Refractometer Calculator - Brewer's Friend
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Refractometer Calculator

Converts refractometer readings taken of wort (Brix WRI) to their actual value in Brix / Plato and Specific Gravity. Supports alcohol correction of refractometer readings when calculating FG (which requires OG).
Part I: OG Brix WRI Correction:
OG - (Brix WRI):
Wort Correction Factor:

OG - Corrected:

Part II: FG Brix WRI Alcohol Present:
Original Gravity:
FG - (Brix WRI):
Wort Correction Factor:

OG - Corrected:
FG - Corrected:
Alcohol By Volume:

To help clear up confusion with terminology, at Brewer's Friend we have decided to call a Brix measurement of wort: Brix WRI (wort refraction index). Brix WRI makes it clear the measurement pertains to wort and is unadjusted. Only after dividing Brix WRI by the wort correction factor do we arrive at the actual Brix / Plato reading. It is helpful to know that Brix and Plato are nominally the same to 3 decimal places, so the corrected reading can be treated as Plato (°P).

For instructions on how to determine your refractometer's wort correction factor, see our post about that.

For more information about refractometer use in general: Using your Refractometer Correctly for Maximum Accuracy in Home Brewing.

Refractometer readings which contain alcohol must be adjusted by an additional factor. This calculator uses the formula presented in Zymurgy magazine, in the July/August 2017 issue: Novotny, P. Revisiting The Refractometer: Improved fermentation monitoring through refractometry. Zymurgy 2017, 40 (4), 48–54.

The ABV calculation uses the 'alternate' equation. Read more about ABV equations here.

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Legal Disclaimer: The Brewer's Friend Refractometer Calculator is for entertainment purposes and should not be used for professional brewing. No warranty or guarantee of accuracy is provided on the information provided by this calculator.