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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.

Network188.136.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
188.136.0.0
Broadcast address
188.137.255.255
First usable
188.136.0.1
Last usable
188.137.255.254
Usable hosts
131,070 (131,072 less the network and broadcast addresses)
Subnet mask
255.254.0.0
Wildcard mask
0.1.255.255 (Cisco ACLs, OSPF)
Prefix length
/15
Type
Public public
Old class
B (default /16)
As numbers
Hex BC880000 · Integer 3163029504 to 3163160575
Reverse DNS zones
136.188.in-addr.arpa
137.188.in-addr.arpa
/15 is not on a 8-bit boundary, so it takes 2 /16 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10111100.10001000.00000000.00000000188.136.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10111100.10001000.00000000.00000000188.136.0.0
Broadcast10111100.10001001.11111111.11111111188.137.255.255
Split into smaller subnets/25
/16 (2)/17 (4)/18 (8)/19 (16)/20 (32)/21 (64)/22 (128)/23 (256)/24 (512)/25 (1,024)/26 (2,048)/27 (4,096)

188.136.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1188.136.0.0/25188.136.0.1 to 188.136.0.126188.136.0.127126
2188.136.0.128/25188.136.0.129 to 188.136.0.254188.136.0.255126
3188.136.1.0/25188.136.1.1 to 188.136.1.126188.136.1.127126
4188.136.1.128/25188.136.1.129 to 188.136.1.254188.136.1.255126
5188.136.2.0/25188.136.2.1 to 188.136.2.126188.136.2.127126
6188.136.2.128/25188.136.2.129 to 188.136.2.254188.136.2.255126
7188.136.3.0/25188.136.3.1 to 188.136.3.126188.136.3.127126
8188.136.3.128/25188.136.3.129 to 188.136.3.254188.136.3.255126
9188.136.4.0/25188.136.4.1 to 188.136.4.126188.136.4.127126
10188.136.4.128/25188.136.4.129 to 188.136.4.254188.136.4.255126
11188.136.5.0/25188.136.5.1 to 188.136.5.126188.136.5.127126
12188.136.5.128/25188.136.5.129 to 188.136.5.254188.136.5.255126
13188.136.6.0/25188.136.6.1 to 188.136.6.126188.136.6.127126
14188.136.6.128/25188.136.6.129 to 188.136.6.254188.136.6.255126
15188.136.7.0/25188.136.7.1 to 188.136.7.126188.136.7.127126
16188.136.7.128/25188.136.7.129 to 188.136.7.254188.136.7.255126
17188.136.8.0/25188.136.8.1 to 188.136.8.126188.136.8.127126
18188.136.8.128/25188.136.8.129 to 188.136.8.254188.136.8.255126
19188.136.9.0/25188.136.9.1 to 188.136.9.126188.136.9.127126
20188.136.9.128/25188.136.9.129 to 188.136.9.254188.136.9.255126
21188.136.10.0/25188.136.10.1 to 188.136.10.126188.136.10.127126
22188.136.10.128/25188.136.10.129 to 188.136.10.254188.136.10.255126
23188.136.11.0/25188.136.11.1 to 188.136.11.126188.136.11.127126
24188.136.11.128/25188.136.11.129 to 188.136.11.254188.136.11.255126
25188.136.12.0/25188.136.12.1 to 188.136.12.126188.136.12.127126
26188.136.12.128/25188.136.12.129 to 188.136.12.254188.136.12.255126
27188.136.13.0/25188.136.13.1 to 188.136.13.126188.136.13.127126
28188.136.13.128/25188.136.13.129 to 188.136.13.254188.136.13.255126
29188.136.14.0/25188.136.14.1 to 188.136.14.126188.136.14.127126
30188.136.14.128/25188.136.14.129 to 188.136.14.254188.136.14.255126
31188.136.15.0/25188.136.15.1 to 188.136.15.126188.136.15.127126
