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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.

Network208.136.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
208.136.0.0
Broadcast address
208.143.255.255
First usable
208.136.0.1
Last usable
208.143.255.254
Usable hosts
524,286 (524,288 less the network and broadcast addresses)
Subnet mask
255.248.0.0
Wildcard mask
0.7.255.255 (Cisco ACLs, OSPF)
Prefix length
/13
Type
Public public
Old class
C (default /24)
As numbers
Hex D0880000 · Integer 3498573824 to 3499098111
Reverse DNS zones
136.208.in-addr.arpa
137.208.in-addr.arpa
138.208.in-addr.arpa
139.208.in-addr.arpa
140.208.in-addr.arpa
141.208.in-addr.arpa
142.208.in-addr.arpa
143.208.in-addr.arpa
/13 is not on a 8-bit boundary, so it takes 8 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address11010000.10001000.00000000.00000000208.136.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11010000.10001000.00000000.00000000208.136.0.0
Broadcast11010000.10001111.11111111.11111111208.143.255.255
Split into smaller subnets/25
/14 (2)/15 (4)/16 (8)/17 (16)/18 (32)/19 (64)/20 (128)/21 (256)/22 (512)/23 (1,024)/24 (2,048)/25 (4,096)

208.136.0.0/13 makes 4,096 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1208.136.0.0/25208.136.0.1 to 208.136.0.126208.136.0.127126
2208.136.0.128/25208.136.0.129 to 208.136.0.254208.136.0.255126
3208.136.1.0/25208.136.1.1 to 208.136.1.126208.136.1.127126
4208.136.1.128/25208.136.1.129 to 208.136.1.254208.136.1.255126
5208.136.2.0/25208.136.2.1 to 208.136.2.126208.136.2.127126
6208.136.2.128/25208.136.2.129 to 208.136.2.254208.136.2.255126
7208.136.3.0/25208.136.3.1 to 208.136.3.126208.136.3.127126
8208.136.3.128/25208.136.3.129 to 208.136.3.254208.136.3.255126
9208.136.4.0/25208.136.4.1 to 208.136.4.126208.136.4.127126
10208.136.4.128/25208.136.4.129 to 208.136.4.254208.136.4.255126
11208.136.5.0/25208.136.5.1 to 208.136.5.126208.136.5.127126
12208.136.5.128/25208.136.5.129 to 208.136.5.254208.136.5.255126
13208.136.6.0/25208.136.6.1 to 208.136.6.126208.136.6.127126
14208.136.6.128/25208.136.6.129 to 208.136.6.254208.136.6.255126
15208.136.7.0/25208.136.7.1 to 208.136.7.126208.136.7.127126
16208.136.7.128/25208.136.7.129 to 208.136.7.254208.136.7.255126
17208.136.8.0/25208.136.8.1 to 208.136.8.126208.136.8.127126
18208.136.8.128/25208.136.8.129 to 208.136.8.254208.136.8.255126
19208.136.9.0/25208.136.9.1 to 208.136.9.126208.136.9.127126
20208.136.9.128/25208.136.9.129 to 208.136.9.254208.136.9.255126
21208.136.10.0/25208.136.10.1 to 208.136.10.126208.136.10.127126
22208.136.10.128/25208.136.10.129 to 208.136.10.254208.136.10.255126
23208.136.11.0/25208.136.11.1 to 208.136.11.126208.136.11.127126
24208.136.11.128/25208.136.11.129 to 208.136.11.254208.136.11.255126
25208.136.12.0/25208.136.12.1 to 208.136.12.126208.136.12.127126
26208.136.12.128/25208.136.12.129 to 208.136.12.254208.136.12.255126
27208.136.13.0/25208.136.13.1 to 208.136.13.126208.136.13.127126
28208.136.13.128/25208.136.13.129 to 208.136.13.254208.136.13.255126
29208.136.14.0/25208.136.14.1 to 208.136.14.126208.136.14.127126
