Scale servings or use what is in the pantry
The active factor is the target serving count divided by original servings, a direct multiplier, or the smallest available-to-required ingredient ratio. A 4-serving recipe scaled to 10 uses 2.5×: 200 g flour becomes 500 g and 2 eggs become 5. If the recipe needs 300 g flour but only 240 g is available, the batch factor is 0.8. If another constraint is stricter, that ingredient limits the batch.
Switching modes replaces the active factor. It never multiplies a serving adjustment by a pan adjustment in secret. Fractional eggs are displayed as fractional amounts, not silently rounded up.
Convert pan sizes using usable capacity
Round pan usable volume is π × (internal diameter / 2)² × intended batter depth. Rectangle and square volumes use internal length × width × depth. Pan count multiplies capacity. When batter depth is unchanged, the depth cancels and an 8-inch round pan to a 9-inch round pan requires (9 / 8)² = 1.265625 times the batter. For shaped, tapered, tube or Bundt pans, enter measured usable volume at the intended fill level rather than brim capacity or a guessed universal percentage.
Cup standards and ingredient density
A US customary cup is 236.5882365 mL; a metric or Australian cup is 250 mL. A US tablespoon is about 14.78676478125 mL, a metric tablespoon is 15 mL, and an Australian tablespoon is 20 mL. Mass ounces and fluid ounces are different dimensions. Converting an unknown ingredient from cups to grams needs a measured or sourced ingredient-specific weight per reference volume. The tool refuses to invent one.
Practical eighth-cup fractions are displayed separately from unrounded arithmetic. Use cooking judgment for leavening, seasoning, temperature, bake time and food safety.
Frequently asked questions
Can I scale to the flour I have?
Yes. Select flour as an available ingredient and enter the amount; multiple constraints use the smallest compatible ratio.
Why won't a cup become grams automatically?
Cup is volume and gram is mass. An ingredient-specific density is required.
Will a larger pan keep the same baking time?
Not necessarily. Batter depth, heat transfer and recipe chemistry affect cooking behavior.