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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.

Network207.136.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
207.136.0.0
Broadcast address
207.143.255.255
First usable
207.136.0.1
Last usable
207.143.255.254
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 CF880000 · Integer 3481796608 to 3482320895
Reverse DNS zones
136.207.in-addr.arpa
137.207.in-addr.arpa
138.207.in-addr.arpa
139.207.in-addr.arpa
140.207.in-addr.arpa
141.207.in-addr.arpa
142.207.in-addr.arpa
143.207.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
Address11001111.10001000.00000000.00000000207.136.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11001111.10001000.00000000.00000000207.136.0.0
Broadcast11001111.10001111.11111111.11111111207.143.255.255
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)

207.136.0.0/13 makes 4,096 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1207.136.0.0/25207.136.0.1 to 207.136.0.126207.136.0.127126
2207.136.0.128/25207.136.0.129 to 207.136.0.254207.136.0.255126
3207.136.1.0/25207.136.1.1 to 207.136.1.126207.136.1.127126
4207.136.1.128/25207.136.1.129 to 207.136.1.254207.136.1.255126
5207.136.2.0/25207.136.2.1 to 207.136.2.126207.136.2.127126
6207.136.2.128/25207.136.2.129 to 207.136.2.254207.136.2.255126
7207.136.3.0/25207.136.3.1 to 207.136.3.126207.136.3.127126
8207.136.3.128/25207.136.3.129 to 207.136.3.254207.136.3.255126
9207.136.4.0/25207.136.4.1 to 207.136.4.126207.136.4.127126
10207.136.4.128/25207.136.4.129 to 207.136.4.254207.136.4.255126
11207.136.5.0/25207.136.5.1 to 207.136.5.126207.136.5.127126
12207.136.5.128/25207.136.5.129 to 207.136.5.254207.136.5.255126
13207.136.6.0/25207.136.6.1 to 207.136.6.126207.136.6.127126
14207.136.6.128/25207.136.6.129 to 207.136.6.254207.136.6.255126
15207.136.7.0/25207.136.7.1 to 207.136.7.126207.136.7.127126
16207.136.7.128/25207.136.7.129 to 207.136.7.254207.136.7.255126
17207.136.8.0/25207.136.8.1 to 207.136.8.126207.136.8.127126
18207.136.8.128/25207.136.8.129 to 207.136.8.254207.136.8.255126
19207.136.9.0/25207.136.9.1 to 207.136.9.126207.136.9.127126
20207.136.9.128/25207.136.9.129 to 207.136.9.254207.136.9.255126
21207.136.10.0/25207.136.10.1 to 207.136.10.126207.136.10.127126
22207.136.10.128/25207.136.10.129 to 207.136.10.254207.136.10.255126
23207.136.11.0/25207.136.11.1 to 207.136.11.126207.136.11.127126
24207.136.11.128/25207.136.11.129 to 207.136.11.254207.136.11.255126
25207.136.12.0/25207.136.12.1 to 207.136.12.126207.136.12.127126
26207.136.12.128/25207.136.12.129 to 207.136.12.254207.136.12.255126
27207.136.13.0/25207.136.13.1 to 207.136.13.126207.136.13.127126
28207.136.13.128/25207.136.13.129 to 207.136.13.254207.136.13.255126
29207.136.14.0/25207.136.14.1 to 207.136.14.126207.136.14.127126
30207.136.14.128/25207.136.14.129 to 207.136.14.254207.136.14.255126
31207.136.15.0/25207.136.15.1 to 207.136.15.126207.136.15.127126
32207.136.15.128/25207.136.15.129 to 207.136.15.254207.136.15.255126
33207.136.16.0/25207.136.16.1 to 207.136.16.126207.136.16.127126
