How much fuel does your body actually need? Enter your stats and find out — maintenance, loss, and gain targets in one read.
Sex
yr
Units
cm
kg
Maintenance calories
2,556kcal / day
Moderately active (3–5 days / wk)
BMR (at rest)1,649 kcal
Mild weight loss −0.25 kg / wk2,306 kcal
Weight loss −0.5 kg / wk2,056 kcal
Mild weight gain +0.25 kg / wk2,806 kcal
Weight gain +0.5 kg / wk3,056 kcal
Estimates use the Mifflin-St Jeor equation. Real needs vary by body composition, metabolic health, and genetics — treat these as a starting point, not a prescription.
A calorie calculator estimates how many calories your body needs daily based on your age, weight, height, sex, and activity level. Whether you're trying to lose weight, build muscle, or maintain your current fitness, knowing your daily calorie requirements is the foundation of any successful nutrition plan.
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What is the Calorie Calculator?
A calorie calculator is a tool that determines your total daily energy expenditure (TDEE)—the number of calories your body burns through basal metabolism (at rest) plus physical activity. It uses your personal data to estimate how many calories you need to consume each day to maintain, lose, or gain weight.
How it works
The calculator first computes your Basal Metabolic Rate (BMR)—the calories you burn just existing—using your age, weight, height, and sex (usually via the Harris-Benedict or Mifflin-St Jeor equation). It then multiplies your BMR by an activity factor (sedentary, lightly active, moderately active, etc.) to get your TDEE. The result tells you how many calories to eat daily for weight loss (typically 300–500 below TDEE), maintenance (at TDEE), or gain (300–500 above TDEE).
Weight is in kilograms, height in centimetres, and age in years. The activity factor ranges from 1.2 (sedentary) to 1.9 (very active). Multiply your BMR by this factor to get your total daily energy expenditure.
Examples
Input
Result
Notes
30-year-old woman, 70 kg, 165 cm, moderately active (exercise 3–5 days/week)
2,100 calories/day TDEE; eat ~1,600 to lose 0.5 kg/week, or 2,100 to maintain
This woman's BMR is roughly 1,500 kcal; the 1.4 activity factor accounts for regular workouts
25-year-old man, 85 kg, 180 cm, lightly active (office work + 2 gym sessions/week)
2,550 calories/day TDEE; eat ~2,050 for steady fat loss, or 3,050 to gain muscle
A 500-calorie deficit supports ~0.5 kg fat loss weekly; a +500 surplus with strength training builds muscle
45-year-old man, 95 kg, 178 cm, sedentary (desk job, no exercise)
2,200 calories/day TDEE; even without dieting, adding 30 min walks daily can increase TDEE by 150–250 kcal
Sedentary workers often underestimate calorie intake; the small activity boost demonstrates why movement matters
How to use the Calorie Calculator
Enter your age (in years), weight (in kg or lbs), and height (in cm or feet/inches)
Select your sex (male or female) to apply the correct BMR formula
Choose your activity level: sedentary, lightly active, moderately active, very active, or extremely active
The calculator computes your BMR, then multiplies it by your activity factor to show your TDEE
Review your daily calorie needs for maintenance, and see recommended ranges for weight loss (−300 to −500 kcal) or gain (+300 to +500 kcal)
Use the result as a baseline for meal planning, tracking apps, or discussing nutrition with a healthcare provider
Benefits
Personalised baseline: Know exactly how many calories *your* body burns, not a generic average
Evidence-based goal-setting: Whether losing 0.5 kg/week or building muscle, you have a calorie target grounded in science
Time-saving: No guesswork—get your TDEE in seconds instead of researching formulas or hiring a nutritionist
Adaptable to real life: Adjust for seasonal activity changes, holiday periods, or new fitness routines
Free and private: Calculate instantly without signing up, sharing data, or paying for a premium app
Tips & common mistakes
Common mistakes
Overestimating activity level: Choosing 'very active' when you're moderately active inflates calories and stalls weight loss; be honest about workouts
Ignoring metabolic adaptation: After weeks of dieting, your BMR drops slightly (adaptive thermogenesis); recalculate every 4–6 weeks if losing weight
Treating TDEE as gospel: Calculators estimate within ±10–20%; actual needs vary by genetics, hormones, and digestion; adjust based on real results
Forgetting hidden calories: Even with the correct TDEE, oils, sauces, drinks, and bites add up; track intake for a week to ground-truth the math
Tips
Start with a moderate deficit (−300 kcal/day) rather than extreme (−1,000 kcal/day) to preserve muscle, energy, and sanity over months
Pair your TDEE with a tracking app (MyFitnessPal, Cronometer) to log meals and verify you're hitting your target; don't eyeball it
Increase protein intake when in a deficit or surplus (0.8–1.2 g per lb bodyweight) to preserve muscle and feel full longer
Recalculate quarterly as your weight, fitness, or life circumstances change; your needs shift as you progress
Frequently asked questions
Does the calculator account for metabolism differences between people?
The formula is population-averaged (±10–20% variance). Factors like age, hormones, medications, and genetics affect real metabolism; if results don't match weight changes after 2–3 weeks, adjust intake by ±100–200 kcal and reassess.
What's the difference between BMR and TDEE?
BMR is calories burned at complete rest; TDEE adds daily movement and exercise. A sedentary office worker might have BMR 1,500 kcal but TDEE 1,900 kcal (including a 30-min walk). The activity factor bridges the gap.
Should I eat the same calories every day, or can I vary?
Weekly averages matter more than daily perfection. Eat 2,000 ± 200 kcal most days; one day at 2,500 and another at 1,700 average to the same weekly total and work just as well for progress.
Why do online calculators give different results?
Different formulas (Harris-Benedict vs. Mifflin-St Jeor vs. Roza-Shizgal) and activity multipliers vary slightly. Mifflin-St Jeor is more modern and accurate for most people; if two tools differ by >200 kcal, use the average and track real results.
Can I use this to gain weight or build muscle?
Yes. Add 300–500 kcal above your TDEE and eat protein-rich food (0.8–1.2 g per lb bodyweight) while strength training. This creates a surplus for muscle growth without excess fat gain.
How often should I recalculate?
Every 4–6 weeks if your weight changes significantly, or quarterly if stable. As you lose weight, your TDEE drops (less mass = fewer calories burned); recalculating keeps your deficit realistic and prevents plateau.