How this works
Daily calorie needs come in two layers. Your Basal Metabolic Rate (BMR) is what you burn at rest — keeping organs running and body temperature steady. Multiply that by an activity factor to get your Total Daily Energy Expenditure (TDEE) — your real daily burn including movement, exercise, and digestion. From there, eat at TDEE to maintain weight, ~500 below for steady fat loss, or ~300 above for lean muscle gain. The calculator handles all three steps in one go.
The formula
Activity factors: 1.2 sedentary (desk job, no exercise), 1.375 light (1–3 sessions/week), 1.55 moderate (3–5 sessions), 1.725 active (6–7 sessions), 1.9 very active (twice-daily training or hard physical job). The 500/300 cut and gain targets are starting points — adjust by 100–200 kcal after a few weeks based on actual weight change.
Example calculation
- A 30-year-old man, 175 cm, 75 kg, with a desk job and 4 weekly gym sessions chooses "moderate" activity.
- BMR ≈ 1,699 kcal/day. TDEE = 1,699 × 1.55 ≈ 2,633 kcal/day to maintain weight.
- For fat loss: 2,633 − 500 ≈ 2,133 kcal/day. For lean gain: 2,633 + 300 ≈ 2,933 kcal/day.
Frequently asked questions
Why are the deficit and surplus different sizes (500 vs 300)?
A 500 kcal deficit gives ~0.5 kg (~1 lb) of weight loss per week, the upper end of what most experts consider sustainable without losing muscle. A 300 kcal surplus is enough to support ~0.25–0.5 kg of muscle gain per week — much more than that and the extra calories tend to be stored as fat rather than turned into lean tissue.
How accurate is this for me personally?
The BMR estimate is within ~10% for most adults, and the activity multipliers can vary by another 10–15% person to person. Treat the result as a starting point. Track weight weekly for 3–4 weeks: if weight stays flat, you're at maintenance; if it moves more or less than expected, adjust calories by 100–200 kcal/day.
What about macros — protein, carbs, fat?
The most defensible default: 1.6–2.2 g protein per kg of bodyweight (preserves muscle in a deficit, supports growth in a surplus), 0.8–1.0 g fat per kg as a floor for hormone health, the rest as carbs. Athletes can go higher on carbs; lower-activity individuals can go lower. Calorie target matters most; macros matter at the margins.
Should I eat back exercise calories?
Usually no — your activity multiplier already includes typical weekly exercise. Eating back tracker-reported burns on top of that risks double-counting (and most fitness trackers overestimate burn by 20–50%). If your activity changes a lot week to week, just shift to a higher or lower activity factor instead.