Calorie Calculator: Free Daily TDEE & Deficit Tool

Calculate your Total Daily Energy Expenditure (TDEE), Basal Metabolic Rate (BMR), and daily calorie deficit targets for healthy weight loss, maintenance, or muscle gain.

Calculate Your Daily Energy Needs

Enter your information below for an educational estimate.

Your Results

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BMI

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BMI Category

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BMR (Selected)

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TDEE

BMR Formula Comparison

Mifflin-St Jeor

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Default. Most accurate for general population.

Harris-Benedict

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Revised. Historically significant.

Katch-McArdle

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Uses lean body mass.

TDEE Breakdown

Target Daily Calories

—kcal / day

Macronutrient Breakdown

Protein

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Carbs

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Fat

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Weight Change Projections

Weight change projections at 1, 2, 3, 6, and 12 months
Period	Change (lbs)	Change (kg)	Total Weight

Projections are mathematical estimates assuming consistent daily calorie target. Individual results vary due to metabolic adaptation, adherence, and other factors.

Medical Disclaimer

This calculator provides educational estimates of daily energy needs based on population prediction equations. Individual metabolic rates vary due to genetics, body composition, medical conditions, and other factors. These estimates should not replace personalized nutrition guidance from a qualified healthcare professional or registered dietitian. Consult a healthcare provider before starting any weight management program.

Quick Summary

Estimate daily energy expenditure and macronutrient requirements using validated Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle equations. Customize calorie deficits (0.25–2.0 lbs/week) and view 1–12 month weight projections with adjustable AMDR macronutrient splits. Free, accurate, and completely private.

How It Works

Enter your basic information — Age (18–100), sex assigned at birth, height (metric or imperial), and current weight.
Select your activity level — Choose from 5 levels ranging from sedentary to extra active based on your typical weekly exercise and daily movement.
Choose your goal — Maintain current weight, lose weight (0.25–2.0 lb/week), or gain weight (0.25–1.0 lb/week).
Optionally enter body fat percentage — If known, enables the Katch-McArdle equation for a more accurate BMR estimate using lean body mass.
Choose a BMR formula — Mifflin-St Jeor (default, most accurate for general population), Harris-Benedict (revised), or Katch-McArdle (requires body fat %).
Adjust macronutrient targets (optional) — Fine-tune the percentage of calories from protein, carbohydrates, and fat within AMDR guidelines.
Review your complete results — The calculator displays your BMI, BMR from all three equations, TDEE breakdown, target calories, macronutrient distribution, and weight change projections at 1, 2, 3, 6, and 12 months.

Formula Used

Three validated BMR equations drive this calculator — Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle — each paired with the energy balance principle:

TDEE = BMR + TEF + Physical Activity

Mifflin-St Jeor (1990) — Recommended by the American Dietetic Association for clinical use:

Male: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) + 5
Female: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) − 161

Harris-Benedict (Revised 1984):

Male: BMR = 13.397 × weight(kg) + 4.799 × height(cm) − 5.677 × age(y) + 88.362
Female: BMR = 9.247 × weight(kg) + 3.098 × height(cm) − 4.330 × age(y) + 447.593

Katch-McArdle: BMR = 370 + (21.6 × Lean Body Mass in kg), where LBM = weight × (1 − body fat % / 100)

Activity multipliers — Sedentary: 1.2, Lightly Active: 1.375, Moderately Active: 1.55, Very Active: 1.725, Extra Active: 1.9

Weight change principle — 1 pound ≈ 3,500 calories (1 kg ≈ 7,700 calories). Target calories = TDEE ± (desired weekly change / 7). Minimum 800 kcal/day.

Macronutrient energy values: Protein: 4 kcal/g, Carbohydrates: 4 kcal/g, Fat: 9 kcal/g

Key sources: Mifflin et al. (1990), Harris & Benedict (1918), Institute of Medicine DRIs (2005), ACSM Nutrition and Athletic Performance, ISSN Position Stand.

