Brix to Specific Gravity Converter
Convert refractometer readings to the gravity scale the rest of your recipe uses — or go the other way — using the published conversion polynomials.
The conversion used
SG = 12 ÷ (258.6 − ((12 ÷ 258.2) × 227.1)) + 1 = 1.04838
The two directions are independent published fits rather than exact inverses, so a value converted one way and back can land a hundredth or two from where it started.
| Brix / Plato | Specific gravity | Gravity points |
|---|---|---|
| 4° | 1.0157 | 15.7 |
| 8° | 1.0318 | 31.8 |
| 10° | 1.0400 | 40.0 |
| 12° | 1.0484 | 48.4 |
| 14° | 1.0568 | 56.8 |
| 16° | 1.0654 | 65.4 |
| 18° | 1.0741 | 74.1 |
| 20° | 1.0830 | 83.0 |
| 24° | 1.1011 | 101.1 |
Two ways of saying the same thing
Both scales describe how much sugar is dissolved in your wort; they just express it differently. Brix and Plato state it as a percentage by weight — 12 °Bx means roughly 12 grams of sugar per 100 grams of solution. Specific gravity states it as density relative to water, so that same wort reads about 1.048.
Which one you meet depends on your equipment. Refractometers are almost always marked in Brix and need only a couple of drops. Hydrometers read specific gravity and need a full sample tube. Recipes and calculators overwhelmingly assume gravity, which is why converting once at the point of measurement saves confusion later.
Worked example
A refractometer reads 12 °Bx.
SG = 12 ÷ (258.6 − ((12 ÷ 258.2) × 227.1)) + 1 = 1.0484
That is 48.4 gravity points. Converting straight back gives 12.0016 °Bx — the small drift from using two independent fits.
Common mistake
Using a refractometer for the final gravity reading. It is the single most common source of a wildly wrong ABV in homebrewing: alcohol shifts the refractive index, the reading comes out high, and the resulting beer looks as though it barely fermented. Convert pre-fermentation readings freely; take the final one with a hydrometer.
Keep going
- Once a Brix reading is in specific gravity, the ABV calculator turns the original and final numbers into strength. ABV Calculator
- The same converted gravities also give apparent attenuation, which is the faster way to tell whether a fermentation actually finished. Attenuation Calculator
Frequently Asked Questions
Are Brix and degrees Plato the same thing?
Near enough for brewing. Both express dissolved sugar as a percentage by weight, from slightly different original calibrations, and they diverge by hundredths of a degree at the concentrations beer occupies. Brix is the wine and refractometer convention; Plato is the brewing-industry one. Treat a reading in either as interchangeable here.
Why does converting a value and converting it back not return the same number?
Because the two directions are separate published polynomial fits, not algebraic inverses of each other. Convert 12 °Bx to gravity and back and you land at about 12.0016. That drift is inherent in using fitted curves and is far smaller than the precision you can actually read off a hydrometer.
Can I use my refractometer after fermentation starts?
Not without correcting it. Refractometers measure how light bends through the sample, and alcohol bends light differently from sugar, so once alcohol is present the reading runs high. Before fermentation a refractometer is genuinely convenient — two drops instead of a full sample tube.
What is a gravity point?
Just the decimal part of a specific gravity reading multiplied by 1000. A wort at 1.048 has 48 gravity points. Brewers use them because they add and scale cleanly — doubling volume halves the points, which is exactly the arithmetic dilution and blending need.
Which scale should I actually work in?
Whichever your equipment reads, then convert once. Most homebrew recipes and calculators assume specific gravity, so if you measure in Brix it is worth converting immediately and recording gravity, rather than carrying two scales through every subsequent calculation.
Sources. Both conversion polynomials are from Brewer's Friend's Brix converter, retrieved 19 September 2026, which attributes the Brix-to-gravity fit to Brew Your Own magazine and the gravity-to-Brix fit to Wikipedia's Brix article. A refractometer post-fermentation correction is deliberately not offered here, because none of the published calculators for it document the equation they use.
Related Calculators
- ABV Calculator — Gravity & Alcohol
- Attenuation Calculator — Gravity & Alcohol
- Dilution & blending Calculator — Gravity & Alcohol
- IBU Calculator — Hops & Bitterness