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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.

Network160.166.0.0/15
Usable hosts131,070
Subnet mask255.254.0.0
Addresses131,072
Network address
160.166.0.0
Broadcast address
160.167.255.255
First usable
160.166.0.1
Last usable
160.167.255.254
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 A0A60000 · Integer 2695233536 to 2695364607
Reverse DNS zones
166.160.in-addr.arpa
167.160.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
Address10100000.10100110.00000000.00000000160.166.0.0
Subnet mask11111111.11111110.00000000.00000000255.254.0.0
Network10100000.10100110.00000000.00000000160.166.0.0
Broadcast10100000.10100111.11111111.11111111160.167.255.255
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)

160.166.0.0/15 makes 1,024 subnets of /25; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1160.166.0.0/25160.166.0.1 to 160.166.0.126160.166.0.127126
2160.166.0.128/25160.166.0.129 to 160.166.0.254160.166.0.255126
3160.166.1.0/25160.166.1.1 to 160.166.1.126160.166.1.127126
4160.166.1.128/25160.166.1.129 to 160.166.1.254160.166.1.255126
5160.166.2.0/25160.166.2.1 to 160.166.2.126160.166.2.127126
6160.166.2.128/25160.166.2.129 to 160.166.2.254160.166.2.255126
7160.166.3.0/25160.166.3.1 to 160.166.3.126160.166.3.127126
8160.166.3.128/25160.166.3.129 to 160.166.3.254160.166.3.255126
9160.166.4.0/25160.166.4.1 to 160.166.4.126160.166.4.127126
10160.166.4.128/25160.166.4.129 to 160.166.4.254160.166.4.255126
11160.166.5.0/25160.166.5.1 to 160.166.5.126160.166.5.127126
12160.166.5.128/25160.166.5.129 to 160.166.5.254160.166.5.255126
13160.166.6.0/25160.166.6.1 to 160.166.6.126160.166.6.127126
14160.166.6.128/25160.166.6.129 to 160.166.6.254160.166.6.255126
15160.166.7.0/25160.166.7.1 to 160.166.7.126160.166.7.127126
16160.166.7.128/25160.166.7.129 to 160.166.7.254160.166.7.255126
17160.166.8.0/25160.166.8.1 to 160.166.8.126160.166.8.127126
18160.166.8.128/25160.166.8.129 to 160.166.8.254160.166.8.255126
19160.166.9.0/25160.166.9.1 to 160.166.9.126160.166.9.127126
20160.166.9.128/25160.166.9.129 to 160.166.9.254160.166.9.255126
21160.166.10.0/25160.166.10.1 to 160.166.10.126160.166.10.127126
22160.166.10.128/25160.166.10.129 to 160.166.10.254160.166.10.255126
23160.166.11.0/25160.166.11.1 to 160.166.11.126160.166.11.127126
24160.166.11.128/25160.166.11.129 to 160.166.11.254160.166.11.255126
25160.166.12.0/25160.166.12.1 to 160.166.12.126160.166.12.127126
26160.166.12.128/25160.166.12.129 to 160.166.12.254160.166.12.255126
27160.166.13.0/25160.166.13.1 to 160.166.13.126160.166.13.127126
28160.166.13.128/25160.166.13.129 to 160.166.13.254160.166.13.255126
29160.166.14.0/25160.166.14.1 to 160.166.14.126160.166.14.127126
30160.166.14.128/25160.166.14.129 to 160.166.14.254160.166.14.255126
31160.166.15.0/25160.166.15.1 to 160.166.15.126160.166.15.127126
32160.166.15.128/25160.166.15.129 to 160.166.15.254160.166.15.255126
33160.166.16.0/25160.166.16.1 to 160.166.16.126160.166.16.127126
34160.166.16.128/25160.166.16.129 to 160.166.16.254160.166.16.255126
