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Weight Loss Tool

Resting Metabolic
Rate Calculator

Calculate your resting calorie burn using the scientifically validated Mifflin-St Jeor equation — the gold standard for weight loss planning.

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Your Measurements

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kg
cm

What is RMR & Why It Matters for Weight Loss

Your Resting Metabolic Rate (RMR) is the total number of calories your body burns while at complete rest to sustain essential life functions — including breathing, blood circulation, organ function, and cellular repair. RMR represents the single largest component of your daily calorie expenditure, accounting for 60–75% of all calories burned in a typical day.

For anyone focused on weight loss, understanding your RMR is not optional — it is the foundational number that governs every calorie decision you make. Without knowing how many calories your body needs at rest, any diet plan is guesswork. Your RMR sets the absolute minimum calorie floor: eating below your RMR for extended periods triggers adaptive thermogenesis, slowing your metabolism and accelerating muscle loss.

The scientifically sound approach is to first calculate your RMR (which you've done here), then multiply it by an activity factor to find your Total Daily Energy Expenditure (TDEE), and finally eat 300–500 calories below that TDEE number. This protects your lean muscle mass while still creating a fat-burning deficit. To check your body composition starting point, use our BMI calculator or body fat calculator.

For those on a caloric deficit, protein intake becomes critical. A high-quality protein source like SUPPS Isolate Whey Protein helps you preserve lean muscle tissue while losing fat — ensuring your weight loss comes from the right places.

The Mifflin-St Jeor Formula Explained

This RMR calculator uses the Mifflin-St Jeor equation, published in 1990 by Mifflin MD, St Jeor ST, and colleagues. It is recognized by the American Dietetic Association as the most accurate predictive equation for estimating resting metabolic rate in healthy, non-obese and obese individuals alike. It has become the preferred formula over the older Harris-Benedict equation due to its improved accuracy across diverse modern populations.

For Men:

RMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5

For Women:

RMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

Note: These formulas estimate resting metabolic activity only. To determine the total calories you burn each day (including exercise, walking, and digestion), multiply your RMR by an activity factor or use our TDEE calculator.

RMR vs. BMR: What's the Difference?

RMR (Resting Metabolic Rate) and BMR (Basal Metabolic Rate) are often used interchangeably, but they are technically different measurements:

  • RMR (Resting Metabolic Rate)

    Measured under normal resting conditions, making it more practical and slightly higher (~3–5%) than BMR. Uses the Mifflin-St Jeor equation (1990), recommended by the American Dietetic Association for modern populations.

  • BMR (Basal Metabolic Rate)

    Measured under strict laboratory conditions (12+ hour fast, complete darkness, thermal neutrality). Commonly uses the Harris-Benedict equation. Calculate yours with our BMR calculator.

For practical dieting and weight loss purposes, RMR is the more useful measurement because it reflects real-world resting conditions. The Mifflin-St Jeor formula has been validated against indirect calorimetry and shown to predict RMR within 10% for a large majority of individuals.

How to Use Your RMR for Sustainable Weight Loss

Your RMR is the starting line of any effective weight loss program. Here is a step-by-step framework to turn your RMR number into an actionable fat loss plan:

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Calculate Your TDEE

Multiply your RMR by your activity level (1.2 – 1.9) to find your Total Daily Energy Expenditure. This is the number of calories you burn every day including all movement.

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Create a Moderate Deficit

Subtract 300–500 calories from your TDEE. This creates a sustainable deficit that promotes ~0.25–0.5 kg of fat loss per week without metabolic adaptation or muscle catabolism.

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Never Eat Below Your RMR

Eating below your RMR triggers hormonal stress responses, muscle catabolism, and metabolic slowdown. Your RMR is the safety floor — your deficit should come from TDEE, not from going below RMR.

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Prioritize Protein

Aim for 1.6–2.2g of protein per kg of body weight. Use our Protein Calculator to find your exact target. Supplement with SUPPS Isolate to hit your daily goal conveniently.

