Nutrition Calculators

About these tools

The Weight & Calories section answers "how much energy?" This section answers the next question: "what, and how, do I eat?" It brings together the tools that work at the level of food — grams of protein, the split between carbohydrate and fat, the calories in a dish you cooked yourself, and the conversions you need to measure and scale a recipe accurately.

Why protein and macros moved here

The Protein and Macro calculators used to sit with the calorie tools. They still start from a calorie or body-weight figure, but their output is a description of food — grams of protein, carbohydrate and fat to spread across meals — so they belong beside the recipe and measurement tools you would use to hit those numbers. Their web addresses did not change. The Water Intake Calculator stays in Wellness, because hydration is about drinks and daily habits rather than the composition of meals.

How the pieces fit together

A typical path: find maintenance calories in the TDEE Calculator, set a protein range with the Protein Calculator, divide the rest into carbohydrate and fat with the Macro Calculator, then check a favourite recipe with the Recipe Calories per Serving Calculator. If the portion doesn't fit, resize the recipe with the Recipe Scaler, and use the Cooking Measurement Converter to turn cups into grams so the counts are reliable.

Where the numbers come from

Protein guidance comes from the National Academies' Dietary Reference Intakes (the 0.8 g/kg RDA and the 10–35% acceptable range) and the International Society of Sports Nutrition position stand for active people. Food energy values come from USDA FoodData Central, ingredient cup weights from USDA portion data and the King Arthur Baking ingredient weight chart, unit definitions from NIST, and label rounding from FDA regulations.

Food, not just numbers

Targets are tools, not rules. The Dietary Guidelines for Americans emphasize an overall pattern of vegetables, fruits, whole grains, varied protein foods and dairy, with limited added sugars, saturated fat and sodium. People with kidney disease, diabetes, food allergies or a history of disordered eating should set protein, carbohydrate and calorie goals with a doctor or registered dietitian.

The calculators in detail

Protein Calculator

Gives a daily protein range in grams from your weight and activity level, from the 0.8 g/kg RDA up to the 1.4–2.0 g/kg range the International Society of Sports Nutrition suggests for people who train.

Macro Calculator

Splits a calorie target into grams of protein, carbohydrate and fat for losing, maintaining or gaining, with an optional custom protein amount and a donut chart of the split. The page compares its splits with the National Academies' acceptable ranges.

Recipe Calories per Serving Calculator

Adds up the calories in up to eight ingredients — chosen from a list of 20 staples with USDA FoodData Central values, or entered from a package label — and divides by servings. It shows the exact figure and the rounded number an FDA-style nutrition label would print.

Recipe Scaler

Multiplies every ingredient by servings wanted ÷ original servings and rounds the result to eighths or thirds, with the exact decimal alongside. It reads whole numbers, fractions, mixed numbers and ranges, and leaves lines like "salt to taste" for you to judge. The page includes a pan-area table so a scaled batter keeps the same depth.

Cooking Measurement Converter

Converts between cups, tablespoons, teaspoons, fluid ounces, milliliters, grams, ounces and pounds. Volume-to-volume and weight-to-weight conversions are exact by NIST definition; volume-to-weight uses a grams-per-cup density for the ingredient you choose, from USDA FoodData Central or the King Arthur Baking ingredient weight chart.

Oven Temperature Converter

Converts Fahrenheit, Celsius and gas mark using the exact temperature formula and the standard gas mark scale (gas 1 = 275°F, rising 25°F per mark). It also shows the fan or convection equivalent using published rules of thumb: about 25°F lower (King Arthur Baking) or 20°C lower (BBC Good Food).