BMR Calculator
Calculate resting calorie burn based on age, gender, height, and weight.
BMR Calculator Information
Why wellness teams rely on this BMR snapshot
The BMR calculator gives coaches, clinicians, and busy households an instant view of how many calories their bodies burn at rest using the most cited formulas. It serves as the foundational number for any nutrition plan, whether the goal is weight loss, muscle gain, or metabolic health recovery.
Dual-unit entry panels keep kilograms, pounds, and centimetres in sync so you can grab measurements from any scale without rekeying conversions. This flexibility ensures that whether you are reading a medical chart or a gym scale, you can enter data quickly and accurately.
Use the paired outputs to brief dietitians, adjust training loads, or align budget allocations with anticipated nutrition costs. By understanding your baseline energy needs, you can make informed decisions about grocery shopping and meal prep services.
Designed for confident planning discussions
Hourly and per-kilogram views make it easier to translate a daily BMR into meal timing, supplementation strategies, or hospital monitoring notes. Seeing that your body burns ~60 calories an hour just existing can be a powerful reframing tool for understanding hunger cues.
The layout mirrors intake forms used in clinics, so you can review results alongside the calorie calculator and BMI calculator without toggling apps. It integrates seamlessly into a broader health tracking ecosystem.
Saved default profiles let you switch between male and female coefficients instantly, a useful shortcut for household comparisons or coaching rosters. This feature saves time when managing plans for multiple family members or clients.
BMR Calculator Deep Dive
Tool Overview
The BMR Calculator answers a critical question: "How much energy does my body need just to survive?" Your Basal Metabolic Rate (BMR) accounts for 60-70% of your total daily energy expenditure. It is the energy required for your heart to beat, your lungs to breathe, and your cells to divide.
This tool provides a clinical baseline. Unlike TDEE (Total Daily Energy Expenditure), which includes exercise, BMR is your "coma calories" what you would burn if you stayed in bed all day. Knowing this number is the first step in creating any nutrition plan, as eating below your BMR for extended periods is generally not recommended without medical supervision.
The Science: Mifflin-St Jeor vs. Harris-Benedict
We provide results from the two most respected equations in metabolic science.
Mifflin-St Jeor (1990)
The Modern Standard. Considered the most accurate equation for the general population today. It was derived from a study of 498 healthy individuals and is less likely to overestimate needs in overweight individuals compared to older formulas.
Harris-Benedict (1984 Revised)
The Classic. Originally created in 1919 and revised in 1984. It is still widely used in clinical settings but tends to overestimate BMR by about 5-15% in modern, more sedentary populations.
Which one should I use? For most people, the Mifflin-St Jeor result is the safer, more accurate baseline. If you are very muscular, the Harris-Benedict number might be closer to reality.
How to Use This Calculator
To get a precise BMR estimate, follow these steps:
Step 1: Measure Accurately
Use your morning "dry weight" (after using the toilet, before eating/drinking). Measure height without shoes. These small details ensure the formula works as intended.
Step 2: Understand the Output
The calculator gives you a daily calorie number (e.g., 1,600 kcal). This is your floor, not your target. If you eat only this amount, you will lose weight because you are not accounting for movement (NEAT) or exercise.
Step 3: Apply Activity Factors
To find your maintenance calories (TDEE), multiply your BMR by an activity factor:
Sedentary: BMR x 1.2
Lightly Active: BMR x 1.375
Moderately Active: BMR x 1.55
Very Active: BMR x 1.725
What Influences Your BMR?
- Muscle Mass: Muscle is metabolically expensive. It burns about 6 calories per pound per day at rest, whereas fat burns only 2. This is why resistance training is key to increasing your BMR.
- Age: BMR naturally declines by about 1-2% per decade after age 20, largely due to muscle loss. Staying active can mitigate this drop.
- Genetics: Some people naturally have a faster or slower metabolism, though the variance is usually smaller than people think (often within 200-300 calories).
- Hormones: Thyroid hormones (T3/T4) directly regulate metabolic rate. Hypothyroidism can significantly lower BMR.
Limitations & Considerations
While these formulas are robust, they are statistical averages.
- Body Composition: The formulas use total weight. They do not distinguish between 100kg of muscle and 100kg of fat. For athletes, BMR calculators often underestimate needs.
- Metabolic Adaptation: If you have been dieting for a long time, your actual BMR might be lower than the calculated number because your body has adapted to conserve energy.
- Illness/Fever: BMR increases significantly during illness (about 7% for every degree Fahrenheit of fever) to fuel the immune response.
Disclaimer: This tool is for informational purposes only. Consult a healthcare professional before making drastic changes to your diet.