Calorie Calculator
This free Calorie Calculator estimates your daily energy needs using proven formulas like Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle. Enter your age, sex, height, weight, and activity level to calculate your BMR, TDEE, and recommended calories for weight loss, maintenance, or muscle gain. The tool also creates personalized macro targets for protein, fats, and carbohydrates—based on preset ratios or custom settings. Whether you're tracking nutrition, planning meals, or starting a fitness program, this calculator gives you accurate, science-based estimates. Everything runs privately in your browser, and results update instantly.
What Is a Calorie Calculator?
A calorie calculator estimates how many calories your body needs each day based on your basal metabolic rate (BMR) and activity level. BMR is the calories burned at complete rest; multiplying by an activity factor gives your Total Daily Energy Expenditure (TDEE). Eating below TDEE creates a deficit for weight loss; eating above creates a surplus for muscle gain. A 35-year-old woman, 5'4", 160 lbs, lightly active has a TDEE of ~1,994 cal/day — eating 1,494 cal/day creates a 500-cal deficit for ~1 lb/week loss.
How to Use This Calorie Calculator
Enter your age, sex, height, weight, and activity level. The calculator outputs your BMR (Mifflin-St Jeor), TDEE, and calorie targets for weight loss, maintenance, and gain. Use the weight loss target (TDEE − 500) as your daily calorie limit, tracking intake with a food log app. Adjust every 2–3 weeks as your weight changes and recalculate.
Worked Example: Jennifer's Weight Loss Calories
35-year-old woman, 5'4", 160 lbs, lightly active (1–2 workouts/week).
BMR: ~1,450 cal/day | TDEE: ~1,994 cal/day
Weight loss (1 lb/week): 1,494 cal | Maintenance: 1,994 cal | Muscle gain: 2,494 cal
At 1,494 cal/day: loses ~4–5 lbs/month sustainably
Do NOT go below 1,200 cal/day (women) or 1,500 (men) without medical supervision
Daily Calorie Targets by Goal (TDEE: 2,000)
| Goal | Daily Calories | Deficit/Surplus | Expected Rate | Weeks to 10 lbs |
|---|---|---|---|---|
| Aggressive loss | 1,500 | −500 cal | 1 lb/week | ~10 weeks |
| Moderate loss | 1,700 | −300 cal | 0.6 lb/week | ~17 weeks |
| Mild loss | 1,800 | −200 cal | 0.4 lb/week | ~25 weeks |
| Maintenance | 2,000 | 0 | No change | — |
| Mild gain | 2,200 | +200 cal | 0.4 lb/week | — |
| Muscle gain | 2,500 | +500 cal | ~1 lb/week | — |
Macro Breakdown for 1,800 Calories
| Approach | Protein | Carbs | Fats | Best For |
|---|---|---|---|---|
| Balanced | 30% (135g) | 40% (180g) | 30% (60g) | General health |
| High Protein | 40% (180g) | 30% (135g) | 30% (60g) | Muscle building |
| Low Carb | 35% (158g) | 20% (90g) | 45% (90g) | Fat loss, keto |
| Endurance | 25% (113g) | 50% (225g) | 25% (50g) | Runners, cyclists |
Tips for Hitting Your Daily Calorie Goal
Prioritize protein (0.7–1g per lb of body weight) to preserve muscle during a deficit — it also provides the highest satiety per calorie. Build meals around high-volume, low-calorie foods: vegetables, lean proteins, broth-based soups. Track food for at least 2 weeks even if estimating — research shows people systematically underestimate intake by 20–30%. Liquid calories (juice, soda, lattes) are the most common hidden source of surplus — switching to water and black coffee alone can eliminate 300–600 calories per day for many people.
Frequently Asked Questions About Calorie Calculators
How many calories should I eat to lose weight?
Eat TDEE − 500 calories/day for ~1 lb/week loss. For a 2,000 cal TDEE, that's 1,500 cal. Don't go below 1,200 (women) or 1,500 (men) without medical supervision — severe restriction causes muscle loss and metabolic adaptation that makes long-term weight management harder.
What is the difference between BMR and TDEE?
BMR (Basal Metabolic Rate) is calories burned at complete rest — just to keep your organs functioning. TDEE (Total Daily Energy Expenditure) adds activity-related calorie burn. A sedentary person's TDEE is BMR × 1.2; a very active person's is BMR × 1.9. TDEE is the number you use for nutrition planning.
How accurate are online calorie calculators?
BMR formulas (Mifflin-St Jeor is most validated) are accurate within ±10% for most people. The bigger error is in self-reported activity level — most people overestimate how active they are. Choose one activity level lower than you think, track your actual weight change for 2–3 weeks, and adjust.
Why am I not losing weight at a calorie deficit?
Most common reasons: 1) Underestimating intake by 20–30% (very common without weighing food). 2) Overestimating activity/exercise burn. 3) Metabolic adaptation after prolonged restriction. 4) Hormonal factors. Try a 2-week accurate food log with a kitchen scale before assuming the calculator is wrong.
How many calories do I need to build muscle?
A lean bulk requires approximately TDEE + 200–500 calories, with protein at 0.8–1g per lb of body weight. The muscle-gain rate is slow (~0.25–0.5 lb/week for men, half that for women), so a massive surplus mostly adds fat. A 200–300 calorie surplus with progressive overload training is optimal for muscle gain with minimal fat gain.
Do I need to count calories to lose weight?
Not necessarily — but calorie awareness is the most evidence-based approach. Structured plans (Mediterranean diet, whole foods, high protein) can create deficits without explicit counting. However, research consistently shows that people who track food at least periodically lose more weight and maintain it better than those who rely entirely on intuitive eating.