Plato to Specific Gravity Calculator

Formula Used

The calculator converts degrees Plato to specific gravity with this common brewing equation:

SG = 1 + P / (258.6 - ((P / 258.2) × 227.1))

Here, P is the Plato value. Temperature correction is added with:

Corrected SG = SG + ((Sample Temperature - Calibration Temperature) × Coefficient)

Gravity points are calculated as:

Points = (Corrected SG - 1) × 1000

Density is estimated as:

Density = Corrected SG × Water Density

When final Plato is entered, the calculator also estimates alcohol and attenuation:

ABV = (Original SG - Final SG) × 131.25

Apparent Attenuation = ((Original SG - Final SG) / (Original SG - 1)) × 100

Real Extract = (0.1808 × Original Plato) + (0.8192 × Final Plato)

How to Use This Calculator

1. Enter the original Plato reading from your wort or recipe.
2. Add final Plato if you want alcohol and attenuation estimates.
3. Enter the sample and calibration temperatures.
4. Use zero as the correction coefficient if no correction is needed.
5. Enter batch volume to estimate total extract mass.
6. Choose decimal places for cleaner or deeper results.
7. Press the calculate button to show results above the form.
8. Use CSV or PDF export buttons to save the result.

Example Data Table

Understanding Plato and Specific Gravity

Plato is a brewing scale that shows dissolved extract by weight. One degree Plato means one gram of extract in one hundred grams of solution. Specific gravity compares wort density with water. Brewers use both values because different books, labs, and software often prefer different scales.

Why This Conversion Matters

A Plato reading helps estimate sugar strength before fermentation. Specific gravity helps track starting gravity, final gravity, attenuation, and alcohol estimates. Converting between them keeps recipes consistent. It also helps when a hydrometer, refractometer, or recipe sheet uses another scale. The calculator supports temperature correction, final extract comparison, density output, and export options.

How Brewers Use the Result

Original Plato can become original gravity. Final Plato can become final gravity. The difference between both gravity values estimates alcohol and apparent attenuation. The result is not a lab certificate. It is a practical brewing estimate. Good sampling, proper instrument calibration, and stable sample temperature still matter. Degassed beer and clear wort usually give better readings.

Advanced Options Included

The sample temperature field lets you apply a simple correction. The coefficient field controls how strongly gravity changes per degree. Use zero when you do not want correction. Water density is used to estimate liquid density in kilograms per cubic meter. Batch volume helps show total extract weight. Precision controls rounded output.

Best Practice

Measure a cooled sample when possible. Record the instrument calibration temperature. Avoid bubbles, pulp, grain bits, and foam. Mix the wort before sampling. For hot wort, cool it before reading, or use a correction with care. Very strong worts may need laboratory tools. Refractometers also need alcohol correction after fermentation. Keep notes for every batch. These notes make future recipe changes easier. Use this calculator as a planning guide, then confirm key numbers with your brewing instruments.

For repeat batches, compare the exported table with your brew log. Small gravity changes can reveal mash efficiency shifts, dilution mistakes, or recipe variations. A consistent conversion method reduces confusion between brewers. It also helps when sharing recipes across regions. Many European sources use Plato. Many homebrew recipes use gravity. This page bridges both habits in one simple workflow. Clean records make recipe development faster and reliable.

FAQs