30208.136.14.128/25208.136.14.129 to 208.136.14.254208.136.14.255126
31208.136.15.0/25208.136.15.1 to 208.136.15.126208.136.15.127126
32208.136.15.128/25208.136.15.129 to 208.136.15.254208.136.15.255126
33208.136.16.0/25208.136.16.1 to 208.136.16.126208.136.16.127126
34208.136.16.128/25208.136.16.129 to 208.136.16.254208.136.16.255126
35208.136.17.0/25208.136.17.1 to 208.136.17.126208.136.17.127126
36208.136.17.128/25208.136.17.129 to 208.136.17.254208.136.17.255126
37208.136.18.0/25208.136.18.1 to 208.136.18.126208.136.18.127126
38208.136.18.128/25208.136.18.129 to 208.136.18.254208.136.18.255126
39208.136.19.0/25208.136.19.1 to 208.136.19.126208.136.19.127126
40208.136.19.128/25208.136.19.129 to 208.136.19.254208.136.19.255126
41208.136.20.0/25208.136.20.1 to 208.136.20.126208.136.20.127126
42208.136.20.128/25208.136.20.129 to 208.136.20.254208.136.20.255126
43208.136.21.0/25208.136.21.1 to 208.136.21.126208.136.21.127126
44208.136.21.128/25208.136.21.129 to 208.136.21.254208.136.21.255126
45208.136.22.0/25208.136.22.1 to 208.136.22.126208.136.22.127126
46208.136.22.128/25208.136.22.129 to 208.136.22.254208.136.22.255126
47208.136.23.0/25208.136.23.1 to 208.136.23.126208.136.23.127126
48208.136.23.128/25208.136.23.129 to 208.136.23.254208.136.23.255126
49208.136.24.0/25208.136.24.1 to 208.136.24.126208.136.24.127126
50208.136.24.128/25208.136.24.129 to 208.136.24.254208.136.24.255126
51208.136.25.0/25208.136.25.1 to 208.136.25.126208.136.25.127126
52208.136.25.128/25208.136.25.129 to 208.136.25.254208.136.25.255126
53208.136.26.0/25208.136.26.1 to 208.136.26.126208.136.26.127126
54208.136.26.128/25208.136.26.129 to 208.136.26.254208.136.26.255126
55208.136.27.0/25208.136.27.1 to 208.136.27.126208.136.27.127126
56208.136.27.128/25208.136.27.129 to 208.136.27.254208.136.27.255126
57208.136.28.0/25208.136.28.1 to 208.136.28.126208.136.28.127126
58208.136.28.128/25208.136.28.129 to 208.136.28.254208.136.28.255126
59208.136.29.0/25208.136.29.1 to 208.136.29.126208.136.29.127126
60208.136.29.128/25208.136.29.129 to 208.136.29.254208.136.29.255126
61208.136.30.0/25208.136.30.1 to 208.136.30.126208.136.30.127126
62208.136.30.128/25208.136.30.129 to 208.136.30.254208.136.30.255126
63208.136.31.0/25208.136.31.1 to 208.136.31.126208.136.31.127126
64208.136.31.128/25208.136.31.129 to 208.136.31.254208.136.31.255126
65208.136.32.0/25208.136.32.1 to 208.136.32.126208.136.32.127126
66208.136.32.128/25208.136.32.129 to 208.136.32.254208.136.32.255126
67208.136.33.0/25208.136.33.1 to 208.136.33.126208.136.33.127126
68208.136.33.128/25208.136.33.129 to 208.136.33.254208.136.33.255126
69208.136.34.0/25208.136.34.1 to 208.136.34.126208.136.34.127126
70208.136.34.128/25208.136.34.129 to 208.136.34.254208.136.34.255126
71208.136.35.0/25208.136.35.1 to 208.136.35.126208.136.35.127126
72208.136.35.128/25208.136.35.129 to 208.136.35.254208.136.35.255126
73208.136.36.0/25208.136.36.1 to 208.136.36.126208.136.36.127126
74208.136.36.128/25208.136.36.129 to 208.136.36.254208.136.36.255126
75208.136.37.0/25208.136.37.1 to 208.136.37.126208.136.37.127126
76208.136.37.128/25208.136.37.129 to 208.136.37.254208.136.37.255126
