Scaling a recipe starts with one number, the scale factor: divide the servings you want by the servings the recipe makes. Multiply every ingredient by that factor and you’ve got the new quantities.
Formula: Scale factor = desired servings ÷ original servings
Worked example
A recipe serves 4 and you need 6: factor = 6 ÷ 4 = 1.5. Two cups of flour becomes 3; one egg becomes 1.5 (beat an egg and measure half, or round to 2 and adjust). Weighing ingredients makes fractional amounts painless.
What doesn’t scale linearly
- Cooking time — a double batch in the same pan cooks longer, not double; go by temperature and visual cues.
- Pan size — doubling a cake means a bigger pan, or the center won’t cook before the edges burn.
- Salt and strong spices — scale conservatively and taste; they can overpower when multiplied blindly.
Frequently asked questions
How do I scale a recipe? Find the scale factor (desired ÷ original servings) and multiply every ingredient by it.
Does cooking time double? No — it increases somewhat; rely on doneness temperature, not time.
How do I handle “1.5 eggs”? Beat an egg and measure half (about 25 g), or round and adjust liquid.
Skip the math: use the calculator to get your numbers instantly.