TDEE & Calorie Calculator
Your Total Daily Energy Expenditure (TDEE) is your resting burn (BMR) multiplied by how much you actually move — from a desk job to two training sessions a day. It's the number that should sit behind any weight goal.
Enter your details to see your maintenance, cut, and surplus targets.
How it's calculated
We calculate your BMR with the Mifflin-St Jeor formula, then multiply it by an activity factor to get TDEE (Total Daily Energy Expenditure). A pound of body fat holds roughly 3,500 kcal, so a daily deficit or surplus of about 500 kcal moves the scale by around 0.5 kg (1 lb) a week. These are population averages — your real-world results depend on sleep, stress, hormones, and how consistently you track, so treat the number as a starting estimate to adjust from.
Where the activity multipliers come from
The multipliers (roughly 1.2 for sedentary through 1.9 for very active) originate from doubly-labelled water studies — a research technique that tracks real energy expenditure in free-living people by measuring isotope turnover, rather than relying on self-reported activity. Sedentary (×1.2) describes someone with a desk job and little deliberate exercise; lightly active (×1.375) fits 1–3 light sessions a week; moderately active (×1.55) suits 3–5 sessions; very active (×1.725) suits daily training or a physical job; and extremely active (×1.9) fits twice-daily training or manual labour combined with exercise. Most people overestimate which band they're in — a few gym sessions a week without a physically demanding job usually lands in "lightly" or "moderately" active, not higher.
A worked example
Take someone with a BMR of 1,600 kcal who trains three times a week alongside a desk job — moderately active, ×1.55. TDEE = 1,600 × 1.55 = 2,480 kcal. To lose roughly 0.5 kg a week, they'd eat around 1,980 kcal/day (a 500 kcal deficit); to gain muscle steadily, around 2,980 kcal/day (a 500 kcal surplus). Neither number is exact — it's a starting point to weigh yourself against for 2–3 weeks and adjust from there.
Why the number needs revisiting over time
TDEE isn't fixed. As you lose weight, your BMR falls too (a smaller body needs fewer calories to maintain), so a deficit that worked at 80 kg will produce a smaller deficit — or none at all — once you're at 72 kg unless you recalculate. The reverse applies when gaining weight or muscle. A reasonable habit is to recheck your TDEE every 4–6 weeks, or sooner if your weight has moved more than 2–3 kg, rather than eating the same fixed number for months on end.
Frequently asked questions
How many calories do I need to lose weight?
A moderate deficit of 300–500 kcal/day below your maintenance (TDEE) figure is a sustainable starting point for most adults — roughly 0.25–0.5 kg of loss per week. Read the full breakdown in calorie deficit for weight loss: the honest math.
What is TDEE?
Total Daily Energy Expenditure is your BMR (resting burn) multiplied by an activity factor that accounts for how much you move through the day, from a sedentary desk job to twice-daily training. It's the number this calculator gives you for "maintain weight."
Should I eat back the calories I burn exercising?
If your activity level selection already reflects your typical training volume, no — the calculator has already accounted for it. Only add back calories separately if you had an unusually intense session outside your normal pattern, like a one-off long hike or event.
Is the "3,500 kcal = 1 lb" rule accurate?
It's a useful rough guide for setting an initial target, but not an exact law — metabolic adaptation, water weight, and activity changes all mean the real number shifts as your weight changes. Treat it as a starting estimate, then adjust based on 2–3 weeks of real results rather than the theoretical math alone.
Which activity level should I actually pick?
Be honest rather than aspirational — most people overestimate. If you have a desk job and exercise 3–5 times a week, "moderately active" is usually correct, not "very active." Picking too high a multiplier is the single most common reason people don't lose weight despite "eating at a deficit" on paper.
Why did my calorie needs change since I last calculated?
TDEE moves with your weight, age, and activity level — it's not a one-time number. As you lose or gain weight, your BMR shifts accordingly, so it's worth recalculating every 4–6 weeks or after a meaningful weight change rather than eating the same fixed target indefinitely.