A recipe's conversion factor is the new total yield divided by the original total yield. A soup that serves 10 scaled to 25 has a factor of 25 ÷ 10 = 2.5, so 2 litres of stock becomes 5. If portion size changes too, multiply portions by size first: 20 × 4 oz against 8 × 6 oz gives 80 ÷ 48 = 1.6667.
Cooks, caterers and school kitchens rarely make a recipe at its printed yield. This calculator works out the single number that every ingredient is multiplied by when you move from the yield a recipe makes to the yield you need. It handles the common professional case where the portion size changes as well as the head count, by comparing total yield (portions times portion size) rather than portions alone. It also shows the new batch as a percentage of the original and, if you type one ingredient quantity, that quantity already scaled. The factor is exact arithmetic; it cannot know that spices, salt, thickeners and leavening often need less than a straight multiplication in very large batches, or that pans and cooking times change with volume.
Type how many portions the recipe makes and how many you need.
Keep the same size, or pick Change the size and enter the current and new portion sizes in one shared unit.
Optionally type one quantity from the recipe to see it multiplied by the factor.
Multiply every ingredient by the conversion factor; the working shows how it was found.
Result Conversion factor: 2.5
New batch as % of original: 250%
Original total yield: 10
New total yield: 25
Scaled ingredient amount: 5
Every ingredient is multiplied by 2.5, so 2 litres of stock becomes 5 litres.
Result Conversion factor: 1.6667
New batch as % of original: 166.7%
Original total yield: 48
New total yield: 80
Scaled ingredient amount: 5
Smaller portions mean the batch only grows by two-thirds, not 2.5 times; 3 cups of rice becomes 5 cups.
Result Conversion factor: 0.3333
New batch as % of original: 33.3%
Original total yield: 12
New total yield: 4
Scaled ingredient amount: —
A factor of one third: 3 eggs becomes 1 egg.
Factor = (new portions × new portion size) ÷ (original portions × original portion size)
Factorportionsportion sizeThis is the factor method taught in foodservice training. When portion size stays the same the sizes cancel and the factor is simply new portions divided by original portions. A factor above 1 enlarges the recipe, below 1 reduces it. Each ingredient quantity is multiplied by the factor, and the results are then rounded to practical kitchen measures, ideally after converting volumes to weights.
Divide the yield you want by the yield the recipe gives. For 25 servings from a recipe for 10, the factor is 25 ÷ 10 = 2.5. Multiply every ingredient by that number.
Because the amount of food depends on portions times their size. Twenty 4 oz portions is 80 oz of food, while eight 6 oz portions is 48 oz, so the factor is 80 ÷ 48 = 1.6667, not 20 ÷ 8 = 2.5. Ignoring the size change would overproduce by half.
Any unit works, provided both sizes use the same one: ounces, grams, millilitres or cups. The unit cancels in the division, so the factor itself has no unit.
Many chefs scale seasonings, leaveners and thickeners a little below the full factor in large batches, then adjust by taste. The calculator gives the arithmetic figure as the starting point.
The new batch is smaller than the original. A factor of 0.3333 means a third of every ingredient, so 3 eggs becomes 1 egg and 300 g of flour becomes 100 g.
Not in proportion. Larger volumes take longer to heat through and may need wider pans or several batches, so use the original time as a guide and check doneness by temperature or texture.
Using this tool in an assignment, article or report? Copy a citation, or a link for your website.
Tools Directory Editorial Team. (2026, October 14). Recipe Yield Calculator. Tools Directory. Retrieved October 27, 2026, from https://tools.milunir.com/cooking/recipe-scaling-and-conversions/recipe-yield-calculator/
Tools Directory Editorial Team. “Recipe Yield Calculator.” Tools Directory, 14 Oct. 2026, https://tools.milunir.com/cooking/recipe-scaling-and-conversions/recipe-yield-calculator/. Accessed 27 Oct. 2026.
Tools Directory Editorial Team. “Recipe Yield Calculator.” Tools Directory. Last modified October 14, 2026. Accessed October 27, 2026. https://tools.milunir.com/cooking/recipe-scaling-and-conversions/recipe-yield-calculator/.
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