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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.

Network255.0.0.0/13
Usable hosts524,286
Subnet mask255.248.0.0
Addresses524,288
Network address
255.0.0.0
Broadcast address
255.7.255.255
First usable
255.0.0.1
Last usable
255.7.255.254
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
Reserved 240.0.0.0/4
Future use; not usable on most systems
Old class
E (reserved)
As numbers
Hex FF000000 · Integer 4278190080 to 4278714367
Reverse DNS zones
0.255.in-addr.arpa
1.255.in-addr.arpa
2.255.in-addr.arpa
3.255.in-addr.arpa
4.255.in-addr.arpa
5.255.in-addr.arpa
6.255.in-addr.arpa
7.255.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
Address11111111.00000000.00000000.00000000255.0.0.0
Subnet mask11111111.11111000.00000000.00000000255.248.0.0
Network11111111.00000000.00000000.00000000255.0.0.0
Broadcast11111111.00000111.11111111.11111111255.7.255.255
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)

255.0.0.0/13 makes 4,096 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1255.0.0.0/25255.0.0.1 to 255.0.0.126255.0.0.127126
2255.0.0.128/25255.0.0.129 to 255.0.0.254255.0.0.255126
3255.0.1.0/25255.0.1.1 to 255.0.1.126255.0.1.127126
4255.0.1.128/25255.0.1.129 to 255.0.1.254255.0.1.255126
5255.0.2.0/25255.0.2.1 to 255.0.2.126255.0.2.127126
6255.0.2.128/25255.0.2.129 to 255.0.2.254255.0.2.255126
7255.0.3.0/25255.0.3.1 to 255.0.3.126255.0.3.127126
8255.0.3.128/25255.0.3.129 to 255.0.3.254255.0.3.255126
9255.0.4.0/25255.0.4.1 to 255.0.4.126255.0.4.127126
10255.0.4.128/25255.0.4.129 to 255.0.4.254255.0.4.255126
11255.0.5.0/25255.0.5.1 to 255.0.5.126255.0.5.127126
12255.0.5.128/25255.0.5.129 to 255.0.5.254255.0.5.255126
13255.0.6.0/25255.0.6.1 to 255.0.6.126255.0.6.127126
14255.0.6.128/25255.0.6.129 to 255.0.6.254255.0.6.255126
15255.0.7.0/25255.0.7.1 to 255.0.7.126255.0.7.127126
16255.0.7.128/25255.0.7.129 to 255.0.7.254255.0.7.255126
17255.0.8.0/25255.0.8.1 to 255.0.8.126255.0.8.127126
18255.0.8.128/25255.0.8.129 to 255.0.8.254255.0.8.255126
19255.0.9.0/25255.0.9.1 to 255.0.9.126255.0.9.127126
20255.0.9.128/25255.0.9.129 to 255.0.9.254255.0.9.255126
21255.0.10.0/25255.0.10.1 to 255.0.10.126255.0.10.127126
22255.0.10.128/25255.0.10.129 to 255.0.10.254255.0.10.255126
23255.0.11.0/25255.0.11.1 to 255.0.11.126255.0.11.127126
24255.0.11.128/25255.0.11.129 to 255.0.11.254255.0.11.255126
25255.0.12.0/25255.0.12.1 to 255.0.12.126255.0.12.127126
26255.0.12.128/25255.0.12.129 to 255.0.12.254255.0.12.255126
27255.0.13.0/25255.0.13.1 to 255.0.13.126255.0.13.127126
28255.0.13.128/25255.0.13.129 to 255.0.13.254255.0.13.255126
29255.0.14.0/25255.0.14.1 to 255.0.14.126255.0.14.127126
30255.0.14.128/25255.0.14.129 to 255.0.14.254255.0.14.255126