77208.136.38.0/25208.136.38.1 to 208.136.38.126208.136.38.127126
78208.136.38.128/25208.136.38.129 to 208.136.38.254208.136.38.255126
79208.136.39.0/25208.136.39.1 to 208.136.39.126208.136.39.127126
80208.136.39.128/25208.136.39.129 to 208.136.39.254208.136.39.255126
81208.136.40.0/25208.136.40.1 to 208.136.40.126208.136.40.127126
82208.136.40.128/25208.136.40.129 to 208.136.40.254208.136.40.255126
83208.136.41.0/25208.136.41.1 to 208.136.41.126208.136.41.127126
84208.136.41.128/25208.136.41.129 to 208.136.41.254208.136.41.255126
85208.136.42.0/25208.136.42.1 to 208.136.42.126208.136.42.127126
86208.136.42.128/25208.136.42.129 to 208.136.42.254208.136.42.255126
87208.136.43.0/25208.136.43.1 to 208.136.43.126208.136.43.127126
88208.136.43.128/25208.136.43.129 to 208.136.43.254208.136.43.255126
89208.136.44.0/25208.136.44.1 to 208.136.44.126208.136.44.127126
90208.136.44.128/25208.136.44.129 to 208.136.44.254208.136.44.255126
91208.136.45.0/25208.136.45.1 to 208.136.45.126208.136.45.127126
92208.136.45.128/25208.136.45.129 to 208.136.45.254208.136.45.255126
93208.136.46.0/25208.136.46.1 to 208.136.46.126208.136.46.127126
94208.136.46.128/25208.136.46.129 to 208.136.46.254208.136.46.255126
95208.136.47.0/25208.136.47.1 to 208.136.47.126208.136.47.127126
96208.136.47.128/25208.136.47.129 to 208.136.47.254208.136.47.255126
97208.136.48.0/25208.136.48.1 to 208.136.48.126208.136.48.127126
98208.136.48.128/25208.136.48.129 to 208.136.48.254208.136.48.255126
99208.136.49.0/25208.136.49.1 to 208.136.49.126208.136.49.127126
100208.136.49.128/25208.136.49.129 to 208.136.49.254208.136.49.255126
101208.136.50.0/25208.136.50.1 to 208.136.50.126208.136.50.127126
102208.136.50.128/25208.136.50.129 to 208.136.50.254208.136.50.255126
103208.136.51.0/25208.136.51.1 to 208.136.51.126208.136.51.127126
104208.136.51.128/25208.136.51.129 to 208.136.51.254208.136.51.255126
105208.136.52.0/25208.136.52.1 to 208.136.52.126208.136.52.127126
106208.136.52.128/25208.136.52.129 to 208.136.52.254208.136.52.255126
107208.136.53.0/25208.136.53.1 to 208.136.53.126208.136.53.127126
108208.136.53.128/25208.136.53.129 to 208.136.53.254208.136.53.255126
109208.136.54.0/25208.136.54.1 to 208.136.54.126208.136.54.127126
110208.136.54.128/25208.136.54.129 to 208.136.54.254208.136.54.255126
111208.136.55.0/25208.136.55.1 to 208.136.55.126208.136.55.127126
112208.136.55.128/25208.136.55.129 to 208.136.55.254208.136.55.255126
113208.136.56.0/25208.136.56.1 to 208.136.56.126208.136.56.127126
114208.136.56.128/25208.136.56.129 to 208.136.56.254208.136.56.255126
115208.136.57.0/25208.136.57.1 to 208.136.57.126208.136.57.127126
116208.136.57.128/25208.136.57.129 to 208.136.57.254208.136.57.255126
117208.136.58.0/25208.136.58.1 to 208.136.58.126208.136.58.127126
118208.136.58.128/25208.136.58.129 to 208.136.58.254208.136.58.255126
119208.136.59.0/25208.136.59.1 to 208.136.59.126208.136.59.127126
120208.136.59.128/25208.136.59.129 to 208.136.59.254208.136.59.255126
121208.136.60.0/25208.136.60.1 to 208.136.60.126208.136.60.127126
122208.136.60.128/25208.136.60.129 to 208.136.60.254208.136.60.255126
