Serving Size Calculator
Scale any recipe from one serving size to another. Enter your ingredients and adjust for any number of guests.
Planning before cooking? Scale servings here. Dividing food already cooked? Calculate portions from the finished batch weight.
Scale your recipe
Party planning guide
How much food per person for common dishes at events.
How the serving size calculator works
The calculator finds one number, the scaling factor. It divides the servings you need by the servings the recipe makes. It then multiplies every ingredient amount by that factor and rounds the answer to two decimal places.
scaling factor = servings you need ÷ servings the recipe makes
A recipe for 4 that must feed 6 has a factor of 6 ÷ 4 = 1.5. A recipe for 12 cut down to 4 has a factor of 4 ÷ 12, shown as 0.33x. The badge shows the rounded factor. The math uses the full value, so 3 cups in that recipe becomes exactly 1 cup.
Worked example: the recipe in the calculator
The calculator opens with a three-line recipe that makes 4 servings: 2 cups flour, 1 cup sugar and 3 eggs. This table lists what it returns for each preset button.
| You need | Factor | Flour (cups) | Sugar (cups) | Eggs |
|---|---|---|---|---|
| 2 servings | 0.5x | 1 | 0.50 | 1.50 |
| 4 servings | 1x | 2 | 1 | 3 |
| 6 servings | 1.5x | 3 | 1.50 | 4.50 |
| 8 servings | 2x | 4 | 2 | 6 |
| 12 servings | 3x | 6 | 3 | 9 |
| 25 servings | 6.25x | 12.50 | 6.25 | 18.75 |
| 50 servings | 12.5x | 25 | 12.50 | 37.50 |
| 100 servings | 25x | 50 | 25 | 75 |
Turn the decimals into amounts you can measure
The calculator answers in decimals. Measuring cups and spoons use fractions. In US customary units 1 cup is 16 tablespoons and 1 tablespoon is 3 teaspoons, so a decimal part of a cup converts like this.
| Decimal part | Fraction | Tablespoons and teaspoons | Teaspoons |
|---|---|---|---|
| 0.13 | 1/8 cup | 2 tbsp | 6 tsp |
| 0.25 | 1/4 cup | 4 tbsp | 12 tsp |
| 0.33 | 1/3 cup | 5 tbsp + 1 tsp | 16 tsp |
| 0.50 | 1/2 cup | 8 tbsp | 24 tsp |
| 0.67 | 2/3 cup | 10 tbsp + 2 tsp | 32 tsp |
| 0.75 | 3/4 cup | 12 tbsp | 36 tsp |
Eggs do not come in decimals. For 4.50 eggs, use 4 whole eggs, beat a fifth egg and add half of it. This site works with about 50 g for one large egg without the shell, so half an egg is about 25 g.
What straight multiplication gets wrong
This calculator multiplies every line by the same factor. That suits flour, sugar, butter, liquids, meat and vegetables. It does not always suit salt, spices, baking powder, baking soda or yeast in a large batch. It also says nothing about pan size or cooking time. The guide on how to scale recipes covers those cases and names its sources.
The calculator keeps the unit you typed. It does not change cups into grams. For that, use the cups to grams converter or the recipe unit converter.
Party planning amounts
The party planning guide multiplies an amount per person by your guest count. These are the planning amounts built into this calculator. They are rules of thumb for a mixed group of adults, not a standard. Raise them for a long event or for hungry guests. Lower them when you serve many dishes.
| Dish | Per person | 10 guests | 25 guests | 50 guests | 100 guests |
|---|---|---|---|---|---|
| Main protein (meat/fish) | 170g (6oz) | 1.7 kg (4 lb) | 4.3 kg (9 lb) | 8.5 kg (19 lb) | 17.0 kg (37 lb) |
| Rice or pasta (dry) | 75g | 0.8 kg (2 lb) | 1.9 kg (4 lb) | 3.8 kg (8 lb) | 7.5 kg (17 lb) |
| Salad greens | 50g | 0.5 kg (1 lb) | 1.3 kg (3 lb) | 2.5 kg (6 lb) | 5.0 kg (11 lb) |
| Bread/rolls | 2 pieces | 20 pieces | 50 pieces | 100 pieces | 200 pieces |
| Cake/dessert | 100g slice | 1.0 kg (2 lb) | 2.5 kg (6 lb) | 5.0 kg (11 lb) | 10.0 kg (22 lb) |
| Appetizers (mixed) | 6 pieces | 60 pieces | 150 pieces | 300 pieces | 600 pieces |
| Soup | 250mL | 2.5 L | 6.3 L | 12.5 L | 25.0 L |
| Vegetables (side) | 125g | 1.3 kg (3 lb) | 3.1 kg (7 lb) | 6.3 kg (14 lb) | 12.5 kg (28 lb) |