TDEE vs BMR: Which Number Should You Use?

BMR and TDEE are two numbers that come up in almost every weight-loss or fitness plan, and they are often confused. Knowing the difference helps you set a realistic calorie target instead of guessing.

What is BMR?

Basal Metabolic Rate (BMR) is the energy your body uses at complete rest to keep you alive, covering breathing, circulation and cell repair. It is the minimum, not the number you should eat to. A common estimate is the Mifflin-St Jeor equation:

• Men: 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5
• Women: 10 x weight (kg) + 6.25 x height (cm) - 5 x age - 161

What is TDEE?

Total Daily Energy Expenditure (TDEE) is the energy you burn across the whole day including movement, exercise and digestion. It is estimated by multiplying BMR by an activity factor, roughly 1.2 for a sedentary lifestyle up to about 1.9 for very hard daily training.

Worked example

A 35-year-old man weighing 80 kg and 178 cm tall:

BMR = 800 + 1,112.5 - 175 + 5 = 1,742.5 kcal.

With a lightly active factor of 1.375, TDEE = 1,742.5 x 1.375 = about 2,396 kcal a day.

Calculate yours with the TDEE Calculator UK.

Which one should you use?

Use TDEE to plan how much to eat. Eating around your TDEE maintains weight. A moderate deficit of about 500 kcal a day below TDEE leads to roughly 0.45 kg of loss a week for most people. BMR is useful as a reference floor, since eating far below it is not advisable without medical supervision.

Limits of the estimates

These formulas are estimates and individuals vary by 10% or more. Track your weight and average intake for two to three weeks and adjust. If you have a medical condition, are pregnant or have a history of disordered eating, speak to a GP or registered dietitian before restricting calories.

Frequently Asked Questions

Is BMR the same as TDEE?

No. BMR is energy used at rest. TDEE includes all daily activity and is the number used for calorie targets.

How many calories below TDEE should I eat to lose weight?

A deficit of around 300 to 500 kcal a day is a commonly recommended, sustainable starting point.

Which formula is most accurate?

Mifflin-St Jeor is widely used and generally performs well for most adults, but it is still an estimate.

Should I eat below my BMR?

Generally no, not without medical supervision.

This article is for general information only and is not financial, legal or medical advice. Rules and figures change, so check the official sources below and speak to a qualified adviser for decisions that matter.