35160.166.17.0/25160.166.17.1 to 160.166.17.126160.166.17.127126
36160.166.17.128/25160.166.17.129 to 160.166.17.254160.166.17.255126
37160.166.18.0/25160.166.18.1 to 160.166.18.126160.166.18.127126
38160.166.18.128/25160.166.18.129 to 160.166.18.254160.166.18.255126
39160.166.19.0/25160.166.19.1 to 160.166.19.126160.166.19.127126
40160.166.19.128/25160.166.19.129 to 160.166.19.254160.166.19.255126
41160.166.20.0/25160.166.20.1 to 160.166.20.126160.166.20.127126
42160.166.20.128/25160.166.20.129 to 160.166.20.254160.166.20.255126
43160.166.21.0/25160.166.21.1 to 160.166.21.126160.166.21.127126
44160.166.21.128/25160.166.21.129 to 160.166.21.254160.166.21.255126
45160.166.22.0/25160.166.22.1 to 160.166.22.126160.166.22.127126
46160.166.22.128/25160.166.22.129 to 160.166.22.254160.166.22.255126
47160.166.23.0/25160.166.23.1 to 160.166.23.126160.166.23.127126
48160.166.23.128/25160.166.23.129 to 160.166.23.254160.166.23.255126
49160.166.24.0/25160.166.24.1 to 160.166.24.126160.166.24.127126
50160.166.24.128/25160.166.24.129 to 160.166.24.254160.166.24.255126
51160.166.25.0/25160.166.25.1 to 160.166.25.126160.166.25.127126
52160.166.25.128/25160.166.25.129 to 160.166.25.254160.166.25.255126
53160.166.26.0/25160.166.26.1 to 160.166.26.126160.166.26.127126
54160.166.26.128/25160.166.26.129 to 160.166.26.254160.166.26.255126
55160.166.27.0/25160.166.27.1 to 160.166.27.126160.166.27.127126
56160.166.27.128/25160.166.27.129 to 160.166.27.254160.166.27.255126
57160.166.28.0/25160.166.28.1 to 160.166.28.126160.166.28.127126
58160.166.28.128/25160.166.28.129 to 160.166.28.254160.166.28.255126
59160.166.29.0/25160.166.29.1 to 160.166.29.126160.166.29.127126
60160.166.29.128/25160.166.29.129 to 160.166.29.254160.166.29.255126
61160.166.30.0/25160.166.30.1 to 160.166.30.126160.166.30.127126
62160.166.30.128/25160.166.30.129 to 160.166.30.254160.166.30.255126
63160.166.31.0/25160.166.31.1 to 160.166.31.126160.166.31.127126
64160.166.31.128/25160.166.31.129 to 160.166.31.254160.166.31.255126
65160.166.32.0/25160.166.32.1 to 160.166.32.126160.166.32.127126
66160.166.32.128/25160.166.32.129 to 160.166.32.254160.166.32.255126
67160.166.33.0/25160.166.33.1 to 160.166.33.126160.166.33.127126
68160.166.33.128/25160.166.33.129 to 160.166.33.254160.166.33.255126
69160.166.34.0/25160.166.34.1 to 160.166.34.126160.166.34.127126
70160.166.34.128/25160.166.34.129 to 160.166.34.254160.166.34.255126
71160.166.35.0/25160.166.35.1 to 160.166.35.126160.166.35.127126
72160.166.35.128/25160.166.35.129 to 160.166.35.254160.166.35.255126
73160.166.36.0/25160.166.36.1 to 160.166.36.126160.166.36.127126
74160.166.36.128/25160.166.36.129 to 160.166.36.254160.166.36.255126
75160.166.37.0/25160.166.37.1 to 160.166.37.126160.166.37.127126
76160.166.37.128/25160.166.37.129 to 160.166.37.254160.166.37.255126
77160.166.38.0/25160.166.38.1 to 160.166.38.126160.166.38.127126
78160.166.38.128/25160.166.38.129 to 160.166.38.254160.166.38.255126
79160.166.39.0/25160.166.39.1 to 160.166.39.126160.166.39.127126
80160.166.39.128/25160.166.39.129 to 160.166.39.254160.166.39.255126