32188.136.15.128/25188.136.15.129 to 188.136.15.254188.136.15.255126
33188.136.16.0/25188.136.16.1 to 188.136.16.126188.136.16.127126
34188.136.16.128/25188.136.16.129 to 188.136.16.254188.136.16.255126
35188.136.17.0/25188.136.17.1 to 188.136.17.126188.136.17.127126
36188.136.17.128/25188.136.17.129 to 188.136.17.254188.136.17.255126
37188.136.18.0/25188.136.18.1 to 188.136.18.126188.136.18.127126
38188.136.18.128/25188.136.18.129 to 188.136.18.254188.136.18.255126
39188.136.19.0/25188.136.19.1 to 188.136.19.126188.136.19.127126
40188.136.19.128/25188.136.19.129 to 188.136.19.254188.136.19.255126
41188.136.20.0/25188.136.20.1 to 188.136.20.126188.136.20.127126
42188.136.20.128/25188.136.20.129 to 188.136.20.254188.136.20.255126
43188.136.21.0/25188.136.21.1 to 188.136.21.126188.136.21.127126
44188.136.21.128/25188.136.21.129 to 188.136.21.254188.136.21.255126
45188.136.22.0/25188.136.22.1 to 188.136.22.126188.136.22.127126
46188.136.22.128/25188.136.22.129 to 188.136.22.254188.136.22.255126
47188.136.23.0/25188.136.23.1 to 188.136.23.126188.136.23.127126
48188.136.23.128/25188.136.23.129 to 188.136.23.254188.136.23.255126
49188.136.24.0/25188.136.24.1 to 188.136.24.126188.136.24.127126
50188.136.24.128/25188.136.24.129 to 188.136.24.254188.136.24.255126
51188.136.25.0/25188.136.25.1 to 188.136.25.126188.136.25.127126
52188.136.25.128/25188.136.25.129 to 188.136.25.254188.136.25.255126
53188.136.26.0/25188.136.26.1 to 188.136.26.126188.136.26.127126
54188.136.26.128/25188.136.26.129 to 188.136.26.254188.136.26.255126
55188.136.27.0/25188.136.27.1 to 188.136.27.126188.136.27.127126
56188.136.27.128/25188.136.27.129 to 188.136.27.254188.136.27.255126
57188.136.28.0/25188.136.28.1 to 188.136.28.126188.136.28.127126
58188.136.28.128/25188.136.28.129 to 188.136.28.254188.136.28.255126
59188.136.29.0/25188.136.29.1 to 188.136.29.126188.136.29.127126
60188.136.29.128/25188.136.29.129 to 188.136.29.254188.136.29.255126
61188.136.30.0/25188.136.30.1 to 188.136.30.126188.136.30.127126
62188.136.30.128/25188.136.30.129 to 188.136.30.254188.136.30.255126
63188.136.31.0/25188.136.31.1 to 188.136.31.126188.136.31.127126
64188.136.31.128/25188.136.31.129 to 188.136.31.254188.136.31.255126
65188.136.32.0/25188.136.32.1 to 188.136.32.126188.136.32.127126
66188.136.32.128/25188.136.32.129 to 188.136.32.254188.136.32.255126
67188.136.33.0/25188.136.33.1 to 188.136.33.126188.136.33.127126
68188.136.33.128/25188.136.33.129 to 188.136.33.254188.136.33.255126
69188.136.34.0/25188.136.34.1 to 188.136.34.126188.136.34.127126
70188.136.34.128/25188.136.34.129 to 188.136.34.254188.136.34.255126
71188.136.35.0/25188.136.35.1 to 188.136.35.126188.136.35.127126
72188.136.35.128/25188.136.35.129 to 188.136.35.254188.136.35.255126
73188.136.36.0/25188.136.36.1 to 188.136.36.126188.136.36.127126
74188.136.36.128/25188.136.36.129 to 188.136.36.254188.136.36.255126
75188.136.37.0/25188.136.37.1 to 188.136.37.126188.136.37.127126
76188.136.37.128/25188.136.37.129 to 188.136.37.254188.136.37.255126
77188.136.38.0/25188.136.38.1 to 188.136.38.126188.136.38.127126
