About My TDEE Calculator

Hi, and thanks for stopping by. I’m Robert, and I run My TDEE Calculator. I got into training seriously in my early twenties, and like most people I started by guessing my calories and hoping for the best. It took me the better part of a year to work out that the guess was the whole problem. Every calculator I found either buried the maths or asked me to sign up for something. I wanted one that just gave you the number, showed you where it came from, and got out of the way. So I built it.

What I enjoy most is hearing from people using it. If the calculator helped you, if something looks wrong, or if there’s a feature you wish it had, please get in touch, I read every message.

About This Site

My TDEE Calculator estimates your Total Daily Energy Expenditure: the number of calories your body burns across an average day. Enter a few details and you’ll also get your BMR, BMI, a healthy weight range, and daily macro targets for protein, carbs, and fat.

A few things that matter to me about how it works:

It runs entirely in your browser. Your age, weight, height, and body-fat figures never leave your device. Nothing is sent to a server, nothing is stored in a database, and there’s no account to create. Close the tab and it’s gone.

It’s free, with no upsell. I’m not selling meal plans, coaching, or supplements on the back of it. It’s fast. If you find it useful, sharing it is the single biggest help you can give the site.

Formulas Used

I’d rather show you the maths than ask you to trust a black box. Here’s exactly what’s happening when you press calculate.

Mifflin-St Jeor Equation

This is the default. Published in 1990 and still the formula most dietitians reach for when estimating resting energy needs in the general population.

Where m is mass in kilograms, h is height in centimetres, and a is age in years.

Your BMR is then multiplied by an activity factor — from sedentary through to twice-daily athletic training — to give your TDEE.

Katch-McArdle Equation

If you fill in the optional body-fat percentage field, the calculator switches to Katch-McArdle instead. Because it works from lean body mass rather than total weight, it’s generally the most accurate of the three — but only if your body-fat figure is accurate to begin with.

Where LBM is lean body mass in kilograms, calculated as your weight minus your fat mass.

Worth knowing: bathroom scales that report body fat are rough at best. Skinfold calipers used consistently by the same person are better for tracking change over time, and a DEXA scan is the gold standard if you want a genuine baseline — most large hospitals and university sports science departments offer them.

Revised Harris-Benedict Equation

The original Harris-Benedict dates to 1919 and was revised in 1984. It tends to run slightly higher than Mifflin-St Jeor, but plenty of people still prefer it, so [we calculate it alongside the others / it’s shown as an alternative estimate].

What these numbers can and can’t tell you

Every one of these equations produces an estimate. Real energy expenditure shifts with genetics, hormones, sleep, medication, illness, how much you fidget, and how much muscle you carry. Research generally puts these formulas within about 10% of measured expenditure for most healthy adults — useful, but not exact.

So treat your result as a starting point, not a verdict. Eat at that number for two to three weeks, track your weight honestly, and adjust based on what actually happens on the scale. Your own data beats any formula.

Disclosure

My TDEE Calculator is free to use, and running it costs money — hosting, domain, and the time that goes into keeping it accurate. Those costs are covered by advertising displayed through third-party ad networks, including Google AdSense.

Advertisers have no say in what I write. I don’t publish sponsored posts dressed up as editorial, and I don’t recommend products in exchange for payment.

Please also read our Privacy Policy and Terms of Use.

A note on your health

This site provides general educational information. It is not medical advice and it’s not a substitute for talking to a qualified professional.

Please speak to a doctor or registered dietitian before making significant changes to how you eat or train — particularly if you’re pregnant or breastfeeding, under 18, over 65, managing a condition like diabetes or thyroid disease, taking medication that affects appetite or metabolism, or have any history of disordered eating. Very low calorie intakes carry real risks and shouldn’t be attempted without supervision.

Say hello

Questions, corrections, feature ideas, or just to tell me the calculator helped — all welcome. Head to the contact page .