34207.136.16.128/25207.136.16.129 to 207.136.16.254207.136.16.255126
35207.136.17.0/25207.136.17.1 to 207.136.17.126207.136.17.127126
36207.136.17.128/25207.136.17.129 to 207.136.17.254207.136.17.255126
37207.136.18.0/25207.136.18.1 to 207.136.18.126207.136.18.127126
38207.136.18.128/25207.136.18.129 to 207.136.18.254207.136.18.255126
39207.136.19.0/25207.136.19.1 to 207.136.19.126207.136.19.127126
40207.136.19.128/25207.136.19.129 to 207.136.19.254207.136.19.255126
41207.136.20.0/25207.136.20.1 to 207.136.20.126207.136.20.127126
42207.136.20.128/25207.136.20.129 to 207.136.20.254207.136.20.255126
43207.136.21.0/25207.136.21.1 to 207.136.21.126207.136.21.127126
44207.136.21.128/25207.136.21.129 to 207.136.21.254207.136.21.255126
45207.136.22.0/25207.136.22.1 to 207.136.22.126207.136.22.127126
46207.136.22.128/25207.136.22.129 to 207.136.22.254207.136.22.255126
47207.136.23.0/25207.136.23.1 to 207.136.23.126207.136.23.127126
48207.136.23.128/25207.136.23.129 to 207.136.23.254207.136.23.255126
49207.136.24.0/25207.136.24.1 to 207.136.24.126207.136.24.127126
50207.136.24.128/25207.136.24.129 to 207.136.24.254207.136.24.255126
51207.136.25.0/25207.136.25.1 to 207.136.25.126207.136.25.127126
52207.136.25.128/25207.136.25.129 to 207.136.25.254207.136.25.255126
53207.136.26.0/25207.136.26.1 to 207.136.26.126207.136.26.127126
54207.136.26.128/25207.136.26.129 to 207.136.26.254207.136.26.255126
55207.136.27.0/25207.136.27.1 to 207.136.27.126207.136.27.127126
56207.136.27.128/25207.136.27.129 to 207.136.27.254207.136.27.255126
57207.136.28.0/25207.136.28.1 to 207.136.28.126207.136.28.127126
58207.136.28.128/25207.136.28.129 to 207.136.28.254207.136.28.255126
59207.136.29.0/25207.136.29.1 to 207.136.29.126207.136.29.127126
60207.136.29.128/25207.136.29.129 to 207.136.29.254207.136.29.255126
61207.136.30.0/25207.136.30.1 to 207.136.30.126207.136.30.127126
62207.136.30.128/25207.136.30.129 to 207.136.30.254207.136.30.255126
63207.136.31.0/25207.136.31.1 to 207.136.31.126207.136.31.127126
64207.136.31.128/25207.136.31.129 to 207.136.31.254207.136.31.255126
65207.136.32.0/25207.136.32.1 to 207.136.32.126207.136.32.127126
66207.136.32.128/25207.136.32.129 to 207.136.32.254207.136.32.255126
67207.136.33.0/25207.136.33.1 to 207.136.33.126207.136.33.127126
68207.136.33.128/25207.136.33.129 to 207.136.33.254207.136.33.255126
69207.136.34.0/25207.136.34.1 to 207.136.34.126207.136.34.127126
70207.136.34.128/25207.136.34.129 to 207.136.34.254207.136.34.255126
71207.136.35.0/25207.136.35.1 to 207.136.35.126207.136.35.127126
72207.136.35.128/25207.136.35.129 to 207.136.35.254207.136.35.255126
73207.136.36.0/25207.136.36.1 to 207.136.36.126207.136.36.127126
74207.136.36.128/25207.136.36.129 to 207.136.36.254207.136.36.255126
75207.136.37.0/25207.136.37.1 to 207.136.37.126207.136.37.127126
76207.136.37.128/25207.136.37.129 to 207.136.37.254207.136.37.255126
77207.136.38.0/25207.136.38.1 to 207.136.38.126207.136.38.127126
78207.136.38.128/25207.136.38.129 to 207.136.38.254207.136.38.255126
79207.136.39.0/25207.136.39.1 to 207.136.39.126207.136.39.127126
