TDEE Calculator

Understanding how many calories your body actually needs each day is the foundation of every effective nutrition plan.

Reviewed by: CalcMojo Editorial Team

This calorie calculator uses the Mifflin-St Jeor equation, widely regarded as the most accurate predictive formula for estimating resting metabolic rate in healthy adults, to determine your Total Daily Energy Expenditure (TDEE). Enter your age, sex, height, weight, and activity level, and the tool returns a personalized daily calorie target along with adjusted numbers for weight loss, moderate weight loss, and weight gain.

TDEE represents the total number of calories your body burns in a 24-hour period, combining your Basal Metabolic Rate (BMR) with the energy cost of physical activity and the thermic effect of food. Most people significantly overestimate or underestimate their actual calorie needs, which is the primary reason diets stall or fail altogether. A 160-pound moderately active woman, for example, may assume she needs 2,000 calories per day when her actual TDEE is closer to 1,850, a difference that adds up to roughly a pound of fat gain every three weeks.

Whether you are trying to lose weight, build muscle, or simply maintain your current body composition, knowing your TDEE gives you a concrete number to plan around. This calculator removes the guesswork and puts evidence-based math behind your daily nutrition decisions.

How the Mifflin-St Jeor Equation Works

The Mifflin-St Jeor equation was developed in 1990 by researchers M.D. Mifflin and S.T. St Jeor and published in the American Journal of Clinical Nutrition. It estimates your Basal Metabolic Rate (BMR), which is the number of calories your body requires at complete rest to maintain basic life functions such as breathing, circulation, and cell production.

For men: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) + 5

For women: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161

Once BMR is calculated, the equation multiplies it by an activity factor to produce your TDEE:

• Sedentary (little or no exercise): BMR x 1.2
• Lightly active (light exercise 1-3 days per week): BMR x 1.375
• Moderately active (moderate exercise 3-5 days per week): BMR x 1.55
• Very active (hard exercise 6-7 days per week): BMR x 1.725
• Extra active (very hard exercise, physical job, or training twice per day): BMR x 1.9

For example, a 30-year-old male who weighs 80 kg and stands 178 cm tall would have a BMR of approximately 1,780 calories. If he exercises moderately 4 days per week, his TDEE would be roughly 2,759 calories per day.

The Mifflin-St Jeor equation has been shown in multiple validation studies, including a 2005 review by the American Dietetic Association, to predict measured resting metabolic rate within 10% for the majority of healthy, non-obese adults, making it more accurate than the older Harris-Benedict equation for most populations.

Why TDEE Matters More Than BMR Alone

BMR tells you how many calories your body burns at absolute rest, essentially the energy cost of keeping you alive if you stayed in bed all day. But nobody lives at absolute rest. TDEE accounts for all the calories you actually burn throughout your day, including:

Exercise Activity Thermogenesis (EAT). This is the energy you expend during intentional exercise: running, weight training, cycling, swimming, or any structured workout. For most people, EAT accounts for 5% to 10% of total daily expenditure, though it can be higher for serious athletes.

Non-Exercise Activity Thermogenesis (NEAT). This is the energy you burn through all non-exercise movement: walking, fidgeting, standing, cooking, cleaning, and typing. NEAT varies enormously between individuals and can account for 15% to 50% of total daily calories. People with active jobs (nurses, construction workers, retail workers) have significantly higher NEAT than desk workers.

Thermic Effect of Food (TEF). Your body expends energy digesting and processing food, typically about 10% of your total calorie intake. Protein has the highest thermic effect (20-30% of its calories are burned during digestion), followed by carbohydrates (5-10%) and fat (0-3%).

Understanding TDEE gives you a complete picture of your daily energy balance. If you eat fewer calories than your TDEE, you lose weight. If you eat more, you gain weight. If you match it, you maintain. Use our BMR Calculator to see your BMR in isolation, or our Macro Calculator to break your calorie target into protein, carbs, and fat.

