BMR Calculator

How many calories would you burn if you stayed in bed all day binge-watching shows? That number is your Basal Metabolic Rate (BMR). It's the "idling speed" of your body's engine.

What this calculator does

• Coma Calories: Your base burn rate at 0% activity.
• TDEE: Your Total Daily Energy Expenditure (BMR + Activity).
• Goal Setting: How much to eat to lose or gain weight.

The Formula

We use the Mifflin-St Jeor Equation (The gold standard). $\text{BMR} = (10 \times \text{weight}) + (6.25 \times \text{height}) - (5 \times \text{age}) + S$

• S: +5 for men, -161 for women.

Unlike math class, here's what that means

• BMR: The floor. Never eat below this.
• TDEE: The ceiling. Eat below this to lose weight.
• Calculated: If BMR is 1,500 and you exercise lightly, TDEE might be 2,000. To lose weight, eat 1,750 (Deficit).

Example Calculation

Woman: 30 years old, 5'6", 150 lbs.

1. Math: Complicated inputs...
2. Result: 1,450 Calories/day (BMR).
3. Active: If she works out 3x/week, she burns 2,000 Calories/day (TDEE).

Did You Know? 💡

• Brain Drain: Your brain uses 20% of your BMR energy. Thinking is expensive.
• Muscle Multiplier: 1 lb of muscle burns ~6 calories/day at rest. 1 lb of fat burns ~2 calories. Building muscle speeds up your metabolism 24/7.
• Starvation Mode: If you eat way below your BMR, your body thinks there is a famine and shuts down non-essential systems (like hair growth and being warm) to save energy.

Expert Insight

The "Slow Metabolism" Myth: Most people don't have a "slow metabolism." They usually just underestimate how much they eat (creamer, sauces, snacks) and overestimate how much they move. Tracking accurately is usually the fix.

Why this matters

Guessing your calories usually leads to failure. Knowing your exact numbers allows you to eat as much as possible while still losing weight. It's science, not magic.

Frequently Asked Questions

Does BMR drop with age? Yes, about 2% per decade. This is mostly because we lose muscle as we age. Lift weights to stop the drop!

Should I eat back exercise calories? Use TDEE. If you select "Moderately Active," the calculator already accounts for your workouts. Do not add them again or you are double-counting (and overeating).

Is 1200 calories enough? For a toddler? Yes. For a grown adult? Usually no. Eating at BMR (usually 1400+) is safer and more sustainable.

Related Calculators

• Calories Burned: Check your workout intensity.
• BMI Calculator: Check your health stats.

Disclaimer: This is an estimate. Your thyroid and genetics track their own data.