Converters
Gravity, instrument corrections, alcohol, dilution and carbonation
Tools for the calculations you have to do at the fermenter: converting gravity between specific gravity and degrees Brix, refractometer and hydrometer corrections, strength and attenuation, wort dilution and carbonation. Everything is open without registration and uses the same formulas as the scans.beer journal, so the calculator and your records never disagree.
Converting SG to Brix and back
Specific gravity to degrees Brix and back, in gravity points.
Open the calculator →Hydrometer temperature correction
Bringing a hydrometer reading to the calibration temperature.
Open the calculator →Refractometer alcohol correction
Instrument correction (WCF) and alcohol correction using the Novotný model.
Open the calculator →Alcohol and attenuation
Strength and attenuation from original and final gravity.
Open the calculator →Diluting and boiling off wort
How much water to add or boil off to reach the target gravity.
Open the calculator →Carbonation under pressure
Pressure for target CO₂ saturation at a given temperature.
Open the calculator →Priming sugar for carbonation
How much sugar to add when bottling.
Open the calculator →Bitterness calculation (IBU)
How many IBUs the hops give during the boil.
Open the calculator →Mash water and mash temperature
How much water to add and to what temperature to heat it.
Open the calculator →Beer colour: EBC, SRM and Lovibond
EBC, SRM and Lovibond with a preview of the colour itself.
Open the calculator →Yeast starter and pitching rate
Whether you have enough yeast and what starter to make.
Open the calculator →About the formulas
The converters and the journal use the same formulas. SG ↔ Brix conversion is a cubic approximation matching the Brewer’s Friend tables; the hydrometer correction is the ratio of water densities from the Tanaka et al. table (Metrologia, 2001); the refractometer alcohol correction is the Novotný model in A. Ascher’s edition (2021), which works correctly throughout fermentation, unlike the Terrill formula, which gives unphysical values at high original gravity; alcohol uses M. Hall’s “Brew by the Numbers”; carbonation follows Henry’s law on the same CO₂ solubility curve as the priming calculation.
The results are estimates. They are meant for keeping records and checking against targets, not for replacing laboratory analysis.
Working with your instruments
- 1. Measure gravity at 20 °C or apply a temperature correction.
- 2. Convert the reading to the scale you prefer — Brix or specific gravity.
- 3. With a refractometer, apply the instrument correction first, then the alcohol correction.
- 4. Compare the result with the recipe target and, if needed, dilute or boil down the wort.
This order mirrors how the journal handles measurements: raw readings are stored as they are, and every conversion and correction is computed on read.