Calculate Plato degrees or specific gravity from the other value with this Plato to SG calculator for brewing measurements and recipes.

Approximate sucrose-equivalent conversion for nonnegative extract in unfermented wort. Temperature correction, alcohol effects and refractometer calibration are not included.

1°P represents 1% sucrose by solution mass. Approximation is intended for brewing, not precision concentration analysis.

Related Calculators

Plato To SG Formula

The following formula is used to calculate the specific gravity (SG) from Plato degrees (°P).

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

Variables:

  • SG is the specific gravity
  • °P is the Plato degrees

Calculate the denominator as 258.6 − (P/258.2) × 227.1, divide P by that denominator, and add 1. The consistent inverse is P = 258.6(SG − 1) / [1 + (227.1/258.2)(SG − 1)]. This is an empirical brewing approximation; temperature and alcohol corrections are separate.

Plato Degrees to Specific Gravity (SG) Conversion Table
Plato Degrees (°P) Specific Gravity (SG)
21.0078
31.0117
41.0157
51.0197
61.0237
7.51.0298
81.0318
91.0359
101.0400
111.0442
121.0484
12.51.0505
131.0526
141.0568
151.0611
161.0654
17.51.0720
181.0741
201.0830
221.0920
Formula used: SG = 1 + (P / (258.6 – (P / 258.2) × 227.1)). Values rounded to 4 decimals.

What Does “Plato to SG” Mean?

A Plato to SG (Specific Gravity) conversion is used in brewing beer to measure the density of the liquid in comparison to water. Plato is a sucrose-equivalent extract scale: 1°P corresponds to 1% sucrose by solution mass. Wort contains other dissolved substances, and alcohol affects fermented-beer density. Specific Gravity, on the other hand, measures the relative density of the liquid compared to water. Therefore, converting Plato to SG allows brewers to understand the sugar content in their brew, which is crucial for determining the potential alcohol content.