TDEE Calculator (Total Daily Energy Expenditure)

Total Daily Energy Expenditure, or TDEE, is a general estimate of how many calories your body uses in an average day, taking into account both your resting metabolism and your activity level. It is a widely used starting point for understanding calorie needs, though it is general information rather than a personal prescription.

Understanding roughly where your maintenance calories sit can be useful context, whether you are simply curious about your own energy needs or thinking about a gradual, sensible change to your eating habits alongside general lifestyle advice from the NHS.

This calculator estimates your BMR and TDEE, along with general calorie ranges for maintaining, gently reducing, or gently increasing your weight, based on commonly used formulas.

How to use the TDEE calculator

Enter your gender, age, height and weight, in metric or imperial units, along with your activity level. The calculator shows your estimated BMR, your TDEE, and general calorie figures for maintenance, a mild deficit, and a mild surplus.

How the calculation works

This calculator uses the Mifflin-St Jeor equation, one of the most commonly used formulas for estimating BMR, which takes your weight, height, age and gender into account. Your BMR is then multiplied by an activity factor, ranging from 1.2 for a sedentary lifestyle up to 1.9 for very physically demanding routines, to estimate your TDEE.

Choosing the right activity level matters a lot, so it is worth being realistic. Sedentary means little or no structured exercise, closer to a desk based routine with minimal walking. Lightly active suits someone doing light exercise a few times a week. Moderately active fits regular exercise most days. Very active and extra active are for people training hard most days, or doing physically demanding work on top of exercise. Most people who think of themselves as active actually sit in the light to moderate categories rather than the higher ones, so it is worth being honest rather than generous when picking a level.

The calorie ranges shown for mild loss and mild gain simply adjust your TDEE by around 250 calories a day in either direction, reflecting a gentle, gradual approach rather than an aggressive target. This calculator deliberately avoids suggesting large calorie deficits, since sustainable, modest changes tend to work better for most people over time.

Worked example

Take a 35 year old man, 180cm tall, weighing 85kg, with a moderately active lifestyle. His estimated BMR comes to around 1,805 calories a day. Applying the moderate activity multiplier gives an estimated TDEE of around 2,798 calories a day.

For general reference, a mild calorie deficit would sit around 2,548 calories a day, and a mild surplus around 3,048 calories a day. These figures are general information based on common formulas, not a personal recommendation, and should be considered alongside your own health circumstances.

A note on using this information sensibly

Calorie needs vary a great deal between individuals, and factors this calculator cannot account for, including underlying health conditions, medication, and genuine differences in metabolism, all play a role. If you are considering any significant change to your diet, or have any health concerns at all, the NHS recommends speaking to your GP or a registered dietitian, who can give guidance tailored to you rather than a general formula.

It is worth treating any calorie target as a rough guide to experiment with gradually, adjusting based on how you actually feel and how your weight responds over several weeks, rather than following a number precisely.

This calculator will not suggest an aggressive deficit, and deliberately will not go below general, widely recognised minimums for healthy adults. If you are looking for a rapid change, please pause and speak to a healthcare professional rather than pursuing an extreme approach, since very low calorie intakes can be harmful and are rarely sustainable in the long run.

Related calculators

For a simpler, well known measure, try our BMI calculator. Our ideal weight calculator gives a healthy weight range for your height using several formulas, and our BMI guide covers NHS weight categories and their limitations in more depth. If you are tracking other life stage health calculators, our pregnancy due date calculator may also be useful.