Why two BMR calculators can give different answers
Before comparing results, check the equation, units and whether an activity multiplier has already been applied.
BMR calculator →Check which equation is being used
The simplified equation on this site adds 5 for its male parameters and subtracts 161 for its female parameters. With the same age of 30, weight of 70 kg and height of 175 cm, those versions give 1648.75 and 1482.75 kcal per day. Their 166 kcal difference comes from the constants. The equation grouping is a modeling choice and does not describe every individual physiological situation.
Check what the output represents
Another site may multiply a resting value by an activity factor and label the result broadly as calorie needs. For example, 1482.75 × 1.2 = 1779.3. That larger number is a different estimate, not necessarily an error in the resting formula. Also inspect centimetres versus inches, kilograms versus pounds and the age convention. Comparing outputs without matching their inputs can conceal a simple mismatch.
Agreement has a limited meaning
Two calculators using the same formula should agree within rounding, but agreement does not prove that either predicts an individual precisely. Actual energy expenditure can differ from equation estimates. Use these tools to understand assumptions rather than to choose whichever number best matches a desired diet. If precise assessment matters, discuss an appropriate measurement or clinical evaluation with a qualified professional.
Try the calculators
- BMR calculator
Estimate resting energy with Mifflin–St Jeor.
- Calorie calculator
Estimate maintenance energy for your activity level.
- BMI calculator
Calculate body mass index from height and weight.