Hydrometer Temperature Correction Calculator
Since hydrometers are calibrated to be accurate at very specific temperatures, it is useful to adjust your hydrometer reading based on the difference between the temperature of your wort and your hydrometers calibrated temperature.
About The Calculator
This formula has been adjusted to accommodate hydrometers with different calibration temperatures. Generally speaking, older hydrometers will be calibrated at 59°F, while newer hydrometers are mostly calibrated to 68°F.
If you are unsure of what temperature your hydrometer is calibrated at, you can generally find this information on the hydrometer itself, its documentation/packaging, or of course checking with the manufacturer.
Hydrometer Temperature Correction Formula
CG = corrected gravity
MG = measured gravity
TR = temperature at time of reading
TC = calibration temperature of hydrometer
CG = MG * ((1.00130346 – 0.000134722124 * TR + 0.00000204052596 * TR – 0.00000000232820948 * TR) / (1.00130346 – 0.000134722124 * TC + 0.00000204052596 * TC – 0.00000000232820948 * TC))
**Remember P.E.M.D.A.S!
Recommend Digital Hydrometer
- Designed for home brewing.
- Instantly check the specific gravity and temperature of your brew while it's fermenting.
- Don't have to open your fermenter or take a sample for a SG or temp reading.
- Compatible with Apple iPhone/iPad or Android smartphone/tablet or Tilt Pi. Most Bluetooth 4.0+ devices will work with the Tilt hydrometer.
- Option to log data to the cloud using our free Google Sheets template or other 3rd party cloud platforms.
Frequently Asked Questions
How Do I Know the Calibration Temperature of My Hydrometer?
The calibration temperature of your hydrometer is usually indicated on the hydrometer itself or its accompanying documentation or packaging. If you’re still unsure, you can contact the manufacturer for this information.
What Is the Formula for Hydrometer Temperature Correction?
The formula for correcting the gravity reading based on temperature is:
CG = MG \times \left( \frac{1.00130346 – 0.000134722124 \times TR + 0.00000204052596 \times TR – 0.00000000232820948 \times TR}{1.00130346 – 0.000134722124 \times TC + 0.00000204052596 \times TC – 0.00000000232820948 \times TC} \right)
Where (CG) is the corrected gravity, (MG) is the measured gravity, (TR) is the temperature at the time of reading, and (TC) is the calibration temperature of the hydrometer.
What Does P.E.M.D.A.S Mean in the Context of the Formula?
P.E.M.D.A.S stands for Parentheses, Exponents, Multiplication and Division (from left to right), and Addition and Subtraction (from left to right).
It’s a mnemonic for the order of operations in mathematics, which you should follow when using the hydrometer temperature correction formula.
Are Older and Newer Hydrometers Calibrated Differently?
Yes, older hydrometers are generally calibrated at 59°F, while newer ones are mostly calibrated to 68°F. This is important to know when you are using the temperature correction formula.
Is There a Digital Alternative to Traditional Hydrometers?
Yes, there are digital hydrometers like the Tilt Digital Wireless Hydrometer and Thermometer. These devices allow you to instantly check the specific gravity and temperature of your brew without having to open your fermenter.
They are compatible with Apple iPhone/iPad or Android smartphone/tablet and offer the option to log data to the cloud.
Lead marketer, brewer, dad, and husband. Pretty much an all-round awesome guy. Self proclaimed coffee addict who’s been home brewing beer (among other things) for 25+ yrs. Also an aspiring pro-brewer and micro-brewery owner!