Calorie Calculator
Calculate how many calories you need per day to lose weight, maintain, or gain muscle. Based on Mifflin-St Jeor equation with activity multiplier.
Educational purpose only. Results are estimates based on standard formulas. This calculator does not constitute financial, tax, legal, or medical advice. For decisions affecting your personal finances or health, consult a qualified professional. How we ensure accuracy →
About the Calorie Calculator
A calorie calculator is the most powerful starting point for any health, fitness, or weight management goal. With over 895,000 monthly searches worldwide, it is the single most searched fitness tool on the internet — because knowing exactly how many calories your body needs each day is the foundation of every effective nutrition plan. Whether your goal is weight loss, muscle gain, athletic performance, or simply maintaining your current weight, our free calorie calculator delivers a personalised daily calorie target based on your age, sex, height, current weight, and activity level. The tool calculates your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest just to sustain vital functions like breathing, circulation, and cell repair — and then multiplies it by your activity level to produce your Total Daily Energy Expenditure (TDEE), also called your maintenance calories. From there, it generates specific targets: subtract 500 calories per day from TDEE for approximately 1 lb of fat loss per week, or add 250–500 calories for lean muscle gain. The calculator uses the Mifflin-St Jeor equation, validated in multiple peer-reviewed studies as the most accurate BMR formula for the general population, and works in both metric (kg/cm) and imperial (lb/ft/in) units. Understanding your calorie needs transforms random dieting into a precise, data-driven process — the same approach used by Olympic athletes, bodybuilders, and registered dietitians worldwide.
Formula
BMR (men) = 10W + 6.25H − 5A + 5 | BMR (women) = 10W + 6.25H − 5A − 161 | TDEE = BMR × Activity Factor | Deficit: TDEE − 500 ≈ 1 lb/week loss
How It Works
The calculation runs in two steps. Step 1 — Basal Metabolic Rate (BMR) using Mifflin-St Jeor: Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5. Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161. Example for a 30-year-old woman weighing 70 kg at 165 cm: BMR = 700 + 1031 − 150 − 161 = 1,420 calories/day at rest. Step 2 — Multiply BMR by your activity multiplier to get TDEE: Sedentary (desk job, no exercise) = BMR × 1.2. Lightly active (1–3 days/week exercise) = BMR × 1.375. Moderately active (3–5 days/week) = BMR × 1.55. Very active (6–7 days/week hard training) = BMR × 1.725. Extra active (athlete or twice-daily training) = BMR × 1.9. For our example woman, moderately active: TDEE = 1,420 × 1.55 = 2,201 calories/day maintenance. Weight loss target: 2,201 − 500 = 1,701 calories/day for ~1 lb/week. Sustainable loss: 2,201 − 250 = 1,951 calories/day for ~0.5 lb/week. The calorie estimator also breaks your target into recommended macros — protein, carbohydrates, and fat — tailored to your specific goal.
Tips & Best Practices
- ✓The "3,500 calories = 1 pound" rule is a useful estimate, but real-world fat loss slows after 4–6 weeks as your body adapts — recalculate your TDEE every 10–15 lbs lost.
- ✓Never drop below 1,200 calories/day (women) or 1,500 calories/day (men) without medical supervision — severe restriction lowers your metabolic rate, causes muscle loss, and creates nutritional deficiencies.
- ✓Protein has the highest thermic effect of food (TEF) at 20–30%: your body burns 20–30% of protein calories during digestion itself, making high-protein diets inherently more efficient for fat loss.
- ✓NEAT (Non-Exercise Activity Thermogenesis) — walking, fidgeting, standing at a desk, taking stairs — accounts for 200–600 extra calories/day between active and sedentary people. Increasing NEAT is often easier and more sustainable than adding structured exercise.
- ✓A 250–300 calorie/day deficit preserves more muscle mass and is far easier to sustain than a 500+ deficit — slow, steady loss consistently outperforms aggressive crash dieting for long-term results.
- ✓Most people underestimate food intake by 20–40% when eyeballing portions. Using a food scale and a calorie tracker app dramatically improves accuracy.
- ✓Calorie needs decrease with age: BMR drops approximately 2% per decade after 30, meaning a 50-year-old needs roughly 100–150 fewer calories/day than they did at 30 to maintain the same weight.
