Scale a recipe in seconds
Set the original and new serving counts. The ingredient amounts update as you plan.
How the scaling factor works
The scaler divides the new number of servings by the original number and multiplies every ingredient by that factor. Going from 4 servings to 6 gives a factor of 1.5, so 2 cups of flour becomes 3 cups and ½ cup of butter becomes ¾ cup. Halving a recipe uses a factor of 0.5.
What does not scale in a straight line
Eggs rarely divide neatly: round to the nearest whole egg, or beat one and measure out part of it (a large egg is about 3 tablespoons). Salt, strong spices and chili are safer scaled a little under the factor and adjusted to taste. Baking powder and soda can usually be scaled directly for doubling, but for anything larger than double it is better to bake in batches.
Pan size and baking time change too. A doubled cake batter needs two pans or a pan with twice the area, not a deeper pan; if the batter is deeper, lower the oven by about 25°F and bake longer, checking early. Stovetop recipes need a wider pot rather than a taller one so liquids reduce at the same rate.
Scale by weight when you can
Awkward results like ⅝ cup or 2⅔ tablespoons are much easier on a kitchen scale. Convert the recipe to grams first with the grams to cups converter, scale the grams, and weigh each ingredient. For spoon and cup fractions, see the measuring cup fraction chart.