Half Recipe Calculator

How to halve a recipe without the guesswork

Scaling a recipe is one multiplication, but the units are what trip people up. Halving a recipe means dividing every ingredient by two, and because recipes are written in cups, tablespoons and teaspoons, the answer often lands on a fraction that no measuring cup shows. That is the whole problem this calculator solves: it does the division and then converts the result into spoons you can measure.

The conversions worth memorising are short:

• 1 cup = 16 tablespoons = 48 teaspoons
• 1 tablespoon = 3 teaspoons
• 1/4 cup = 4 tablespoons = 12 teaspoons
• 1/3 cup = 5 tablespoons + 1 teaspoon

With those, half of 3/4 cup becomes 6 tablespoons, half of 1/3 cup becomes 2 tablespoons + 2 teaspoons, and half of 1/2 cup becomes 4 tablespoons. None of those need a fraction of a cup measure, which is why the calculator shows the spoon equivalent every time. The USDA Food Safety and Inspection Service is the reference for the food-safety side of working with smaller batches.

Worked example: halving a batch of chocolate chip cookies

A standard cookie recipe makes about 48 cookies from these ingredients. Halving it should give 24.

• 2 1/4 cups flour → 1 cup + 2 tablespoons
• 1 teaspoon baking soda → 1/2 teaspoon
• 1 teaspoon salt → 1/2 teaspoon
• 1 cup butter → 1/2 cup (one stick)
• 3/4 cup white sugar → 6 tablespoons
• 3/4 cup brown sugar → 6 tablespoons
• 1 teaspoon vanilla → 1/2 teaspoon
• 2 eggs → 1 egg
• 2 cups chocolate chips → 1 cup

The flour is the interesting one. Half of 2 1/4 cups is 1 1/8 cups, which no measuring set has, but 1 1/8 cups is exactly 1 cup + 2 tablespoons, so that is what you measure. Weighing is cleaner still: at about 120 g per cup, 2 1/4 cups is 270 g, so half is 135 g on the scale.

The oven temperature stays at 375°F. The time does not halve, check the smaller batch at about 8 to 9 minutes instead of the original 9 to 11, and watch it rather than trusting the clock.

Worked example: scaling a soup down for two

An eight-serving chicken soup scaled to four servings:

• 8 cups chicken broth → 4 cups (one quart)
• 2 lb chicken → 1 lb
• 1 large onion → 1/2 onion (about 1/2 cup diced)
• 3 carrots → 1 1/2 carrots
• 2 tablespoons olive oil → 1 tablespoon
• 1 teaspoon salt → 1/2 teaspoon, then taste
• 1/2 teaspoon black pepper → 1/4 teaspoon

Two things do not halve. Salt is the obvious one, 1/2 teaspoon in half the liquid tastes slightly stronger than 1 teaspoon in the full pot, because the surface area and evaporation differ, so start low and adjust at the end. Simmer time is the other: a half batch of soup still needs about 25 minutes rather than the original 30, not 15, because the chicken has to cook through regardless of the volume.

Everything else scales cleanly. Halving the broth to 4 cups is exactly one quart, which is a standard carton, so there is no leftover to store. That is the quiet advantage of cooking for two, the amounts often land on package sizes.

Common measurements, halved and doubled

Every value below is exact, not rounded. Use the spoon column when a halved fraction is not on your measuring cups.

Weight-based recipes are simpler than any of this. Half of 240 g is 120 g, half of 500 g is 250 g, and a digital scale handles both without a single fraction. If you bake often, grams will save you more time than any conversion chart, the FDA's food information pages cover labelling and nutrition basics if you want the background on why weights are more consistent than volumes.

What does not halve neatly

Four things resist a clean division, and knowing them in advance is what separates a recipe that works from one that does not.

Eggs. One large egg is about 3 tablespoons by volume. Halving a two-egg recipe is easy, one egg. Halving a one-egg recipe means beating it and using about 1 1/2 tablespoons, which leaves a leftover you should refrigerate and use within a day.

Leavening. Baking powder and baking soda should be halved with everything else, but they are the most sensitive to small errors, so measure them carefully rather than eyeballing. Halving a recipe does not mean cutting the leavening more than the flour.

Pan size. A halved batter in the original pan spreads thinner and bakes faster, sometimes drying out. A smaller pan keeps the depth similar. An 8-inch square pan holds roughly double a 6-inch round one, so dropping a size usually matches a halved batch.

Time. Temperature never changes and time rarely halves. As a rule, check a halved batch at about two-thirds of the original time and then every couple of minutes. Food safety is the one thing you should not shorten casually, the foodsafety.gov guidance on internal temperatures applies whether you are cooking for two or ten.

Scaling up, and other handy ratios

The same calculator works in the other direction. Doubling a recipe means multiplying every ingredient by two, and one and a half times means multiplying by 1.5, the calculator handles all of them from the same amount field, so you never do the arithmetic twice.

Some rules that make scaling easier to remember:

• Halve = ÷2, third = ÷3, double = ×2, 1.5× = ×1.5.
• Cups, tablespoons and grams all scale linearly; so do ounces by weight.
• When scaling up, increase pan size or bake in batches rather than piling batter deeper.
• Salt, leavening and strong spices are the ingredients worth checking twice, in both directions.

Finally, treat the results as a starting point rather than a guarantee. Recipes assume standard-size ingredients, a "large onion" can weigh 8 ounces or 14, so a halved recipe built from a huge onion will taste different from one built from a small one. Use the calculator for the math, then taste as you go. Every figure here is an estimate for planning; nothing you enter leaves your browser.