SG to Plato and Density to Brix Converter

Frequently asked questions

What is the difference between Plato and Brix?

Both express dissolved solids as percent sucrose by weight and agree within about 0.1° across normal beverage ranges. Plato comes from brewing (ASBC) tables and is usually converted from specific gravity. Brix comes from sugar industry (ICUMSA) tables, which are built on the density of sucrose solutions at 20 °C. Brewers use Plato; winemakers, cider makers, and kombucha producers usually use Brix.

Why does Brix convert from density instead of specific gravity?

The ICUMSA Brix tables are defined against density in g/cm³ at 20 °C, and digital density meters report density directly. Converting from density skips a step. Specific gravity is a ratio to water, so at 20 °C / 20 °C, density equals SG × 0.99820 g/cm³.

How accurate is this conversion?

The polynomial fits track the reference tables within roughly 0.05° from 0 to 30°. That is tighter than a typical hydrometer reading. For QC or compliance work, measure density directly with a calibrated density meter.

Can I convert a refractometer Brix reading to density?

Before fermentation, yes, as an approximation. Refractometers measure refractive index, not density, and are calibrated to sucrose, so juice and wort readings drift from true Brix. Once fermentation starts, alcohol distorts the refractive index and the reading needs an alcohol correction before it means anything. Do not enter uncorrected refractometer readings from a fermenting or finished sample.

Why does my finished wine or beer read below 1.000 SG or 0.9982 g/cm³?

Ethanol is less dense than water, so a dry fermented beverage can read below the density of water. The converted Plato or Brix value is apparent extract, not true sugar content, and can be negative. Residual sugar and real extract require lab analysis.

What temperature are these values referenced to?

20 °C (68 °F). Correct hydrometer readings to their calibration temperature before converting. Density meters typically control sample temperature and report at 20 °C directly.