Specific gravity and degrees Plato measure the same thing — dissolved extract concentration in wort or beer — on two different scales, and homebrewers move between them constantly: German and Central European recipes, refractometers, and a fair amount of brewing software all default to Plato, while most North American hydrometers are marked in specific gravity.
The conversion table
| SG | °Plato |
|---|---|
| 1.000 | 0.0 |
| 1.010 | 2.6 |
| 1.020 | 5.1 |
| 1.030 | 7.6 |
| 1.040 | 10.0 |
| 1.044 | 11.0 |
| 1.050 | 12.4 |
| 1.052 | 12.9 |
| 1.060 | 14.7 |
| 1.070 | 17.1 |
| 1.080 | 19.3 |
| 1.090 | 21.6 |
| 1.100 | 23.8 |
| 1.110 | 25.9 |
| 1.120 | 28.1 |
These figures come from the same cubic approximation this site's ABV calculator uses internally to derive attenuation and calories from your gravity readings — it isn't a separate lookup table, it's the live formula evaluated at each SG value shown.
Where this comes from, and how precise it actually is
The relationship between SG and Plato isn't linear — you can see it in the table itself, where each 0.010 step in SG corresponds to a slightly different-sized step in Plato as gravity climbs. This site uses a widely-published cubic polynomial fit (the same one used in most brewing software, including BeerSmith, Brewer's Friend and Brewfather) rather than the simpler linear "divide by four" shortcut some brewers use by hand, because the linear shortcut drifts increasingly inaccurate above roughly 1.070 SG. The cubic fit stays accurate to within about 0.05°P across the normal 1.000-1.150 brewing range — genuinely useful for recipe formulation and process tracking, but not laboratory-precision, and this site says so rather than implying more accuracy than the fit actually has.
Brix, and why it isn't listed separately
Brix reads within about 0.2° of Plato for wort-strength solutions — close enough that this site treats them as numerically equal for practical homebrewing use, a common convention, rather than running a second near-identical table. Brix shows up more often in winemaking and cider-making, where a refractometer calibrated in Brix is the standard tool; Plato is the traditional brewing-science scale. If you're reading a refractometer marked in Brix on fermenting or fermented beer rather than fresh wort, note that the raw reading needs correcting for alcohol's effect on refractive index before it means anything as a gravity value — see refractometer correction, explained.
Using this alongside the calculator
A conversion chart is useful for a quick lookup, but every calculator on this site that touches gravity — ABV, dilution and blending — takes specific gravity as its input and computes Plato internally where it's needed, so you never have to convert by hand mid-recipe. If you're working from a Plato or Brix reading rather than an SG hydrometer, convert it here first, or read it directly off whichever scale your own instrument reports and treat this table as a sanity check rather than a required step.