# Resting Metabolic Rate Calculator Calculate the calories your body burns daily at complete rest using proven, science-based metabolic rate estimation models and formulas. --- - **Canonical URL:** https://dothecalculation.com/calculators/rmr-calculator - **Category:** Health and fitness - **Publisher:** Do The Calculation (https://dothecalculation.com) - **Cost:** Free, no account or sign-up required - **Privacy:** Runs entirely in the browser; inputs are never sent to a server - **Methodology:** https://dothecalculation.com/methodology - **Reviewed by:** Dr. Robert Chen, PhD, PhD in Nutritional Science, UC Berkeley (https://dothecalculation.com/about/team/robert-chen) --- ## Calculate your Resting Metabolic Rate Estimate your Resting Metabolic Rate (RMR) using the clinical Harris-Benedict equation, reflecting your baseline calorie burn. - Resting metabolic rate baseline - Harris-Benedict formula estimates - Daily calorie maintenance guidelines ## Understanding Resting Metabolic Rate (RMR) Your Resting Metabolic Rate (RMR) is the number of calories your body burns at rest to maintain basic physiological processes (respiration, circulation, temperature control, organ function). While BMR requires strict fasting and laboratory rest conditions, RMR is measured under less restrictive conditions, typically yielding slightly higher results (by 5-10%). This tool estimates RMR using the **Mifflin-St Jeor equation**, and layers in the **Katch-McArdle equation** whenever you provide a body fat percentage, since a lean-mass-based formula is more accurate for muscular or leaner individuals. ## The Mifflin-St Jeor and Katch-McArdle Formulas To calculate RMR from total body weight, apply the Mifflin-St Jeor equation for men and women: $$\text{Men: RMR} = 10 \times \text{Weight (kg)} + 6.25 \times \text{Height (cm)} - 5 \times \text{Age (years)} + 5$$ $$\text{Women: RMR} = 10 \times \text{Weight (kg)} + 6.25 \times \text{Height (cm)} - 5 \times \text{Age (years)} - 161$$ If you provide a body fat percentage, the calculator instead computes your Lean Body Mass (LBM) and applies the Katch-McArdle equation, which strips out fat mass since fat tissue is far less metabolically active than muscle: $$\text{LBM (kg)} = \text{Weight (kg)} \times \left(1 - \frac{\text{Body Fat \%}}{100}\right)$$ $$\text{RMR (Katch-McArdle)} = 370 + 21.6 \times \text{LBM (kg)}$$ These formulas demonstrate how metabolic rate scales with mass: heavier and taller individuals require more energy to sustain basic tissues, while metabolic rate naturally declines with age due to muscle mass loss. ## BMR vs. RMR: The Key Differences BMR and RMR are often used interchangeably, but they differ in measurement protocols. BMR requires the subject to be in a post-absorptive state (fasted 12 hours) and measured immediately upon waking in a clinical setting. RMR is measured at rest but does not require strict fasting or sleeping overnight at the facility, making it slightly higher due to the lingering thermic effect of food and mild physical movement. ## Using RMR to Structure Daily Calorie Goals To find your total maintenance calories, multiply your RMR by an activity factor (similar to TDEE). Never consume fewer calories than your RMR for extended periods; extreme deficits cause the body to burn muscle tissue for fuel and adaptively slow metabolic rate. ## How to Use This Calculator Enter your weight in kilograms, height in centimeters, age in years, and select your gender. Optionally enter a body fat percentage: if provided, the calculator adds a Katch-McArdle lean-mass estimate alongside the standard Mifflin-St Jeor figure, which is generally more accurate for people who know their body composition. ## Worked Example: 70 kg, 175 cm, 30-Year-Old Male Weight 70 kg, height 175 cm, age 30, male, body fat percentage not provided. Mifflin-St Jeor: \(10 \times 70 + 6.25 \times 175 - 5 \times 30 + 5 = 700 + 1093.75 - 150 + 5 = 1{,}648.75\) kcal/day. Since no body fat percentage was entered, the Katch-McArdle estimate is not shown — adding one (say, 15%) would instead compute LBM of \(70 \times 0.85 = 59.5\) kg and an RMR of \(370 + 21.6 \times 59.5 \approx 1{,}655\) kcal/day, a close match here since 15% body fat is near this person's implied composition. ## Related Calculators Compare this resting baseline to your full daily burn with the [TDEE calculator](/calculators/tdee-calculator), or check your BMR estimate with the [BMR