Get your personalized daily calorie needs using three scientifically-validated formulas. Includes goal-based targets for weight loss, maintenance, and muscle gain — plus macro breakdown.
A calorie calculator estimates how many calories your body needs each day based on age, gender, height, weight, and activity level. It calculates your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE) using formulas like Mifflin-St Jeor. To lose weight, eat below your TDEE; to gain muscle, eat above it. Most adults need 1,600-2,400 calories per day for weight maintenance, depending on individual factors.
Enter your details below. Results update instantly as you adjust any value.
| Goal | Daily Calories | Weekly Change |
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This calculator gives you a personalized daily calorie target in under a minute. Here's exactly what to do:
A calorie is a unit of energy. Specifically, one food calorie (or kilocalorie, kcal) is the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius. When you eat a 200-calorie apple, you're consuming 200,000 small calories of chemical energy stored in the apple's molecules — which is why nutrition labels technically read "kilocalories" even though everyone calls them "calories."
That said, calories aren't the whole story. Where your calories come from affects hunger, energy, body composition (muscle vs. fat), and long-term health. 2,000 calories of broccoli would be biologically impossible to eat (you'd need 13+ pounds of it) and incredibly different from 2,000 calories of cookies. The calculator below gives you a calorie target — but the food choices you make to hit that target determine how you feel and look.
This calculator offers three scientifically-validated formulas for estimating your Basal Metabolic Rate (BMR). Each has strengths and limitations:
Published in 1990 and considered the gold standard by the American Dietetic Association. Research shows it predicts resting energy needs within 10% for about 82% of healthy adults.
The original was published in 1919 and revised in 1984 by Roza and Shizgal. It's a bit older but still widely used and produces results within a few percent of Mifflin-St Jeor for most people.
This formula uses lean body mass directly instead of total weight, making it more accurate for very lean people (athletes, bodybuilders) or very high-body-fat individuals where total weight doesn't reflect metabolic tissue.
All three formulas calculate BMR (Basal Metabolic Rate) — the calories you'd burn lying in bed all day. To get TDEE (Total Daily Energy Expenditure), the calculator multiplies BMR by an activity factor (1.2 to 1.9 depending on how active you are). TDEE is what you actually need to eat to maintain your current weight.
Try all three formulas in this calculator and average them. If they all give similar numbers (within 100 kcal), you can trust the result. If they're very different, your body composition is unusual (very muscular or very lean) — go with Katch-McArdle.
Let's walk through an actual calculation. Meet "Alex" — a 30-year-old man, 5'10" (178 cm), 160 lbs (72.5 kg), who does moderate exercise 3-5 times per week.
Alex's maintenance calories: ~2,623 kcal · Weight loss: ~2,123 kcal · Muscle gain: ~2,923 kcal
This is the single biggest mistake people make. Most people overestimate their activity level by one full tier, which can throw off their calorie target by 200-400 calories per day. Here's exactly what each level means:
To pick correctly, ask yourself: "In a typical week, how many days do I actually sweat and breathe hard from exercise?" Walking your dog doesn't count unless it's vigorous and at least 45 minutes. Light yoga doesn't count unless you finish covered in sweat.
If you're not losing weight on the calculator's recommended calories after 2-3 weeks, the most likely culprit is overestimated activity level — not a "broken metabolism." Drop down one tier and recalculate.
Weight loss happens at a caloric deficit — eating less than you burn. The standard math: a pound of body fat stores about 3,500 calories. So a daily deficit of 500 calories should produce roughly 1 pound of weight loss per week.
| Goal | Daily Deficit | Weekly Loss | Sustainability |
|---|---|---|---|
| Slow & easy | -250 kcal | ~0.5 lb | Excellent — barely noticeable |
| Standard | -500 kcal | ~1 lb | Good — most popular target |
| Aggressive | -750 kcal | ~1.5 lb | Moderate — hunger noticeable |
| Very aggressive | -1,000 kcal | ~2 lb | Low — only short-term |
The "best" deficit depends on how much weight you have to lose. If you're 50+ pounds above your goal, you can sustainably run a 1,000-calorie deficit. If you're chasing the last 10 pounds, a 250-calorie deficit is more realistic — and the slower pace actually preserves more muscle.
Never eat below your BMR for more than a few days at a time. Going below BMR (typically 1,200-1,500 kcal for women, 1,500-1,800 for men) puts your body in conservation mode, slowing metabolism and risking nutrient deficiencies.
