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Health Calculator • Ages and inputs vary

BMR Calculator

Estimate basal metabolic rate.

Browser-Side • No Sign-Up • Instant Result
Adult age in years.
Used by the Mifflin-St Jeor formula.
Enter body weight in kilograms.
Enter height in centimeters.
Tip: Enter clean values and keep units consistent. The calculator starts empty and updates the live result panel after calculation.
Reviewed August 6, 2026. The calculator interface, result labels, calculation guidance, examples, and limitations were checked by the FreeToolLabs Editorial Team. This page provides an educational estimate. It does not diagnose a condition or replace advice from a qualified healthcare professional.
Prepared and reviewed by FreeToolLabs Editorial TeamLast reviewed: August 6, 2026

What Is a BMR Calculator and How Does It Work?

A BMR Calculator helps users estimate basal metabolic rate, the calories the body may use at rest. This page uses Age, Gender, Weight (kg), and Height (cm) to produce Daily calories, Weekly calories, Formula, Weight, Height, and Status. The calculation runs in the browser, so users can change one input at a time and immediately compare a new scenario without creating an account.

The tool is designed around the specific meaning of BMR Calculator, not a generic one-number estimate. It keeps the entered values, the main answer, and the supporting results together so the method is easier to follow and verify. For a related comparison, the Macro Calculator Plan daily protein, carbs, and fat targets. may provide another useful perspective.

How to Use This BMR Calculator

  1. Enter or select Age using the unit or format shown on the page.
  2. Enter or select Gender using the unit or format shown on the page.
  3. Enter or select Weight (kg) using the unit or format shown on the page.
  4. Enter or select Height (cm) using the unit or format shown on the page.
  5. Select the main calculate or start button.
  6. Review Daily calories, Weekly calories, Formula, Weight, Height, and Status in the live result panel.

Use values that belong to the same situation, date, project, account, or person. Do not mix units or combine assumptions from different scenarios. Empty fields should be completed only when they apply to the calculation.

The BMR Formula: How the Result Is Calculated

Mifflin–St Jeor: men = 10W + 6.25H − 5A + 5; women = 10W + 6.25H − 5A − 161, with weight in kilograms, height in centimeters, and age in years

Mifflin–St Jeor: men = 10W + 6.25H − 5A + 5; women = 10W + 6.25H − 5A − 161, with weight in kilograms, height in centimeters, and age in years

The calculator applies the formula or procedure to the entered values and then rounds the displayed answer for readability. Intermediate values may retain greater precision, so manually rounded inputs can produce a slightly different final number.

Understanding Your BMR Estimate and Supporting Results

estimated daily and weekly resting calories together with the formula and measurements used. The live result panel also displays Daily calories, Weekly calories, Formula, Weight, Height, and Status. Read those values together rather than relying only on the largest number.

Supporting metrics are included to show the calculation context. When a result seems unexpected, check the unit system, signs, dates, rates, percentages, and optional fields before changing the conclusion.

How Accurate Is the BMR Calculator?

BMR is an estimate; body composition, illness, medication, hormones, pregnancy, and individual metabolism can produce different needs. The formula can be mathematically correct while the real-world result remains approximate because measurements, future rates, timing, product specifications, personal conditions, or external rules may differ.

For important decisions, compare the estimate with original records, product documentation, professional guidance, or an official calculator that applies to the exact situation.

BMR Calculation Examples

Worked example

A 35-year-old woman weighing 65 kg at 165 cm is evaluated by substituting those values into the Mifflin–St Jeor equation.

A 35-year-old woman weighing 65 kg at 165 cm is evaluated by substituting those values into the Mifflin–St Jeor equation.

Checking a second scenario

Repeat the calculation after changing only one important input. This makes it easier to see which value has the greatest effect and helps detect an accidental unit, date, rate, or decimal-entry error.

Limitations and Responsible Use of the BMR Calculator

This calculator provides an educational estimate and does not diagnose a medical condition or replace guidance from a qualified healthcare professional.

Important: Keep the inputs and assumptions with the result. A calculator can organize arithmetic consistently, but it cannot confirm that every measurement, rate, rule, health condition, project condition, or future event has been included.
Authoritative references

Official resources for BMR Calculator

Use these official resources to verify definitions, assumptions, and current guidance. The tool provides an estimate and is not a substitute for personalized professional advice.

Frequently Asked Questions About the BMR Calculator

The BMR Calculator is designed to estimate basal metabolic rate, the calories the body may use at rest. It shows Daily calories, Weekly calories, Formula, Weight, and Height so the answer can be reviewed in context.
Enter Age, Gender, Weight (kg), and Height (cm). Use values from the same scenario and keep units consistent with the labels shown beside each field.
Mifflin–St Jeor: men = 10W + 6.25H − 5A + 5; women = 10W + 6.25H − 5A − 161, with weight in kilograms, height in centimeters, and age in years
Review the main result together with Daily calories, Weekly calories, Formula, Weight, and Height. Supporting values help explain what was included and make input mistakes easier to identify.
The arithmetic follows the stated method, but the practical accuracy depends on the inputs and assumptions. BMR is an estimate; body composition, illness, medication, hormones, pregnancy, and individual metabolism can produce different needs
Other tools may use different formulas, defaults, rounding, unit conversions, timing conventions, or assumptions. Compare the exact inputs and method before treating two results as inconsistent.
This calculator provides an educational estimate and does not diagnose a medical condition or replace guidance from a qualified healthcare professional.
Measure or enter each value carefully, confirm units and dates, review every option, and repeat the calculation after correcting uncertain inputs. Keep a copy of the assumptions when comparing scenarios.

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