31255.0.15.0/25255.0.15.1 to 255.0.15.126255.0.15.127126
32255.0.15.128/25255.0.15.129 to 255.0.15.254255.0.15.255126
33255.0.16.0/25255.0.16.1 to 255.0.16.126255.0.16.127126
34255.0.16.128/25255.0.16.129 to 255.0.16.254255.0.16.255126
35255.0.17.0/25255.0.17.1 to 255.0.17.126255.0.17.127126
36255.0.17.128/25255.0.17.129 to 255.0.17.254255.0.17.255126
37255.0.18.0/25255.0.18.1 to 255.0.18.126255.0.18.127126
38255.0.18.128/25255.0.18.129 to 255.0.18.254255.0.18.255126
39255.0.19.0/25255.0.19.1 to 255.0.19.126255.0.19.127126
40255.0.19.128/25255.0.19.129 to 255.0.19.254255.0.19.255126
41255.0.20.0/25255.0.20.1 to 255.0.20.126255.0.20.127126
42255.0.20.128/25255.0.20.129 to 255.0.20.254255.0.20.255126
43255.0.21.0/25255.0.21.1 to 255.0.21.126255.0.21.127126
44255.0.21.128/25255.0.21.129 to 255.0.21.254255.0.21.255126
45255.0.22.0/25255.0.22.1 to 255.0.22.126255.0.22.127126
46255.0.22.128/25255.0.22.129 to 255.0.22.254255.0.22.255126
47255.0.23.0/25255.0.23.1 to 255.0.23.126255.0.23.127126
48255.0.23.128/25255.0.23.129 to 255.0.23.254255.0.23.255126
49255.0.24.0/25255.0.24.1 to 255.0.24.126255.0.24.127126
50255.0.24.128/25255.0.24.129 to 255.0.24.254255.0.24.255126
51255.0.25.0/25255.0.25.1 to 255.0.25.126255.0.25.127126
52255.0.25.128/25255.0.25.129 to 255.0.25.254255.0.25.255126
53255.0.26.0/25255.0.26.1 to 255.0.26.126255.0.26.127126
54255.0.26.128/25255.0.26.129 to 255.0.26.254255.0.26.255126
55255.0.27.0/25255.0.27.1 to 255.0.27.126255.0.27.127126
56255.0.27.128/25255.0.27.129 to 255.0.27.254255.0.27.255126
57255.0.28.0/25255.0.28.1 to 255.0.28.126255.0.28.127126
58255.0.28.128/25255.0.28.129 to 255.0.28.254255.0.28.255126
59255.0.29.0/25255.0.29.1 to 255.0.29.126255.0.29.127126
60255.0.29.128/25255.0.29.129 to 255.0.29.254255.0.29.255126
61255.0.30.0/25255.0.30.1 to 255.0.30.126255.0.30.127126
62255.0.30.128/25255.0.30.129 to 255.0.30.254255.0.30.255126
63255.0.31.0/25255.0.31.1 to 255.0.31.126255.0.31.127126
64255.0.31.128/25255.0.31.129 to 255.0.31.254255.0.31.255126
65255.0.32.0/25255.0.32.1 to 255.0.32.126255.0.32.127126
66255.0.32.128/25255.0.32.129 to 255.0.32.254255.0.32.255126
67255.0.33.0/25255.0.33.1 to 255.0.33.126255.0.33.127126
68255.0.33.128/25255.0.33.129 to 255.0.33.254255.0.33.255126
69255.0.34.0/25255.0.34.1 to 255.0.34.126255.0.34.127126
70255.0.34.128/25255.0.34.129 to 255.0.34.254255.0.34.255126
71255.0.35.0/25255.0.35.1 to 255.0.35.126255.0.35.127126
72255.0.35.128/25255.0.35.129 to 255.0.35.254255.0.35.255126
73255.0.36.0/25255.0.36.1 to 255.0.36.126255.0.36.127126
74255.0.36.128/25255.0.36.129 to 255.0.36.254255.0.36.255126
75255.0.37.0/25255.0.37.1 to 255.0.37.126255.0.37.127126
76255.0.37.128/25255.0.37.129 to 255.0.37.254255.0.37.255126
77255.0.38.0/25255.0.38.1 to 255.0.38.126255.0.38.127126
