Calculatorboom

Calorie Calculator

Calculate your BMR and daily calorie needs (TDEE) based on your age, height, weight, and activity level — with calorie targets for every goal.

Your age in years. The Mifflin-St Jeor formula subtracts 5 calories per year of age — metabolic rate naturally slows slightly as you get older.
yrs
Biological sex affects BMR. Males have a higher BMR than females of the same age, height, and weight due to greater average lean muscle mass.
Your standing height. The formula uses height in centimeters internally — the calculator converts feet and inches automatically.
ft in
Your current body weight. The formula uses kilograms internally — lbs are converted automatically.
lbs
How active you are on a typical week. This is the biggest variable after BMR — the multiplier ranges from 1.2 (desk job, no exercise) to 1.9 (athlete or physical labor every day).

BMR

1783 cal/day

Calories burned at complete rest

TDEE

Calories burned with your activity level

A 30-year-old male who is moderately active burns approximately 2763 calories per day (TDEE). The basal metabolic rate (BMR) — calories burned at complete rest — is 1783 cal/day. To lose ~1 lb per week, target 2263 calories/day.

Maintenance Macros — 30 / 40 / 30 split at 2763 cal/day

  • Protein 207 g  ·  828 kcal
  • Carbs 276 g  ·  1105 kcal
  • Fat 92 g  ·  828 kcal

What is a Calorie Calculator?

A calorie calculator estimates how many calories your body burns each day — your Total Daily Energy Expenditure (TDEE). It starts by computing your Basal Metabolic Rate (BMR), the calories your body needs to sustain basic functions at complete rest, then multiplies by an activity factor to account for movement and exercise.

Knowing your TDEE lets you set a precise calorie target for any goal: eat at TDEE to maintain weight, below it to lose, or above it to gain. A 500-calorie daily deficit produces roughly 1 pound of fat loss per week; a 500-calorie surplus supports roughly 1 pound of gain per week — simple, consistent arithmetic.

Daily Calorie Targets

Goal Calories/day
Extreme Weight Loss 1763
Weight Loss 2263
Mild Weight Loss 2513
Maintain Weight (TDEE)
Mild Weight Gain 3013
Weight Gain 3263

How Is BMR Calculated? The Mifflin-St Jeor Formula

This calculator uses the Mifflin-St Jeor equation, the most accurate BMR formula for most adults according to a 2005 review in the Journal of the American Dietetic Association. It outperforms the older Harris-Benedict formula (1919) by about 5% on average.

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

TDEE is then computed as BMR × activity multiplier. The multipliers range from 1.2 (completely sedentary) to 1.9 (extremely active — think professional athlete or someone with a demanding physical job who also trains hard). Most people fall between 1.375 (light activity) and 1.55 (moderate activity).

Choosing the Right Activity Multiplier

The activity multiplier is the biggest source of error in TDEE estimates. Most people overestimate how active they are. A common guide:

  • Sedentary (×1.2) — desk job, drive to work, no intentional exercise. About 3,000–5,000 steps/day.
  • Lightly Active (×1.375) — 1–3 days of light cardio or weight training per week, otherwise sitting.
  • Moderately Active (×1.55) — exercise 3–5 days/week with real effort; or a walking-heavy job.
  • Very Active (×1.725) — training 6–7 days/week, or a physical trade (construction, landscaping).
  • Extra Active (×1.9) — twice-daily training, or an athlete with a physically demanding job.

When in doubt, start one level lower than you think. It is easy to adjust upward when the scale does not move; it is harder to diagnose why results stall when TDEE is overestimated from the start.

Understanding Macronutrients

Macronutrients — protein, carbohydrates, and fat — provide all dietary calories. Each gram of protein and carbohydrate provides 4 calories; each gram of fat provides 9 calories. The macro split above (30/40/30 by calories) is a balanced general-purpose starting point, not a prescription:

  • Protein (30%) — essential for muscle maintenance and satiety. Higher protein is especially important during a calorie deficit to prevent muscle loss.
  • Carbohydrates (40%) — the primary fuel for the brain and high-intensity exercise. Whole food sources (oats, rice, vegetables) keep energy stable.
  • Fat (30%) — supports hormone production, fat-soluble vitamin absorption, and long-duration energy. Minimum viable intake is ~0.35 g/lb of bodyweight.

How Fast Is Safe Weight Loss or Gain?

One pound of body fat contains approximately 3,500 calories. A sustained 500-calorie daily deficit produces ~1 lb/week of fat loss — widely considered the upper edge of what is sustainable without significant muscle loss. A 250-calorie deficit yields ~0.5 lb/week, which is easier to sustain and preserves more muscle.

