Plan your next step
Free fitness calculators for maintenance calories, exercise energy and adult BMI. Choose a tool, enter your measurements and get an estimate with a clear explanation.
Daily calorie needs
Estimate maintenance energy needs for adults 18 and older.
How this estimate works
We use the Mifflin–St Jeor resting-energy equation: 10 × weight in kg + 6.25 × height in cm − 5 × age, then +5 (male) or −161 (female). We multiply by your selected activity factor to estimate maintenance calories. The binary sex constants are a limitation of the original equation.
Activity categories are rough estimates. Track your energy, training and weight trend over several weeks before adjusting. Do not add exercise calories again if they are already represented by your activity level.
Original Mifflin–St Jeor study · NIDDK weight-planning guidance
Next step: build a repeatable beginner workout plan.
Exercise calories burned
Estimate total energy used during a session, including resting energy.
How exercise calories are estimated
Calories = MET × 3.5 × body weight in kilograms ÷ 200 × minutes. MET values describe typical activity intensity, not your personal measured effort. Terrain, rest periods and fitness can change actual energy use substantially.
These are gross calories, including what your body would use at rest. They are not a precise food allowance.
Next step: explore the beginner cardio guide.
Adult BMI calculator
For adults age 20 and older. BMI is a screening measure, not a diagnosis.
Understanding BMI
BMI = weight in kilograms ÷ height in metres squared. Adult categories: below 18.5 underweight; 18.5 to below 25 healthy weight; 25 to below 30 overweight; 30 or more obesity. BMI does not distinguish muscle from fat or describe fat distribution. It should be interpreted alongside other health information.
Children and teenagers need age-specific assessment. Read the CDC adult BMI guidance.
Next step: choose an achievable beginner fitness routine.
These tools provide general estimates. Calorie planning is not intended for pregnancy, breastfeeding, eating-disorder management or personalised medical care. Ask a qualified professional when these circumstances apply. Results are calculated in your browser; no measurements are saved by these calculators.