Body Fat Mass Calculator
Calculate your fat mass and lean mass in kilograms.
About the Body Fat Mass Calculator
The Body Fat Mass Calculator is a free, private tool that runs entirely in your browser — your inputs never leave your device, and the answer appears the instant you enter them.
Health numbers — BMI, BMR, calorie needs, ideal weight — are the foundation of any fitness or weight plan. This Body Fat Mass Calculator computes one of them accurately so you can set goals based on your body's actual numbers rather than generic advice.
The calculation follows established medical formulas: the Mifflin-St Jeor equation for BMR, the standard BMI classification, and the activity multipliers used by dietitians to estimate total daily energy needs.
For Pakistanis, the same BMI and calorie standards apply, but body composition varies — which is why these tools are starting points, not diagnoses. Combine the number with professional advice for serious health goals.
Track the number over time rather than once. Whether it is BMI trending down or calorie needs changing with activity, the trend tells you whether your plan is working.
The Body Fat Mass Calculator is one of a large, connected suite of Pakistani calculators on GuruAlpha, so if a related figure comes up next, the tool for it is a click away.
How to use the health calculator
- 1
Enter your weight, height, age and sex as labelled.
- 2
Adjust activity level where the tool asks.
- 3
Read your BMI, BMR or calorie target, updated live.
- 4
Repeat periodically to track your trend.
Frequently Asked Questions
How is the body fat mass calculator result calculated?
This tool uses the standard, transparent method for body fat mass calculator — you enter the values shown and it applies the recognised formula, updating the result live as you type. All figures are estimates for guidance.
Is BMI accurate for everyone?
BMI is a screening tool, not a diagnosis. Muscular individuals may show a high BMI while being healthy, and it doesn't account for age, sex or body composition. Use it as a guide, not a verdict.
How many calories should I eat to lose weight?
Eat 300–500 calories below your total daily energy needs (BMR × activity factor). A deficit of 500 calories per day leads to roughly 0.5 kg of fat loss per week.