Evidence

The estimation models used by this calculator are based on peer-reviewed research and clinical guidelines:

The Mifflin-St Jeor equation (1990) was developed from a study of 498 healthy individuals and is recommended by the American Dietetic Association as the most accurate BMR prediction equation for the general population
The Harris-Benedict equation was originally published in 1918 and revised in 1984. While historically significant and still used in many clinical settings, research shows it tends to overestimate BMR by 5–15% compared to measured values
The Katch-McArdle equation provides BMR estimates using lean body mass and is considered more accurate for athletes and individuals with known body composition
The Institute of Medicine (2005) established the Acceptable Macronutrient Distribution Ranges (AMDR): protein 10–35%, carbohydrates 45–65%, fat 20–35% of total calories
The energy balance principle (3,500 calories per pound) is derived from the classic work of Wishnofsky (1958) and remains the standard framework for weight change estimation, though individual results vary due to metabolic adaptation
The ACSM and ISSN provide evidence-based guidelines on nutrition and athletic performance, including macronutrient timing and energy availability for physically active individuals

All estimates are educational — individual energy expenditure varies due to genetics, body composition, medical conditions, medications, and metabolic adaptation. This calculator should not be used for medical decision-making.

How to Interpret Your Results

The calculator provides educational estimates of your daily energy needs and weight change projections:

BMR (Basal Metabolic Rate) — The calories your body burns at rest to maintain vital functions. Shown for all three available equations for comparison.
TDEE (Total Daily Energy Expenditure) — Your total estimated daily calorie burn, including BMR, TEF (10%), and physical activity. This is the starting point for all calorie targets.
Target Calories — The daily calorie target for your selected goal. For weight maintenance, this equals TDEE. For weight loss or gain, it is adjusted by the goal calorie change.
Macronutrient Breakdown — Recommended grams of protein, carbohydrates, and fat based on your target calories and selected percentages.
Weight Projections — Estimated weight change at 1, 2, 3, 6, and 12 months based on your daily deficit or surplus. These are mathematical projections that assume consistent adherence — individual results vary.

Important: These are educational estimates based on population prediction equations. Individual metabolic rates vary significantly. Factors such as genetics, muscle mass, medical conditions (e.g., thyroid disorders), medications, and prior weight loss history can affect your actual energy expenditure. The calculator does not account for metabolic adaptation — the physiological reduction in metabolic rate that occurs during prolonged calorie restriction.

When to consult a healthcare provider: Before starting any weight management program, especially if you have underlying medical conditions (diabetes, thyroid disorders, cardiovascular disease, kidney disease), a history of eating disorders, are pregnant or breastfeeding, or are under 18 or over 65 years of age. Consult a registered dietitian for personalized nutrition guidance.

Medical Disclaimer

The information provided by Qurekit's calculators is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or treatment. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

Frequently Asked Questions

What is TDEE?

Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period. It includes three components: your Basal Metabolic Rate (BMR), which accounts for approximately 60–75% of total energy expenditure — the calories burned at rest to maintain vital functions; the Thermic Effect of Food (TEF), approximately 10% of total calories burned digesting and processing food; and physical activity energy expenditure, which includes both planned exercise and non-exercise activity thermogenesis (NEAT). TDEE is used as the starting point for calorie targets for weight maintenance, loss, or gain.

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body needs to perform basic life-sustaining functions while at rest, such as breathing, circulating blood, regulating body temperature, and maintaining cell function. BMR accounts for approximately 60–75% of total daily energy expenditure and is primarily determined by lean body mass. This calculator provides BMR estimates using three equations: the Mifflin-St Jeor equation (most accurate for the general population), the Harris-Benedict equation (revised, historically significant), and the Katch-McArdle equation (most accurate when body fat percentage is known, as it uses lean body mass directly). BMR decreases with age due to natural loss of lean muscle mass.

What is the Mifflin-St Jeor equation?

The Mifflin-St Jeor equation is widely considered the most accurate BMR estimation formula for the general population. Published in 1990 by Mifflin and St Jeor, it was developed using a diverse sample of 498 healthy individuals. The equation is: For males, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) + 5. For females, BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(y) − 161. The American Dietetic Association recommends the Mifflin-St Jeor equation as the most reliable for clinical use. It is this calculator's default formula.

