Calorie Calculator
Calculate your daily calorie needs for weight loss, maintenance, or muscle gain. Uses Mifflin-St Jeor and Harris-Benedict formulas based on age, height,
Calculator
Adjust values & calculateDaily Calorie Targets
Formula
This calculator uses the Mifflin-St Jeor equation to estimate basal metabolic rate. Here s = +5 for men and -161 for women. Maintenance calories are estimated by multiplying BMR by an activity factor.
Last reviewed: January 2026
Worked Examples
Example 1: Sedentary Adult Male — Maintenance Calories (TDEE)
Example 2: Active Young Female — Weight Loss Deficit
Example 3: Athletic Male — High Activity Performance Nutrition
Background & Theory
The Calorie Calculator - Daily Caloric Needs Estimator applies the following established principles and formulas. Health and medicine calculators are grounded in validated physiological measurement methods established through decades of clinical research. Body Mass Index, or BMI, is calculated by dividing weight in kilograms by height in meters squared (kg/m²), a formula originating from Adolphe Quetelet's 19th-century statistical work and later codified by the WHO into standard classifications: underweight below 18.5, normal weight 18.5 to 24.9, overweight 25 to 29.9, and obese at 30 and above. Basal Metabolic Rate quantifies the minimum energy required to sustain life at rest. The Mifflin-St Jeor equation, published in 1990 and widely regarded as the most accurate for most adults, calculates BMR as (10 × weight in kg) + (6.25 × height in cm) − (5 × age) ± sex adjustment. The older Harris-Benedict equations, revised in 1984 by Roza and Shizgal, remain in common use. Total Daily Energy Expenditure is derived by multiplying BMR by a physical activity factor ranging from 1.2 for sedentary individuals to 1.9 for extremely active ones, following the methodology validated by doubly labeled water studies. Body fat percentage can be estimated without laboratory equipment using the U.S. Navy circumference method, which uses neck, waist, and hip measurements, or via BMI-derived equations adjusted for age and sex. The Jackson-Pollock skinfold method offers higher precision with calipers. Blood pressure classification, according to the American College of Cardiology and the 2017 ACC/AHA guidelines, defines normal as below 120/80 mmHg, elevated as 120 to 129 systolic, and hypertension stage 1 as 130 to 139 systolic or 80 to 89 diastolic. Target heart rate zones for aerobic exercise are derived from maximum heart rate estimates, most commonly using the formula 220 minus age in years, with moderate-intensity training typically defined as 50 to 70 percent of maximum heart rate and vigorous intensity at 70 to 85 percent, consistent with CDC and American Heart Association guidelines. These thresholds guide safe and effective cardiovascular conditioning.
History
The history behind the Calorie Calculator - Daily Caloric Needs Estimator traces back through the following developments. The history of health measurement stretches back to ancient Greece, where Hippocrates around 400 BCE laid the foundation for observational medicine by systematically recording patient symptoms, diet, and environment. His humoral theory, though scientifically superseded, established the principle that the body operates as an interconnected system subject to measurable imbalance. The transformation toward modern medicine accelerated in the 19th century. Louis Pasteur and Robert Koch developed germ theory in the 1860s and 1870s, identifying microorganisms as disease agents and enabling targeted interventions. Florence Nightingale, working during the Crimean War in the 1850s, introduced statistical analysis to nursing practice, demonstrating through data visualization that sanitation reduced mortality. Her work is foundational to evidence-based health measurement. The discovery of vitamins in the early 20th century, beginning with Casimir Funk's coinage of the term in 1912 and culminating in the isolation of vitamins A through K, created the field of nutritional science and gave rise to dietary reference intake frameworks. The World Health Organization, founded in 1948, subsequently established global standards for health metrics, disease classification through the International Classification of Diseases, and recommended daily allowances. The BMI as a clinical screening tool gained traction in the 1970s through Ancel Keys' large-scale epidemiological work, which validated Quetelet's index as a population-level obesity indicator. Through the 1980s and 1990s, the Framingham Heart Study produced landmark data linking cholesterol, blood pressure, and lifestyle factors to cardiovascular disease risk, directly shaping the numeric thresholds still used in health calculators. The evidence-based medicine movement, formalized by Gordon Guyatt and colleagues at McMaster University in the early 1990s, demanded that all health recommendations derive from systematically graded clinical evidence. The digital health era beginning in the 2000s brought these formulas to consumer devices, wearable sensors, and smartphone applications, expanding access to health self-monitoring on a global scale and enabling population-level data collection that continues to refine clinical reference ranges.
Frequently Asked Questions
Sources & References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy
Calorie Calculator Formula
BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age + s (s = +5 male, -161 female)
The Mifflin-St Jeor equation calculates Basal Metabolic Rate (BMR) — calories burned at rest. BMR is multiplied by an activity factor (1.2 sedentary to 1.9 extremely active) to get Total Daily Energy Expenditure (TDEE), which represents maintenance calories. Weight loss requires eating below TDEE, weight gain requires eating above TDEE.