78255.0.38.128/25255.0.38.129 to 255.0.38.254255.0.38.255126
79255.0.39.0/25255.0.39.1 to 255.0.39.126255.0.39.127126
80255.0.39.128/25255.0.39.129 to 255.0.39.254255.0.39.255126
81255.0.40.0/25255.0.40.1 to 255.0.40.126255.0.40.127126
82255.0.40.128/25255.0.40.129 to 255.0.40.254255.0.40.255126
83255.0.41.0/25255.0.41.1 to 255.0.41.126255.0.41.127126
84255.0.41.128/25255.0.41.129 to 255.0.41.254255.0.41.255126
85255.0.42.0/25255.0.42.1 to 255.0.42.126255.0.42.127126
86255.0.42.128/25255.0.42.129 to 255.0.42.254255.0.42.255126
87255.0.43.0/25255.0.43.1 to 255.0.43.126255.0.43.127126
88255.0.43.128/25255.0.43.129 to 255.0.43.254255.0.43.255126
89255.0.44.0/25255.0.44.1 to 255.0.44.126255.0.44.127126
90255.0.44.128/25255.0.44.129 to 255.0.44.254255.0.44.255126
91255.0.45.0/25255.0.45.1 to 255.0.45.126255.0.45.127126
92255.0.45.128/25255.0.45.129 to 255.0.45.254255.0.45.255126
93255.0.46.0/25255.0.46.1 to 255.0.46.126255.0.46.127126
94255.0.46.128/25255.0.46.129 to 255.0.46.254255.0.46.255126
95255.0.47.0/25255.0.47.1 to 255.0.47.126255.0.47.127126
96255.0.47.128/25255.0.47.129 to 255.0.47.254255.0.47.255126
97255.0.48.0/25255.0.48.1 to 255.0.48.126255.0.48.127126
98255.0.48.128/25255.0.48.129 to 255.0.48.254255.0.48.255126
99255.0.49.0/25255.0.49.1 to 255.0.49.126255.0.49.127126
100255.0.49.128/25255.0.49.129 to 255.0.49.254255.0.49.255126
101255.0.50.0/25255.0.50.1 to 255.0.50.126255.0.50.127126
102255.0.50.128/25255.0.50.129 to 255.0.50.254255.0.50.255126
103255.0.51.0/25255.0.51.1 to 255.0.51.126255.0.51.127126
104255.0.51.128/25255.0.51.129 to 255.0.51.254255.0.51.255126
105255.0.52.0/25255.0.52.1 to 255.0.52.126255.0.52.127126
106255.0.52.128/25255.0.52.129 to 255.0.52.254255.0.52.255126
107255.0.53.0/25255.0.53.1 to 255.0.53.126255.0.53.127126
108255.0.53.128/25255.0.53.129 to 255.0.53.254255.0.53.255126
109255.0.54.0/25255.0.54.1 to 255.0.54.126255.0.54.127126
110255.0.54.128/25255.0.54.129 to 255.0.54.254255.0.54.255126
111255.0.55.0/25255.0.55.1 to 255.0.55.126255.0.55.127126
112255.0.55.128/25255.0.55.129 to 255.0.55.254255.0.55.255126
113255.0.56.0/25255.0.56.1 to 255.0.56.126255.0.56.127126
114255.0.56.128/25255.0.56.129 to 255.0.56.254255.0.56.255126
115255.0.57.0/25255.0.57.1 to 255.0.57.126255.0.57.127126
116255.0.57.128/25255.0.57.129 to 255.0.57.254255.0.57.255126
117255.0.58.0/25255.0.58.1 to 255.0.58.126255.0.58.127126
118255.0.58.128/25255.0.58.129 to 255.0.58.254255.0.58.255126
119255.0.59.0/25255.0.59.1 to 255.0.59.126255.0.59.127126
120255.0.59.128/25255.0.59.129 to 255.0.59.254255.0.59.255126
121255.0.60.0/25255.0.60.1 to 255.0.60.126255.0.60.127126
122255.0.60.128/25255.0.60.129 to 255.0.60.254255.0.60.255126
123255.0.61.0/25255.0.61.1 to 255.0.61.126255.0.61.127126
