Scale a recipe for more guests without ruining it

Why you’d do this

A recipe that serves four is easy. The same recipe for ten is where things go wrong: multiplying by 2.5 gives you “1 and 7/8 teaspoons” of something, a third of a gram of something else, and a quantity of rice that you are not sure will actually be enough. Most scaling mistakes come from two places — rounding numbers in a way your measuring tools cannot follow, and assuming that everything in a recipe grows at the same rate as the guest list.

Two tools handle the arithmetic so you can spend your attention on the cooking. Recipe Scaler resizes an ingredient list and rounds each amount the way a kitchen can actually measure it. Portion Planner answers the other question — how much to buy when you are feeding a crowd — as a range.

How, with the named tool

Recipe Scaler

1. Under Scale by, choose Servings to resize by head count, or One ingredient to resize around an amount you already have.
2. In Servings mode, fill Recipe serves and You need it to serve, or tap Half, Double or Triple. In One ingredient mode, use Pick the ingredient to scale by and then Amount you have.
3. Under Ingredients, fill each row with an amount, a unit (cup, tbsp, tsp, ml, l, g, kg, oz, lb, piece or no unit) and the ingredient name. Tap Add ingredient for another row.
4. Read the table. Each original amount sits next to its scaled amount, and the line Every amount × factor shows the multiplier that was applied. Copy scaled list takes the result with you.

The One ingredient mode is the useful one when you are short of something: if the recipe wants 400 g of flour and you only have 300 g, pin the flour, enter 300, and everything else scales down by the same factor.

Portion Planner

1. Type the number of people in Guests.
2. Pick a Serving style: Light, Normal or Generous. The multiplier it applies is shown next to your guest count (Light 0.8, Normal 1, Generous 1.25).
3. Read the quantities under Main, Meat & poultry and Sides & extras. Each item has a per-person range and a total range.
4. Copy shopping list turns the totals into text.

What to watch for

Rounding follows the unit, and that is deliberate. Volume and count amounts snap to the fractions a measuring set can produce — 1/8, 1/4, 1/3, 1/2, 2/3 and 3/4 — so you never see a repeating decimal. Weights never snap to a fraction: they round to a precision a kitchen scale can display, because a third of a gram is not something you can weigh out. The cost of snapping is that a scaled figure is rounded, not exact. If a recipe is sensitive, weigh rather than measure by volume.

The scaler multiplies every row by the same factor, and real recipes do not always behave that way. Salt, strong spices, chilli and leavening agents are usually the ingredients people adjust by taste when they cook for a crowd instead of trusting a straight multiplication. That is general cooking experience, not something the tool adjusts for: it will triple your spices if you ask it to triple the recipe. Scale, then taste and adjust those ingredients in steps, adding rather than guessing high.

Quantities change; pan size, time and oven temperature do not scale with them. This is the tool’s own caution: scaling changes quantities only. Doubling a recipe does not mean doubling the baking time, and a larger volume in the same pan will be deeper and cook differently. Use a bigger tray or two pans, and watch the dish rather than the clock the first time.

The portion ranges are common practice, not a standard. Portion Planner shows commonly used hosting estimates. There is no official published figure for how much rice or lamb a guest eats, and the planner says so. Every quantity is a range on purpose, because appetites, the number of dishes on the table and how long the gathering runs all move it. It lists quantities only — no calories or nutrition data.

FAQ

Why does the scaled list show 1/3 cup but never 1/3 gram?

Volume and count amounts snap to cooking fractions because a measuring set has a 1/3 cup. Weights round to a decimal precision instead, since a kitchen scale shows grams and tenths, not fractions of a gram.

Can I just double the cooking time when I double the recipe?

No. Scaling changes quantities only, and cooking times, pan sizes and oven temperatures do not scale with them. Cook until the dish is done by how it looks and feels, and check early.

How accurate are the Portion Planner amounts?

They are ranges based on commonly used hosting estimates, not an official standard. Choose a serving style, read the range, and adjust to your guests: a buffet with many dishes needs less of each, a gathering where leftovers are expected needs more.