Fat Intake Calculator
Work out how many grams of fat to eat a day. Enter a calorie target directly, or let the calculator estimate your calories from your age, sex, height, weight and activity, then convert the recommended 20 to 35 percent of calories into grams. You also get the saturated fat limit, calories from fat, and easy food equivalents.
Formula
Worked example
On a 2,000 kcal diet aiming for 30% of calories from fat: 2,000 × 0.30 = 600 fat calories, then 600 ÷ 9 ≈ 67 g of fat per day. The 20-35% range works out to about 44 to 78 g, and saturated fat should stay under roughly 22 g (10% of calories).
How fat intake is calculated
Dietary fat is the most energy-dense macronutrient, supplying about 9 calories per gram compared with 4 for protein and carbohydrate. To turn a calorie target into grams of fat, you multiply your daily calories by the share you want from fat and divide by 9. The Dietary Guidelines for Americans recommend that adults get 20 to 35 percent of their total calories from fat, so this calculator shows the low and high ends of that range alongside the percentage you choose. Children and teenagers have slightly different ranges, which the calculator applies automatically when you enter a younger age.
Estimating your calories from body stats
If you do not already know your calorie target, switch the calculator to estimate it from your age, sex, height, weight and activity level. It uses the Mifflin-St Jeor equation to estimate your basal metabolic rate, the energy your body burns at rest, then multiplies that by an activity factor from 1.2 for sedentary up to 1.9 for very active to get your total daily energy expenditure. You can also nudge the figure for a weight goal, subtracting about 500 calories a day to lose weight or adding around 300 to gain. The fat target then follows from those calories just as it would from a number you typed in.
Why fat type matters more than total
Within a sensible total, the kind of fat you eat matters most for health. Unsaturated fats, found in olive oil, nuts, seeds, avocados and oily fish, support heart health and should make up the bulk of your intake. Saturated fat should stay below 10 percent of daily calories under the Dietary Guidelines, and the American Heart Association suggests an even stricter ceiling of 7 percent for people focused on heart health. Artificial trans fats should be avoided entirely. Replacing saturated fat with unsaturated fat, rather than with refined carbohydrate, is the change most consistently linked to better cardiovascular outcomes in long-term research.
Fitting fat into your overall diet
Fat, protein and carbohydrate together make up your total calories, so raising one lowers room for the others. If you set fat near 35 percent, you leave less room for carbohydrate, which suits lower-carb eating patterns; nearer 20 percent leaves more room for grains, fruit and starchy vegetables. To make the grams concrete, the calculator translates your target into everyday equivalents, since one tablespoon of olive oil carries about 14 grams of fat. Essential fatty acids and fat-soluble vitamins A, D, E and K all depend on some dietary fat, so very low-fat diets carry their own trade-offs. Aim for a balance you can sustain.
Fat grams by calorie level
| Daily calories | Low (20%) | Recommended (30%) | High (35%) |
|---|---|---|---|
| 1500 | 33 g | 50 g | 58 g |
| 1800 | 40 g | 60 g | 70 g |
| 2000 | 44 g | 67 g | 78 g |
| 2500 | 56 g | 83 g | 97 g |
| 3000 | 67 g | 100 g | 117 g |
Daily fat in grams across the recommended 20-35% of calories. One gram of fat supplies 9 kcal, so grams = calories × percent ÷ 9.
Frequently asked questions
How many grams of fat should I eat per day?
For most adults, 20-35% of daily calories from fat is recommended. On a 2,000-calorie diet that is roughly 44-78 grams per day, with about 67 grams at the common 30% target. Multiply your own calories by the percentage and divide by 9 to get your number, or let this calculator estimate your calories from your age, sex, height and weight first.
How does the calculator estimate my calories?
When you choose the body-stats mode, it uses the Mifflin-St Jeor equation to estimate your basal metabolic rate from your sex, weight, height and age, then multiplies by an activity factor (1.2 sedentary to 1.9 very active) for your total daily energy expenditure. A weight goal can subtract about 500 calories a day for loss or add about 300 for gain.
Why divide by 9?
Each gram of dietary fat provides about 9 kilocalories of energy, more than double the 4 kcal per gram from protein or carbohydrate. Dividing your fat calories by 9 converts that energy back into grams, the unit shown on nutrition labels.
How much saturated fat is too much?
The Dietary Guidelines cap saturated fat at under 10% of daily calories, about 22 grams on a 2,000-calorie diet. The American Heart Association suggests under 7% (about 16 grams) for people focused on heart health. You can pick either target in the calculator. Trans fats should be avoided entirely.
Is a low-fat or high-fat diet better?
Both can be healthy if total calories and fat quality are appropriate. What matters most is favoring unsaturated fats, limiting saturated fat, and avoiding trans fats. This is general information, not medical advice, so talk to a doctor or dietitian for personalized guidance.