78188.136.38.128/25188.136.38.129 to 188.136.38.254188.136.38.255126
79188.136.39.0/25188.136.39.1 to 188.136.39.126188.136.39.127126
80188.136.39.128/25188.136.39.129 to 188.136.39.254188.136.39.255126
81188.136.40.0/25188.136.40.1 to 188.136.40.126188.136.40.127126
82188.136.40.128/25188.136.40.129 to 188.136.40.254188.136.40.255126
83188.136.41.0/25188.136.41.1 to 188.136.41.126188.136.41.127126
84188.136.41.128/25188.136.41.129 to 188.136.41.254188.136.41.255126
85188.136.42.0/25188.136.42.1 to 188.136.42.126188.136.42.127126
86188.136.42.128/25188.136.42.129 to 188.136.42.254188.136.42.255126
87188.136.43.0/25188.136.43.1 to 188.136.43.126188.136.43.127126
88188.136.43.128/25188.136.43.129 to 188.136.43.254188.136.43.255126
89188.136.44.0/25188.136.44.1 to 188.136.44.126188.136.44.127126
90188.136.44.128/25188.136.44.129 to 188.136.44.254188.136.44.255126
91188.136.45.0/25188.136.45.1 to 188.136.45.126188.136.45.127126
92188.136.45.128/25188.136.45.129 to 188.136.45.254188.136.45.255126
93188.136.46.0/25188.136.46.1 to 188.136.46.126188.136.46.127126
94188.136.46.128/25188.136.46.129 to 188.136.46.254188.136.46.255126
95188.136.47.0/25188.136.47.1 to 188.136.47.126188.136.47.127126
96188.136.47.128/25188.136.47.129 to 188.136.47.254188.136.47.255126
97188.136.48.0/25188.136.48.1 to 188.136.48.126188.136.48.127126
98188.136.48.128/25188.136.48.129 to 188.136.48.254188.136.48.255126
99188.136.49.0/25188.136.49.1 to 188.136.49.126188.136.49.127126
100188.136.49.128/25188.136.49.129 to 188.136.49.254188.136.49.255126
101188.136.50.0/25188.136.50.1 to 188.136.50.126188.136.50.127126
102188.136.50.128/25188.136.50.129 to 188.136.50.254188.136.50.255126
103188.136.51.0/25188.136.51.1 to 188.136.51.126188.136.51.127126
104188.136.51.128/25188.136.51.129 to 188.136.51.254188.136.51.255126
105188.136.52.0/25188.136.52.1 to 188.136.52.126188.136.52.127126
106188.136.52.128/25188.136.52.129 to 188.136.52.254188.136.52.255126
107188.136.53.0/25188.136.53.1 to 188.136.53.126188.136.53.127126
108188.136.53.128/25188.136.53.129 to 188.136.53.254188.136.53.255126
109188.136.54.0/25188.136.54.1 to 188.136.54.126188.136.54.127126
110188.136.54.128/25188.136.54.129 to 188.136.54.254188.136.54.255126
111188.136.55.0/25188.136.55.1 to 188.136.55.126188.136.55.127126
112188.136.55.128/25188.136.55.129 to 188.136.55.254188.136.55.255126
113188.136.56.0/25188.136.56.1 to 188.136.56.126188.136.56.127126
114188.136.56.128/25188.136.56.129 to 188.136.56.254188.136.56.255126
115188.136.57.0/25188.136.57.1 to 188.136.57.126188.136.57.127126
116188.136.57.128/25188.136.57.129 to 188.136.57.254188.136.57.255126
117188.136.58.0/25188.136.58.1 to 188.136.58.126188.136.58.127126
118188.136.58.128/25188.136.58.129 to 188.136.58.254188.136.58.255126
119188.136.59.0/25188.136.59.1 to 188.136.59.126188.136.59.127126
120188.136.59.128/25188.136.59.129 to 188.136.59.254188.136.59.255126
121188.136.60.0/25188.136.60.1 to 188.136.60.126188.136.60.127126
122188.136.60.128/25188.136.60.129 to 188.136.60.254188.136.60.255126
123188.136.61.0/25188.136.61.1 to 188.136.61.126188.136.61.127126