Deficits larger than 1,000 calories/day (more than 2 lbs/week) typically cause muscle loss, fatigue, nutrient deficiencies, and metabolic adaptation. A floor of 1,200 calories/day for women and 1,500 for men is a common minimum to maintain adequate micronutrient intake without medical supervision.

Example — Your Current Inputs

A 30-year-old male who is moderately active burns approximately 2763 calories per day (TDEE). The basal metabolic rate (BMR) — calories burned at complete rest — is 1783 cal/day. To lose ~1 lb per week, target 2263 calories/day.

Maintenance macros: approximately 207 g protein, 276 g carbs, 92 g fat per day.

Additional Example — A 28-Year-Old Female Runner

A 28-year-old woman, 5'6" (168 cm), 140 lbs (63.5 kg), who runs 4 days a week (moderately active, ×1.55):

  • BMR ≈ 1,467 cal/day (Mifflin-St Jeor)
  • TDEE ≈ 2,274 cal/day
  • Weight loss target: ~1,774 cal/day (−500 cal deficit)
  • Maintenance macros: ~170 g protein, ~227 g carbs, ~76 g fat

On rest days her actual expenditure may be closer to 1,760 cal (×1.2). Eating 2,274 every day still produces fat loss over time — the TDEE is a weekly average, not a daily precision target.

About These Parameters

Age
BMR decreases by approximately 1–2% per decade after age 30 due to declining muscle mass and metabolic rate changes. The Mifflin-St Jeor formula subtracts 5 calories per year of age. Strength training slows — and can partially reverse — this decline by preserving lean muscle mass.
Gender
Biological males have a higher average BMR than females of the same age, height, and weight, primarily because of greater average lean muscle mass. Muscle tissue burns more calories at rest than fat tissue. The formula adds 5 for males and subtracts 161 for females to capture this difference.
Height and Weight
Both height and weight have a positive relationship with BMR — taller and heavier people have more body mass to maintain. As you lose weight, your BMR will decrease slightly, which is why recalculating after every 10 lbs of change is recommended to keep targets accurate.
Activity Level
The activity multiplier is the most error-prone input. Non-exercise activity thermogenesis (NEAT) — fidgeting, walking, standing — varies enormously between individuals and accounts for 15–50% of total daily expenditure. If results after 2–3 weeks do not match the expected weight trend, adjust the activity level rather than changing the goal calories.

Frequently Asked Questions

Why does my weight stall even when eating at the deficit?

Metabolic adaptation is the most common culprit. As you lose weight, your body reduces TDEE through three mechanisms: lower BMR (less mass to maintain), reduced NEAT (subconscious movement decreases), and improved exercise efficiency (the same workout burns fewer calories as your body adapts). This is why recalculating TDEE after every 10–15 lbs of weight change is important. A 2-week diet break at maintenance calories can also temporarily reverse some adaptation.

Is it better to eat less or exercise more to create a deficit?

Both work, but diet is far more efficient at creating a calorie deficit. A 30-minute run burns roughly 300–400 calories — equivalent to a single snack. Reducing food intake by 500 calories requires less effort and time for most people. However, exercise preserves muscle mass during a deficit (especially resistance training), improves cardiovascular health, and increases TDEE over time. The optimal strategy combines both: a moderate dietary deficit plus regular resistance training.

How accurate is the Mifflin-St Jeor formula?

Studies show that Mifflin-St Jeor predicts measured resting metabolic rate within 10% for approximately 82% of people. The main sources of error are body composition (very lean or very obese individuals are predicted less accurately), and the activity multiplier (which is always an estimate). For research-grade accuracy, indirect calorimetry (a metabolic cart) is the gold standard but is expensive and impractical for everyday use. Treat the TDEE as a calibrated starting estimate, not a precise measurement.

Do I need to hit my macros exactly, or just hit the calorie total?

For fat loss or gain, total calories matter most — this is well-supported by the research. Hitting protein targets is the second priority because adequate protein (roughly 0.7–1 g per lb of bodyweight during a deficit) is critical for preserving lean mass. Carb-to-fat ratios are mostly a matter of personal preference, sustainability, and individual response. Focus on consistent protein and total calories first; fine-tune the carb/fat split later.

Should I eat back the calories I burn from exercise?

This calculator already accounts for exercise in the activity multiplier — the TDEE includes your workouts. You should not add extra calories on top of the TDEE for planned exercise. If you chose "moderately active" because you train 4 days/week, those calories are already included. Only eat back exercise calories if you used "sedentary" and plan to account for exercise separately — a less common approach that increases tracking complexity.

Popular Calorie Calculations

See also