Calorie Needs Context Calculator
Estimate a general maintenance-calorie context from your inputs and activity setting. This tool does not prescribe a calorie deficit, diet or weight-loss target.
Last reviewed August 22, 2026
Your numbers stay in your browser, nothing is sent or saved.
How the estimate works
This tool estimates resting energy expenditure with the Mifflin–St Jeor formula and applies the selected activity factor to provide general maintenance context. It is an estimate, not a measured metabolic test.
Why it is not a deficit calculator
A general formula cannot safely determine how much a particular person should eat to lose weight. Medical conditions, medicines, pregnancy, eating-disorder history, body composition, activity and food tolerance can change what is appropriate. Discuss personal calorie or weight goals with a qualified clinician or registered dietitian.
Frequently asked questions
What does this calorie tool estimate?
It estimates maintenance energy context from age, height, weight, sex and selected activity level. It is not a measured metabolic test and does not prescribe a calorie intake.
Can this tool tell me how many calories to eat to lose weight?
No. A general formula cannot safely set a personal calorie target. Ask a qualified clinician or registered dietitian for personal guidance.
Why can calorie estimates be wrong?
Formulas use population averages and cannot capture every person's body composition, health, activity or changes over time. Treat the result as context, not a diagnosis or prescription.
Sources & further reading
- Mifflin MD, St Jeor ST, et al., resting energy expenditure equation.
- NIDDK: Maintaining a healthy weight