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Adaptive TDEE calculator
Estimate recent energy expenditure from your own intake and weight trend instead of an activity multiplier.
Adaptive TDEE calculator
Example valuesEstimate recent energy expenditure from your own intake and weight trend instead of an activity multiplier.
No account needed. Calculations happen in your browser; your entries are not saved or sent to Century.
Example · Observed daily expenditure
2,464kcal/day
This describes observed energy balance, not a measurement of metabolic adaptation.
- Scenario range
- 2,371–2,543 kcal/day
- Weekly weight trend
- -0.24 kg
How it’s calculated
A least-squares line estimates weekly weight change from four or more weekly average weights. Observed daily expenditure is average reported intake minus estimated daily weight change multiplied by 7,700 kcal/kg. Because energy density changes with body composition and water shifts, the tool also shows a broad scenario using 5,000–10,000 kcal/kg. It cannot measure metabolic adaptation or diagnose a slow metabolism.
Reference: NIH NIDDK: research behind the Body Weight Planner
For general wellness information. This tool does not diagnose health conditions or replace medical advice.
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Adaptive TDEE calculator: use your own data
What to enter
Estimate recent energy expenditure from your own intake and weight trend instead of an activity multiplier.
It estimates expenditure consistent with your reported intake and recent weight trend. It cannot separate metabolic adaptation from changes in activity, logging error or water weight.
Read the result in context
Fit the trend across all four averages. A falling weight trend implies observed expenditure above reported intake, within a broad uncertainty range.
A fixed calorie value per kilogram of body-weight change is only an approximation. The range shows how a different energy-density assumption changes the result.
Where this estimate stops
Weekly averages are preferable. Day-to-day body weight changes with hydration, meals, and other factors unrelated to tissue gain or loss.
View activity and recovery patterns together in Century.
Frequently asked questions
How many weeks of data do I need?
Enter at least four weekly average weights and your average daily intake over the same period. Longer, consistent logs reduce the impact of a single unusual weigh-in.
Does this measure metabolic adaptation?
No. It estimates expenditure consistent with your reported intake and recent weight trend. It cannot separate metabolic adaptation from changes in activity, logging error or water weight.
Why does the calculator show a range?
A fixed calorie value per kilogram of body-weight change is only an approximation. The range shows how a different energy-density assumption changes the result.
Should I use single morning weights?
Weekly averages are preferable. Day-to-day body weight changes with hydration, meals, and other factors unrelated to tissue gain or loss.