Basal Metabolic Rate is the energy your body uses at complete rest to maintain basic functions breathing, circulation, cell production and temperature regulation. It typically accounts for 60 to 70% of total daily energy expenditure. Most calculators estimate it using the Mifflin St Jeor equation.

What's the difference between BMR, RMR and TDEE?

BMR is measured at complete rest under strict laboratory conditions. RMR is measured under less strict conditions and comes out slightly higher. TDEE is total daily energy expenditure BMR multiplied by an activity factor, covering everything you burn in a day.

Which BMR formula is most accurate?

Mifflin St Jeor for most people. The Academy of Nutrition and Dietetics formally recommended it in 2005 as the preferred method for healthy adults, and it's accurate to within about ±10% of measured values. Katch McArdle is more accurate if you have a reliable body fat measurement. Harris Benedict, from 1919, tends to overestimate by 5 to 15%.

How accurate are BMR calculators?

Within roughly ±10% for most adults about 87% of the time for non obese adults, 80% for underweight and 75% for people with obesity. On a BMR of 1,400 calories, that's a range of about 1,260 to 1,540. Treat the result as a starting point and adjust based on what you observe over several weeks.

No. BMR is what your body needs at complete rest it doesn't account for any movement during the day. If you're modelling intake, TDEE is the relevant number. Eating at BMR would put most people well below their actual needs.

What's the lowest safe calorie intake?

Commonly cited minimums are around 1,200 calories a day for women and 1,500 for men, and even those warrant professional supervision. Below those levels it becomes difficult to meet nutrient requirements, and risks including muscle loss, hormonal disruption and gallstones increase. This calculator won't display a target below those floors.

Why does my smartwatch show a different number?

Wearables estimate expenditure from heart rate, motion and your profile using proprietary algorithms, and different devices report different things some active calories, some total. Their error margins are substantial. For resting metabolism, a formula based estimate is generally more stable; for tracking relative change day to day, wearables are useful.

Does metabolism slow with age?

Gradually, though less dramatically than commonly believed. Much of the observed decline reflects changes in body composition particularly loss of muscle mass rather than metabolism itself slowing. Maintaining muscle through resistance training offsets a meaningful part of it.

Should I use metric or imperial?

Either the calculator converts. The formulas are defined in metric, so imperial inputs are converted to kilograms and centimetres before calculation. Canadians commonly give height in feet and inches and weight in pounds, and that works fine here.

What's the difference between a dietitian and a nutritionist?

'Dietitian' is a protected title regulated by a provincial college in every Canadian province it requires an accredited degree, supervised practical training, and accountability to a professional body. 'Nutritionist' is not protected in most provinces, so anyone can use it. For clinical guidance, look for a registered dietitian.

Is this calculator free?

Yes. No account, no email, no limits and we don't sell supplements, meal plans or weight loss programmes.

BMR Calculator Canada

Your basal metabolic rate is the energy your body uses at complete rest before you get out of bed, before you eat, before you move.

Enter your details in metric or imperial and we'll estimate it using the formula dietitians actually use, along with the accuracy range you should know about before relying on the number.

BMR Calculator Canada

Gender

Age

Unit System

Feet

Inches

Weight (lbs)

Your Basal Metabolic Rate (BMR)

1737

Calories / Day at complete rest

Hourly Burn Rate: ~72.4 kcal / hour · Harris-Benedict Eq: 1804 kcal/day

Total Daily Energy Expenditure (TDEE) by Activity

Activity Level	Multiplier	Daily Calories (kcal)
Sedentary (little or no exercise)	1.2x	2084 kcal
Lightly Active (1-3 days/week)	1.375x	2388 kcal
Moderately Active (3-5 days/week)	1.55x	2692 kcal
Very Active (6-7 days/week)	1.725x	2996 kcal
Extra Active (physical job / 2x training)	1.9x	3300 kcal

Your Basal Metabolic Rate (BMR) represents the amount of energy your body expends while at rest in a neutrally temperate environment. Calculated using the Mifflin-St Jeor formula endorsed by Dietitians of Canada.