What is the difference between Mifflin-St Jeor and Harris-Benedict?

The Harris-Benedict equation was originally developed in 1919 and revised in 1984. The Mifflin-St Jeor equation, published in 1990, was developed using a more diverse and modern population sample. Research consistently shows that Mifflin-St Jeor is more accurate for the general population — studies report it estimates BMR within ±10% of measured values in approximately 80% of individuals. The Harris-Benedict equation tends to overestimate BMR by 5–15%, particularly in overweight and older populations. Both equations provide estimates, not exact measurements. This calculator includes both so you can compare them.

What is the Katch-McArdle equation?

The Katch-McArdle equation estimates BMR using lean body mass (LBM), making it the most accurate formula when body fat percentage is known. The equation is: BMR = 370 + (21.6 × LBM in kg), where LBM = total body weight × (1 − body fat percentage / 100). Because it directly accounts for muscle mass, it is preferred for athletes and individuals who know their body composition. If Katch-McArdle is selected but body fat percentage is not provided, the calculator automatically uses Mifflin-St Jeor and displays a notice. The equation was developed by Katch and McArdle and published in their exercise physiology textbook.

How should I adjust calories for weight loss or gain?

Weight change follows the energy balance principle: approximately 3,500 calories equals one pound of body weight (7,700 calories per kilogram). For weight loss, a daily calorie deficit of 250–1,000 calories typically produces a loss of 0.5–2 pounds per week. The CDC recommends a deficit of 500–1,000 calories per day for safe weight loss of 1–2 pounds per week. For weight gain, a surplus of 250–500 calories per day typically produces a gain of 0.5–1 pound per week. This calculator provides five weight loss rates (0.25 lb, 0.5 lb, 1 lb, 1.5 lb, 2 lb per week) and three gain rates (0.25 lb, 0.5 lb, 1 lb per week). The minimum safe intake is 800 calories per day.

How are macronutrients calculated?

Macronutrient targets are calculated as percentages of your target daily calorie intake. Protein and carbohydrates each provide 4 calories per gram, while fat provides 9 calories per gram. The calculator uses default percentages of 30% protein, 50% carbohydrates, and 20% fat, based on the Acceptable Macronutrient Distribution Ranges (AMDR) established by the Institute of Medicine. You can adjust these percentages using the sliders, provided they remain within AMDR guidelines: protein 10–35% of calories, carbohydrates 45–65%, and fat 20–35%. The calculator automatically adjusts the fat percentage when you change protein or carbohydrates to maintain a total of 100%.

What is body fat percentage and how do I estimate it?

Body fat percentage is the proportion of your total body weight that is composed of fat mass. It can be measured using methods such as DEXA scans (most accurate), hydrostatic weighing, air displacement plethysmography (Bod Pod), skinfold calipers, and bioelectrical impedance analysis (BIA). Home scales with BIA and consumer devices provide estimates, but these tend to have higher error margins. If you do not know your body fat percentage, you can leave it blank — the calculator will use the Mifflin-St Jeor equation, which does not require it. The optional body fat field accepts values between 3% and 70%.

Is this calculator accurate for everyone?

No. This calculator provides estimates from population equations, not measurements of your individual metabolism. BMR equations have a standard error of approximately ±200–300 calories per day for most individuals — your actual BMR may differ by this margin or more. Factors affecting accuracy include genetic variation, muscle mass, medical conditions (thyroid disorders, for example), medications that affect metabolic rate, and prior weight loss history. This tool provides estimates for informational purposes and should not replace personalized nutrition guidance from a qualified healthcare professional or registered dietitian.

Should I talk to a healthcare provider?

Yes. Before starting any weight change program, consult a qualified healthcare professional or registered dietitian. This is especially important if you have underlying medical conditions such as diabetes, thyroid disorders, cardiovascular disease, kidney disease, or eating disorders; or if you are pregnant, breastfeeding, or over age 65. If your BMI is below 18.5 or above 40, professional guidance is recommended. This calculator is not a substitute for professional medical advice, diagnosis, or treatment.