124188.136.61.128/25188.136.61.129 to 188.136.61.254188.136.61.255126
125188.136.62.0/25188.136.62.1 to 188.136.62.126188.136.62.127126
126188.136.62.128/25188.136.62.129 to 188.136.62.254188.136.62.255126
127188.136.63.0/25188.136.63.1 to 188.136.63.126188.136.63.127126
128188.136.63.128/25188.136.63.129 to 188.136.63.254188.136.63.255126
129188.136.64.0/25188.136.64.1 to 188.136.64.126188.136.64.127126
130188.136.64.128/25188.136.64.129 to 188.136.64.254188.136.64.255126
131188.136.65.0/25188.136.65.1 to 188.136.65.126188.136.65.127126
132188.136.65.128/25188.136.65.129 to 188.136.65.254188.136.65.255126
133188.136.66.0/25188.136.66.1 to 188.136.66.126188.136.66.127126
134188.136.66.128/25188.136.66.129 to 188.136.66.254188.136.66.255126
135188.136.67.0/25188.136.67.1 to 188.136.67.126188.136.67.127126
136188.136.67.128/25188.136.67.129 to 188.136.67.254188.136.67.255126
137188.136.68.0/25188.136.68.1 to 188.136.68.126188.136.68.127126
138188.136.68.128/25188.136.68.129 to 188.136.68.254188.136.68.255126
139188.136.69.0/25188.136.69.1 to 188.136.69.126188.136.69.127126
140188.136.69.128/25188.136.69.129 to 188.136.69.254188.136.69.255126
141188.136.70.0/25188.136.70.1 to 188.136.70.126188.136.70.127126
142188.136.70.128/25188.136.70.129 to 188.136.70.254188.136.70.255126
143188.136.71.0/25188.136.71.1 to 188.136.71.126188.136.71.127126
144188.136.71.128/25188.136.71.129 to 188.136.71.254188.136.71.255126
145188.136.72.0/25188.136.72.1 to 188.136.72.126188.136.72.127126
146188.136.72.128/25188.136.72.129 to 188.136.72.254188.136.72.255126
147188.136.73.0/25188.136.73.1 to 188.136.73.126188.136.73.127126
148188.136.73.128/25188.136.73.129 to 188.136.73.254188.136.73.255126
149188.136.74.0/25188.136.74.1 to 188.136.74.126188.136.74.127126
150188.136.74.128/25188.136.74.129 to 188.136.74.254188.136.74.255126
151188.136.75.0/25188.136.75.1 to 188.136.75.126188.136.75.127126
152188.136.75.128/25188.136.75.129 to 188.136.75.254188.136.75.255126
153188.136.76.0/25188.136.76.1 to 188.136.76.126188.136.76.127126
154188.136.76.128/25188.136.76.129 to 188.136.76.254188.136.76.255126
155188.136.77.0/25188.136.77.1 to 188.136.77.126188.136.77.127126
156188.136.77.128/25188.136.77.129 to 188.136.77.254188.136.77.255126
157188.136.78.0/25188.136.78.1 to 188.136.78.126188.136.78.127126
158188.136.78.128/25188.136.78.129 to 188.136.78.254188.136.78.255126
159188.136.79.0/25188.136.79.1 to 188.136.79.126188.136.79.127126
160188.136.79.128/25188.136.79.129 to 188.136.79.254188.136.79.255126
161188.136.80.0/25188.136.80.1 to 188.136.80.126188.136.80.127126
162188.136.80.128/25188.136.80.129 to 188.136.80.254188.136.80.255126
163188.136.81.0/25188.136.81.1 to 188.136.81.126188.136.81.127126
164188.136.81.128/25188.136.81.129 to 188.136.81.254188.136.81.255126
165188.136.82.0/25188.136.82.1 to 188.136.82.126188.136.82.127126
166188.136.82.128/25188.136.82.129 to 188.136.82.254188.136.82.255126
167188.136.83.0/25188.136.83.1 to 188.136.83.126188.136.83.127126
168188.136.83.128/25188.136.83.129 to 188.136.83.254188.136.83.255126
169188.136.84.0/25188.136.84.1 to 188.136.84.126188.136.84.127126
