How to use this calculator
- Take the alcoholmeter reading in % by volume (%vol, the same as % ABV).
- Measure the temperature of the sample itself, not the room.
- Enter both values, choosing °C or °F, and press Calculate.
- The result is the alcohol strength the same sample would read at 20 °C.
How alcohol temperature correction works
An alcoholmeter is a hydrometer graduated directly in % alcohol by volume for a mixture of ethanol and water at one reference temperature, normally 20 °C. Liquids expand as they warm, and an ethanol–water mixture expands more than water does, so its density falls. A warm sample therefore readshigher than its true strength and a cold sample reads lower.
This calculator looks up your reading in a reference table of alcoholmeter readings against sample temperature — the same table used by the ABV Corrector iPhone app — and interpolates linearly between the nearest table points in both reading and temperature. The table is not published on this site; the calculation runs on our server and only the result is returned.
Example
A spirit reads 40.0 %vol on an alcoholmeter at a sample temperature of30 °C. Because the sample is 10 °C warmer than the reference temperature, the reading is too high. The corrected strength at 20 °C is 35.97 %vol. The same 40.0 %vol reading taken at 15 °C corrects to 42.00 %vol.
Supported range
The calculator returns a result only where the reference table has data:
- 0.5–70 %vol from 10 °C to 35 °C (the lowest supported reading rises to about 3 %vol at 35 °C).
- 91–98 %vol from 5 °C to about 34 °C.
- Not covered: readings between 70 and 91 %vol, and 50–55 %vol above 30 °C.
Accuracy & limitations
- The result can only be as accurate as your alcoholmeter and thermometer. For a 40 %vol spirit, a 1 °C thermometer error shifts the result by about 0.4 %vol.
- Results are rounded to 0.01 %vol; between table points the result is a linear interpolation.
- Valid only for mixtures of ethanol and water. Sugar, botanicals or other dissolved solids make alcoholmeter readings unreliable.
- Let the sample and instrument reach the same temperature, and read at the bottom of the meniscus unless your instrument specifies otherwise.
- For legal, tax or labelling purposes, use the method and tables required by your regulator.
FAQ
Why does an alcoholmeter reading change with temperature?
Ethanol and water expand and contract with temperature at different rates, so the density of the mixture changes. An alcoholmeter measures density and is graduated for one reference temperature; at any other temperature it reads too high (warm) or too low (cold).
What reference temperature does this calculator use?
Results are corrected to 20 °C, the reference temperature used by most modern alcoholmeters. If your instrument is graduated for a different temperature, such as 15 °C or 60 °F, these results do not apply directly.
Is this the same as hydrometer temperature correction for beer or wine?
No. This calculator corrects an alcoholmeter reading of a spirit (ethanol and water only) in % by volume. Brewing hydrometers measure specific gravity of wort or must, which contains sugar; use the hydrometer correction calculator for those readings.
Can I use it for liqueurs, wine or beer?
Not reliably. Sugar and other dissolved solids change density, so an alcoholmeter gives a wrong reading in anything other than a clean ethanol–water mixture, regardless of temperature correction.
Why do some combinations say they are outside the reference table?
The calculator only interpolates between points that exist in its reference table and never extrapolates. Readings between 70 and 91 %vol, and some combinations near the edges of the table, are not covered, so no result is shown rather than an estimate.