Total Daily Energy Expenditure is an estimate of calories you burn per day including activity. It starts from BMR (basal metabolic rate) and multiplies by an activity factor.

How large should a calorie deficit be?

A common sustainable deficit is around 300 to 500 kcal per day for many adults, but needs vary. Aggressive deficits are harder to maintain and may increase muscle loss risk without coaching.

How accurate is Mifflin–St Jeor?

It is widely used for estimates but individual metabolism differs. Track trends over weeks and adjust with a dietitian or doctor if you have medical conditions.

Do I need to count macros?

Not necessarily. Calorie balance drives weight change for most people, but protein, fibre and food quality support satiety and health. A professional can help set macro targets.

Last updated: 01.05.2026

Calorie Deficit Calculator

Estimate maintenance calories (TDEE) and a daily calorie target for weight loss using Mifflin–St Jeor and activity multipliers.

Calorie target

Mifflin–St Jeor BMR × activity − your deficit.

BMR: 1689 kcal/day

TDEE (est.): 2618 kcal/day

Target intake: 2218 kcal/day

Using the calorie deficit calculator safely

Select your sex, age, height, weight and typical activity level. The tool estimates BMR with the Mifflin–St Jeor equation, multiplies by an activity factor to approximate TDEE, then subtracts your chosen daily deficit to suggest a calorie target.

Results round to whole calories for readability. If the target falls very low, treat it as a sign to reassess deficit size or speak with a professional rather than following the number blindly.

Why estimates differ from wearables and lab tests

Fitness trackers, smart scales and indirect calorimetry can all disagree. Online equations use population averages. Your job type, genetics, sleep, stress and medications change expenditure. Use this calculator as a starting point and refine based on real-world weight trend over several weeks.

Pair calorie guidance with resistance training and adequate protein where appropriate to support lean mass while losing fat.