Using Your TDEE for Weight Loss

To lose weight, you need to create a calorie deficit, meaning you consume fewer calories than your TDEE. The size of that deficit determines the rate of weight loss.

Moderate deficit (250-500 calories per day). This produces a weight loss of approximately 0.5 to 1 pound per week. A moderate deficit is sustainable for most people and preserves more muscle mass during the process. If your TDEE is 2,400, eating 1,900-2,150 calories per day falls in this range.

Aggressive deficit (500-1,000 calories per day). This targets 1 to 2 pounds per week, which is generally considered the maximum safe rate of weight loss for most adults. However, deficits at the higher end of this range are difficult to maintain, often lead to muscle loss, and can trigger metabolic adaptation where your body reduces its energy expenditure in response to prolonged restriction.

Very low calorie diets (below 1,200 for women or 1,500 for men). These should only be followed under medical supervision. Extreme restriction can cause nutrient deficiencies, gallstones, muscle wasting, and metabolic disruption.

The most effective approach for most people is a moderate deficit combined with adequate protein intake (0.7-1.0 grams per pound of body weight) and resistance training to preserve lean mass. Use the Calorie Deficit Calculator to model specific deficit scenarios and timelines.

Using Your TDEE for Muscle Gain

Building muscle requires a calorie surplus, typically 200-500 calories above your TDEE. This surplus provides the extra energy and raw materials your body needs to synthesize new muscle tissue when combined with progressive resistance training.

A smaller surplus (200-300 calories) minimizes fat gain during the bulking process, though muscle gain will be slower. A larger surplus (400-500 calories) accelerates muscle growth but comes with more fat accumulation. Most intermediate to advanced trainees find that a surplus of 250-350 calories above TDEE is the practical sweet spot.

Protein requirements during a muscle-building phase are higher than maintenance, generally 0.8-1.2 grams per pound of body weight per day. The remaining surplus calories should come primarily from carbohydrates, which fuel intense training and support recovery. Use our Macro Calculator to calculate the optimal protein, carb, and fat split for your calorie target.

Common Mistakes When Estimating Calories

Overestimating activity level. This is the most common error. People who work desk jobs and exercise 3 times per week often select "very active" when "lightly active" or "moderately active" is more accurate. Be honest about your weekly activity. If in doubt, choose the lower option and adjust based on results over 2-3 weeks.

Ignoring liquid calories. Beverages like coffee drinks, smoothies, juice, alcohol, and soda can add 300-800 calories per day without registering as food. A single large latte with flavored syrup can contain 350-400 calories.

Underestimating portion sizes. Research consistently shows that people underestimate the calorie content of their meals by 20-50%. Using a food scale for at least the first few weeks provides a much more accurate picture than eyeballing portions.

Not adjusting over time. As you lose weight, your TDEE decreases because a smaller body requires less energy to maintain. Recalculate your TDEE every 10-15 pounds lost and adjust your calorie target accordingly.

Eating back exercise calories. Fitness trackers and cardio machines are notoriously inaccurate at estimating calories burned during exercise, often overestimating by 30-50%. If your TDEE already includes your activity level, you do not need to eat additional calories on workout days. Use our Calories Burned Calculator for more accurate exercise calorie estimates.

Activity Level Guide

Choosing the right activity multiplier is critical to an accurate TDEE estimate. Here is a practical guide to help you self-assess.

Sedentary (1.2). You work a desk job, drive to work, and get minimal structured exercise. Daily step count is typically under 5,000.

Lightly Active (1.375). You walk regularly, exercise 1-3 times per week with moderate intensity, or have a job that involves some walking. Daily step count is 5,000-7,500.

Moderately Active (1.55). You exercise at moderate to high intensity 3-5 times per week, or have a physically active job combined with some exercise. Daily step count is 7,500-10,000.

Very Active (1.725). You train intensely 6-7 days per week, or have a very physically demanding job (construction, farming). Daily step count exceeds 12,500.