What BMR Actually Is

Basal metabolic rate is the energy your body uses to keep you alive at complete rest breathing, circulating blood, producing cells, maintaining body temperature, running your brain.

It's the largest part of what you burn. For most people BMR accounts for roughly 60 to 70% of total daily energy expenditure. Everything else moving around, exercising, digesting food sits on top of it.

It's measured under strict conditions. A true BMR measurement requires an overnight fast, complete rest, and a thermally neutral environment. Almost nobody has had this done. What a calculator gives you is an estimate of that number, derived from population data.

BMR, RMR and TDEE

BMR (Basal)

Energy at complete rest, measured under strict laboratory conditions.

RMR (Resting)

Measured under less strict conditions, slightly higher. Generally treated as interchangeable.

TDEE (Total Expenditure)

Total daily energy: BMR × activity multiplier. This is what determines your daily caloric needs.

The Formulas, and Which to Use

Mifflin St Jeor (The Preferred Default)

Recommended by the Academy of Nutrition and Dietetics in 2005. Performs most consistently across all body types.

Men: BMR = (10 × weight in kg) + (6.25 × height in cm) minus (5 × age) + 5

Women: BMR = (10 × weight in kg) + (6.25 × height in cm) minus (5 × age) minus 161

Harris Benedict (Historical Standard)

Published in 1919, revised in 1984. Tends to overestimate by 5 to 15% for modern sedentary adults.

Katch McArdle (If You Know Lean Body Mass)

BMR = 370 + (21.6 × lean body mass in kg). Highly accurate for athletes and individuals with DEXA body fat scans.

Activity Multipliers

Level	Multiplier	Roughly means
Sedentary	1.2	Desk job, little exercise
Lightly active	1.375	Light exercise 1 to 3 days per week
Moderately active	1.55	Moderate exercise 3 to 5 days per week
Very active	1.725	Hard exercise 6 to 7 days per week
Extra active	1.9	Physical job plus training

Why Use the CalcVault BMR Calculator

3 Recognized FormulasMifflin St Jeor, Harris Benedict, and Katch McArdle with lean mass.

Realistic Accuracy RangesShows ±10% clinical error bands so you understand the numbers.

Safety Calorie FloorsRespects 1,200/1,500 kcal minimum safety limits to protect your health.

Metric & ImperialSupports kg/cm and lbs/ft inches seamlessly.

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BMR Calculator FAQs

Sources, Review and Support

Sources: Mifflin MD, St Jeor ST, et al. (1990), Harris JA, Benedict FG (1919), Academy of Nutrition and Dietetics evidence-based recommendations, Health Canada, Dietitians of Canada.

NEDIC Support: National Eating Disorder Information Centre helpline: 1 866 NEDIC 20 (1 866 633 4220) toll free. Kids Help Phone: 1 800 668 6868.

Disclaimer: CalcVault is not a healthcare provider. This tool provides educational estimates, not medical or nutritional advice.

BMR Calculator Canada

BMR Calculator Canada

Total Daily Energy Expenditure (TDEE) by Activity

What BMR Actually Is

BMR, RMR and TDEE

The Formulas, and Which to Use

Mifflin St Jeor (The Preferred Default)

Harris Benedict (Historical Standard)

Katch McArdle (If You Know Lean Body Mass)

Activity Multipliers

Why Use the CalcVault BMR Calculator

Related Calculators

CPI Inflation Calculator Canada

RESP Calculator Canada

Child Benefit Calculator

BMR Calculator FAQs

What is BMR?

What's the difference between BMR, RMR and TDEE?

Which BMR formula is most accurate?

How accurate are BMR calculators?

Should I eat my BMR?

What's the lowest safe calorie intake?

Why does my smartwatch show a different number?

Does metabolism slow with age?

Should I use metric or imperial?

What's the difference between a dietitian and a nutritionist?

Is this calculator free?

Sources, Review and Support