Basal Metabolism Calculator — Start Now
A basal metabolism calculator estimates your BMR (the calories you burn at rest) and pairs it with activity levels so you can see daily calorie needs at a glance.
Quick summary
This basal metabolism calculator estimates BMR and applies activity multipliers to show daily calorie needs. The page includes an activity chart, formulas, examples, FAQs, and references to help you set realistic weight loss targets.
Introduction
Basal metabolic rate is the minimum energy your body uses to keep your heart beating, lungs working, and core temperature stable. It represents the largest part of daily calorie burn for most people, which is why BMR is the starting point for any weight loss plan.
BMR is not the same as total daily energy expenditure (TDEE). To estimate the calories you actually need to maintain weight, you add movement and exercise. If you want a deeper maintenance estimate, compare these results with the TDEE calculator for weight loss and use both numbers to guide your daily intake.
Basal Metabolism Calculator
This calculator uses your age, sex, height, and weight to estimate BMR using the Mifflin-St Jeor equation. The results show your BMR in calories per day along with a chart that applies common activity multipliers so you can see a realistic calorie range for sedentary, moderate, or highly active days.
Once you know your maintenance range, you can set a deficit that matches your goal. The calorie deficit calculator for weight loss helps convert that range into a specific daily target.
Calculator
Enter your age, sex, height, and weight to estimate basal metabolism (BMR). The table uses your BMR to show daily calorie needs at common activity levels.
| Activity level | Calories/day |
|---|---|
| Sedentary (little or no exercise) | 1,635 |
| Exercise 1-3 times/week | 1,874 |
| Exercise 4-5 times/week | 2,112 |
| Daily exercise or intense exercise 3-4 times/week | 2,351 |
| Intense exercise 6-7 times/week | 2,589 |
| Very intense exercise daily, or physical job | 2,725 |
Exercise: 15-30 minutes of elevated heart rate activity. Intense exercise: 45-120 minutes of elevated heart rate activity. Very intense exercise: 2+ hours of elevated heart rate activity.
BMR activity chart
The chart below shows an example for a BMR of 1,667 calories/day. Your calculator results will generate a personalized chart, but this example helps you understand how activity multipliers change daily calorie needs.
| Activity level | Calories/day |
|---|---|
| Sedentary (little or no exercise) | 2,000 |
| Exercise 1-3 times/week | 2,292 |
| Exercise 4-5 times/week | 2,583 |
| Daily exercise or intense exercise 3-4 times/week | 2,875 |
| Intense exercise 6-7 times/week | 3,167 |
| Very intense exercise daily, or physical job | 3,334 |
Formula
The Mifflin-St Jeor formula estimates BMR, then activity multipliers convert it into daily calorie needs. Weight is in kilograms, height is in centimeters, and age is in years.
Example calculation
Example: Female, 32 years old, 5'6" (168 cm), 165 lb (75 kg). BMR = 10 × 75 + 6.25 × 168 − 5 × 32 − 161 = 1,487 calories/day.
If she exercises 3-5 times per week (activity factor 1.55), daily calorie needs are 1,487 × 1.55 = 2,305 calories/day. A 15% deficit would target about 1,960 calories/day.
FAQ
Is BMR the same as resting metabolic rate?
They are close. BMR is measured under strict lab conditions, while resting metabolic rate is slightly higher and measured under more relaxed conditions.
How often should I update my BMR?
Recalculate after a 5-10 lb (2-5 kg) weight change or every 4-6 weeks if you are actively losing weight.
Why do I feel hungry even at maintenance?
Hunger is influenced by sleep, stress, protein, and activity. Use the fat loss calculator to compare maintenance versus deficit targets.
Does strength training change BMR?
Building muscle can raise BMR slightly over time, but most of the daily calorie difference comes from activity and movement.
Resources
These evidence-based references explain resting energy expenditure formulas and healthy weight management guidance.
Evidence-based references: PubMed: Predictive equation for resting energy expenditure, CDC: Healthy weight loss, NIDDK: Healthy eating and activity.