How to Boost Your Resting Metabolic Rate

While age, genetics, and height are fixed, several evidence-backed strategies can increase your resting metabolism:

  • 1. Build Lean Muscle Mass: Muscle tissue is significantly more metabolically active than fat tissue. For every kilogram of muscle you add, your RMR increases by an estimated 13 kcal/day. Prioritize compound exercises (squats, deadlifts, bench press) and use our One-Rep Max Calculator to track progressive overload.
  • 2. Increase Protein Intake: Protein has the highest thermic effect of food (TEF) — your body uses 20–30% of protein calories just to digest it, compared to 5–10% for carbs and 0–3% for fats. A high-protein diet with SUPPS Isolate Whey boosts your metabolism through digestion alone.
  • 3. Support Training Intensity: Higher intensity workouts cause greater post-exercise oxygen consumption (EPOC), which elevates your metabolic rate for hours after training. Power through harder sessions with a clean pre-workout formula for sustained energy without unnecessary calories.
  • 4. Protect Muscle During Training: Catabolism during long training sessions reduces lean mass and RMR over time. Using Athena EAA intra-workout provides essential amino acids that defend muscle fibers from breakdown.
  • 5. Supplement with Creatine: SUPPS Creatine supports ATP regeneration during resistance training, enabling you to lift heavier and build more muscle — directly increasing your resting metabolic rate.

Fuel Your Weight Loss Journey

Reaching your calorie targets is easier with the right supplements. From high-protein recovery to zero-calorie workout fuel, explore SUPPS' science-backed formulas engineered for results.

Frequently Asked Questions

What is RMR?

RMR (Resting Metabolic Rate) is the number of calories your body burns while at rest to maintain vital functions such as breathing, circulating blood, and cell production. It accounts for roughly 60–75% of total daily calorie expenditure.

How is RMR different from BMR?

BMR is measured under strict lab conditions (12+ hour fast, darkness), while RMR is measured under normal resting conditions. RMR is slightly higher and more practical for diet planning. This calculator uses the Mifflin-St Jeor equation for RMR, while our BMR calculator uses Harris-Benedict.

How do I use RMR to lose weight?

Multiply your RMR by an activity factor to find your TDEE. Eat 300–500 kcal below your TDEE to lose 0.25–0.5 kg per week. Never eat below your RMR — this causes metabolic slowdown and muscle loss. Pair your deficit with high-protein intake using SUPPS Isolate.

Can I increase my resting metabolic rate?

Yes. The most effective method is building lean muscle through resistance training, since muscle burns more calories at rest than fat. High-protein diets, quality sleep, and supplements like creatine and EAAs support this process.

What formula does this calculator use?

This calculator uses the Mifflin-St Jeor equation (1990), recommended by the American Dietetic Association. Men: (10 × kg) + (6.25 × cm) − (5 × age) + 5. Women: (10 × kg) + (6.25 × cm) − (5 × age) − 161.

Why does RMR decrease with age?

Aging naturally reduces muscle mass (sarcopenia) and alters hormone levels, lowering RMR. Regular strength training, adequate protein, and supplements like EAAs and creatine can help counteract this decline.

Scientific References

  • [1]
    Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO: A new predictive equation for resting energy expenditure in healthy individuals. The American Journal of Clinical Nutrition, 1990;51(2):241–247. This landmark study established the Mifflin-St Jeor equation, now considered the gold standard for RMR estimation.
  • [2]
    Frankenfield D, Roth-Yousey L, Compher C: Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults. Journal of the American Dietetic Association, 2005;105(5):775–789. This meta-analysis confirmed the Mifflin-St Jeor equation as the most accurate predictor of RMR across diverse populations.
  • [3]
    Westerterp KR: Diet induced thermogenesis. Nutrition & Metabolism, 2004;1:5. This research documented the thermic effect of food (TEF) across macronutrients, establishing protein's superior metabolic impact at 20–30% TEF.