170188.136.84.128/25188.136.84.129 to 188.136.84.254188.136.84.255126
171188.136.85.0/25188.136.85.1 to 188.136.85.126188.136.85.127126
172188.136.85.128/25188.136.85.129 to 188.136.85.254188.136.85.255126
173188.136.86.0/25188.136.86.1 to 188.136.86.126188.136.86.127126
174188.136.86.128/25188.136.86.129 to 188.136.86.254188.136.86.255126
175188.136.87.0/25188.136.87.1 to 188.136.87.126188.136.87.127126
176188.136.87.128/25188.136.87.129 to 188.136.87.254188.136.87.255126
177188.136.88.0/25188.136.88.1 to 188.136.88.126188.136.88.127126
178188.136.88.128/25188.136.88.129 to 188.136.88.254188.136.88.255126
179188.136.89.0/25188.136.89.1 to 188.136.89.126188.136.89.127126
180188.136.89.128/25188.136.89.129 to 188.136.89.254188.136.89.255126
181188.136.90.0/25188.136.90.1 to 188.136.90.126188.136.90.127126
182188.136.90.128/25188.136.90.129 to 188.136.90.254188.136.90.255126
183188.136.91.0/25188.136.91.1 to 188.136.91.126188.136.91.127126
184188.136.91.128/25188.136.91.129 to 188.136.91.254188.136.91.255126
185188.136.92.0/25188.136.92.1 to 188.136.92.126188.136.92.127126
186188.136.92.128/25188.136.92.129 to 188.136.92.254188.136.92.255126
187188.136.93.0/25188.136.93.1 to 188.136.93.126188.136.93.127126
188188.136.93.128/25188.136.93.129 to 188.136.93.254188.136.93.255126
189188.136.94.0/25188.136.94.1 to 188.136.94.126188.136.94.127126
190188.136.94.128/25188.136.94.129 to 188.136.94.254188.136.94.255126
191188.136.95.0/25188.136.95.1 to 188.136.95.126188.136.95.127126
192188.136.95.128/25188.136.95.129 to 188.136.95.254188.136.95.255126
193188.136.96.0/25188.136.96.1 to 188.136.96.126188.136.96.127126
194188.136.96.128/25188.136.96.129 to 188.136.96.254188.136.96.255126
195188.136.97.0/25188.136.97.1 to 188.136.97.126188.136.97.127126
196188.136.97.128/25188.136.97.129 to 188.136.97.254188.136.97.255126
197188.136.98.0/25188.136.98.1 to 188.136.98.126188.136.98.127126
198188.136.98.128/25188.136.98.129 to 188.136.98.254188.136.98.255126
199188.136.99.0/25188.136.99.1 to 188.136.99.126188.136.99.127126
200188.136.99.128/25188.136.99.129 to 188.136.99.254188.136.99.255126
201188.136.100.0/25188.136.100.1 to 188.136.100.126188.136.100.127126
202188.136.100.128/25188.136.100.129 to 188.136.100.254188.136.100.255126
203188.136.101.0/25188.136.101.1 to 188.136.101.126188.136.101.127126
204188.136.101.128/25188.136.101.129 to 188.136.101.254188.136.101.255126
205188.136.102.0/25188.136.102.1 to 188.136.102.126188.136.102.127126
206188.136.102.128/25188.136.102.129 to 188.136.102.254188.136.102.255126
207188.136.103.0/25188.136.103.1 to 188.136.103.126188.136.103.127126
208188.136.103.128/25188.136.103.129 to 188.136.103.254188.136.103.255126
209188.136.104.0/25188.136.104.1 to 188.136.104.126188.136.104.127126
210188.136.104.128/25188.136.104.129 to 188.136.104.254188.136.104.255126
211188.136.105.0/25188.136.105.1 to 188.136.105.126188.136.105.127126
212188.136.105.128/25188.136.105.129 to 188.136.105.254188.136.105.255126
213188.136.106.0/25188.136.106.1 to 188.136.106.126188.136.106.127126
214188.136.106.128/25188.136.106.129 to 188.136.106.254188.136.106.255126
