Step 1: Convert to metric
Example: a 47-year-old woman, 5′3″ and 165 lb.
- Weight: 165 ÷ 2.2046 = 74.8 kg
- Height: 63 inches × 2.54 = 160.0 cm
Step 2: Calculate BMR
Mifflin-St Jeor for women: 10 × kg + 6.25 × cm − 5 × age − 161
10 × 74.8 + 6.25 × 160.0 − 5 × 47 − 161 = 748 + 1,000 − 235 − 161 ≈ 1,353 calories/day
For men, use +5 instead of −161.
Step 3: Choose an activity factor
| Level | Factor | This example |
|---|---|---|
| Sedentary | 1.2 | 1,623 |
| Lightly active | 1.375 | 1,860 |
| Moderately active | 1.55 | 2,096 |
| Very active | 1.725 | 2,333 |
| Extra active | 1.9 | 2,570 |
Step 4: Multiply
She walks for exercise two or three times a week, so “lightly active” fits: 1,353 × 1.375 ≈ 1,860 calories a day. That is her estimated TDEE. The calculator above should show the same number; small differences come only from rounding.
Common mistakes
- Mixing units: putting pounds into the kilogram slot roughly doubles that term.
- Overstating activity: describe an average week, not your most active one.
- Counting exercise twice: if the activity factor includes your workouts, don’t add tracker exercise calories on top.
- Treating it as exact: the result is an estimate; round it and refine it with real-life data.
Frequently asked questions
What is the TDEE formula?
TDEE = BMR × activity factor. BMR usually comes from the Mifflin-St Jeor equation (10 × kg + 6.25 × cm − 5 × age, +5 for men or −161 for women), and the activity factor ranges from 1.2 (sedentary) to 1.9 (extra active).
How do I calculate TDEE from BMR?
Multiply your BMR by the activity factor that matches a typical week: 1.2 sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extra active.
Do I need to convert pounds and inches?
Yes, the standard equations use kilograms and centimeters. Divide pounds by 2.2046 to get kilograms and multiply inches by 2.54 to get centimeters.
Can I calculate TDEE from my own food and weight logs?
Yes. If you log intake and weight for several weeks, your average intake plus or minus the energy implied by your weight change approximates your real TDEE. How to find your maintenance calories explains a simple version.