81160.166.40.0/25160.166.40.1 to 160.166.40.126160.166.40.127126
82160.166.40.128/25160.166.40.129 to 160.166.40.254160.166.40.255126
83160.166.41.0/25160.166.41.1 to 160.166.41.126160.166.41.127126
84160.166.41.128/25160.166.41.129 to 160.166.41.254160.166.41.255126
85160.166.42.0/25160.166.42.1 to 160.166.42.126160.166.42.127126
86160.166.42.128/25160.166.42.129 to 160.166.42.254160.166.42.255126
87160.166.43.0/25160.166.43.1 to 160.166.43.126160.166.43.127126
88160.166.43.128/25160.166.43.129 to 160.166.43.254160.166.43.255126
89160.166.44.0/25160.166.44.1 to 160.166.44.126160.166.44.127126
90160.166.44.128/25160.166.44.129 to 160.166.44.254160.166.44.255126
91160.166.45.0/25160.166.45.1 to 160.166.45.126160.166.45.127126
92160.166.45.128/25160.166.45.129 to 160.166.45.254160.166.45.255126
93160.166.46.0/25160.166.46.1 to 160.166.46.126160.166.46.127126
94160.166.46.128/25160.166.46.129 to 160.166.46.254160.166.46.255126
95160.166.47.0/25160.166.47.1 to 160.166.47.126160.166.47.127126
96160.166.47.128/25160.166.47.129 to 160.166.47.254160.166.47.255126
97160.166.48.0/25160.166.48.1 to 160.166.48.126160.166.48.127126
98160.166.48.128/25160.166.48.129 to 160.166.48.254160.166.48.255126
99160.166.49.0/25160.166.49.1 to 160.166.49.126160.166.49.127126
100160.166.49.128/25160.166.49.129 to 160.166.49.254160.166.49.255126
101160.166.50.0/25160.166.50.1 to 160.166.50.126160.166.50.127126
102160.166.50.128/25160.166.50.129 to 160.166.50.254160.166.50.255126
103160.166.51.0/25160.166.51.1 to 160.166.51.126160.166.51.127126
104160.166.51.128/25160.166.51.129 to 160.166.51.254160.166.51.255126
105160.166.52.0/25160.166.52.1 to 160.166.52.126160.166.52.127126
106160.166.52.128/25160.166.52.129 to 160.166.52.254160.166.52.255126
107160.166.53.0/25160.166.53.1 to 160.166.53.126160.166.53.127126
108160.166.53.128/25160.166.53.129 to 160.166.53.254160.166.53.255126
109160.166.54.0/25160.166.54.1 to 160.166.54.126160.166.54.127126
110160.166.54.128/25160.166.54.129 to 160.166.54.254160.166.54.255126
111160.166.55.0/25160.166.55.1 to 160.166.55.126160.166.55.127126
112160.166.55.128/25160.166.55.129 to 160.166.55.254160.166.55.255126
113160.166.56.0/25160.166.56.1 to 160.166.56.126160.166.56.127126
114160.166.56.128/25160.166.56.129 to 160.166.56.254160.166.56.255126
115160.166.57.0/25160.166.57.1 to 160.166.57.126160.166.57.127126
116160.166.57.128/25160.166.57.129 to 160.166.57.254160.166.57.255126
117160.166.58.0/25160.166.58.1 to 160.166.58.126160.166.58.127126
118160.166.58.128/25160.166.58.129 to 160.166.58.254160.166.58.255126
119160.166.59.0/25160.166.59.1 to 160.166.59.126160.166.59.127126
120160.166.59.128/25160.166.59.129 to 160.166.59.254160.166.59.255126
121160.166.60.0/25160.166.60.1 to 160.166.60.126160.166.60.127126
122160.166.60.128/25160.166.60.129 to 160.166.60.254160.166.60.255126
123160.166.61.0/25160.166.61.1 to 160.166.61.126160.166.61.127126
124160.166.61.128/25160.166.61.129 to 160.166.61.254160.166.61.255126
125160.166.62.0/25160.166.62.1 to 160.166.62.126160.166.62.127126
