How to use this Calorie calculator
- Enter the sex equation, adult age, body weight and height.
- Choose the activity assumption that best represents your overall day.
- Choose a scenario and select Calculate. Compare the estimate with your observed intake, weight trend, recovery and performance over time.
The formula and method
The starting estimate is simplified Mifflin–St Jeor: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, with +5 for the male equation or −161 for the female equation.
Estimated maintenance = resting expenditure × your selected activity multiplier. The five multipliers range from 1.2 to 1.9 and are broad assumptions, not measurements of your activity.
The maintenance scenario uses that estimate unchanged. The deficit scenario multiplies it by 0.85; the surplus scenario multiplies it by 1.10. Those settings are illustrative arithmetic choices, not a claim that either adjustment is right for everyone.
Worked example
A 30-year-old active male weighing 80 kg at 180 cm has an estimated BMR of 1,780 kcal. With moderate activity (1.55 multiplier), his TDEE is approximately 2,759 kcal/day. For steady fat loss, a 15% deficit yields an intake target of roughly 2,345 kcal/day.
Understanding the estimate
- The formula estimates a starting point; actual expenditure varies between people and from day to day.
- The tool does not predict a guaranteed weekly rate of weight change or calculate a personal minimum safe intake.
- It is not intended to manage pregnancy, eating-disorder recovery or a medical condition.
Frequently asked questions
Why is the deficit set to 15%?
It is a clearly labeled scenario to demonstrate the effect of an adjustment. You can compare it with maintenance; it is not an individualized recommendation.
Does a calorie surplus guarantee muscle gain?
No. This tool performs energy arithmetic. Training, recovery, individual circumstances and changes in body composition affect the outcome.
Why might my real maintenance differ?
The resting equation and activity multiplier are estimates. Food records and weight trends also contain measurement noise, so compare trends rather than a single day.