Why It's Important to Know Your BMR and TDEE
The WellnessFacts BMR/TDEE Calculator estimates your maintenance calories using Mifflin–St Jeor by default, with an optional Advanced mode for Katch–McArdle via a body-fat slider and quick picks. It supports metric/imperial inputs and activity levels, then outputs BMR, TDEE, and goal presets (lose/maintain/gain) with suggested macros. It’s mobile-friendly, remembers your last inputs, and includes one-tap Copy/Share for easy saving and sharing.
Understanding your BMR (Basal Metabolic Rate) and TDEE (Total Daily Energy Expenditure) is a game-changer when it comes to managing your weight, improving your health, and reaching your fitness goals.
Your BMR is the number of calories your body needs just to stay alive — to keep your heart beating, lungs breathing, and body functioning at rest. It represents your minimum daily energy requirement.
But most of us don’t lie still all day — that’s where TDEE comes in. Your TDEE includes your BMR plus the calories you burn through movement and daily activity — whether you’re working out, walking the dog, or just doing laundry.
Here’s why knowing both matters:
Weight loss: To lose fat, you need to eat fewer calories than your TDEE. Knowing the exact number helps you avoid cutting too much (which can backfire) or too little (which stalls results).
Muscle gain: To build lean mass, you need a slight calorie surplus. Your TDEE shows how much fuel your body actually needs.
Maintenance: Not trying to change your weight? TDEE helps you maintain it without guesswork.
Avoid under-eating or over-eating: Many people rely on general advice that may not fit their metabolism or lifestyle. BMR/TDEE gives you personalized numbers, not averages.
In a net-shell, BMR and TDEE are your calorie compass — they help you plan meals, fuel workouts, and set realistic goals based on your body and lifestyle. Whether you're a beginner or an athlete, these numbers give you the insight to work smarter, not harder.
Frequently asked questions
What is BMR?
Basal Metabolic Rate (BMR) is the number of calories your body needs at rest to maintain essential functions like breathing and circulation.
What is TDEE and how is it different from BMR?
Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. BMR estimates resting needs; TDEE estimates your daily maintenance calories including movement and exercise.
Which formula does this calculator (BMR/TDEE) use?
By default it uses the Mifflin–St Jeor equation. In Advanced mode, you can switch to Katch–McArdle if you know your body fat percentage to calculate BMR from lean body mass.
Do I need to enter my body fat percentage?
No. Body fat is optional. Use it only if you want the Katch–McArdle method. Without it, the calculator uses Mifflin–St Jeor, which works well for most people."
How do I use TDEE to lose or gain weight?
Compare your intake to TDEE. For fat loss, aim about 10–25% below TDEE. For muscle gain, aim about 5–15% above TDEE. Adjust weekly based on progress."
Are the activity multipliers accurate?
They are evidence-based estimates. Individual needs vary, so use them as a starting point and fine-tune by tracking body weight, measurements, and performance over time.
Should I ever eat below my BMR?
Consistently eating below BMR is not recommended. Use a modest deficit based on TDEE for fat loss while maintaining adequate protein, fiber, and micronutrients.
Does the BMR/TDEE calculator support metric and imperial units?
Yes. You can enter height and weight in metric (cm, kg) or imperial (ft/in, lb) and switch units at any time.
Is this medical advice?
No. The calculator provides educational estimates. Consult a healthcare professional for personalized guidance, especially if you have medical conditions or special nutrition needs.