What is TDEE?
Your Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a day. It is the sum of your Basal Metabolic Rate (BMR) — the energy your body uses just to stay alive — plus everything on top: walking, training, digesting food and fidgeting. TDEE is the single most useful number in nutrition, because every fat-loss or muscle-gain plan comes down to eating below or above it.
How this calculator works
The calculator first estimates your BMR with the Mifflin-St Jeor equation, which validation studies have repeatedly found to be the most accurate of the common BMR formulas for the general population:
| Sex | Equation |
|---|---|
| Men | BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 |
| Women | BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161 |
Your BMR is then multiplied by an activity factor between 1.2 (sedentary) and 1.9 (athlete) to produce your TDEE. Choosing the right factor is where most people go wrong: training four times a week does not make you "very active" if you spend the other 22 hours at a desk. When in doubt, pick the lower option — you can always adjust upward if you lose weight faster than expected.
Setting cutting and bulking targets
The calculator suggests a cut at 20% below maintenance and a bulk at 10% above. A 20% deficit typically produces roughly 0.5–1% of body weight lost per week — fast enough to see progress, moderate enough to preserve muscle and training performance. Aggressive deficits beyond 25–30% tend to cost strength, energy and adherence.
For bulking, a modest 10% surplus is deliberate. Muscle is built slowly; eating far above maintenance mostly accelerates fat gain, not muscle gain. Most natural lifters do well gaining around 0.25–0.5% of body weight per month while training hard and eating enough protein.
Treat the number as a starting point
Every equation is an estimate; individual metabolisms vary by a few hundred calories in either direction. The professional approach is simple: eat at your calculated target for two to three weeks, weigh yourself under consistent conditions, and adjust. Weight stable on a cut? Drop 150–200 calories. Gaining too fast on a bulk? Trim the surplus. Your own scale data always beats any formula.