126160.166.62.128/25160.166.62.129 to 160.166.62.254160.166.62.255126
127160.166.63.0/25160.166.63.1 to 160.166.63.126160.166.63.127126
128160.166.63.128/25160.166.63.129 to 160.166.63.254160.166.63.255126
129160.166.64.0/25160.166.64.1 to 160.166.64.126160.166.64.127126
130160.166.64.128/25160.166.64.129 to 160.166.64.254160.166.64.255126
131160.166.65.0/25160.166.65.1 to 160.166.65.126160.166.65.127126
132160.166.65.128/25160.166.65.129 to 160.166.65.254160.166.65.255126
133160.166.66.0/25160.166.66.1 to 160.166.66.126160.166.66.127126
134160.166.66.128/25160.166.66.129 to 160.166.66.254160.166.66.255126
135160.166.67.0/25160.166.67.1 to 160.166.67.126160.166.67.127126
136160.166.67.128/25160.166.67.129 to 160.166.67.254160.166.67.255126
137160.166.68.0/25160.166.68.1 to 160.166.68.126160.166.68.127126
138160.166.68.128/25160.166.68.129 to 160.166.68.254160.166.68.255126
139160.166.69.0/25160.166.69.1 to 160.166.69.126160.166.69.127126
140160.166.69.128/25160.166.69.129 to 160.166.69.254160.166.69.255126
141160.166.70.0/25160.166.70.1 to 160.166.70.126160.166.70.127126
142160.166.70.128/25160.166.70.129 to 160.166.70.254160.166.70.255126
143160.166.71.0/25160.166.71.1 to 160.166.71.126160.166.71.127126
144160.166.71.128/25160.166.71.129 to 160.166.71.254160.166.71.255126
145160.166.72.0/25160.166.72.1 to 160.166.72.126160.166.72.127126
146160.166.72.128/25160.166.72.129 to 160.166.72.254160.166.72.255126
147160.166.73.0/25160.166.73.1 to 160.166.73.126160.166.73.127126
148160.166.73.128/25160.166.73.129 to 160.166.73.254160.166.73.255126
149160.166.74.0/25160.166.74.1 to 160.166.74.126160.166.74.127126
150160.166.74.128/25160.166.74.129 to 160.166.74.254160.166.74.255126
151160.166.75.0/25160.166.75.1 to 160.166.75.126160.166.75.127126
152160.166.75.128/25160.166.75.129 to 160.166.75.254160.166.75.255126
153160.166.76.0/25160.166.76.1 to 160.166.76.126160.166.76.127126
154160.166.76.128/25160.166.76.129 to 160.166.76.254160.166.76.255126
155160.166.77.0/25160.166.77.1 to 160.166.77.126160.166.77.127126
156160.166.77.128/25160.166.77.129 to 160.166.77.254160.166.77.255126
157160.166.78.0/25160.166.78.1 to 160.166.78.126160.166.78.127126
158160.166.78.128/25160.166.78.129 to 160.166.78.254160.166.78.255126
159160.166.79.0/25160.166.79.1 to 160.166.79.126160.166.79.127126
160160.166.79.128/25160.166.79.129 to 160.166.79.254160.166.79.255126
161160.166.80.0/25160.166.80.1 to 160.166.80.126160.166.80.127126
162160.166.80.128/25160.166.80.129 to 160.166.80.254160.166.80.255126
163160.166.81.0/25160.166.81.1 to 160.166.81.126160.166.81.127126
164160.166.81.128/25160.166.81.129 to 160.166.81.254160.166.81.255126
165160.166.82.0/25160.166.82.1 to 160.166.82.126160.166.82.127126
166160.166.82.128/25160.166.82.129 to 160.166.82.254160.166.82.255126
167160.166.83.0/25160.166.83.1 to 160.166.83.126160.166.83.127126
168160.166.83.128/25160.166.83.129 to 160.166.83.254160.166.83.255126
169160.166.84.0/25160.166.84.1 to 160.166.84.126160.166.84.127126
170160.166.84.128/25160.166.84.129 to 160.166.84.254160.166.84.255126
