How to Use the Recipe Scaling Calculator
Scale an ingredient list by entering the original and target servings, then click Calculate. The result shows the scale factor, formula, original quantities, scaled quantities, and units.
- Enter Current (original) servings and Target servings.
- Enter each ingredient name and non-negative quantity. Add an optional Unit (label only) value.
- Click Add ingredient for another row.
- Use the trash-icon button on a row, which has the accessible label Remove ingredient, to remove that ingredient before calculating.
- Choose a Rounding policy, then click Calculate.
- Use Reset to restore the starting fields and rows.
Formula and Result
Scale factor = Target servings / Original servings
Scaled quantity = Original quantity x Scale factor
After calculation, the result shows the scale factor, original and target servings, the formula, and a table with original quantities, scaled quantities, and units.
Rounding and Units
The options are No rounding (full precision), Nearest 0.1, Nearest 0.25, and Nearest whole number. The selected policy affects the displayed scaled quantity only. Original quantities are displayed to three decimal places, and the scale factor is displayed to four decimal places. With No rounding (full precision), the scaled quantity is displayed to four decimal places.
Unit (label only) is free text. Surrounding whitespace is trimmed, and the calculator does not convert units.
Input Validation and Empty Rows
Current (original) servings and Target servings must be greater than zero. Used ingredient rows need a name and a quantity of zero or more. Rows with both the ingredient name and quantity blank are ignored, including rows that contain only a unit. At least one completed ingredient is required.
Copying, Downloading, and Printing the Result
- Copy result places the plain-text result on the clipboard when clipboard writing succeeds. If it fails, the interface displays “Could not copy - select and copy manually.”
- Download result (.txt) creates a plain-text download.
- Print table prints the result area, including the “Scaled ingredient table” heading and table.
Limitations and Calculator Scope
The calculation is plain multiplication by the target-to-original servings ratio. Leavening, spice, seasoning, and cook or bake time may not scale linearly in real recipes, so review the quantities before using them.
The calculator does not estimate calories or nutrition, provide food-safety guidance, or automatically suggest replacement ingredients.
Privacy and Calculator Processing
The calculator script performs the arithmetic using the ingredient and serving values entered on the page. This does not establish a broader site-wide privacy or security guarantee.
Frequently Asked Questions
How does this recipe scaling calculator work?
Enter your current servings and target servings. The calculator divides target by current to get a scale factor, then multiplies every ingredient quantity you entered by that scale factor to get the scaled quantity.
What is the scale factor formula?
Scale factor = Target servings / Original servings. Scaled quantity = Original quantity x Scale factor. For example, scaling a 4-serving recipe to 6 servings gives a scale factor of 1.5, so 200 g of an ingredient becomes 300 g.
What is the rounding policy and does it affect accuracy?
The rounding policy controls the displayed scaled quantity: No rounding (full precision), Nearest 0.1, Nearest 0.25, or Nearest whole number. Original quantities are displayed to three decimal places, while the selected policy controls the scaled quantity; with No rounding, it is displayed to four decimal places. The scale factor is displayed to four decimal places.
Does this account for things that don't scale linearly, like spice or leavening?
No. This calculator performs plain linear multiplication only. Review the scaled amounts and adjust to taste or experience before using them.
Does this tool give food-safety or nutrition advice?
No. It performs only quantity arithmetic. It does not estimate calories or nutrition and does not provide food-safety guidance. It is not professional culinary advice.