Brix to SG, ABV, and Specific Gravity Calculator

A Brix reading alone does not tell you much. Converting Brix to SG and ABV is the first step in turning a raw refractometer reading into something you can actually use. Calculate your potential ABV, correct for temperature, and get your specific gravity in one place. Whether you are working with grape must, apple juice, or honey must, enter your number and see exactly what your batch can achieve before fermentation begins.

What Is Brix and Why Do Brewers Use It?

Brix (°Bx) measures sugar concentration in a liquid. One degree Brix means one gram of sucrose is dissolved in 100 grams of solution. A reading of 20°Bx tells you that roughly 20% of that liquid by weight is sugar.

Sugar is what yeast converts into alcohol during fermentation. So your Brix reading before fermentation gives you a direct estimate of how much alcohol your batch can potentially reach.

Different fermentation communities use different scales for the same thing:

Comparison Table

Scale	Used By	Measures
Brix (°Bx)	Winemakers, food science	Sugar % by weight
Degrees Plato (°P)	Commercial brewers	Sugar % by weight
Specific Gravity (SG)	Homebrewers	Liquid density vs water

All three scales measure dissolved sugar concentration; they just express it differently. The Brix, Plato, and Balling scales are close enough to use interchangeably at typical brewing ranges.

Brix vs Plato: Key Differences for Brewers?

Brix and Plato are not identical scales, but the difference between them is small enough that most brewers treat them as the same number.

The Balling scale was the original version, developed in the 19th century to measure sugar in solution. Degrees Plato is a more precise revision of Balling, adopted by professional brewers. Brix is the modern international standard used in winemaking and food science.

In typical brewing ranges (10°Bx to 30°Bx), Brix and Plato are almost identical, differing by less than 0.1. For homebrewers, converting between them usually isn’t necessary.

Where the difference matters:

• Commercial breweries report in Plato for quality control and recipe documentation.
• If you are following a professional recipe that lists °P, treat it as °Bx without converting.
• For precise Plato-to-SG conversion, use the formula below.

Plato to SG Formula: SG = 1 + (°Plato / (258.6 − (0.8796 × °Plato)))

Brix to Specific Gravity Conversion

Specific gravity (SG) compares the density of your liquid to pure water, which has an SG of exactly 1.000. Sugar dissolved in liquid makes it denser, pushing SG above 1.000.

Typical SG ranges before fermentation:

Before fermentation, typical SG readings depend on the liquid. Grape must usually falls between 1.070 and 1.110, while apple juice for cider reads lower at 1.045–1.065. Honey must for mead tends to run higher, anywhere from 1.080 to 1.130, depending on your honey-to-water ratio. The relationship between Brix and SG is nonlinear. As sugar concentration rises, density does not increase at a perfectly even rate; it curves. This is why a simple multiplier gives an approximate answer, but the polynomial formula gives an accurate one.

• Brix to SG Formula: SG = (Brix / (258.6 − ((Brix / 258.2) × 227.1))) + 1
• SG to Brix Formula: Brix = (((182.4601 × SG − 775.6821) × SG + 1262.7794) × SG − 669.5622)

The calculator at the top of this page handles both directions automatically.

How to Calculate ABV from Brix

Brix-based ABV gives you the potential alcohol content, meaning the maximum alcohol your liquid can produce if fermentation completes fully.

Brix to ABV Conversion

Brix measures the sugar content in your liquid. Since sugar converts into alcohol during fermentation, Brix can be used to estimate potential ABV.

Each degree Brix produces roughly 0.55% to 0.60% ABV, depending on yeast efficiency and fermentation conditions.

Why Brix ABV is Only an Estimate

Brix-based ABV is always a potential value, not the final alcohol content.

If fermentation does not complete fully, some sugar remains unconverted, resulting in a lower actual ABV than calculated.

Step-by-Step Brix ABV Calculation

Measure the Brix of your juice before fermentation

Use the standard conversion factor and apply the formula:

$ABV = Brix \times 0.59$ABV=Brix×0.59

Brix Formula Example

Brix = 20

ABV = 20 × 0.59 = 11.8%

Dry Wine vs Sweet Wine: How Brix Changes the Result

Two wines can start at the same Brix reading but finish at very different ABV levels depending on how fermentation is managed.

• Dry wine ferments almost all available sugar into alcohol. FG drops close to 1.000, and the actual ABV approaches the potential figure.
• Sweet wine retains unfermented sugar. FG stays higher, and ABV ends up lower than the Brix reading suggested, because not all that sugar became alcohol.

This is why harvest Brix alone does not determine final wine strength. How far fermentation runs matters just as much.

Typical harvest Brix for wine grapes:

• Below 20°Bx: May need chaptalization to reach standard ABV
• 20 – 24°Bx: Standard table wine range, 11–14% ABV
• Above 26°Bx: High-alcohol or dessert wine territory

Harvest Brix targets vary by wine style and grape variety. A winemaker's target Brix at picking is not just about alcohol; it is a balance between ripeness, acidity, and flavor development. Here are typical harvest Brix ranges for common wine styles:

For a direct Brix to Plato conversion, first convert Brix to SG using the formula above, then apply:

°Plato Formula: °Plato = −460.234 + (662.649 × SG) − (202.414 × SG²)

At typical fermentation starting points — 10°Bx to 26°Bx — Brix and Plato values sit within 0.1 of each other. The conversion becomes meaningful when matching a commercial recipe precisely or reporting in Plato for professional documentation.

