Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a day, accounting for your resting metabolism plus all physical activity. It is calculated by multiplying your Basal Metabolic Rate (BMR) by an activity factor that reflects your typical exercise level.

Which formula is more accurate — Mifflin-St Jeor or Harris-Benedict?

The Mifflin-St Jeor equation (1990) is generally considered more accurate for most modern adults and is the preferred formula among registered dietitians. The original Harris-Benedict equation (1919) tends to overestimate calorie needs by roughly 5%. The revised Harris-Benedict (1984) narrows this gap, but Mifflin-St Jeor remains the clinical standard.

How accurate are the calorie counts?

TDEE formulas estimate energy needs based on population averages. Individual results can vary by ±200–300 kcal/day due to factors such as genetics, body composition, hormones, and non-exercise activity thermogenesis (NEAT). Use the result as a starting point, then adjust intake based on real-world weight changes over 2–4 weeks.

Should I eat at maintenance or a deficit?

It depends on your goal. Eating at your TDEE maintains current weight. A deficit of 500 kcal/day typically produces about 0.5 kg (1 lb) of fat loss per week, while a 1,000 kcal deficit targets ~1 kg/week — though very-low-calorie approaches can increase muscle loss. A modest surplus of 250–500 kcal/day supports muscle gain with minimal fat accumulation. Consult a registered dietitian for a plan tailored to your specific needs.

How do I accurately calculate my TDEE?

For the most accurate result, weigh yourself first thing in the morning, measure your height precisely, and pick the activity level that honestly reflects your weekly exercise. Use the Mifflin-St Jeor formula, then verify in the real world: track intake and bodyweight for 2–4 weeks. If weight holds steady, that intake is your true TDEE — adjust the estimate up or down by 100–200 kcal as needed.

TDEE Calculator

Enter your age, sex, weight, height, and activity level to instantly calculate your BMR and TDEE. Choose between the Mifflin-St Jeor and Harris-Benedict equations, then view personalized calorie targets for weight loss, maintenance, or muscle gain.

Your Details

Unit System

Sex

Male Female

Age (years)

Weight (kg)

Height

Activity Level

Formula

Mifflin-St Jeor is the current clinical standard.

Results

Real-time calculation

Fill in your details to see your results.

Age, sex, weight, and height are required.

Summary

A TDEE calculator estimates your Total Daily Energy Expenditure — the calories your body burns each day from resting metabolism plus activity. It first finds your Basal Metabolic Rate (BMR) from age, sex, weight, and height using the Mifflin-St Jeor or Harris-Benedict equation, then multiplies BMR by an activity factor. The result gives maintenance calories plus targets for weight loss and gain.

How it works

Select your preferred unit system: Metric (kg/cm) or Imperial (lb/ft+in).
Choose your sex, then enter your age, weight, and height.
Select your typical activity level from the dropdown menu.
Optionally switch between the Mifflin-St Jeor and Harris-Benedict formulas.
Your BMR, TDEE, and five calorie targets appear instantly in the results panel.

Use cases

Determine your daily calorie maintenance level before starting a diet.
Calculate a calorie deficit to reach a healthy weight-loss pace of 0.5-1 kg per week.
Plan a caloric surplus for a lean bulking phase during strength training.

Frequently Asked Questions

Last updated: 2026-05-23 · Reviewed by Nham Vu