Calorie Calculator — Worked Examples
Example 1: Sedentary Adult Male — Maintenance Calories (TDEE)
Problem: A 42-year-old male, 5 ft 11 in (180.3 cm), 185 lbs (83.9 kg), sedentary office worker with no structured exercise. What are his maintenance calories?
Solution: Height = 5 ft 11 in = 180.3 cm\nWeight = 185 lbs = 83.9 kg\n\nBMR (Mifflin-St Jeor, male):\n= 10 x 83.9 + 6.25 x 180.3 - 5 x 42 + 5\n= 839 + 1,126.9 - 210 + 5\n= 1,761 cal/day\n\nTDEE (sedentary multiplier x 1.2):\n= 1,761 x 1.2 = 2,113 cal/day\n\nThis is his maintenance intake to hold current weight with minimal activity.
Result: BMR: 1,761 cal/day | TDEE (maintenance): 2,113 cal/day
Example 2: Active Young Female — Weight Loss Deficit
Problem: A 26-year-old female, 5 ft 5 in (165.1 cm), 155 lbs (70.3 kg), lightly active (walks daily, gym 2x/week). She wants to lose 1 lb per week. What deficit target should she use?
Solution: Height = 5 ft 5 in = 165.1 cm\nWeight = 155 lbs = 70.3 kg\n\nBMR (Mifflin-St Jeor, female):\n= 10 x 70.3 + 6.25 x 165.1 - 5 x 26 - 161\n= 703 + 1,031.9 - 130 - 161\n= 1,444 cal/day\n\nTDEE (light activity x 1.375):\n= 1,444 x 1.375 = 1,985 cal/day\n\nWeight loss target (-500 cal deficit = ~1 lb/week):\n= 1,985 - 500 = 1,485 cal/day\n\nMacros at 30/40/30 split on deficit:\nProtein = 1,485 x 0.30 / 4 = 111 g\nCarbs = 1,485 x 0.40 / 4 = 149 g\nFat = 1,485 x 0.30 / 9 = 50 g
Result: BMR: 1,444 | TDEE: 1,985 | Weight loss target: 1,485 cal/day | Macros: 111 g protein, 149 g carbs, 50 g fat
Example 3: Athletic Male — High Activity Performance Nutrition
Problem: A 24-year-old male, 6 ft 0 in (182.9 cm), 175 lbs (79.4 kg), trains 6 days per week (strength and conditioning). What are his calorie needs for performance and lean muscle gain?
Solution: Height = 6 ft 0 in = 182.9 cm\nWeight = 175 lbs = 79.4 kg\n\nBMR (Mifflin-St Jeor, male):\n= 10 x 79.4 + 6.25 x 182.9 - 5 x 24 + 5\n= 794 + 1,143.1 - 120 + 5\n= 1,822 cal/day\n\nTDEE (very active x 1.725):\n= 1,822 x 1.725 = 3,143 cal/day\n\nLean gain target (+250 cal surplus):\n= 3,143 + 250 = 3,393 cal/day\n\nMacros for performance (35/40/25 split):\nProtein = 3,393 x 0.35 / 4 = 297 g\nCarbs = 3,393 x 0.40 / 4 = 339 g\nFat = 3,393 x 0.25 / 9 = 94 g
Result: BMR: 1,822 | TDEE: 3,143 | Lean gain target: 3,393 cal/day | Macros: 297 g protein, 339 g carbs, 94 g fat
Calorie Calculator — Frequently Asked Questions
How does the calorie calculator estimate daily needs?
Calorie Calculator uses the Mifflin-St Jeor equation to estimate basal metabolic rate and then applies an activity multiplier to estimate total daily energy expenditure. That gives a practical maintenance-calorie estimate.
Why can calorie needs change over time?
Body weight, activity level, muscle mass, age, and day-to-day movement all influence energy needs. A calculator gives a starting estimate, but real-world tracking is what fine-tunes the target.
How accurate are calorie calculators?
They are estimates, not exact measurements. For many people they are close enough to begin, but actual maintenance calories should be confirmed by watching weight and intake over a few weeks.
How does exercise intensity affect calorie burn?
Exercise intensity and calorie burn have a nuanced relationship. Higher-intensity exercise burns significantly more calories per minute — a 155 lb person burns roughly 400 calories/hour walking at 3.5 mph, 600 calories/hour jogging at 5 mph, and 900 calories/hour running at 8 mph. High-intensity interval training (HIIT) produces a meaningful excess post-exercise oxygen consumption (EPOC) or afterburn effect: metabolism remains elevated 6-15% above baseline for up to 24 hours, burning an extra 50-150 calories. However, HIIT can only be sustained 2-3 times per week before recovery suffers. Moderate-intensity steady-state cardio is sustainable daily and accumulates large total calorie expenditure over a week. The most effective approach pairs regular moderate-intensity sessions with 1-2 HIIT sessions weekly, adapted to your current fitness level.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Can I use the results for professional or academic purposes?
You may use the results for reference and educational purposes. For professional reports, academic papers, or critical decisions, we recommend verifying outputs against peer-reviewed sources or consulting a qualified expert in the relevant field.