124255.0.61.128/25255.0.61.129 to 255.0.61.254255.0.61.255126
125255.0.62.0/25255.0.62.1 to 255.0.62.126255.0.62.127126
126255.0.62.128/25255.0.62.129 to 255.0.62.254255.0.62.255126
127255.0.63.0/25255.0.63.1 to 255.0.63.126255.0.63.127126
128255.0.63.128/25255.0.63.129 to 255.0.63.254255.0.63.255126
129255.0.64.0/25255.0.64.1 to 255.0.64.126255.0.64.127126
130255.0.64.128/25255.0.64.129 to 255.0.64.254255.0.64.255126
131255.0.65.0/25255.0.65.1 to 255.0.65.126255.0.65.127126
132255.0.65.128/25255.0.65.129 to 255.0.65.254255.0.65.255126
133255.0.66.0/25255.0.66.1 to 255.0.66.126255.0.66.127126
134255.0.66.128/25255.0.66.129 to 255.0.66.254255.0.66.255126
135255.0.67.0/25255.0.67.1 to 255.0.67.126255.0.67.127126
136255.0.67.128/25255.0.67.129 to 255.0.67.254255.0.67.255126
137255.0.68.0/25255.0.68.1 to 255.0.68.126255.0.68.127126
138255.0.68.128/25255.0.68.129 to 255.0.68.254255.0.68.255126
139255.0.69.0/25255.0.69.1 to 255.0.69.126255.0.69.127126
140255.0.69.128/25255.0.69.129 to 255.0.69.254255.0.69.255126
141255.0.70.0/25255.0.70.1 to 255.0.70.126255.0.70.127126
142255.0.70.128/25255.0.70.129 to 255.0.70.254255.0.70.255126
143255.0.71.0/25255.0.71.1 to 255.0.71.126255.0.71.127126
144255.0.71.128/25255.0.71.129 to 255.0.71.254255.0.71.255126
145255.0.72.0/25255.0.72.1 to 255.0.72.126255.0.72.127126
146255.0.72.128/25255.0.72.129 to 255.0.72.254255.0.72.255126
147255.0.73.0/25255.0.73.1 to 255.0.73.126255.0.73.127126
148255.0.73.128/25255.0.73.129 to 255.0.73.254255.0.73.255126
149255.0.74.0/25255.0.74.1 to 255.0.74.126255.0.74.127126
150255.0.74.128/25255.0.74.129 to 255.0.74.254255.0.74.255126
151255.0.75.0/25255.0.75.1 to 255.0.75.126255.0.75.127126
152255.0.75.128/25255.0.75.129 to 255.0.75.254255.0.75.255126
153255.0.76.0/25255.0.76.1 to 255.0.76.126255.0.76.127126
154255.0.76.128/25255.0.76.129 to 255.0.76.254255.0.76.255126
155255.0.77.0/25255.0.77.1 to 255.0.77.126255.0.77.127126
156255.0.77.128/25255.0.77.129 to 255.0.77.254255.0.77.255126
157255.0.78.0/25255.0.78.1 to 255.0.78.126255.0.78.127126
158255.0.78.128/25255.0.78.129 to 255.0.78.254255.0.78.255126
159255.0.79.0/25255.0.79.1 to 255.0.79.126255.0.79.127126
160255.0.79.128/25255.0.79.129 to 255.0.79.254255.0.79.255126
161255.0.80.0/25255.0.80.1 to 255.0.80.126255.0.80.127126
162255.0.80.128/25255.0.80.129 to 255.0.80.254255.0.80.255126
163255.0.81.0/25255.0.81.1 to 255.0.81.126255.0.81.127126
164255.0.81.128/25255.0.81.129 to 255.0.81.254255.0.81.255126
165255.0.82.0/25255.0.82.1 to 255.0.82.126255.0.82.127126
166255.0.82.128/25255.0.82.129 to 255.0.82.254255.0.82.255126
167255.0.83.0/25255.0.83.1 to 255.0.83.126255.0.83.127126
168255.0.83.128/25255.0.83.129 to 255.0.83.254255.0.83.255126
169255.0.84.0/25255.0.84.1 to 255.0.84.126255.0.84.127126