80207.136.39.128/25207.136.39.129 to 207.136.39.254207.136.39.255126
81207.136.40.0/25207.136.40.1 to 207.136.40.126207.136.40.127126
82207.136.40.128/25207.136.40.129 to 207.136.40.254207.136.40.255126
83207.136.41.0/25207.136.41.1 to 207.136.41.126207.136.41.127126
84207.136.41.128/25207.136.41.129 to 207.136.41.254207.136.41.255126
85207.136.42.0/25207.136.42.1 to 207.136.42.126207.136.42.127126
86207.136.42.128/25207.136.42.129 to 207.136.42.254207.136.42.255126
87207.136.43.0/25207.136.43.1 to 207.136.43.126207.136.43.127126
88207.136.43.128/25207.136.43.129 to 207.136.43.254207.136.43.255126
89207.136.44.0/25207.136.44.1 to 207.136.44.126207.136.44.127126
90207.136.44.128/25207.136.44.129 to 207.136.44.254207.136.44.255126
91207.136.45.0/25207.136.45.1 to 207.136.45.126207.136.45.127126
92207.136.45.128/25207.136.45.129 to 207.136.45.254207.136.45.255126
93207.136.46.0/25207.136.46.1 to 207.136.46.126207.136.46.127126
94207.136.46.128/25207.136.46.129 to 207.136.46.254207.136.46.255126
95207.136.47.0/25207.136.47.1 to 207.136.47.126207.136.47.127126
96207.136.47.128/25207.136.47.129 to 207.136.47.254207.136.47.255126
97207.136.48.0/25207.136.48.1 to 207.136.48.126207.136.48.127126
98207.136.48.128/25207.136.48.129 to 207.136.48.254207.136.48.255126
99207.136.49.0/25207.136.49.1 to 207.136.49.126207.136.49.127126
100207.136.49.128/25207.136.49.129 to 207.136.49.254207.136.49.255126
101207.136.50.0/25207.136.50.1 to 207.136.50.126207.136.50.127126
102207.136.50.128/25207.136.50.129 to 207.136.50.254207.136.50.255126
103207.136.51.0/25207.136.51.1 to 207.136.51.126207.136.51.127126
104207.136.51.128/25207.136.51.129 to 207.136.51.254207.136.51.255126
105207.136.52.0/25207.136.52.1 to 207.136.52.126207.136.52.127126
106207.136.52.128/25207.136.52.129 to 207.136.52.254207.136.52.255126
107207.136.53.0/25207.136.53.1 to 207.136.53.126207.136.53.127126
108207.136.53.128/25207.136.53.129 to 207.136.53.254207.136.53.255126
109207.136.54.0/25207.136.54.1 to 207.136.54.126207.136.54.127126
110207.136.54.128/25207.136.54.129 to 207.136.54.254207.136.54.255126
111207.136.55.0/25207.136.55.1 to 207.136.55.126207.136.55.127126
112207.136.55.128/25207.136.55.129 to 207.136.55.254207.136.55.255126
113207.136.56.0/25207.136.56.1 to 207.136.56.126207.136.56.127126
114207.136.56.128/25207.136.56.129 to 207.136.56.254207.136.56.255126
115207.136.57.0/25207.136.57.1 to 207.136.57.126207.136.57.127126
116207.136.57.128/25207.136.57.129 to 207.136.57.254207.136.57.255126
117207.136.58.0/25207.136.58.1 to 207.136.58.126207.136.58.127126
118207.136.58.128/25207.136.58.129 to 207.136.58.254207.136.58.255126
119207.136.59.0/25207.136.59.1 to 207.136.59.126207.136.59.127126
120207.136.59.128/25207.136.59.129 to 207.136.59.254207.136.59.255126
121207.136.60.0/25207.136.60.1 to 207.136.60.126207.136.60.127126
122207.136.60.128/25207.136.60.129 to 207.136.60.254207.136.60.255126
123207.136.61.0/25207.136.61.1 to 207.136.61.126207.136.61.127126
124207.136.61.128/25207.136.61.129 to 207.136.61.254207.136.61.255126
