A gravity unit converter translates between the three main scales used to measure sugar content in beer wort and wine must: Specific Gravity (SG), degrees Brix, and degrees Plato. Brewers and winemakers rely on accurate gravity readings to predict alcohol content, monitor fermentation progress, and hit recipe targets. Type a value in any field and the other units update instantly.
Gravity Converter
Hydrometer reading
Refractometer reading
Professional brewing scale
Refractometer Correction (Post-Fermentation)
Alcohol skews refractometer readings. Enter your OG and current Brix reading to get a corrected FG.
When to Use Each Scale
Specific Gravity (SG)
- Measured with a hydrometer
- Standard in homebrewing
- Not affected by alcohol
- Needs a large sample (~100 ml)
- Range: 1.000 – 1.120+
Brix (°Bx)
- Measured with a refractometer
- Common in winemaking
- Only a few drops needed
- Alcohol skews readings
- Range: 0 – ~30°Bx
Plato (°P)
- Used in professional brewing
- European & craft standard
- Nearly identical to Brix
- Calibrated for wort, not sucrose
- Range: 0 – ~30°P
Quick Reference Table
| SG | Brix (°Bx) | Plato (°P) | Points | Pot. ABV |
|---|
How to Use the Gravity Unit Converter
Whether you are brewing your first extract kit or running a commercial brewery, accurate gravity readings are essential for hitting your target alcohol level, monitoring fermentation health, and reproducing recipes reliably. This free gravity converter makes it simple to move between the three most common scales: Specific Gravity, Brix, and Plato.
Step 1: Enter a Value in Any Field
Type a number into the Specific Gravity, Brix, or Plato input field. The other two fields update automatically using precision polynomial formulas. For example, entering 1.048 in the SG field will show approximately 11.9 Brix and 11.9 Plato. You can also edit Brix or Plato and the SG field will recalculate.
Step 2: Read the Derived Values
Below the input fields, four cards display useful derived metrics. Gravity Points strip the leading 1. from SG for easier recipe math (1.050 = 50 points). Potential ABV estimates the maximum alcohol if the wort ferments completely to 1.000. Gravity Units show points per gallon for scaling recipes, and Density shows the wort density in grams per liter.
Step 3: Use the Refractometer Correction
If you are checking fermentation progress with a refractometer, the post-fermentation Brix reading will be inaccurate because alcohol bends light differently than sugar water. Enter your original Brix reading and your current refractometer Brix in the correction section to get a corrected Final Gravity. This uses the standard wort correction factor formula widely accepted in homebrewing.
Step 4: Consult the Reference Table
The quick reference table lists common gravity values from 1.030 to 1.120 in 0.005 increments with all three units, points, and potential ABV side by side. This is handy when designing recipes or comparing your readings to style guidelines.
Understanding the Scales
Specific Gravity is a ratio of your wort's density to water and is measured with a hydrometer. It is the most common scale in homebrewing. Brix measures the percentage of sucrose by weight and is read with a refractometer, which needs only a few drops of liquid. Plato is nearly identical to Brix but was calibrated specifically for brewing wort; it is the standard in professional and European breweries. For pre-fermentation wort, Brix and Plato are interchangeable for all practical purposes.
Tips for Accurate Readings
Always calibrate your hydrometer or refractometer before each brew day. Hydrometers are temperature-sensitive, so take readings at the calibration temperature (usually 60 °F or 20 °C) or apply a correction. Refractometers should be zeroed with distilled water. After fermentation begins, always use a hydrometer for the most accurate gravity reading, or apply the refractometer correction provided by this gravity converter.
Frequently Asked Questions
Is this gravity converter really free?
Yes, the gravity unit converter is completely free with no limits and no account required. All calculations run locally in your browser. Nothing is stored or sent to any server.
Is my data safe and private?
Absolutely. Every conversion happens entirely in your browser using JavaScript. No data is transmitted to any server, stored in any database, or shared with anyone.
What is the difference between Specific Gravity, Brix, and Plato?
All three measure the sugar content of a liquid but use different scales. Specific Gravity compares the density of wort to water (1.000). Brix measures the percentage of sucrose by weight and is read with a refractometer. Plato also measures sugar percentage by weight and is commonly used in professional and European brewing.
Are Brix and Plato the same thing?
They are very close but not identical. Brix measures pure sucrose content, while Plato was calibrated specifically for brewing wort which contains various sugars and proteins. For practical brewing purposes the difference is negligible, usually less than 0.05 degrees, so brewers often treat them as interchangeable.
When should I use a refractometer vs a hydrometer?
A refractometer reads in Brix and needs only a few drops of wort, making it ideal for measuring original gravity on brew day. A hydrometer reads in Specific Gravity and requires a larger sample but is more reliable for final gravity readings since alcohol does not affect its accuracy.
Can I use a refractometer to measure final gravity?
You can, but the reading must be corrected because alcohol changes how light refracts through the sample. The refractometer will read lower than the actual Brix value. Use a wort correction factor or a dedicated refractometer correction calculator to get an accurate final gravity from a post-fermentation refractometer reading.
What are gravity points and how are they used?
Gravity points are Specific Gravity multiplied by 1000 minus 1000. For example, an SG of 1.050 equals 50 points. Brewers use points for quick math when scaling recipes because they are proportional to the amount of dissolved sugar. Doubling the grain at the same volume roughly doubles the points.
How accurate are the conversion formulas?
The converter uses the ASBC polynomial formula for SG-to-Plato conversion, which is accurate to within 0.01 degrees Plato across the normal brewing range of 1.000 to 1.120 SG. For most homebrewing purposes the precision far exceeds what a hydrometer or refractometer can measure.