123208.136.61.0/25208.136.61.1 to 208.136.61.126208.136.61.127126
124208.136.61.128/25208.136.61.129 to 208.136.61.254208.136.61.255126
125208.136.62.0/25208.136.62.1 to 208.136.62.126208.136.62.127126
126208.136.62.128/25208.136.62.129 to 208.136.62.254208.136.62.255126
127208.136.63.0/25208.136.63.1 to 208.136.63.126208.136.63.127126
128208.136.63.128/25208.136.63.129 to 208.136.63.254208.136.63.255126
129208.136.64.0/25208.136.64.1 to 208.136.64.126208.136.64.127126
130208.136.64.128/25208.136.64.129 to 208.136.64.254208.136.64.255126
131208.136.65.0/25208.136.65.1 to 208.136.65.126208.136.65.127126
132208.136.65.128/25208.136.65.129 to 208.136.65.254208.136.65.255126
133208.136.66.0/25208.136.66.1 to 208.136.66.126208.136.66.127126
134208.136.66.128/25208.136.66.129 to 208.136.66.254208.136.66.255126
135208.136.67.0/25208.136.67.1 to 208.136.67.126208.136.67.127126
136208.136.67.128/25208.136.67.129 to 208.136.67.254208.136.67.255126
137208.136.68.0/25208.136.68.1 to 208.136.68.126208.136.68.127126
138208.136.68.128/25208.136.68.129 to 208.136.68.254208.136.68.255126
139208.136.69.0/25208.136.69.1 to 208.136.69.126208.136.69.127126
140208.136.69.128/25208.136.69.129 to 208.136.69.254208.136.69.255126
141208.136.70.0/25208.136.70.1 to 208.136.70.126208.136.70.127126
142208.136.70.128/25208.136.70.129 to 208.136.70.254208.136.70.255126
143208.136.71.0/25208.136.71.1 to 208.136.71.126208.136.71.127126
144208.136.71.128/25208.136.71.129 to 208.136.71.254208.136.71.255126
145208.136.72.0/25208.136.72.1 to 208.136.72.126208.136.72.127126
146208.136.72.128/25208.136.72.129 to 208.136.72.254208.136.72.255126
147208.136.73.0/25208.136.73.1 to 208.136.73.126208.136.73.127126
148208.136.73.128/25208.136.73.129 to 208.136.73.254208.136.73.255126
149208.136.74.0/25208.136.74.1 to 208.136.74.126208.136.74.127126
150208.136.74.128/25208.136.74.129 to 208.136.74.254208.136.74.255126
151208.136.75.0/25208.136.75.1 to 208.136.75.126208.136.75.127126
152208.136.75.128/25208.136.75.129 to 208.136.75.254208.136.75.255126
153208.136.76.0/25208.136.76.1 to 208.136.76.126208.136.76.127126
154208.136.76.128/25208.136.76.129 to 208.136.76.254208.136.76.255126
155208.136.77.0/25208.136.77.1 to 208.136.77.126208.136.77.127126
156208.136.77.128/25208.136.77.129 to 208.136.77.254208.136.77.255126
157208.136.78.0/25208.136.78.1 to 208.136.78.126208.136.78.127126
158208.136.78.128/25208.136.78.129 to 208.136.78.254208.136.78.255126
159208.136.79.0/25208.136.79.1 to 208.136.79.126208.136.79.127126
160208.136.79.128/25208.136.79.129 to 208.136.79.254208.136.79.255126
161208.136.80.0/25208.136.80.1 to 208.136.80.126208.136.80.127126
162208.136.80.128/25208.136.80.129 to 208.136.80.254208.136.80.255126
163208.136.81.0/25208.136.81.1 to 208.136.81.126208.136.81.127126
164208.136.81.128/25208.136.81.129 to 208.136.81.254208.136.81.255126
165208.136.82.0/25208.136.82.1 to 208.136.82.126208.136.82.127126
166208.136.82.128/25208.136.82.129 to 208.136.82.254208.136.82.255126
167208.136.83.0/25208.136.83.1 to 208.136.83.126208.136.83.127126
168208.136.83.128/25208.136.83.129 to 208.136.83.254208.136.83.255126
