BMR Calculator
Use your own numbers after reviewing the formula and worked example.
Quick answer
BMR estimates energy used at rest; a daily energy estimate multiplies BMR by an activity factor.
Formula or method
Keep units, percentages and time periods consistent. The formula is useful as a transparent check on the calculator result and helps explain why changing one input changes the answer.
Step-by-step
- Estimate BMR.
- Choose an activity level.
- Multiply BMR by the factor.
- Treat the result as a starting estimate.
Worked example
If BMR is 1,500 kcal/day and activity factor is 1.55, estimated daily energy is about 2,325 kcal/day.
How to interpret the result
Energy equations are population estimates; actual needs vary with body composition, activity, health and other factors.
When the answer is used for a purchase, loan, payroll decision, construction order, school grade, health estimate or other real-world choice, verify the assumptions that matter in that context. Accurate arithmetic still depends on accurate inputs.
Common mistakes
- Calling BMR total daily needs.
- Choosing activity factor from one workout only.
- Treating the result as exact.
Authoritative reference
The BMR equation is predictive rather than a direct measurement; activity multipliers add additional estimation.
Frequently asked questions
Is BMR what I should eat?
Not necessarily.
What is an activity multiplier?
A factor used to estimate total daily energy from resting energy.
Are calorie calculators exact?
No.