125207.136.62.0/25207.136.62.1 to 207.136.62.126207.136.62.127126
126207.136.62.128/25207.136.62.129 to 207.136.62.254207.136.62.255126
127207.136.63.0/25207.136.63.1 to 207.136.63.126207.136.63.127126
128207.136.63.128/25207.136.63.129 to 207.136.63.254207.136.63.255126
129207.136.64.0/25207.136.64.1 to 207.136.64.126207.136.64.127126
130207.136.64.128/25207.136.64.129 to 207.136.64.254207.136.64.255126
131207.136.65.0/25207.136.65.1 to 207.136.65.126207.136.65.127126
132207.136.65.128/25207.136.65.129 to 207.136.65.254207.136.65.255126
133207.136.66.0/25207.136.66.1 to 207.136.66.126207.136.66.127126
134207.136.66.128/25207.136.66.129 to 207.136.66.254207.136.66.255126
135207.136.67.0/25207.136.67.1 to 207.136.67.126207.136.67.127126
136207.136.67.128/25207.136.67.129 to 207.136.67.254207.136.67.255126
137207.136.68.0/25207.136.68.1 to 207.136.68.126207.136.68.127126
138207.136.68.128/25207.136.68.129 to 207.136.68.254207.136.68.255126
139207.136.69.0/25207.136.69.1 to 207.136.69.126207.136.69.127126
140207.136.69.128/25207.136.69.129 to 207.136.69.254207.136.69.255126
141207.136.70.0/25207.136.70.1 to 207.136.70.126207.136.70.127126
142207.136.70.128/25207.136.70.129 to 207.136.70.254207.136.70.255126
143207.136.71.0/25207.136.71.1 to 207.136.71.126207.136.71.127126
144207.136.71.128/25207.136.71.129 to 207.136.71.254207.136.71.255126
145207.136.72.0/25207.136.72.1 to 207.136.72.126207.136.72.127126
146207.136.72.128/25207.136.72.129 to 207.136.72.254207.136.72.255126
147207.136.73.0/25207.136.73.1 to 207.136.73.126207.136.73.127126
148207.136.73.128/25207.136.73.129 to 207.136.73.254207.136.73.255126
149207.136.74.0/25207.136.74.1 to 207.136.74.126207.136.74.127126
150207.136.74.128/25207.136.74.129 to 207.136.74.254207.136.74.255126
151207.136.75.0/25207.136.75.1 to 207.136.75.126207.136.75.127126
152207.136.75.128/25207.136.75.129 to 207.136.75.254207.136.75.255126
153207.136.76.0/25207.136.76.1 to 207.136.76.126207.136.76.127126
154207.136.76.128/25207.136.76.129 to 207.136.76.254207.136.76.255126
155207.136.77.0/25207.136.77.1 to 207.136.77.126207.136.77.127126
156207.136.77.128/25207.136.77.129 to 207.136.77.254207.136.77.255126
157207.136.78.0/25207.136.78.1 to 207.136.78.126207.136.78.127126
158207.136.78.128/25207.136.78.129 to 207.136.78.254207.136.78.255126
159207.136.79.0/25207.136.79.1 to 207.136.79.126207.136.79.127126
160207.136.79.128/25207.136.79.129 to 207.136.79.254207.136.79.255126
161207.136.80.0/25207.136.80.1 to 207.136.80.126207.136.80.127126
162207.136.80.128/25207.136.80.129 to 207.136.80.254207.136.80.255126
163207.136.81.0/25207.136.81.1 to 207.136.81.126207.136.81.127126
164207.136.81.128/25207.136.81.129 to 207.136.81.254207.136.81.255126
165207.136.82.0/25207.136.82.1 to 207.136.82.126207.136.82.127126
166207.136.82.128/25207.136.82.129 to 207.136.82.254207.136.82.255126
167207.136.83.0/25207.136.83.1 to 207.136.83.126207.136.83.127126
168207.136.83.128/25207.136.83.129 to 207.136.83.254207.136.83.255126
169207.136.84.0/25207.136.84.1 to 207.136.84.126207.136.84.127126
170207.136.84.128/25207.136.84.129 to 207.136.84.254207.136.84.255126