Quick Reference Table: Brix → SG → Potential ABV

Grape must at harvest typically falls in the 20–26°Bx range. Apple juice for cider usually measures 11–15°Bx. Honey must vary widely depending on the honey-to-water ratio. For values outside this table, use the calculator above for a precise result.

Sugar to ABV: How Added Sugar Changes Alcohol Potential

Sometimes, natural sugar levels in your juice or must are not enough to hit your target ABV. Brewers and winemakers add sugar directly to increase potential alcohol content, a process known by different names depending on the craft.

Brix of Common Adjuncts and Sugar Types

When brewers and winemakers add fermentable sugars to raise gravity, different sugar sources contribute different Brix equivalents per gram. This table shows the approximate Brix contribution of common adjuncts so you can calculate how much to add to hit your target OG.

Note that fermentability affects your actual ABV result. Corn sugar at 100% fermentability adds more alcohol per gram than LME at 75%, even if their Brix contributions appear similar. Always factor in fermentability when calculating expected ABV from adjunct additions.

Sugar Additions in Homebrewing

For all-grain homebrewers, a low pre-boil Brix reading is a signal to adjust before pitching yeast. Adding sugar raises OG directly.

Every 46 grams of sugar per liter raises SG by approximately 0.010 SG points, which adds roughly 1.3% to potential ABV.Sugar to ABV formula: ABV increase = (grams of sugar per litre × 0.0013) × 100

Priming Sugar

Priming sugar is added at bottling time in a small, precise dose. It triggers secondary fermentation inside the bottle, creating natural carbonation. It contributes very little to ABV, typically under 0.2%, but it is still a sugar-to-alcohol conversion happening in the bottle.

Using a Refractometer for Brix Readings

A refractometer measures how light bends through a liquid, a property called the refractive index. Sugar in solution bends light more than plain water, so a higher sugar concentration produces a higher Brix reading. The tool needs only a drop or two, making it practical for quick checks without disturbing your whole batch.

Brix Reading Before vs After Fermentation

This is where many homebrewers get caught out. A refractometer behaves differently depending on when you use it.

How to Correct Refractometer Readings After Fermentation (Sean Terrill Formula)

Before fermentation, a refractometer gives you an accurate reading because no alcohol is present. Once fermentation begins, alcohol starts interfering with the light refraction, so mid-fermentation readings need a correction applied before you can trust them. By the time fermentation is complete, the alcohol effect is significant enough that a raw refractometer reading is unreliable — at that stage, a hydrometer is the better tool for your final gravity.

Once alcohol forms in the liquid, it changes how light moves through the sample. Alcohol and sugar refract light differently, so a post-fermentation Brix reading without correction will be lower than the true value. Feed that raw number into an ABV formula, and your result will be off.

Refractometer correction formula for post-fermentation FG: Corrected FG = 1.0000 − 0.0044993(OGBrix) + 0.011774(FGBrix) + 0.00027581(OGBrix²) − 0.0012717(FGBrix²) − 0.0000072800(OGBrix³) + 0.000063293(FGBrix³)

For your definitive FG reading, a hydrometer is the more reliable choice. Use the refractometer for progress checks and the hydrometer to confirm your final number.

H3: Calibrating Your Refractometer. Place a drop of distilled water on the prism; it should read exactly 0°Bx. If it does not, adjust using the calibration screw. Most modern refractometers include ATC (Automatic Temperature Compensation), which handles minor temperature variation during measurement.

Temperature Correction for Accurate Brix and SG Readings

Hydrometers are calibrated at a fixed temperature, usually 60°F (15.6°C) or 68°F (20°C), depending on the model. When your sample is warmer or cooler than that point, the density reading shifts, and your ABV calculation shifts with it.

Why temperature matters:

Temperature Correction Formula: Corrected SG = Measured SG + (0.000132 × (T − Tcal))Where T = sample temperature, Tcal = hydrometer calibration temperature

Temperature correction reference:

At 60°F (15.6°C) — the standard calibration point — no correction is needed. Below that, at 50°F (10°C), subtract 0.001 from your reading. Above calibration, corrections increase gradually: add 0.001 at 68°F, 0.002 at 77°F, 0.003 at 86°F, and 0.005 at 95°F (35°C).

The simplest fix is letting your sample cool to room temperature before measuring. If that is not practical, use the temperature correction tab in the calculator above, enter your sample temperature, and the correction applies automatically.

Brix Ranges Across Different Fermentable Liquids

Brix applies to any sugar-containing liquid going into fermentation. Knowing the typical range for your source liquid helps you set realistic ABV targets before you start.

How Homebrewers Use Brix for ABV Calculation

For all-grain homebrewers, a refractometer and Brix readings fit naturally into the brew day workflow.

Pre-Boil Gravity Check

Before the boil ends, take a Brix reading of your wort. This gives you a pre-boil gravity estimate using only a drop of liquid; there is no need to cool a full hydrometer sample. If the reading is lower than your recipe target, add malt extract or sugar to correct the OG before pitching yeast.

OG Recording and ABV Estimate

Convert your pre-fermentation Brix to SG for your OG record, then estimate potential ABV: ABV = Brix × 0.59

Mid-Fermentation Readings

During active fermentation, Brix readings give you a rough progress check, useful for confirming fermentation is still moving. But alcohol interference makes them approximate. Do not use mid-fermentation Brix readings as your FG.

Final Gravity Confirmation

When fermentation appears finished, switch to a hydrometer for your FG reading. This gives you an accurate final density unaffected by alcohol. From there, the standard OG/FG ABV formula gives you a reliable result.

Common Stuck Fermentation: Causes and Fixes