The serving factor is target servings divided by original servings. Both numbers must be positive. Enter the serving count the original ingredient quantities were written for before choosing a target.
Enter original and target servings
If a recipe serves six and you need nine, enter 6 in Original servings and 9 in Servings you need. The factor is 9 ÷ 6 = 1.5. A 180 g flour row becomes 270 g, and a 90 g butter row becomes 135 g.
To halve the original recipe, choose a target that is half the original serving count. You do not need to edit every ingredient. Keep the original quantities unchanged so you can return to them later.
Correct a serving error before proceeding
An original count of zero cannot define a factor. Negative counts and entries outside the accepted range also need correction. Read the error message above the ingredient table and correct the relevant serving field.
When a field is invalid, do not use a previous result as if it belonged to the new input. Correct the source of the error and review the refreshed quantities.
Review counts, ranges, and notes
A count can become fractional when a recipe is scaled. Decide how you will measure or divide that ingredient in practice. Do not confuse the calculated fraction with a guarantee that a particular package can be divided conveniently.
“To taste” stays an instruction. Ranges and optional ingredients remain subject to the choices you made during review. Check small quantities before selecting a rounded display.
Keep cooking instructions separate
A factor of 1.5 multiplies the supported ingredient quantities. It does not turn a 30-minute cooking instruction into 45 minutes. Pan dimensions, batch layout, and cooking conditions are separate questions.
Preserve the original method text and any notes about how you adapted the recipe. Pan size converter can compare geometry, but it does not predict a finished cooking time.
Save the reviewed target
Check the factor, every unresolved row, and the selected measurement definitions before saving or exporting. If you change the target again, the calculation should start from the original row amounts, not from previously rounded output.