171207.136.85.0/25207.136.85.1 to 207.136.85.126207.136.85.127126
172207.136.85.128/25207.136.85.129 to 207.136.85.254207.136.85.255126
173207.136.86.0/25207.136.86.1 to 207.136.86.126207.136.86.127126
174207.136.86.128/25207.136.86.129 to 207.136.86.254207.136.86.255126
175207.136.87.0/25207.136.87.1 to 207.136.87.126207.136.87.127126
176207.136.87.128/25207.136.87.129 to 207.136.87.254207.136.87.255126
177207.136.88.0/25207.136.88.1 to 207.136.88.126207.136.88.127126
178207.136.88.128/25207.136.88.129 to 207.136.88.254207.136.88.255126
179207.136.89.0/25207.136.89.1 to 207.136.89.126207.136.89.127126
180207.136.89.128/25207.136.89.129 to 207.136.89.254207.136.89.255126
181207.136.90.0/25207.136.90.1 to 207.136.90.126207.136.90.127126
182207.136.90.128/25207.136.90.129 to 207.136.90.254207.136.90.255126
183207.136.91.0/25207.136.91.1 to 207.136.91.126207.136.91.127126
184207.136.91.128/25207.136.91.129 to 207.136.91.254207.136.91.255126
185207.136.92.0/25207.136.92.1 to 207.136.92.126207.136.92.127126
186207.136.92.128/25207.136.92.129 to 207.136.92.254207.136.92.255126
187207.136.93.0/25207.136.93.1 to 207.136.93.126207.136.93.127126
188207.136.93.128/25207.136.93.129 to 207.136.93.254207.136.93.255126
189207.136.94.0/25207.136.94.1 to 207.136.94.126207.136.94.127126
190207.136.94.128/25207.136.94.129 to 207.136.94.254207.136.94.255126
191207.136.95.0/25207.136.95.1 to 207.136.95.126207.136.95.127126
192207.136.95.128/25207.136.95.129 to 207.136.95.254207.136.95.255126
193207.136.96.0/25207.136.96.1 to 207.136.96.126207.136.96.127126
194207.136.96.128/25207.136.96.129 to 207.136.96.254207.136.96.255126
195207.136.97.0/25207.136.97.1 to 207.136.97.126207.136.97.127126
196207.136.97.128/25207.136.97.129 to 207.136.97.254207.136.97.255126
197207.136.98.0/25207.136.98.1 to 207.136.98.126207.136.98.127126
198207.136.98.128/25207.136.98.129 to 207.136.98.254207.136.98.255126
199207.136.99.0/25207.136.99.1 to 207.136.99.126207.136.99.127126
200207.136.99.128/25207.136.99.129 to 207.136.99.254207.136.99.255126
201207.136.100.0/25207.136.100.1 to 207.136.100.126207.136.100.127126
202207.136.100.128/25207.136.100.129 to 207.136.100.254207.136.100.255126
203207.136.101.0/25207.136.101.1 to 207.136.101.126207.136.101.127126
204207.136.101.128/25207.136.101.129 to 207.136.101.254207.136.101.255126
205207.136.102.0/25207.136.102.1 to 207.136.102.126207.136.102.127126
206207.136.102.128/25207.136.102.129 to 207.136.102.254207.136.102.255126
207207.136.103.0/25207.136.103.1 to 207.136.103.126207.136.103.127126
208207.136.103.128/25207.136.103.129 to 207.136.103.254207.136.103.255126
209207.136.104.0/25207.136.104.1 to 207.136.104.126207.136.104.127126
210207.136.104.128/25207.136.104.129 to 207.136.104.254207.136.104.255126
211207.136.105.0/25207.136.105.1 to 207.136.105.126207.136.105.127126
212207.136.105.128/25207.136.105.129 to 207.136.105.254207.136.105.255126
213207.136.106.0/25207.136.106.1 to 207.136.106.126207.136.106.127126
214207.136.106.128/25207.136.106.129 to 207.136.106.254207.136.106.255126