215188.136.107.0/25188.136.107.1 to 188.136.107.126188.136.107.127126
216188.136.107.128/25188.136.107.129 to 188.136.107.254188.136.107.255126
217188.136.108.0/25188.136.108.1 to 188.136.108.126188.136.108.127126
218188.136.108.128/25188.136.108.129 to 188.136.108.254188.136.108.255126
219188.136.109.0/25188.136.109.1 to 188.136.109.126188.136.109.127126
220188.136.109.128/25188.136.109.129 to 188.136.109.254188.136.109.255126
221188.136.110.0/25188.136.110.1 to 188.136.110.126188.136.110.127126
222188.136.110.128/25188.136.110.129 to 188.136.110.254188.136.110.255126
223188.136.111.0/25188.136.111.1 to 188.136.111.126188.136.111.127126
224188.136.111.128/25188.136.111.129 to 188.136.111.254188.136.111.255126
225188.136.112.0/25188.136.112.1 to 188.136.112.126188.136.112.127126
226188.136.112.128/25188.136.112.129 to 188.136.112.254188.136.112.255126
227188.136.113.0/25188.136.113.1 to 188.136.113.126188.136.113.127126
228188.136.113.128/25188.136.113.129 to 188.136.113.254188.136.113.255126
229188.136.114.0/25188.136.114.1 to 188.136.114.126188.136.114.127126
230188.136.114.128/25188.136.114.129 to 188.136.114.254188.136.114.255126
231188.136.115.0/25188.136.115.1 to 188.136.115.126188.136.115.127126
232188.136.115.128/25188.136.115.129 to 188.136.115.254188.136.115.255126
233188.136.116.0/25188.136.116.1 to 188.136.116.126188.136.116.127126
234188.136.116.128/25188.136.116.129 to 188.136.116.254188.136.116.255126
235188.136.117.0/25188.136.117.1 to 188.136.117.126188.136.117.127126
236188.136.117.128/25188.136.117.129 to 188.136.117.254188.136.117.255126
237188.136.118.0/25188.136.118.1 to 188.136.118.126188.136.118.127126
238188.136.118.128/25188.136.118.129 to 188.136.118.254188.136.118.255126
239188.136.119.0/25188.136.119.1 to 188.136.119.126188.136.119.127126
240188.136.119.128/25188.136.119.129 to 188.136.119.254188.136.119.255126
241188.136.120.0/25188.136.120.1 to 188.136.120.126188.136.120.127126
242188.136.120.128/25188.136.120.129 to 188.136.120.254188.136.120.255126
243188.136.121.0/25188.136.121.1 to 188.136.121.126188.136.121.127126
244188.136.121.128/25188.136.121.129 to 188.136.121.254188.136.121.255126
245188.136.122.0/25188.136.122.1 to 188.136.122.126188.136.122.127126
246188.136.122.128/25188.136.122.129 to 188.136.122.254188.136.122.255126
247188.136.123.0/25188.136.123.1 to 188.136.123.126188.136.123.127126
248188.136.123.128/25188.136.123.129 to 188.136.123.254188.136.123.255126
249188.136.124.0/25188.136.124.1 to 188.136.124.126188.136.124.127126
250188.136.124.128/25188.136.124.129 to 188.136.124.254188.136.124.255126
251188.136.125.0/25188.136.125.1 to 188.136.125.126188.136.125.127126
252188.136.125.128/25188.136.125.129 to 188.136.125.254188.136.125.255126
253188.136.126.0/25188.136.126.1 to 188.136.126.126188.136.126.127126
254188.136.126.128/25188.136.126.129 to 188.136.126.254188.136.126.255126
255188.136.127.0/25188.136.127.1 to 188.136.127.126188.136.127.127126
256188.136.127.128/25188.136.127.129 to 188.136.127.254188.136.127.255126

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.