Brix to Specific Gravity Converter
Convert a refractometer or hydrometer reading between Brix, Plato and specific gravity. Enter your measured value, pick the unit, set the wort correction factor if needed, and get SG, °Bx, °P and estimated alcohol potential.
Convert Brix to Specific Gravity
Brix to Specific Gravity Formula
Where:
- \(SG\) — specific gravity (dimensionless, e.g. 1.048)
- \(P\) — extract content in degrees Plato (°P). For a refractometer Brix reading, \(P = {}\)Brix \(\times\) correction factor
- \(ABV_{potential}\) — approximate alcohol by volume if the solution fully ferments to dryness
The first equation is the ASBC (American Society of Brewing Chemists) conversion, widely used to translate between extract percentages and specific gravity. The second gives a quick estimate of the alcohol a must or wort can potentially produce.
Brix to SG – Calculation Example
Example: a refractometer reads 12 °Bx on a juice sample, with a wort correction factor of 1.00.
\[ P = 12 \times 1.00 = 12 \]
\[ SG = 1 + \frac{12}{258.6 - \frac{12}{258.2} \times 227.1} = 1 + \frac{12}{248.05} = 1.0484 \]
\[ ABV \approx (1.0484 - 1) \times 131.25 = 6.35\% \]
Result: Specific gravity 1.0484, Brix 12.00 °Bx, Plato 12.00 °P, approximate alcohol potential 6.35 % ABV.
How to Use the Calculator
- Enter your reading in the Measured Value field (e.g. 12).
- Choose the unit of that reading in the Unit dropdown: Brix (°Bx), Specific Gravity, or Plato (°P).
- Set the Wort Correction Factor. Leave it at 1.00 for juice, wine must or plain sugar solutions; use 1.03–1.05 if you measured beer wort with a refractometer.
- Read the results: Specific Gravity, Brix, Plato and Approximate Alcohol Potential in % ABV.
What Are Brix, Plato and Specific Gravity?
Brix (°Bx) and Plato (°P) both express the percentage of dissolved sugar (extract) by weight: a 12 °Bx solution contains roughly 12 grams of sucrose per 100 grams of liquid. The two scales are practically identical for sugar solutions — Brix is the common term in winemaking and the food industry, while Plato dominates in brewing.
Specific gravity (SG) is the ratio of a liquid's density to the density of pure water, so water has an SG of 1.000. The more sugar is dissolved, the denser the liquid and the higher the SG. A wine must at 1.0484, for instance, is about 4.8% denser than water. Brewers and winemakers use SG because hydrometers read it directly and because the drop in SG during fermentation is what reveals the alcohol actually produced. Since SG is fundamentally a density comparison, it can also be translated into absolute units with a density converter.
The alcohol potential figure estimates the strength of a fully fermented, dry beverage. It assumes all sugar is converted and is only a rough guide: real attenuation, residual sugar and fermentation by-products mean the final ABV usually lands slightly below this number.
Reference Table: Brix to SG (Correction Factor = 1)
| Brix (°Bx) | Specific Gravity | Approx. Alcohol Potential |
|---|---|---|
| 5 | 1.0197 | 2.6 % ABV |
| 10 | 1.0400 | 5.3 % ABV |
| 12 | 1.0484 | 6.4 % ABV |
| 15 | 1.0611 | 8.0 % ABV |
| 20 | 1.0830 | 10.9 % ABV |
| 25 | 1.1057 | 13.9 % ABV |
Assumptions, Limitations and Tips
- Wort correction factor: refractometers are calibrated for sucrose solutions. Beer wort contains proteins and other dissolved solids that bend light differently, so a refractometer Brix reading on wort must be multiplied by a factor of about 1.03–1.05 before converting. Determine your instrument's own factor by comparing it against a hydrometer. The factor applies only to refractometer readings — leave it at 1.00 if you enter SG or Plato directly.
- Fermented samples: this converter is intended for pre-fermentation readings. Once alcohol is present, it changes the refractive index, and a plain Brix-to-SG conversion becomes inaccurate; special formulas are needed to read ABV from a refractometer during or after fermentation.
- Temperature: both hydrometers and refractometers are calibrated to a reference temperature (often 20 °C). Readings taken far from that temperature should be temperature-corrected first.
- Brix vs. Plato: the calculator treats them as equal, which is accurate to within about 0.1% for sugar solutions — well beyond the precision of home instruments.
- Related conversions: if you work with dissolved concentrations in other forms, see the PPM to percent and mg/L converter or the blood sugar unit converter for glucose measurements in mg/dL and mmol/L.
Frequently Asked Questions
How can I convert Brix to specific gravity by hand without a calculator?
For a quick mental estimate, multiply degrees Plato (or Brix) by 4 to get "gravity points." For example, \(12\,^\circ P \times 4 = 48\) points, which means an SG of about 1.048. The rule works best in the 10–15 °P range typical of beer and wine; it drifts slightly at higher sugar levels, so use the full ASBC formula for anything above roughly 20 °P.
What is a good Brix reading for wine must or beer wort?
Wine grapes are typically harvested at 19–25 °Bx, giving roughly 10–13% potential alcohol; dessert wines start higher. Table grapes run lower, around 17–19 °Bx. Beer wort usually falls between 10 and 15 °Bx (about 1.040–1.060 SG), with light lagers at the low end and strong ales above 16 °Bx. Values are only guidelines — target style and yeast tolerance matter more.
How much actual sugar does a Brix reading represent?
One degree Brix equals 1 gram of sucrose per 100 grams of solution, so a 12 °Bx must contains about 12% sugar by weight. To estimate sugar per liter, multiply °Bx by roughly 10: 12 °Bx ≈ 120 g/L. This is useful when a recipe calls for sugar in grams rather than a refractometer reading. Remember the figure counts all dissolved solids, not just fermentable sugar.
How do I calculate the real alcohol content after fermentation is done?
Potential alcohol is only an estimate; for actual ABV you need both the original gravity (OG) and the final gravity (FG) measured with a hydrometer: \(ABV \approx (OG - FG) \times 131.25\). For example, from 1.048 down to 1.010 gives about 5.0% ABV. Residual sugar keeps FG above 1.000 in off-dry drinks, so sweet beverages always show a smaller drop.
Why does my refractometer disagree with my hydrometer?
Refractometers measure light refraction, which is affected by every dissolved solid, while hydrometers measure density directly. Beer wort contains proteins and dextrins that bend light like extra sugar, inflating the Brix reading by about 3–5%. To find your own correction factor, take both readings on the same sample before fermentation, convert the hydrometer SG to Plato, and divide the refractometer Brix by that Plato value.
What are the most common mistakes when converting Brix to SG?
The top errors are: applying the wort correction factor to a hydrometer reading instead of a refractometer one; forgetting that the factor is a multiplier, not a subtraction; using a refractometer reading taken after fermentation has started, when alcohol distorts the result; and ignoring temperature — a sample at 30 °C read on a 20 °C-calibrated instrument can be off by half a degree Brix or more.
Can I convert Brix to other scales like Balling, Baumé or Oechsle?
Balling, Brix and Plato are all near-identical sugar-by-weight scales, so a reading transfers directly between them. Baumé, common in French winemaking, is roughly \(Baumé \approx \frac{Brix}{1.8}\). Oechsle, used in Germany, equals \((SG - 1) \times 1000\) — a must at 1.048 has 48 °Oe. These approximations are fine for home use; commercial labs use exact tables.