Daily energy simulator: TDEE and optional scenarios
This tool shows your estimated daily energy use (TDEE) as a baseline and lets you view scenarios if you choose. All numbers are general-formula estimates to help you understand, not personalised advice on how much to eat.
What the result means
This tool starts from the energy your body uses in a day (TDEE): resting energy (BMR) multiplied by an activity factor. It is a baseline, not an amount you must eat.
If you choose to view a scenario, it shows the numbers for eating 300 or 500 kcal less than TDEE, or about 10% more, only to illustrate an energy change. It is not a recommended target, not personalised advice to eat less or more, and does not mean a 300/500 kcal cut suits everyone.
No eat-less scenario is shown when BMI is below 23, when the result falls below the stopping point (the higher of BMR or 1,200 kcal for women / 1,500 for men), or when you have a health condition. The stopping point is not a safe amount for everyone.
How it is calculated
- Step 1: resting energy (BMR) from the Mifflin-St Jeor equation. Male = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 · Female = … − 161
- Step 2: TDEE = BMR × activity multiplier (1.2 / 1.375 / 1.55 / 1.725 / 1.9), rounded to the nearest 10
- Scenarios (optional): TDEE − 300 · TDEE − 500 · TDEE × 1.10, rounded to the nearest 10
- No eat-less scenario when BMI is below 23 (Thai adult criteria: 18.5–22.9 normal) or the result is below max(BMR, 1,200 women / 1,500 men) · no scenarios at all with a health condition or weight-affecting medicine
- Pounds/inches are converted first per NIST SP 811
Limitations and cautions
- Equation-based estimate using a self-rated activity level; real needs can differ by several hundred kcal
- Scenarios are not personalised advice on how much to eat, and the 1,200 / 1,500 kcal stopping point is not safe or right for everyone. Larger or very active people, older adults and people with health conditions may need much more
- Not for under-18s, pregnancy or breastfeeding, or people with a history of eating disorders · with a health condition or weight-affecting medicine, the tool shows TDEE only
- Weight responds slowly to energy changes and the rate slows over time (Hall 2011), so weekly figures are rough early estimates only
- This tool does not recommend foods or products and is not a treatment plan
Results are estimates or basic screening only, not a medical diagnosis or medical advice.
Related articles
- What is a calorie deficit? Eating less energy than you use, in a way you can keep up ›
- How to manage your weight the healthy way: 5 practical tips ›
- Does a slow metabolism cause weight gain? Facts about how you burn energy ›
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References
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51:241–247 ↗ (opens in a new tab)
- MSD Manuals: Mifflin-St Jeor Equation medical calculator (checked 9 Oct 2026) ↗ (opens in a new tab)
- Bureau of Nutrition, Department of Health (Thailand): Indicator 3.12 report (2022), p. 4 — adult BMI cut-offs used in Thailand (checked 9 Oct 2026) ↗ (opens in a new tab)
- NHLBI/NIH: The Practical Guide — Identification, Evaluation, and Treatment of Overweight and Obesity in Adults, pp. 13 and 29 (checked 16 Oct 2026) ↗ (opens in a new tab)
- Harvard Health Publishing: Calorie counting made easy — intake should not fall below 1,200 (women) or 1,500 (men) kcal a day without professional supervision (checked 16 Oct 2026) ↗ (opens in a new tab)
- Hall KD, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet 2011;378:826–837 ↗ (opens in a new tab)
- Iraki J, et al. Nutrition Recommendations for Bodybuilders in the Off-Season: A Narrative Review. Sports (Basel) 2019;7:154 ↗ (opens in a new tab)
- NIST SP 811 Appendix B.8 — unit conversion factors ↗ (opens in a new tab)
Compiled by Well Nutrition Hub from the sources listed. Content last reviewed 16 Oct 2026.