170255.0.84.128/25255.0.84.129 to 255.0.84.254255.0.84.255126
171255.0.85.0/25255.0.85.1 to 255.0.85.126255.0.85.127126
172255.0.85.128/25255.0.85.129 to 255.0.85.254255.0.85.255126
173255.0.86.0/25255.0.86.1 to 255.0.86.126255.0.86.127126
174255.0.86.128/25255.0.86.129 to 255.0.86.254255.0.86.255126
175255.0.87.0/25255.0.87.1 to 255.0.87.126255.0.87.127126
176255.0.87.128/25255.0.87.129 to 255.0.87.254255.0.87.255126
177255.0.88.0/25255.0.88.1 to 255.0.88.126255.0.88.127126
178255.0.88.128/25255.0.88.129 to 255.0.88.254255.0.88.255126
179255.0.89.0/25255.0.89.1 to 255.0.89.126255.0.89.127126
180255.0.89.128/25255.0.89.129 to 255.0.89.254255.0.89.255126
181255.0.90.0/25255.0.90.1 to 255.0.90.126255.0.90.127126
182255.0.90.128/25255.0.90.129 to 255.0.90.254255.0.90.255126
183255.0.91.0/25255.0.91.1 to 255.0.91.126255.0.91.127126
184255.0.91.128/25255.0.91.129 to 255.0.91.254255.0.91.255126
185255.0.92.0/25255.0.92.1 to 255.0.92.126255.0.92.127126
186255.0.92.128/25255.0.92.129 to 255.0.92.254255.0.92.255126
187255.0.93.0/25255.0.93.1 to 255.0.93.126255.0.93.127126
188255.0.93.128/25255.0.93.129 to 255.0.93.254255.0.93.255126
189255.0.94.0/25255.0.94.1 to 255.0.94.126255.0.94.127126
190255.0.94.128/25255.0.94.129 to 255.0.94.254255.0.94.255126
191255.0.95.0/25255.0.95.1 to 255.0.95.126255.0.95.127126
192255.0.95.128/25255.0.95.129 to 255.0.95.254255.0.95.255126
193255.0.96.0/25255.0.96.1 to 255.0.96.126255.0.96.127126
194255.0.96.128/25255.0.96.129 to 255.0.96.254255.0.96.255126
195255.0.97.0/25255.0.97.1 to 255.0.97.126255.0.97.127126
196255.0.97.128/25255.0.97.129 to 255.0.97.254255.0.97.255126
197255.0.98.0/25255.0.98.1 to 255.0.98.126255.0.98.127126
198255.0.98.128/25255.0.98.129 to 255.0.98.254255.0.98.255126
199255.0.99.0/25255.0.99.1 to 255.0.99.126255.0.99.127126
200255.0.99.128/25255.0.99.129 to 255.0.99.254255.0.99.255126
201255.0.100.0/25255.0.100.1 to 255.0.100.126255.0.100.127126
202255.0.100.128/25255.0.100.129 to 255.0.100.254255.0.100.255126
203255.0.101.0/25255.0.101.1 to 255.0.101.126255.0.101.127126
204255.0.101.128/25255.0.101.129 to 255.0.101.254255.0.101.255126
205255.0.102.0/25255.0.102.1 to 255.0.102.126255.0.102.127126
206255.0.102.128/25255.0.102.129 to 255.0.102.254255.0.102.255126
207255.0.103.0/25255.0.103.1 to 255.0.103.126255.0.103.127126
208255.0.103.128/25255.0.103.129 to 255.0.103.254255.0.103.255126
209255.0.104.0/25255.0.104.1 to 255.0.104.126255.0.104.127126
210255.0.104.128/25255.0.104.129 to 255.0.104.254255.0.104.255126
211255.0.105.0/25255.0.105.1 to 255.0.105.126255.0.105.127126
212255.0.105.128/25255.0.105.129 to 255.0.105.254255.0.105.255126
213255.0.106.0/25255.0.106.1 to 255.0.106.126255.0.106.127126
214255.0.106.128/25255.0.106.129 to 255.0.106.254255.0.106.255126
