How to use the weight change calorie calculator
Estimate time to lose or gain weight with a daily calorie change. Enter weight to lose, daily calorie deficit in the fields above; the total energy, time needed, time needed are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- dw — Weight to lose (kg)
- def — Daily calorie deficit (kcal)
Worked example
With weight to lose = 5 kg, daily calorie deficit = 500 kcal, the calculator gives total energy ≈ 38,500 kcal; time needed ≈ 77 days; time needed ≈ 11 weeks.
Frequently asked questions
What is the formula for the weight change calorie calculation?
Total energy (kcal) = dw × 7700. Time needed (days) = [Total energy] / def. Time needed (weeks) = [Time needed] / 7. Here dw is weight to lose (kg), def is daily calorie deficit (kcal).
What inputs do I need for the weight change calorie calculator?
You need weight to lose in kg, daily calorie deficit in kcal. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.