Medical References

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Version History

Every version is logged with its build date, changes, and evidence sources so you can verify the methodology.

Version v1.0.1

BMR Formula Logic Fix

Built July 3, 2026

Fixed BMR formula selection logic: Katch-McArdle engine no longer silently falls back to Mifflin-St Jeor internally. The fallback is now explicit and tracked. Default formula is Mifflin-St Jeor on load and reset. Body fat label, hint, and warning text update dynamically based on selected formula. New methodology indicator shows which formula was actually used in the calculation.

Changes

Katch-McArdle engine returns null instead of silently falling back to Mifflin-St Jeor when body fat is missing
CalorieResult now includes formulaUsed and formulaUsedName fields to track the formula actually used
Default formula is Mifflin-St Jeor on page load and reset (previously Mifflin was the HTML default but Katch-McArdle fallback was not externally visible)
Body fat label dynamically shows (optional) for Mifflin/Harris-Benedict and (required for Katch-McArdle) for Katch-McArdle
Body fat hint text updates based on formula selection and shows an informational message when body fat is missing with Katch-McArdle
Orange warning appears below body fat field when Katch-McArdle is selected without body fat, informing user that Mifflin-St Jeor will be used instead
Validation no longer blocks calculation for Katch-McArdle without body fat. Fallback proceeds with Mifflin-St Jeor.
New methodology indicator in results shows "Using [formula name] equation", including notice when fallback occurred
Formula change hides previous results to prevent stale calculations
FAQ entry updated to describe explicit fallback behavior
Switching formula no longer triggers stale body fat validation error for Mifflin/Harris-Benedict

Version v1.0.0

Initial Implementation

Built July 3, 2026

Initial implementation of the Calorie Calculator (TDEE / BMR). Estimates basal metabolic rate using three equations (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle), total daily energy expenditure with five activity levels, and optimal macronutrient breakdown based on Acceptable Macronutrient Distribution Ranges (AMDR). Supports metric and imperial units with automatic conversion. Provides weight change projections at 1, 2, 3, 6, and 12 months. Built for educational reference only.

Changes

Initial calculator implementation
BMR calculation: Mifflin-St Jeor (default), Harris-Benedict (revised), Katch-McArdle (requires body fat %)
TDEE calculation with 5 activity levels (Sedentary through Extra Active)
TEF (Thermic Effect of Food) set at 10% of TDEE
Goal selection: Maintain, Lose (0.25–2.0 lb/week), Gain (0.25–1.0 lb/week)
Goal calorie change derived from 3,500 kcal/lb energy balance principle
Macronutrient sliders with auto-adjusting fat percentage to total 100%
AMDR guideline ranges: Protein 10–35%, Carbs 45–65%, Fat 20–35%
Optional body fat percentage for Katch-McArdle equation and lean body mass calculation
BMR formula selector with visual comparison of all three formulas
Weight change projections at 1, 2, 3, 6, and 12 months
BMI calculation with WHO classification categories
Metric (kg/cm) and Imperial (lbs/ft/in) unit system toggle
Minimum safe intake floor of 800 kcal/day
Live field validation with instant error feedback
Reset returns form to clean initial state
Medical references section with authoritative sources (NIH, CDC, ACSM, ISSN, IOM)
FAQ section with 10 educational questions covering TDEE, BMR, equations, macros, and accuracy
Structured data (WebApplication, MedicalWebPage, FAQPage)
BreadcrumbList JSON-LD for SEO
Accessibility: keyboard navigation, aria-live, aria-invalid, focus management
Mobile-responsive layout optimized for 320–1440px
Related tools carousel

Evidence Sources

Mifflin MD, St Jeor ST, et al. Am J Clin Nutr. 1990
Harris JA, Benedict FG. Proc Natl Acad Sci U S A. 1918
Institute of Medicine: Dietary Reference Intakes for Energy (2005)
American College of Sports Medicine (ACSM)
International Society of Sports Nutrition (ISSN)
Centers for Disease Control and Prevention (CDC)
National Institutes of Health (NIH): Weight Management