215207.136.107.0/25207.136.107.1 to 207.136.107.126207.136.107.127126
216207.136.107.128/25207.136.107.129 to 207.136.107.254207.136.107.255126
217207.136.108.0/25207.136.108.1 to 207.136.108.126207.136.108.127126
218207.136.108.128/25207.136.108.129 to 207.136.108.254207.136.108.255126
219207.136.109.0/25207.136.109.1 to 207.136.109.126207.136.109.127126
220207.136.109.128/25207.136.109.129 to 207.136.109.254207.136.109.255126
221207.136.110.0/25207.136.110.1 to 207.136.110.126207.136.110.127126
222207.136.110.128/25207.136.110.129 to 207.136.110.254207.136.110.255126
223207.136.111.0/25207.136.111.1 to 207.136.111.126207.136.111.127126
224207.136.111.128/25207.136.111.129 to 207.136.111.254207.136.111.255126
225207.136.112.0/25207.136.112.1 to 207.136.112.126207.136.112.127126
226207.136.112.128/25207.136.112.129 to 207.136.112.254207.136.112.255126
227207.136.113.0/25207.136.113.1 to 207.136.113.126207.136.113.127126
228207.136.113.128/25207.136.113.129 to 207.136.113.254207.136.113.255126
229207.136.114.0/25207.136.114.1 to 207.136.114.126207.136.114.127126
230207.136.114.128/25207.136.114.129 to 207.136.114.254207.136.114.255126
231207.136.115.0/25207.136.115.1 to 207.136.115.126207.136.115.127126
232207.136.115.128/25207.136.115.129 to 207.136.115.254207.136.115.255126
233207.136.116.0/25207.136.116.1 to 207.136.116.126207.136.116.127126
234207.136.116.128/25207.136.116.129 to 207.136.116.254207.136.116.255126
235207.136.117.0/25207.136.117.1 to 207.136.117.126207.136.117.127126
236207.136.117.128/25207.136.117.129 to 207.136.117.254207.136.117.255126
237207.136.118.0/25207.136.118.1 to 207.136.118.126207.136.118.127126
238207.136.118.128/25207.136.118.129 to 207.136.118.254207.136.118.255126
239207.136.119.0/25207.136.119.1 to 207.136.119.126207.136.119.127126
240207.136.119.128/25207.136.119.129 to 207.136.119.254207.136.119.255126
241207.136.120.0/25207.136.120.1 to 207.136.120.126207.136.120.127126
242207.136.120.128/25207.136.120.129 to 207.136.120.254207.136.120.255126
243207.136.121.0/25207.136.121.1 to 207.136.121.126207.136.121.127126
244207.136.121.128/25207.136.121.129 to 207.136.121.254207.136.121.255126
245207.136.122.0/25207.136.122.1 to 207.136.122.126207.136.122.127126
246207.136.122.128/25207.136.122.129 to 207.136.122.254207.136.122.255126
247207.136.123.0/25207.136.123.1 to 207.136.123.126207.136.123.127126
248207.136.123.128/25207.136.123.129 to 207.136.123.254207.136.123.255126
249207.136.124.0/25207.136.124.1 to 207.136.124.126207.136.124.127126
250207.136.124.128/25207.136.124.129 to 207.136.124.254207.136.124.255126
251207.136.125.0/25207.136.125.1 to 207.136.125.126207.136.125.127126
252207.136.125.128/25207.136.125.129 to 207.136.125.254207.136.125.255126
253207.136.126.0/25207.136.126.1 to 207.136.126.126207.136.126.127126
254207.136.126.128/25207.136.126.129 to 207.136.126.254207.136.126.255126
255207.136.127.0/25207.136.127.1 to 207.136.127.126207.136.127.127126
256207.136.127.128/25207.136.127.129 to 207.136.127.254207.136.127.255126

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.