What is TDEE Calculator?

TDEE Calculator is a free online tool that estimates your daily calorie needs for maintenance, fat loss, or muscle gain in seconds. It uses the Mifflin–St Jeor equation—one of the most accurate formulas for estimating resting metabolic rate—then applies your selected activity level to calculate your Total Daily Energy Expenditure. The result gives you a personalized calorie target you can use for weight control, meal planning, or performance optimization.

Who it's for

• Weight-loss seekers – Anyone aiming to create a sustainable calorie deficit of 250–500 calories per day for steady fat loss without extreme restriction.
• Fitness enthusiasts – People who want to fine-tune their calorie surplus (200–350 calories) to support muscle gain while minimizing excess fat.
• Health-conscious beginners – Those new to tracking nutrition who need a reliable starting point to understand their daily energy needs and build better eating habits.

Key features

Mifflin–St Jeor formula

The calculator relies on the Mifflin–St Jeor equation, validated by research in the American Journal of Clinical Nutrition as one of the most accurate ways to estimate BMR in healthy adults. It calculates your resting metabolic rate based on weight, height, age, and sex, then multiplies it by your activity factor.

Five activity levels

You can choose from Sedentary (1.2) through Athlete (1.9), with clear descriptions for each level—from desk work with no exercise to twice-daily training or physically demanding jobs. This lets you match your lifestyle precisely rather than guessing.

Instant results

Enter your age, gender, weight, and height, then click Calculate. The tool immediately shows your estimated maintenance calories, so you can start planning your deficit or surplus right away.

Practical guidance

The calculator explains how to use your TDEE as a starting estimate—track your weight for 2–3 weeks, then adjust by 100–200 calories if needed. It also offers common deficit and surplus ranges for fat loss and muscle gain.

What stands out

"Treat your TDEE as a starting estimate rather than a perfect number."

Most calculators give you a number and stop there. TDEE Calculator emphasizes that your result is a baseline, not a final answer. It walks you through how to test the estimate against real-world weight changes and make small adjustments over time. This practical, iterative approach helps you avoid the frustration of rigid calorie targets that don't match your actual metabolism.

Worth checking out if…

You want a straightforward, science-backed calorie estimate without signing up, paying, or wading through ads. It's ideal if you're starting a weight-loss or muscle-building phase and need a clear number to begin with, plus the know-how to refine it as you go.