169208.136.84.0/25208.136.84.1 to 208.136.84.126208.136.84.127126
170208.136.84.128/25208.136.84.129 to 208.136.84.254208.136.84.255126
171208.136.85.0/25208.136.85.1 to 208.136.85.126208.136.85.127126
172208.136.85.128/25208.136.85.129 to 208.136.85.254208.136.85.255126
173208.136.86.0/25208.136.86.1 to 208.136.86.126208.136.86.127126
174208.136.86.128/25208.136.86.129 to 208.136.86.254208.136.86.255126
175208.136.87.0/25208.136.87.1 to 208.136.87.126208.136.87.127126
176208.136.87.128/25208.136.87.129 to 208.136.87.254208.136.87.255126
177208.136.88.0/25208.136.88.1 to 208.136.88.126208.136.88.127126
178208.136.88.128/25208.136.88.129 to 208.136.88.254208.136.88.255126
179208.136.89.0/25208.136.89.1 to 208.136.89.126208.136.89.127126
180208.136.89.128/25208.136.89.129 to 208.136.89.254208.136.89.255126
181208.136.90.0/25208.136.90.1 to 208.136.90.126208.136.90.127126
182208.136.90.128/25208.136.90.129 to 208.136.90.254208.136.90.255126
183208.136.91.0/25208.136.91.1 to 208.136.91.126208.136.91.127126
184208.136.91.128/25208.136.91.129 to 208.136.91.254208.136.91.255126
185208.136.92.0/25208.136.92.1 to 208.136.92.126208.136.92.127126
186208.136.92.128/25208.136.92.129 to 208.136.92.254208.136.92.255126
187208.136.93.0/25208.136.93.1 to 208.136.93.126208.136.93.127126
188208.136.93.128/25208.136.93.129 to 208.136.93.254208.136.93.255126
189208.136.94.0/25208.136.94.1 to 208.136.94.126208.136.94.127126
190208.136.94.128/25208.136.94.129 to 208.136.94.254208.136.94.255126
191208.136.95.0/25208.136.95.1 to 208.136.95.126208.136.95.127126
192208.136.95.128/25208.136.95.129 to 208.136.95.254208.136.95.255126
193208.136.96.0/25208.136.96.1 to 208.136.96.126208.136.96.127126
194208.136.96.128/25208.136.96.129 to 208.136.96.254208.136.96.255126
195208.136.97.0/25208.136.97.1 to 208.136.97.126208.136.97.127126
196208.136.97.128/25208.136.97.129 to 208.136.97.254208.136.97.255126
197208.136.98.0/25208.136.98.1 to 208.136.98.126208.136.98.127126
198208.136.98.128/25208.136.98.129 to 208.136.98.254208.136.98.255126
199208.136.99.0/25208.136.99.1 to 208.136.99.126208.136.99.127126
200208.136.99.128/25208.136.99.129 to 208.136.99.254208.136.99.255126
201208.136.100.0/25208.136.100.1 to 208.136.100.126208.136.100.127126
202208.136.100.128/25208.136.100.129 to 208.136.100.254208.136.100.255126
203208.136.101.0/25208.136.101.1 to 208.136.101.126208.136.101.127126
204208.136.101.128/25208.136.101.129 to 208.136.101.254208.136.101.255126
205208.136.102.0/25208.136.102.1 to 208.136.102.126208.136.102.127126
206208.136.102.128/25208.136.102.129 to 208.136.102.254208.136.102.255126
207208.136.103.0/25208.136.103.1 to 208.136.103.126208.136.103.127126
208208.136.103.128/25208.136.103.129 to 208.136.103.254208.136.103.255126
209208.136.104.0/25208.136.104.1 to 208.136.104.126208.136.104.127126
210208.136.104.128/25208.136.104.129 to 208.136.104.254208.136.104.255126
211208.136.105.0/25208.136.105.1 to 208.136.105.126208.136.105.127126
212208.136.105.128/25208.136.105.129 to 208.136.105.254208.136.105.255126
213208.136.106.0/25208.136.106.1 to 208.136.106.126208.136.106.127126