171160.166.85.0/25160.166.85.1 to 160.166.85.126160.166.85.127126
172160.166.85.128/25160.166.85.129 to 160.166.85.254160.166.85.255126
173160.166.86.0/25160.166.86.1 to 160.166.86.126160.166.86.127126
174160.166.86.128/25160.166.86.129 to 160.166.86.254160.166.86.255126
175160.166.87.0/25160.166.87.1 to 160.166.87.126160.166.87.127126
176160.166.87.128/25160.166.87.129 to 160.166.87.254160.166.87.255126
177160.166.88.0/25160.166.88.1 to 160.166.88.126160.166.88.127126
178160.166.88.128/25160.166.88.129 to 160.166.88.254160.166.88.255126
179160.166.89.0/25160.166.89.1 to 160.166.89.126160.166.89.127126
180160.166.89.128/25160.166.89.129 to 160.166.89.254160.166.89.255126
181160.166.90.0/25160.166.90.1 to 160.166.90.126160.166.90.127126
182160.166.90.128/25160.166.90.129 to 160.166.90.254160.166.90.255126
183160.166.91.0/25160.166.91.1 to 160.166.91.126160.166.91.127126
184160.166.91.128/25160.166.91.129 to 160.166.91.254160.166.91.255126
185160.166.92.0/25160.166.92.1 to 160.166.92.126160.166.92.127126
186160.166.92.128/25160.166.92.129 to 160.166.92.254160.166.92.255126
187160.166.93.0/25160.166.93.1 to 160.166.93.126160.166.93.127126
188160.166.93.128/25160.166.93.129 to 160.166.93.254160.166.93.255126
189160.166.94.0/25160.166.94.1 to 160.166.94.126160.166.94.127126
190160.166.94.128/25160.166.94.129 to 160.166.94.254160.166.94.255126
191160.166.95.0/25160.166.95.1 to 160.166.95.126160.166.95.127126
192160.166.95.128/25160.166.95.129 to 160.166.95.254160.166.95.255126
193160.166.96.0/25160.166.96.1 to 160.166.96.126160.166.96.127126
194160.166.96.128/25160.166.96.129 to 160.166.96.254160.166.96.255126
195160.166.97.0/25160.166.97.1 to 160.166.97.126160.166.97.127126
196160.166.97.128/25160.166.97.129 to 160.166.97.254160.166.97.255126
197160.166.98.0/25160.166.98.1 to 160.166.98.126160.166.98.127126
198160.166.98.128/25160.166.98.129 to 160.166.98.254160.166.98.255126
199160.166.99.0/25160.166.99.1 to 160.166.99.126160.166.99.127126
200160.166.99.128/25160.166.99.129 to 160.166.99.254160.166.99.255126
201160.166.100.0/25160.166.100.1 to 160.166.100.126160.166.100.127126
202160.166.100.128/25160.166.100.129 to 160.166.100.254160.166.100.255126
203160.166.101.0/25160.166.101.1 to 160.166.101.126160.166.101.127126
204160.166.101.128/25160.166.101.129 to 160.166.101.254160.166.101.255126
205160.166.102.0/25160.166.102.1 to 160.166.102.126160.166.102.127126
206160.166.102.128/25160.166.102.129 to 160.166.102.254160.166.102.255126
207160.166.103.0/25160.166.103.1 to 160.166.103.126160.166.103.127126
208160.166.103.128/25160.166.103.129 to 160.166.103.254160.166.103.255126
209160.166.104.0/25160.166.104.1 to 160.166.104.126160.166.104.127126
210160.166.104.128/25160.166.104.129 to 160.166.104.254160.166.104.255126
211160.166.105.0/25160.166.105.1 to 160.166.105.126160.166.105.127126
212160.166.105.128/25160.166.105.129 to 160.166.105.254160.166.105.255126
213160.166.106.0/25160.166.106.1 to 160.166.106.126160.166.106.127126
214160.166.106.128/25160.166.106.129 to 160.166.106.254160.166.106.255126
