.113.127126
228199.8.113.128/25199.8.113.129 to 199.8.113.254199.8.113.255126
229199.8.114.0/25199.8.114.1 to 199.8.114.126199.8.114.127126
230199.8.114.128/25199.8.114.129 to 199.8.114.254199.8.114.255126
231199.8.115.0/25199.8.115.1 to 199.8.115.126199.8.115.127126
232199.8.115.128/25199.8.115.129 to 199.8.115.254199.8.115.255126
233199.8.116.0/25199.8.116.1 to 199.8.116.126199.8.116.127126
234199.8.116.128/25199.8.116.129 to 199.8.116.254199.8.116.255126
235199.8.117.0/25199.8.117.1 to 199.8.117.126199.8.117.127126
236199.8.117.128/25199.8.117.129 to 199.8.117.254199.8.117.255126
237199.8.118.0/25199.8.118.1 to 199.8.118.126199.8.118.127126
238199.8.118.128/25199.8.118.129 to 199.8.118.254199.8.118.255126
239199.8.119.0/25199.8.119.1 to 199.8.119.126199.8.119.127126
240199.8.119.128/25199.8.119.129 to 199.8.119.254199.8.119.255126
241199.8.120.0/25199.8.120.1 to 199.8.120.126199.8.120.127126
242199.8.120.128/25199.8.120.129 to 199.8.120.254199.8.120.255126
243199.8.121.0/25199.8.121.1 to 199.8.121.126199.8.121.127126
244199.8.121.128/25199.8.121.129 to 199.8.121.254199.8.121.255126
245199.8.122.0/25199.8.122.1 to 199.8.122.126199.8.122.127126
246199.8.122.128/25199.8.122.129 to 199.8.122.254199.8.122.255126
247199.8.123.0/25199.8.123.1 to 199.8.123.126199.8.123.127126
248199.8.123.128/25199.8.123.129 to 199.8.123.254199.8.123.255126
249199.8.124.0/25199.8.124.1 to 199.8.124.126199.8.124.127126
250199.8.124.128/25199.8.124.129 to 199.8.124.254199.8.124.255126
251199.8.125.0/25199.8.125.1 to 199.8.125.126199.8.125.127126
252199.8.125.128/25199.8.125.129 to 199.8.125.254199.8.125.255126
253199.8.126.0/25199.8.126.1 to 199.8.126.126199.8.126.127126
254199.8.126.128/25199.8.126.129 to 199.8.126.254199.8.126.255126
255199.8.127.0/25199.8.127.1 to 199.8.127.126199.8.127.127126
256199.8.127.128/25199.8.127.129 to 199.8.127.254199.8.127.255126

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.