BMR & TDEE Calculator
Estimate the calories your body burns at complete rest (BMR) and across every activity level (TDEE) using the trusted Mifflin-St Jeor equation. The side-by-side table below lets you compare sedentary, lightly active, moderately active, very active, and extra active totals at a glance.
Your BMR
calories burned at complete rest
TDEE by Activity Level
| Activity Level | Multiplier | TDEE (kcal/day) |
|---|
What BMR and TDEE actually mean
BMR (Basal Metabolic Rate) is the number of calories your body burns simply to keep you alive — heart beating, lungs breathing, cells doing their work. If you stayed in bed all day and didn't move, you'd still burn roughly this many calories.
TDEE (Total Daily Energy Expenditure) is your BMR plus everything else you burn through daily movement, exercise, and digesting food. It's the most important number for nutrition planning: eat below it to lose weight, at it to maintain, above it to gain.
How This Calculator Works
Your basal metabolic rate is estimated with the Mifflin-St Jeor equation, the formula sports-nutrition professionals consider the most reliable for healthy adults. The core calculation is BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years), then you add 5 for men or subtract 161 for women. To get total daily energy expenditure, the calculator multiplies that BMR by an activity factor: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active and 1.9 for extra active. The table shows every level at once so you can see how much your daily movement changes the total.
A Worked Example
Consider a 30-year-old man who is 178 cm tall and weighs 77 kg. Plug the numbers in: (10 × 77) + (6.25 × 178) − (5 × 30) + 5 = 770 + 1112.5 − 150 + 5 = 1,738 calories at complete rest. If he is moderately active, multiply by 1.55: 1,738 × 1.55 = 2,693 calories per day to maintain his weight. Bump his activity to very active and the multiplier rises to 1.725, pushing maintenance up to about 2,998 calories — over 300 extra calories from training harder, without his BMR changing at all.
What Affects Your Result
- Lean muscle mass: Muscle is metabolically active and burns calories at rest, so two people of equal weight can have meaningfully different BMRs.
- Activity level honesty: Most people overestimate how active they are; choosing one level too high is the single most common reason a TDEE comes out too high.
- Age: BMR declines roughly 1–2 percent per decade in adulthood as muscle is lost.
- Sex: Men generally carry more lean mass, which is why the equation adds calories for men and subtracts for women.
- Dieting history: Extended calorie restriction can suppress metabolic rate below what the formula predicts.
- Non-exercise movement (NEAT): Fidgeting, walking and standing vary enormously between people and the fixed multipliers cannot capture that fully.
Frequently Asked Questions
Why does this calculator use Mifflin-St Jeor instead of Harris-Benedict?
The Mifflin-St Jeor equation was published in 1990 and validated against indirect calorimetry, and multiple reviews have found it predicts resting metabolic rate more accurately than the 1919 Harris-Benedict formula, which tends to overestimate. Because most of your daily energy planning hangs off this number, we use the more accurate modern equation.
How accurate is a calculated BMR?
A prediction equation lands within about 10 percent of a person's true measured BMR for most people, but individuals vary. Genetics, thyroid function, lean mass and prior dieting can all shift your real metabolic rate up or down. Treat the figure as a well-informed starting estimate and refine it by tracking your actual weight trend over two to three weeks.
Should I eat my BMR or my TDEE?
Almost always your TDEE, not your BMR. BMR is only what you burn at complete rest and eating that little for long stretches is overly aggressive for most people. Your TDEE accounts for movement and exercise and is the number you adjust around: eat below it to lose weight, at it to maintain, and slightly above it to gain.
Why did my BMR drop as I got older?
The Mifflin-St Jeor equation subtracts five calories for every year of age, reflecting the gradual loss of metabolically active muscle tissue that accompanies aging. Staying strength-trained preserves lean mass and blunts that decline, which is one reason resistance training matters more, not less, as you get older.
These calorie figures are estimates for educational planning only, not medical advice. Individual metabolism varies, so verify the numbers against your real-world weight trend and consult a doctor or registered dietitian before making significant dietary changes.