215160.166.107.0/25160.166.107.1 to 160.166.107.126160.166.107.127126
216160.166.107.128/25160.166.107.129 to 160.166.107.254160.166.107.255126
217160.166.108.0/25160.166.108.1 to 160.166.108.126160.166.108.127126
218160.166.108.128/25160.166.108.129 to 160.166.108.254160.166.108.255126
219160.166.109.0/25160.166.109.1 to 160.166.109.126160.166.109.127126
220160.166.109.128/25160.166.109.129 to 160.166.109.254160.166.109.255126
221160.166.110.0/25160.166.110.1 to 160.166.110.126160.166.110.127126
222160.166.110.128/25160.166.110.129 to 160.166.110.254160.166.110.255126
223160.166.111.0/25160.166.111.1 to 160.166.111.126160.166.111.127126
224160.166.111.128/25160.166.111.129 to 160.166.111.254160.166.111.255126
225160.166.112.0/25160.166.112.1 to 160.166.112.126160.166.112.127126
226160.166.112.128/25160.166.112.129 to 160.166.112.254160.166.112.255126
227160.166.113.0/25160.166.113.1 to 160.166.113.126160.166.113.127126
228160.166.113.128/25160.166.113.129 to 160.166.113.254160.166.113.255126
229160.166.114.0/25160.166.114.1 to 160.166.114.126160.166.114.127126
230160.166.114.128/25160.166.114.129 to 160.166.114.254160.166.114.255126
231160.166.115.0/25160.166.115.1 to 160.166.115.126160.166.115.127126
232160.166.115.128/25160.166.115.129 to 160.166.115.254160.166.115.255126
233160.166.116.0/25160.166.116.1 to 160.166.116.126160.166.116.127126
234160.166.116.128/25160.166.116.129 to 160.166.116.254160.166.116.255126
235160.166.117.0/25160.166.117.1 to 160.166.117.126160.166.117.127126
236160.166.117.128/25160.166.117.129 to 160.166.117.254160.166.117.255126
237160.166.118.0/25160.166.118.1 to 160.166.118.126160.166.118.127126
238160.166.118.128/25160.166.118.129 to 160.166.118.254160.166.118.255126
239160.166.119.0/25160.166.119.1 to 160.166.119.126160.166.119.127126
240160.166.119.128/25160.166.119.129 to 160.166.119.254160.166.119.255126
241160.166.120.0/25160.166.120.1 to 160.166.120.126160.166.120.127126
242160.166.120.128/25160.166.120.129 to 160.166.120.254160.166.120.255126
243160.166.121.0/25160.166.121.1 to 160.166.121.126160.166.121.127126
244160.166.121.128/25160.166.121.129 to 160.166.121.254160.166.121.255126
245160.166.122.0/25160.166.122.1 to 160.166.122.126160.166.122.127126
246160.166.122.128/25160.166.122.129 to 160.166.122.254160.166.122.255126
247160.166.123.0/25160.166.123.1 to 160.166.123.126160.166.123.127126
248160.166.123.128/25160.166.123.129 to 160.166.123.254160.166.123.255126
249160.166.124.0/25160.166.124.1 to 160.166.124.126160.166.124.127126
250160.166.124.128/25160.166.124.129 to 160.166.124.254160.166.124.255126
251160.166.125.0/25160.166.125.1 to 160.166.125.126160.166.125.127126
252160.166.125.128/25160.166.125.129 to 160.166.125.254160.166.125.255126
253160.166.126.0/25160.166.126.1 to 160.166.126.126160.166.126.127126
254160.166.126.128/25160.166.126.129 to 160.166.126.254160.166.126.255126
255160.166.127.0/25160.166.127.1 to 160.166.127.126160.166.127.127126
256160.166.127.128/25160.166.127.129 to 160.166.127.254160.166.127.255126

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.