There's no single answer — but there's a defensible one: for a 30-year-old 200 lb 5'10" male, TDEE ranges from 2,280 (sedentary) to 3,200 (very active). Here's the math and how to land on your personal number.
Worked example
Using the Mifflin-St Jeor formula for a 30-year-old 5'10" (178 cm) 200 lb (91 kg) male:
BMR = 10 × weight_kg + 6.25 × height_cm − 5 × age + 5BMR = 910 + 1112.5 − 150 + 5 = 1,878 calories
Multiply by activity level:
- Sedentary (1.2) — 2,253 calories.
- Lightly active (1.375) — 2,582.
- Moderately active (1.55) — 2,911.
- Very active (1.725) — 3,240.
For weight loss
Subtract 300–500 from TDEE. A moderately active 200 lb male at 2,911 TDEE should eat 2,400–2,600 calories for fat loss of 0.5–1 lb per week. Protein target: 0.8 g per lb bodyweight = 160 g/day.
For maintenance
Eat TDEE. For the same man, that's 2,900 calories — or whatever his specific activity level yields. Trust the weekly average on the scale, not daily fluctuations (which are mostly water and glycogen).
The honest disclaimer
These are estimates within ±10%. Two people with identical stats can differ by 200–300 calories in true TDEE. Track your intake against your weight trend for 2 weeks and adjust up or down from there.
Enter your age, height, weight, and activity. Calibrate against reality after 2 weeks of tracking.