Calculator Suite

Free Calorie Calculator | Calculate Daily Calories & BMR Online

Calculate your daily calorie needs with our free, accurate calorie calculator. Find your BMR, TDEE, and personalized nutrition goals for weight loss or muscle gain

Personal Information
Enter your details to calculate your daily calorie needs

Biological sex affects BMR calculation

Age affects metabolic rate

Current body weight

Height in selected unit

Select the option that best describes your daily activity

What you want to achieve with your diet

Mifflin-St Jeor is more accurate for most people

Quick Presets

Calorie Formulas & Math
The science behind BMR and TDEE calculations

Mifflin-St Jeor Equation (Standard)

BMRmen=(10×W)+(6.25×H)−(5×A)+5BMR_{men} = (10 \times W) + (6.25 \times H) - (5 \times A) + 5
BMRwomen=(10×W)+(6.25×H)−(5×A)−161BMR_{women} = (10 \times W) + (6.25 \times H) - (5 \times A) - 161

WW = Weight in kg

HH = Height in cm

AA = Age in years

Total Daily Energy Expenditure (TDEE)

TDEE=BMR×Activity FactorTDEE = BMR \times \text{Activity Factor}

Common multipliers: Sedentary (1.2), Moderate (1.55), Active (1.725).

Weight Loss Math

Daily Target=TDEE−500 (for 1 lb/week loss)\text{Daily Target} = TDEE - 500 \text{ (for 1 lb/week loss)}

3,500 calories is approximately 1 pound of fat.

Understanding Calories & Weight Control

TL;DR: To manage your weight, you generally need to balance "Energy In" (food) with "Energy Out" (living + moving). This tool calculates your "Energy Out" (TDEE) so you can scientifically set your calorie target.

Real-World Example: The "Activity Trap"

Let's look at Sarah, a 35-year-old office worker:

  • Stats: 5'6", 160 lbs
  • Activity: Sedentary (desk job, no gym)
  • BMR: ~1,450 calories (Calories burned doing nothing)
  • TDEE: ~1,740 calories (Maintenance level)

Her Goal: Lose 1 lb/week (-500 cal/day):

  • Target: 1,240 calories/day

💡 The Better Strategy

1,240 calories is very low and hard to sustain. If Sarah adds a daily 30-minute walk (changing activity to 'Lightly Active'), her TDEE rises to ~1,990. Now her diet target is 1,490 calories—much easier to stick to long-term!

3 Key Checks for Success

  1. Be Interactionally Honest: Most people overestimate their activity. "Moderate" usually means 3-5 vigorous gym sessions a week. If you mostly walk, stick to "Light."
  2. Respect the Minimums: Eating below 1,200 (women) or 1,500 (men) calories can lead to nutrient deficiencies and metabolic slowdown. Don't starve yourself for speed.
  3. Prioritize Protein: When eating in a deficit, your body might burn muscle. High protein intake (0.7-1g per lb of bodyweight) helps you lose fat while keeping muscle.

Assumptions & Limitations

Model Assumptions:
  • Metabolism follows standard equations (Mifflin-St Jeor)
  • Weight loss is linear (approx. 3500 cal = 1 lb)
  • Activity levels are constant week-to-week
real-World Variables NOT Included:
  • Metabolic adaptation (body burning less as you diet)
  • Water weight fluctuations (sodium/carb intake)
  • Hormonal factors (stress, sleep, cycle)

What is a Calorie?

Source: TED-Ed

The Mathematics of Weight Loss

Source: TED-Ed

Frequently Asked Questions

Should I eat back my exercise calories?

Generally, no. If you selected an activity level (like "Moderate") when calculating, your exercise calories are already included in your TDEE. Eating them back would mean double-counting, which often stops weight loss.

Why am I not losing weight on a deficit?

The most common reasons are: 1) Underestimating portion sizes (tracking errors), 2) Overestimating activity calories, or 3) Water retention masking fat loss. If you are stalled for more than 3 weeks, try reducing your intake by another 100-200 calories.

Is 1200 calories enough?

For most adults, 1200 is the absolute floor and arguably too low for long-term health unless you are petite and sedentary. Eating too little can trigger "metabolic adaptation," where your body slows down to survive, making weight loss harder.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is what you burn in a coma. TDEE (Total Daily Energy Expenditure) is BMR plus all your movement. Always use TDEE as your starting point for diet planning, not BMR.