- ✓Liquid calories — juice, alcohol, specialty coffees, smoothies — are the most overlooked calorie source. A single large blended coffee drink can contain 500+ calories without providing any satiety.
Who Uses This Calculator
People beginning a weight loss journey use the calorie calculator as their essential first step — knowing your precise TDEE turns every food choice into a conscious, informed decision rather than guesswork. Athletes and bodybuilders use it to dial in exact surplus calories during bulking phases and precise deficit targets during cutting phases. Registered dietitians and nutritionists use TDEE as the anchor for every personalised meal plan they create. Personal trainers provide calorie targets to gym clients to complement their exercise programming. Endurance athletes — marathon runners, cyclists, triathletes — use it to calculate fuelling needs for heavy training weeks versus recovery weeks. Bariatric surgery patients use pre- and post-operative calculations to understand their dramatically changed energy requirements. Medical professionals treating patients with eating disorders, cancer cachexia, or post-surgical recovery use calorie calculations to prescribe appropriate nutritional interventions. Even people who simply want to stop the cycle of gradual weight gain use the calorie calculator to finally understand exactly how much food their body actually needs every day.
Optimised for: USA · Canada · UK · Australia · Calculations run in your browser · No data stored
Frequently Asked Questions
How many calories should I eat per day to lose weight?
To lose weight, eat 500–750 fewer calories than your Total Daily Energy Expenditure (TDEE). A 500-calorie daily deficit creates approximately 1 lb of fat loss per week. For most women this means 1,200–1,500 calories/day; for most men, 1,500–1,800 calories/day. Never go below 1,200 calories without medical supervision.
What is a calorie deficit and how does it work?
A calorie deficit occurs when you consume fewer calories than your body burns. Since roughly 3,500 calories equals 1 lb of body fat, a consistent 500-calorie daily deficit creates approximately 1 lb of fat loss per week. The calculator determines your maintenance calories so you know exactly how much to reduce.
How many calories do I need to maintain my weight?
Maintenance calories equal your TDEE — your BMR multiplied by your activity level. A sedentary 155 lb woman needs roughly 1,800–2,000 calories/day to maintain weight. A moderately active 185 lb man needs approximately 2,600–2,900 calories/day. Use the calculator with your exact stats for a personalised figure.
What is the Mifflin-St Jeor equation?
Mifflin-St Jeor is the most accurate BMR formula for most people: Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5. Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161. Multiply BMR by your activity factor to get TDEE.
How many calories should I eat to gain muscle?
To gain muscle (lean bulk), eat 250–500 calories above your TDEE — a smaller surplus than many people expect. This rate allows muscle gain of 0.5–1 lb per week while minimising fat gain. Higher surpluses add more fat than muscle. Combine with progressive resistance training for best results.
Does age affect how many calories I need?
Yes — calorie needs decrease with age. Metabolic rate typically drops 1–2% per decade after age 20, primarily due to loss of muscle mass. A 50-year-old may need 150–200 fewer daily calories than a 25-year-old of the same weight and activity level. Resistance training helps preserve muscle and metabolic rate as you age.
How accurate are calorie calculators?
Calorie calculators estimate within ±10% for most people. Individual variation exists due to genetics, body composition (muscle vs fat ratio), gut microbiome, hormones, and medication. Use the calculator result as a starting point, track your weight for 2–3 weeks, and adjust by 100–200 calories if results differ from expectations.
What activity level should I choose?
Sedentary = desk job, little exercise. Lightly active = light exercise 1–3 days/week. Moderately active = moderate exercise 3–5 days/week. Very active = hard exercise 6–7 days/week. Extra active = physical job or twice-daily training. Most people overestimate their activity level — when in doubt, choose one level lower.
How many calories are in a pound of fat?
Approximately 3,500 calories equal one pound of stored body fat. This means a 500-calorie daily deficit × 7 days = 3,500 calories = roughly 1 lb fat lost per week. In practice, weight loss also involves water and muscle changes, so actual fat loss may vary slightly from this theoretical calculation.
What should my calorie split be between protein, carbs, and fat?
A standard macro split for fat loss: 40% protein, 30% carbs, 30% fat. For muscle gain: 30% protein, 50% carbs, 20% fat. Protein should be at minimum 0.7–1g per pound of body weight daily for muscle preservation during a deficit. Use the macro calculator on this site for personalised targets based on your calorie goal.