How the fat target is calculated
You start with your daily calorie figure and choose what share should come from fat. The calculator converts that percentage into calories, then divides by nine because dietary fat is energy dense at about nine calories per gram, more than twice that of protein or carbohydrate.
Because fat is so dense, a 30 percent fat target produces far fewer grams than a 30 percent carbohydrate target would, even though both claim the same slice of calories. The pie chart shows fat calories against the rest of your day.
How much fat you need
Common guidance puts total fat at roughly 20 to 35 percent of calories. Fat is essential: it supports hormone production, helps absorb vitamins A, D, E and K, and provides essential fatty acids the body cannot make.
- Favour unsaturated fats from olive oil, nuts, seeds, avocado and oily fish.
- Limit saturated fat and avoid industrial trans fats.
- Going too low on fat can affect hormones and nutrient absorption.
- Fat is satiating, so a moderate amount can help meals feel filling.
Reading the result
The headline number is the grams of fat to aim for across the whole day, not per meal. The type of fat matters as much as the total, so use the gram target alongside good food choices rather than on its own.
A note on health
This is general nutrition guidance, not medical advice. People with certain heart, liver or digestive conditions may need tailored fat intake. If you are managing a condition or making big dietary changes, consult a doctor or registered dietitian.
Formula
fat grams = (calories · percent / 100) / 9Frequently asked questions
- Why is fat 9 calories per gram?
- Fat packs more chemical energy per gram than protein or carbohydrate (both about 4 calories), so the same weight of fat supplies more than twice the calories.