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TDEE Weight Loss Calculator
This TDEE weight loss calculator estimates your daily calorie burn with the Mifflin-St Jeor equation, then applies a calorie deficit to project fat loss. Enter your stats, pick an activity level and a deficit from 10 to 25 percent, and you will see your maintenance calories, your daily target, and an estimated pounds lost per week. It is an estimate for planning, not medical advice.
How to use
- Enter your sex, age, weight, and height.
- Select the activity level that honestly matches your week.
- Choose a deficit: 10, 15, 20, or 25 percent.
- Click Calculate Weight Loss Plan to see your target and weekly estimate.
Worked example
Take a 30 year old man weighing 200 lb at 5 ft 10 in with moderate activity. His BMR is about 1,873 calories, and times the 1.55 activity multiplier his TDEE is about 2,903 calories per day.
With a 15 percent deficit, the daily target is about 2,468 calories. The weekly loss estimate is 2,903 times 0.15 times 7 divided by 3,500, or about 0.9 lb per week. At that pace, 10 lb takes roughly 11 weeks.
Picking the right deficit
Match the deficit to your timeline and tolerance. A 10 percent deficit is nearly painless but slow, good when you have months. A 15 to 20 percent deficit is the sweet spot for most dieters. A 25 percent deficit works for short aggressive phases but demands high protein and weight training to protect muscle.
Whatever you choose, track your morning weight trend for two to three weeks before judging. Daily fluctuations are noise; the weekly average is the signal.
Frequently asked questions
How does the weekly loss estimate work?
One pound of body fat holds about 3,500 calories. The calculator multiplies your daily deficit by seven and divides by 3,500. Real loss varies with water shifts, food volume, and how closely you follow the target.
What deficit percent is best?
A 15 to 20 percent deficit suits most people: noticeable loss with manageable hunger. A 10 percent deficit is slow but easy to sustain. Above 20 percent, expect more hunger and a higher risk of muscle loss.
Will I lose muscle in a deficit?
Some muscle loss is possible, but you can limit it. Eat enough protein, keep lifting weights, and avoid extreme deficits. That combination tells your body to keep muscle while burning fat.
Why did my weight loss stall after a few weeks?
Early fast drops are mostly water, then fat loss slows to its true rate. Stress, sleep, salty meals, and new training can mask fat loss on the scale for weeks. If weight is flat for three weeks despite honest tracking, your TDEE has likely dropped and it is time to recalculate.
When should I recalculate my numbers?
Recalculate every 10 to 15 pounds lost or about once a month. A lighter body burns fewer calories, so keeping an old target quietly shrinks your deficit until progress stops.
When should I stop dieting?
Take a diet break at maintenance calories every 8 to 12 weeks, or sooner if energy, sleep, or mood suffer. Long deficits raise fatigue and slow progress, so planned breaks help you finish stronger.
Why does the calculator stop me below 1,200 calories?
Very low calorie diets are hard to sustain and can cause nutrient gaps and muscle loss. If your deficit pushes the target under 1,200, pick a smaller deficit or double check your activity level and stats.