calculator](/calculators/bmr-calculator). ## Frequently asked questions ### What is Resting Metabolic Rate (RMR)? RMR is the number of calories your body burns at rest to perform vital life-sustaining processes (breathing, heartbeats, cellular repair). ### How is RMR calculated? The calculator uses the Mifflin-St Jeor equation, which factors in sex, age, height, and weight, plus the Katch-McArdle equation using lean body mass if you provide a body fat percentage. ### How does RMR differ from BMR? BMR requires strict fasting and overnight rest in a laboratory. RMR is measured under less restrictive conditions and is typically 5-10% higher. ### Can I increase my RMR? Yes. Building lean muscle mass through resistance training is the most effective way to permanently raise RMR, as muscle is more metabolically active than fat. ### What is the Mifflin-St Jeor equation for men? RMR = 10 × Weight (kg) + 6.25 × Height (cm) - 5 × Age (years) + 5. ### What is the Mifflin-St Jeor equation for women? RMR = 10 × Weight (kg) + 6.25 × Height (cm) - 5 × Age (years) - 161. ### How does age affect my resting metabolism? RMR naturally declines with age, primarily because muscle mass decreases (sarcopenia). Strength training preserves muscle and metabolic rates. ### Does weight loss lower my RMR? Yes. A smaller body requires fewer calories to maintain. Additionally, prolonged deficits can trigger metabolic adaptation, lowering RMR. ### Is RMR the same as maintenance calories? No. RMR is what you burn at rest. To find maintenance calories (TDEE), multiply your RMR by an activity factor representing your daily movement. ### Why is RMR higher in men? Men typically possess higher skeletal muscle mass and lower essential body fat percentages than women of similar weight, raising resting energy needs. ## Related concepts - **Mifflin-St Jeor Equation** — A widely validated weight-based formula used to estimate resting energy expenditure, considered more accurate than older equations for most modern populations. - **Sarcopenia** — Age-related muscle loss, which is the primary cause of resting metabolic declines. - **TDEE** — Total Daily Energy Expenditure: the total calories burned in a day including activity. ## Related guides - [RMR Calculation Guide: Mifflin and Katch-McArdle](https://dothecalculation.com/blog/health/rmr-calculation-guide) — Estimate resting metabolic rate with the exact DTC formulas, compare Mifflin-St Jeor with Katch-McArdle, and understand the limits. ## Related calculators - [BMR Calculator](https://dothecalculation.com/calculators/bmr-calculator) — Estimate your basal metabolic rate (BMR) and daily calorie needs at rest based on your age, gender, height, and weight for accurate results. - [Karvonen Heart Rate Zone Calculator](https://dothecalculation.com/calculators/heart-rate-reserve-karvonen-calculator) — Estimate your target heart rate training zones using the Karvonen formula based on resting and maximum heart rate for workouts. - [Ideal Weight Calculator](https://dothecalculation.com/calculators/ideal-weight-calculator) — Find your ideal weight range based on height, gender, and body frame using trusted medical formulas for a healthy target. - [Metabolic Age Calculator](https://dothecalculation.com/calculators/metabolic-age-calculator) — Estimate your metabolic age by comparing your basal metabolic rate (BMR) to population health benchmarks for your age group. - [Protein Calculator](https://dothecalculation.com/calculators/protein-calculator) — Estimate your ideal daily protein intake based on body weight, activity level, and fitness goals like building lean muscle. - [Steps to Miles & Calories Calculator](https://dothecalculation.com/calculators/steps-to-miles-calories-calculator) — Convert your daily step count into miles, kilometers and estimated calories burned using your height, weight and walking or jogging pace. --- _This calculator is for educational and gestational planning purposes only. Due dates, trimester timelines, conception windows, ovulation days, biological age ratings, and resting metabolic rates (RMR) are clinical estimates and do not replace personalized OB/GYN medical care, pregnancy diagnostic checks, or medical consultations. Always consult with a licensed physician or OB/GYN professional during pregnancy._ --- _Source: [Do The Calculation](https://dothecalculation.com/calculators/rmr-calculator). Quote freely with attribution and a link to this page._