Building muscle requires a caloric surplus, but how much surplus depends entirely on your training experience. Beginners can build muscle on small surpluses (or even slight deficits) because they have so much "muscle protein synthesis potential." Advanced lifters need bigger surpluses because their bodies are already efficient.
The classic "see food" diet (eat everything in sight) doesn't work — most of the extra calories become body fat. A controlled 200-500 calorie surplus with protein at 0.8-1.0g per pound of body weight is the sweet spot for muscle without excessive fat gain.
Once you have your calorie target, the next question is where those calories come from. The three macronutrients each play a different role:
The macro breakdown in the calculator above defaults to 30% protein, 40% carbs, 30% fat — a balanced split that works for most people. You can mentally adjust based on your goals:
| Goal | Protein | Carbs | Fat |
|---|---|---|---|
| Balanced (Default) | 30% | 40% | 30% |
| Higher Protein (Cutting) | 40% | 30% | 30% |
| Low Carb / Keto | 25% | 5-10% | 65-70% |
| Endurance Athlete | 20% | 55-60% | 20-25% |
| Mediterranean Style | 25% | 45% | 30% |
Most calorie calculator sites won't tell you this, but it's important: these formulas can be off by 10-20% for any individual. Here's why, and how to know if your number is off:
Your calculator number is a starting point, not a magic prescription. Track your weight weekly for 2-3 weeks at the predicted maintenance calories. If you're gaining, drop 100-200 kcal and reassess. If you're losing, add 100-200. Real-world results beat formulas every time.
To lose 1 pound per week safely, eat 500 calories below your TDEE (Total Daily Energy Expenditure). For most women, weight loss happens at 1,200-1,800 calories per day; for most men, 1,500-2,200 calories per day. The exact number depends on your age, height, current weight, and activity level. Use the calculator above for your personalized target.
1,200 calories is the minimum recommended for adult women to maintain basic nutrition and metabolic health, and only appropriate for short periods or for small, sedentary individuals. For most active women, going below 1,500-1,800 calories causes muscle loss, fatigue, and metabolic slowdown. Men typically should not go below 1,500 calories per day. Always consult a healthcare provider before sustained low-calorie diets.
The Mifflin-St Jeor equation is currently considered the most accurate for the general population, with research showing it predicts resting energy needs within 10% for about 82% of people. Harris-Benedict (revised 1984) is similar but slightly less accurate. Katch-McArdle is most accurate if you know your body fat percentage, since it uses lean body mass directly. All three are available in this calculator.
Calorie formulas use averages and can be off by 10-15% for any individual due to genetics, gut microbiome, NEAT (non-exercise activity), and undeclared exercise intensity. Most people overestimate their activity level by one tier — "moderately active" should mean 4-5 intense workouts weekly, not light walking. If your calculated calories aren't producing expected weight changes after 2-3 weeks, adjust by 100-200 calories and reassess.
Your Basal Metabolic Rate (BMR) — the calories you burn just being alive — is roughly 1,200-1,500 kcal/day for women and 1,400-1,800 kcal/day for men. This accounts for 60-70% of total daily energy expenditure. The calculator above shows your BMR separately from your TDEE (which includes activity).
If you used the activity level slider in this calculator, your calories already account for exercise — so do not eat additional "earned" calories from your workout. If you instead used the sedentary multiplier and add exercise calories separately, eat back 50-75% of what fitness trackers estimate (they typically overestimate by 20-40%).
It's a useful approximation but oversimplified. The "3,500 calories = 1 pound" rule comes from 1958 research and assumes only fat loss with no metabolic adaptation. In reality, weight loss slows over time as your body adapts (lower BMR, water loss, muscle changes). A 500-calorie deficit produces about 1 lb/week initially, dropping to 0.5-0.7 lb/week after 6+ months.
This calculator uses the same scientifically-validated formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle) used by nutrition professionals worldwide. The math is exact. However, formulas can only estimate — your actual energy needs may vary by 10-15%. Use the result as a starting point, track your weight for 2-3 weeks, and adjust calories up or down by 100-200 based on real-world results.
No. All calculations happen in your browser. Your age, weight, height, and activity choices stay on your device — nothing is sent to our servers, and no personal data is stored after you close the page.
This calculator provides educational estimates only and does not replace medical or nutritional advice from a qualified healthcare professional. Anyone with a medical condition, eating disorder history, or specific health goals should consult a registered dietitian or physician before making significant dietary changes.