215255.0.107.0/25255.0.107.1 to 255.0.107.126255.0.107.127126
216255.0.107.128/25255.0.107.129 to 255.0.107.254255.0.107.255126
217255.0.108.0/25255.0.108.1 to 255.0.108.126255.0.108.127126
218255.0.108.128/25255.0.108.129 to 255.0.108.254255.0.108.255126
219255.0.109.0/25255.0.109.1 to 255.0.109.126255.0.109.127126
220255.0.109.128/25255.0.109.129 to 255.0.109.254255.0.109.255126
221255.0.110.0/25255.0.110.1 to 255.0.110.126255.0.110.127126
222255.0.110.128/25255.0.110.129 to 255.0.110.254255.0.110.255126
223255.0.111.0/25255.0.111.1 to 255.0.111.126255.0.111.127126
224255.0.111.128/25255.0.111.129 to 255.0.111.254255.0.111.255126
225255.0.112.0/25255.0.112.1 to 255.0.112.126255.0.112.127126
226255.0.112.128/25255.0.112.129 to 255.0.112.254255.0.112.255126
227255.0.113.0/25255.0.113.1 to 255.0.113.126255.0.113.127126
228255.0.113.128/25255.0.113.129 to 255.0.113.254255.0.113.255126
229255.0.114.0/25255.0.114.1 to 255.0.114.126255.0.114.127126
230255.0.114.128/25255.0.114.129 to 255.0.114.254255.0.114.255126
231255.0.115.0/25255.0.115.1 to 255.0.115.126255.0.115.127126
232255.0.115.128/25255.0.115.129 to 255.0.115.254255.0.115.255126
233255.0.116.0/25255.0.116.1 to 255.0.116.126255.0.116.127126
234255.0.116.128/25255.0.116.129 to 255.0.116.254255.0.116.255126
235255.0.117.0/25255.0.117.1 to 255.0.117.126255.0.117.127126
236255.0.117.128/25255.0.117.129 to 255.0.117.254255.0.117.255126
237255.0.118.0/25255.0.118.1 to 255.0.118.126255.0.118.127126
238255.0.118.128/25255.0.118.129 to 255.0.118.254255.0.118.255126
239255.0.119.0/25255.0.119.1 to 255.0.119.126255.0.119.127126
240255.0.119.128/25255.0.119.129 to 255.0.119.254255.0.119.255126
241255.0.120.0/25255.0.120.1 to 255.0.120.126255.0.120.127126
242255.0.120.128/25255.0.120.129 to 255.0.120.254255.0.120.255126
243255.0.121.0/25255.0.121.1 to 255.0.121.126255.0.121.127126
244255.0.121.128/25255.0.121.129 to 255.0.121.254255.0.121.255126
245255.0.122.0/25255.0.122.1 to 255.0.122.126255.0.122.127126
246255.0.122.128/25255.0.122.129 to 255.0.122.254255.0.122.255126
247255.0.123.0/25255.0.123.1 to 255.0.123.126255.0.123.127126
248255.0.123.128/25255.0.123.129 to 255.0.123.254255.0.123.255126
249255.0.124.0/25255.0.124.1 to 255.0.124.126255.0.124.127126
250255.0.124.128/25255.0.124.129 to 255.0.124.254255.0.124.255126
251255.0.125.0/25255.0.125.1 to 255.0.125.126255.0.125.127126
252255.0.125.128/25255.0.125.129 to 255.0.125.254255.0.125.255126
253255.0.126.0/25255.0.126.1 to 255.0.126.126255.0.126.127126
254255.0.126.128/25255.0.126.129 to 255.0.126.254255.0.126.255126
255255.0.127.0/25255.0.127.1 to 255.0.127.126255.0.127.127126
256255.0.127.128/25255.0.127.129 to 255.0.127.254255.0.127.255126

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.