What Is TDEE? BMR, Activity Multipliers & a Worked Example
TDEE is the single most useful number for anyone trying to manage their weight — here's exactly what it means, how it's calculated, and a full worked example you can check your own numbers against.
BMR vs TDEE
BMR (Basal Metabolic Rate) is the number of calories your body burns at complete rest — just to keep your heart beating, your lungs breathing, your brain running, and your body temperature stable. It doesn't include digestion, movement, or exercise.
TDEE (Total Daily Energy Expenditure) is the bigger, more useful number: your BMR plus everything else you burn in a day — digesting food, walking around, doing chores, exercising, even fidgeting. TDEE is what you should compare your calorie intake against if you're trying to lose, gain, or maintain weight, because it reflects your actual total energy use, not just your resting baseline.
The five activity multiplier tiers
TDEE is typically estimated by multiplying BMR by an activity factor. CalorieToday and its calculators use five standard tiers:
- Sedentary — ×1.2: desk job, little to no structured exercise.
- Light — ×1.375: light exercise or sports 1–3 days a week.
- Moderate — ×1.55: moderate exercise or sports 3–5 days a week.
- Active — ×1.725: hard exercise or sports 6–7 days a week.
- Athlete — ×1.9: very hard training, often twice a day.
Picking the right tier matters more than most people expect — the jump from Sedentary to Moderate alone changes your estimated TDEE by nearly 30%. Be honest about your actual week, not the week you're planning to have once you get motivated.
The Mifflin-St Jeor formula
Of the many BMR formulas developed over the decades, Mifflin-St Jeor is generally regarded as the most accurate for the general population, and it's the formula used throughout CalorieToday:
BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years), then +5 for men or −161 for women.
A worked example
Let's calculate TDEE for a 30-year-old woman, 65 kg, 165 cm tall, with moderate activity (exercise 3–5 days a week, multiplier ×1.55):
- Step 1 — weight term: 10 × 65 = 650
- Step 2 — height term: 6.25 × 165 = 1,031.25
- Step 3 — age term: 5 × 30 = 150
- Step 4 — sum: 650 + 1,031.25 − 150 = 1,531.25
- Step 5 — female adjustment: 1,531.25 − 161 = 1,370.25 → BMR ≈ 1,370 cal/day
- Step 6 — apply activity multiplier: 1,370.25 × 1.55 = 2,123.9 → TDEE ≈ 2,124 cal/day
So this person burns roughly 2,124 calories on an average day. To lose about 1 lb/week, she'd target a deficit of roughly 500 cal/day, landing around 1,624 calories — well above the 1,200 cal/day floor recommended as a safe minimum for women, so no adjustment is needed. You can run your own numbers through the same formula with our free TDEE calculator.
Why TDEE estimates are approximations
It's worth being honest about what a formula like Mifflin-St Jeor can and can't do. It was derived from population averages, so it estimates what a typical person of your age, sex, height and weight burns — not what you specifically burn. Two real-world factors push individual TDEE away from the formula's prediction:
- Metabolic adaptation — as you lose weight, your body genuinely needs fewer calories to maintain itself (there's simply less of you), and metabolism can also downshift somewhat beyond what weight loss alone explains, especially during extended dieting.
- NEAT variation (Non-Exercise Activity Thermogenesis) — the calories burned through everyday fidgeting, posture, and incidental movement varies enormously between individuals and can itself drop during a sustained calorie deficit, independent of deliberate exercise.
Because of this, the number from any TDEE calculator — including ours — should be treated as an informed starting point, not a fixed truth. The way to get a genuinely accurate number for your own body is to track your food intake and weight consistently for a few weeks and see what actually happens, then adjust your target based on real data rather than trusting the formula blindly.
Putting your TDEE to work
Once you have a starting TDEE, the practical next step is tracking — logging food against that target and watching your weight trend to confirm (or correct) the estimate. CalorieToday calculates your BMR and TDEE using the exact formula and activity tiers in this article, then automatically recalculates as your weight changes, so your target stays accurate without you having to redo the math by hand.
Try the TDEE calculator for a one-off estimate, or open the CalorieToday app to track it day to day for free.