TDEE Calculator

Disclaimer

This tool gives you an estimate based on what you enter. Your actual calorie needs shift daily based on sleep, stress, hormones, and how your body responds. Do not treat this number as medical advice. Before changing your diet, especially if you have a health condition, speak with your doctor or a registered dietitian.

Expert Review

This calculator runs on the Mifflin-St Jeor equation, the most tested formula for estimating daily calorie needs. Results can be off by 10 percent or more. Work with a registered dietitian before overhauling your diet. Last updated May 25, 2026.

Sources

• American Journal of Clinical Nutrition — Mifflin-St Jeor equation validation research
• National Institutes of Health — calorie balance, BMR, and energy expenditure data
• Centers for Disease Control and Prevention — physical activity and calorie burn guidelines
• Academy of Nutrition and Dietetics — TDEE, macronutrient, and dietary guidance
• Harvard T.H. Chan School of Public Health — energy balance and weight management research

What Is a TDEE Calculator?

Most people eat based on a rough idea and hope it works. Sometimes it does. Mostly it does not. TDEE is the actual number of calories your body burns in a full day. A TDEE calculator takes your age, weight, height, and activity level and gives you that number. Once you have it, you finally know whether you are eating too much, too little, or right where you need to be.

Benefits

• Gives you a real calorie number instead of a random guess
• Breaks it down by goal so you know what to eat to lose, gain, or maintain
• Uses your actual stats, not some generic chart from the internet
• Takes five minutes and gives you a number that stops months of guessing
• Works as your baseline that you can adjust as things change
• Stops you from eating too little and crashing, or too much and wondering why nothing is happening

How Does It Work?

Be honest when you fill it out. That is the only real rule. Put in your age, weight, height, and how active you actually are on a normal day, not your best day. The calculator figures out your BMR first, which is just the calories your body burns doing absolutely nothing. Then it adjusts that number up based on how much you move. The number you get out is your TDEE. Start there and tweak it based on what actually happens over the next few weeks.

Did You Know?

Most people pick the wrong activity level and wonder why the number feels off. Choosing moderately active when you mostly sit at a desk all day is one of the most common mistakes. Your TDEE also drops as you lose weight, so the number that worked in January may not be right by March.

Myth vs. Facts

Myth: Eating below your TDEE means you will lose fat. Fact: Cut too far below it, and your body slows down and pulls energy from muscle instead of fat

Myth: Your TDEE is fixed. Fact: Lose ten pounds, and it drops. Gain muscle, and it goes up. It changes with your lifestyle.

Myth: The calculator gives you a precise number. Fact: It gives you an estimate only. Sleep, stress, and hormones move the real number around daily.

Myth: Working out is what drives your calorie burn. Fact: Your daily burn comes from resting metabolism, everyday movement, exercise, and food digestion.

Privacy Note

You type your numbers in, you get your answer, and that is it. Nothing leaves your screen. No data gets saved, sent, or stored anywhere. It’s just you and the calculator, with no extra eyes watching.

When Should You Use This Calculator?

• When you have been eating the same way for a while, and nothing is changing
• Before starting any new diet, so you have an actual number to work from
• When you lose weight, and your old calorie target suddenly stops working
• After a big lifestyle shift, like a new job, injury, or dropping a workout habit
• When you are switching from trying to lose weight to trying to build muscle
• Anytime you catch yourself eating by feel and want something more concrete to go on

Why Your TDEE Number Goes Stale

Lose weight, and your body needs less fuel to run itself. Simple math. But TDEE also shifts when sleep gets worse, stress piles up, or your daily movement quietly drops without you noticing. The number you calculated in week one is often wrong by week six. Recalculate every four to six weeks or every time something significant changes.

Stop Picking the Wrong Activity Level

Sedentary means desk job, car commute, couch at night. That is most Americans. Here is what each level actually looks like:

• Sedentary — you sit most of the day and barely move outside of that
• Lightly active — a couple of workouts a week, but otherwise sitting all day
• Moderately active — you are genuinely moving every single day, not just hitting the gym twice
• Very active — physical job or training hard five or more days a week
• Extra active — two a day workouts or on your feet all day at work

Be honest. Most people are one level lower than they think.

What Eating Too Little Actually Does to You

Slashing calories feels logical when you want to lose weight. But push too far below your TDEE and your body stops cooperating. Your metabolism slows down. Your body may hold onto fat more stubbornly and start pulling energy from muscle instead. Hunger hormones go out of control, and your energy disappears. A small deficit works well. A massive one just fights you back.

Stop eating in the dark. Run your numbers through the TDEE calculator now and find out what your body actually needs every day. That one number changes how you think about food completely.

Editorial Disclosure: This content was drafted with AI assistance and carefully edited, reviewed, and fact-checked by our editorial team before publication.