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Brix to Specific Gravity (SG) Calculator

SG = 1 + [Brix ÷ (258.6 − (Brix ÷ 258.5) × 227.1)]

Example: 10 Brix (10% sugar) = SG 1.040, with ~5.2% potential alcohol after fermentation.

Convert sugar concentration between Brix, Plato, and Specific Gravity (SG) for beer brewing, winemaking, and cider fermentation. The calculator also estimates potential ABV from starting gravity — critical for recipe formulation and fermentation monitoring.

Sugar Concentration Input

Enter Brix or Plato (they are equivalent scales)

Results

Specific Gravity (SG) 1.040
Potential ABV (if fermented dry) 5.2%
Degrees Plato 10.0 °P

Brix to SG Reference Chart — Brewing & Winemaking

Brix (°Bx) Specific Gravity Potential ABV
0°Bx 1.000 0.0%
5°Bx 1.020 2.6%
10°Bx 1.040 5.2%
15°Bx 1.061 7.9%
20°Bx 1.083 10.8%
23°Bx 1.096 12.6%
25°Bx 1.106 13.8%
30°Bx 1.130 16.9%

Using a Refractometer in Brewing

A refractometer is the go-to tool for measuring Brix in the brewery or winery. A single drop of wort or must is placed on the prism and the Brix reading is taken by looking through the eyepiece at a light source. Readings take seconds — compared to a hydrometer which requires a full sample cylinder.

Important: Refractometers are only accurate for unfermented wort/must. Once fermentation begins, alcohol in solution distorts the light refraction. You must apply an alcohol correction formula: FG = 1.001843 − 0.002318474 × OB − 0.000007775 × OB² − 0.000000034 × OB³ + 0.00574 × FB + 0.00003344 × FB² + 0.000000086 × FB³.

Winemaking & Fruit Wine Brix Targets

Different beverage types have different optimal starting Brix ranges:

Light beer (3–4% ABV)8–10 Brix
Standard beer (4–6% ABV)10–14 Brix
Strong beer / DIPA (8–10%)16–20 Brix
Table wine (11–14% ABV)21–26 Brix
Dessert wine (16–20%)28–36 Brix
Mead starting gravity22–30 Brix

Frequently Asked Questions — Brix & Specific Gravity

What is Brix and how is it used in brewing?
Brix (°Bx) is a measure of sugar concentration in aqueous solutions — specifically the percentage of sucrose by mass. In brewing and winemaking, Brix is measured using a refractometer and indicates the starting sugar content of wort or must. It directly predicts potential alcohol content after fermentation.
How do you convert Brix to Specific Gravity?
The formula is: SG = 1 + (Brix / (258.6 − (Brix / 258.5) × 227.1)). An approximate shortcut: SG ≈ 1 + (Brix × 0.004). For example, 10 Brix ≈ 1.040 SG, 15 Brix ≈ 1.061 SG, 20 Brix ≈ 1.083 SG.
What is the difference between Brix and Plato?
Brix and Plato are nearly identical scales — both measure percent dissolved sugar by mass relative to pure water at 20°C. Plato (°P) is more commonly used in professional brewing and is derived from density measurements, while Brix uses the sucrose refraction index. For practical purposes, 1 °Bx ≈ 1 °P.
How do I calculate potential ABV from Brix?
Step 1: Convert Brix to Starting Gravity (OG). Step 2: After fermentation is complete, convert final Brix to Final Gravity (FG). Step 3: ABV = (OG − FG) × 131.25. Note: After fermentation starts, you must apply a refractometer correction because dissolved alcohol distorts refractometer readings.
What Brix should my must be for a 12% ABV wine?
For 12% ABV wine, you need an OG of approximately 1.091, which corresponds to about 22–23 Brix. Yeast typically ferments wort completely dry (to SG 1.000), so the potential ABV = (OG − 1.000) × 131.25 = (0.091 × 131.25) ≈ 11.9%.

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