LDK to PPG Conversion Calculator

Litre Degrees per Kilogram (LDK) and Points per Pound per Gallon (PPG) are two systems used by brewers and malt suppliers to express the extract potential of malted grains. LDK is the standard on United Kingdom and many European malt specification sheets, while PPG is the standard in the United States and is used by most online brewing calculators and recipe databases. The conversion factor between them comes from the relationship between kilograms and pounds and between litres and US gallons.

The formula is PPG = LDK / 8.3454, where 8.3454 is the product of the pound-to-kilogram ratio (2.20462) and the US-gallon-to-litre ratio (3.78541). The reverse formula is LDK = PPG x 8.3454. The conversion uses US gallons, not Imperial gallons, since that is the reference PPG itself is built on. Both figures answer the same underlying question, how much sugar a given weight of malt yields when dissolved into a given volume of water, and neither number means anything without pinning down which weight unit and which gallon or litre it was measured against, which is exactly what the 8.3454 factor accounts for in a single step.

A malt rated 50 PPG converts to 50 x 8.3454 = 417.27 LDK, and running the reverse formula on that same figure, 417.27 / 8.3454, returns 50 PPG. A second malt rated 305 LDK converts the other way, 305 / 8.3454, to about 36.55 PPG, the two formulas mirroring each other exactly regardless of which direction the conversion runs.

Malt extract potential values are essential for predicting original gravity and building accurate brewing recipes. Because malt suppliers in different regions publish specifications in different unit systems, converting reliably between the two standards bridges the gap between recipe software expectations and malt data sheets, for homebrewers, professional brewers, and malt suppliers alike.

• Homebrewing recipe design: LDK values from a UK malt data sheet convert into PPG for use in US-based recipe calculators built around PPG-based gravity prediction formulas; a pale malt specification of 305 LDK converts to approximately 36.55 PPG for a recipe targeting 1.050 original gravity.
• Professional brewing: PPG values from American hop and grain databases translate into LDK for metric-based brewhouse software or production spreadsheets, which matters for production brewers working across international supply chains where consistent unit conversion maintains batch consistency.
• Malt supplier comparison: Extract potential values from suppliers across different countries normalize onto a common scale regardless of the unit system published, comparing a German pilsner malt at 310 LDK against an American two-row at 37 PPG on equal terms.
• Educational reference: Textbook conversion examples verify against the relationship between kilograms, pounds, litres, and US gallons that produces the 8.3454 conversion factor, with the step-by-step derivation in settings showing the full breakdown of each calculation.
• Recipe scaling across systems: Adapting a recipe originally formulated in one unit system for use in another keeps grain bill calculations producing the intended original gravity.
• Quality control documentation: Recording malt lot specifications in both LDK and PPG formats supports internal records for teams working in different measurement traditions, keeping documentation consistent across brewery locations in different countries.