214208.136.106.128/25208.136.106.129 to 208.136.106.254208.136.106.255126
215208.136.107.0/25208.136.107.1 to 208.136.107.126208.136.107.127126
216208.136.107.128/25208.136.107.129 to 208.136.107.254208.136.107.255126
217208.136.108.0/25208.136.108.1 to 208.136.108.126208.136.108.127126
218208.136.108.128/25208.136.108.129 to 208.136.108.254208.136.108.255126
219208.136.109.0/25208.136.109.1 to 208.136.109.126208.136.109.127126
220208.136.109.128/25208.136.109.129 to 208.136.109.254208.136.109.255126
221208.136.110.0/25208.136.110.1 to 208.136.110.126208.136.110.127126
222208.136.110.128/25208.136.110.129 to 208.136.110.254208.136.110.255126
223208.136.111.0/25208.136.111.1 to 208.136.111.126208.136.111.127126
224208.136.111.128/25208.136.111.129 to 208.136.111.254208.136.111.255126
225208.136.112.0/25208.136.112.1 to 208.136.112.126208.136.112.127126
226208.136.112.128/25208.136.112.129 to 208.136.112.254208.136.112.255126
227208.136.113.0/25208.136.113.1 to 208.136.113.126208.136.113.127126
228208.136.113.128/25208.136.113.129 to 208.136.113.254208.136.113.255126
229208.136.114.0/25208.136.114.1 to 208.136.114.126208.136.114.127126
230208.136.114.128/25208.136.114.129 to 208.136.114.254208.136.114.255126
231208.136.115.0/25208.136.115.1 to 208.136.115.126208.136.115.127126
232208.136.115.128/25208.136.115.129 to 208.136.115.254208.136.115.255126
233208.136.116.0/25208.136.116.1 to 208.136.116.126208.136.116.127126
234208.136.116.128/25208.136.116.129 to 208.136.116.254208.136.116.255126
235208.136.117.0/25208.136.117.1 to 208.136.117.126208.136.117.127126
236208.136.117.128/25208.136.117.129 to 208.136.117.254208.136.117.255126
237208.136.118.0/25208.136.118.1 to 208.136.118.126208.136.118.127126
238208.136.118.128/25208.136.118.129 to 208.136.118.254208.136.118.255126
239208.136.119.0/25208.136.119.1 to 208.136.119.126208.136.119.127126
240208.136.119.128/25208.136.119.129 to 208.136.119.254208.136.119.255126
241208.136.120.0/25208.136.120.1 to 208.136.120.126208.136.120.127126
242208.136.120.128/25208.136.120.129 to 208.136.120.254208.136.120.255126
243208.136.121.0/25208.136.121.1 to 208.136.121.126208.136.121.127126
244208.136.121.128/25208.136.121.129 to 208.136.121.254208.136.121.255126
245208.136.122.0/25208.136.122.1 to 208.136.122.126208.136.122.127126
246208.136.122.128/25208.136.122.129 to 208.136.122.254208.136.122.255126
247208.136.123.0/25208.136.123.1 to 208.136.123.126208.136.123.127126
248208.136.123.128/25208.136.123.129 to 208.136.123.254208.136.123.255126
249208.136.124.0/25208.136.124.1 to 208.136.124.126208.136.124.127126
250208.136.124.128/25208.136.124.129 to 208.136.124.254208.136.124.255126
251208.136.125.0/25208.136.125.1 to 208.136.125.126208.136.125.127126
252208.136.125.128/25208.136.125.129 to 208.136.125.254208.136.125.255126
253208.136.126.0/25208.136.126.1 to 208.136.126.126208.136.126.127126
254208.136.126.128/25208.136.126.129 to 208.136.126.254208.136.126.255126
255208.136.127.0/25208.136.127.1 to 208.136.127.126208.136.127.127126
256208.136.127.128/25208.136.127.129 to 208.136.127.254208.136.127.255126

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.