Fat Calculator
Convert an estimated adult maintenance-energy intake into fat grams using three fixed percentage comparisons.
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What this calculator estimates
Convert an estimated adult maintenance-energy intake into fat grams using three fixed percentage comparisons. The form estimates calories from body details; it has no custom fat-percentage input.
Inputs and calculation method
Enter age, equation option, height, weight and activity level. The tool estimates maintenance with Mifflin–St Jeor × activity. It displays fat at 28% of estimated energy as the main result, with 20% and 35% comparisons.
Formula and units
Fat grams = estimated maintenance kcal × selected preset fraction ÷ 9. The fixed fractions are 0.20, 0.28 and 0.35. Results are rounded to whole grams; 9 kcal per gram is an approximate food-energy factor.
How to use it
- Enter adult age, height in cm and weight in kg.
- Choose the equation option and overall activity category.
- Calculate and compare the fixed 20%, 28% and 35% figures.
- Keep these three alternatives separate; they are not quantities to add together.
Worked example
At age 35, 165 cm, 70 kg, the female equation and Moderate activity (1.55), maintenance is about 2,162.64 kcal/day. The fixed 28% calculation gives 67 g fat after rounding. The 20% and 35% comparisons are 48 g and 84 g.
How to read the result
The main value is a preset energy allocation, not a measured fat requirement. This page does not choose a diet style or assess saturated fat, essential fatty acids or food quality.
Common mistakes
- Assuming 28% was selected from individual health information.
- Confusing fat grams with a percentage of food weight.
- Adding the lower and higher comparisons to the main result.
Method limitations
Estimated energy and the chosen percentage both affect the result. These adult planning comparisons do not account for a clinical diet, pregnancy or growth, and the form does not independently assess appropriate fat intake.
Sources and method references
Supporting guides for this calculator
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Fat Calculator FAQs
Can I enter a preferred fat percentage?
No. The form uses fixed 20%, 28% and 35% calculations.
Can I enter my own calorie target?
No. Calories are estimated from body details and the activity factor.
Does this assess healthy fat sources?
No. It performs grams-from-energy arithmetic and does not evaluate the types of food supplying the fat.
Using the estimate
Use the displayed grams to understand three fixed energy shares. Choose any real eating plan using overall nutrition context rather than the middle preset alone.