RMR Calculator

What is RMR Calculator?

RMR Calculator (Resting Metabolic Rate Calculator) measures the calories your body burns at rest for essential functions like breathing, circulation, and maintaining body temperature. It's similar to BMR but measured in less controlled conditions (e.g., sitting quietly vs. lying fasted). RMR comprises 60-75% of daily energy expenditure, guiding nutrition for weight management, athletic performance, and health. In 2025, with 42% U.S. adult obesity (CDC), understanding RMR helps tailor diets—e.g., exceed for gain, deficit for loss—while preventing metabolic slowdown from crash dieting.

This calculator uses the Harris-Benedict equation, validated for accuracy in adults:

  • Men: RMR = 88.362 + (13.397 × weight kg) + (4.799 × height cm) - (5.677 × age)
  • Women: 447.593 + (9.247 × weight kg) + (3.098 × height cm) - (4.330 × age)

Input age, gender, height (inches), weight (lbs) for RMR and estimated TDEE (with activity). Outputs in calories; adjust for goals (±500 cal). Accurate ±10-15%; for precision, lab testing recommended.

How to Use RMR Calculator

  1. Inputs: Age, gender, height, weight.
  2. Formula: Converts to metric, applies Harris-Benedict for RMR.
  3. TDEE: RMR × activity multiplier (sedentary 1.2; super active 1.9).
  4. Goals: Loss (RMR-500), Maintenance, Gain (RMR+500).

Sample: 30-year-old man, 5'10" (70 in), 180 lbs. RMR: ~1,780 cal. TDEE (moderately active): ~2,759 cal.

Factors Affecting RMR

  • Muscle Mass: +5-10 cal/lb muscle; resistance training boosts 5-7%.
  • Age: Drops 1-2% yearly after 30 (muscle loss).
  • Hormones: Thyroid regulates; hypothyroidism lowers 20-30%.
  • Diet: Crash diets reduce 15-20%; high-protein preserves.
  • Environment: Cold increases 5-10% (shivering); altitude raises 10%.

Tips to Boost RMR

  • Build Muscle: Lift weights 3x/week; gain 1 lb muscle = +50 cal/day burn.
  • Eat Protein: 1.6g/kg; thermic effect 20-30% (vs. carbs 5-10%).
  • Spice Up Meals: Capsaicin (chili) raises 8%; green tea catechins +4%.
  • Stay Active: NEAT (fidget/walk) adds 300-500 cal; HIIT spikes 10-15%.
  • Sleep Well: 7-9 hrs; poor sleep drops 5-20%. Avoid prolonged fasting.

Frequently Asked Questions

RMR vs. BMR?

  • RMR: Measured sitting (less strict); BMR: Lying fasted (~10% lower). Often used interchangeably.

How Accurate?

  • Formulas ±10%; lab RMR (indirect calorimetry) gold standard ($100-300).

For Weight Loss?

  • Set deficit 300-500 cal below TDEE; track weekly—adjust if plateau.

Athletes?

  • Higher RMR (muscle); recalculate post-gains.

Minimum Calories?

  • Women 1,200/1,500 men; below risks nutrient gaps, metabolism drop.

Disclaimers

RMR calculator Estimates only—not medical advice. Harris-Benedict approximates; inaccurate for obese/underweight/extremes. Consult doctor for conditions (e.g., thyroid). CDC/ACSM data (2025). No liability.

Fuel your metabolism—calculate RMR.

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