Extra Active (1.9). You are a competitive athlete training multiple hours per day, or you combine heavy physical labor with regular intense exercise. This level applies to a very small percentage of the population.

If your results do not match your real-world experience after 2-3 weeks of consistent tracking, adjust your activity level up or down by one tier and reassess.

This calculator provides general estimates based on published formulas. It is not medical advice and does not replace consultation with a qualified healthcare provider.

Frequently Asked Questions

What is TDEE and why does it matter?

TDEE stands for Total Daily Energy Expenditure, the total number of calories your body burns in a day including basal metabolism, physical activity, and the thermic effect of food. It matters because your TDEE determines whether you gain, lose, or maintain weight. Eating above TDEE causes weight gain, eating below causes weight loss, and matching it maintains your current weight.

How accurate is the Mifflin-St Jeor equation?

The Mifflin-St Jeor equation predicts resting metabolic rate within 10% for most healthy, non-obese adults according to validation studies, including a 2005 review by the American Dietetic Association. It is generally more accurate than the older Harris-Benedict equation. However, individual variation exists due to genetics, body composition, hormonal factors, and metabolic adaptation.

How many calories should I eat to lose weight?

To lose weight at a sustainable rate of 0.5 to 1 pound per week, eat 250 to 500 calories below your TDEE. For example, if your TDEE is 2,200 calories, a target of 1,700 to 1,950 calories per day would produce steady weight loss while preserving muscle mass. Avoid going below 1,200 calories for women or 1,500 for men without medical supervision.

Should I eat back the calories I burn during exercise?

Generally no, if your TDEE calculation already accounts for your activity level. The activity multiplier built into the Mifflin-St Jeor equation includes your typical exercise. Eating back exercise calories on top of your TDEE-based target can eliminate your deficit. The exception is unusually long or intense sessions beyond your normal routine.

How often should I recalculate my TDEE?

Recalculate every 10 to 15 pounds of weight change, or every 6 to 8 weeks during an active diet phase. As your body weight decreases, your TDEE drops because a smaller body requires fewer calories to maintain. Failing to recalculate is a common reason weight loss plateaus.

What is the difference between BMR and TDEE?

BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest, just to maintain basic life functions. TDEE (Total Daily Energy Expenditure) takes your BMR and adds the calories burned through physical activity and food digestion. TDEE is always higher than BMR and is the number you should use for setting calorie targets.

Why do men and women have different calorie formulas?

Men typically have more lean muscle mass and less body fat than women of the same height and weight, which results in a higher metabolic rate. The Mifflin-St Jeor equation accounts for this with a +5 constant for men and a -161 constant for women. These constants were derived from measured metabolic data in the original 1990 study.

Can TDEE calculators account for metabolic adaptation?

No. TDEE calculators estimate energy expenditure based on standard formulas, but they cannot account for metabolic adaptation, the process by which your body reduces its energy expenditure in response to prolonged calorie restriction. If you have been dieting for an extended period and weight loss has stalled despite consistent adherence, your actual TDEE may be lower than the calculator predicts. A diet break at maintenance calories for 1-2 weeks can help restore metabolic rate.

Sources & Methodology

• BMR calculated using the Mifflin-St Jeor equation (Mifflin MD, St Jeor ST, et al., American Journal of Clinical Nutrition, 1990).
• Activity multipliers based on the standard physical activity level (PAL) scale used in clinical nutrition practice.
• Accuracy validation referenced from Frankenfield DC, Roth-Yousey L, Compher C, "Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Nonobese and Obese Adults," Journal of the American Dietetic Association, 2005.
• Weight loss rate guidelines based on recommendations from the National Institutes of Health (NIH) and American College of Sports Medicine (ACSM).
• Thermic effect of food percentages from Westerterp KR, "Diet induced thermogenesis," Nutrition & Metabolism, 2004.

Default values shown are illustrative. Always verify with your healthcare provider. Data accurate as of: March 2026