Fat intake calculator
How many grams of fat, and of saturated fat, to eat a day.
About this calculator
How much fat should I eat a day? This fat intake calculator estimates your daily calories from your age, sex, size and activity, then shows the recommended fat in grams.
It also gives the limit for saturated fat and a table of fat at different shares of calories, for low-fat to high-fat diets.
How it works
Works out your daily calories with the Mifflin-St Jeor equation and your activity, adjusted for your goal. Fat has 9 kcal per gram, so grams = calories × share ÷ 9. The usual range for adults is 20% to 35% of calories, with saturated fat under 10%.
Last reviewed:
Worked example
- Units: Feet and pounds
- Sex: Female
- Age: 35 years
- Height: 5 ft 7 in
- Weight: 155 lb
- Activity: Light exercise, 1 to 3 days a week
- Goal: Maintain
Fat a day: 44–77 g (20% to 35% of your calories)
Common questions
How much fat should I eat a day?
20% to 35% of calories for adults. On 2,000 kcal a day, that is about 44 to 78 g.
How much saturated fat is too much?
Keep it under 10% of calories, about 22 g on 2,000 kcal. Swapping it for unsaturated fats from oils, nuts and fish is better for the heart.
Are all fats bad?
No. The body needs fat to absorb vitamins A, D, E and K. Trans fats are the type to avoid.
Sources and further reading
The story behind it
Where the idea came from: Fat has 9 kcal per gram, more than twice the 4 kcal of carbohydrate or protein, figures worked out by the chemist Wilbur Atwater in the 1890s.
That is why a little fat adds many calories. Health advice now focuses on the type of fat: replacing saturated fat with unsaturated fats from oils, nuts and fish.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, not medical advice.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
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