TDEE Calculator for Weight Loss
How TDEE Drives Weight Loss
Weight loss fundamentally comes down to one equation: eat fewer calories than your TDEE. Your Total Daily Energy Expenditure is the total number of calories your body burns each day. To lose weight, you need to create a calorie deficit — the gap between what you eat and what you burn.
The size of your deficit determines your rate of loss:
- 250 cal/day deficit: ~0.5 lbs/week loss — minimal muscle loss, easy to sustain
- 500 cal/day deficit: ~1 lb/week loss — the standard recommendation for most people
- 750 cal/day deficit: ~1.5 lbs/week — aggressive but sustainable for those with more weight to lose
- 1,000 cal/day deficit: ~2 lbs/week — maximum safe rate, risk of muscle loss increases significantly
The 500-calorie deficit rule is based on the principle that 1 pound of fat equals approximately 3,500 calories. However, actual weight loss is non-linear because your body adapts through metabolic adaptation, changes in NEAT (non-exercise activity thermogenesis), and water weight fluctuations.
Calculate Your TDEE
Find your maintenance calories, then subtract 500 for steady weight loss of ~1 lb per week.
Calculate My TDEE →Your TDEE minus 500 = your weight loss calorie target.
Calorie Deficit Guide: TDEE to Weight Loss Timeline
| Your TDEE | Moderate Deficit (−500) | Aggressive Deficit (−750) | Time to Lose 20 lbs (moderate) | Time to Lose 20 lbs (aggressive) |
|---|---|---|---|---|
| 1,800 | 1,300 | 1,050* | 40 weeks | 27 weeks |
| 2,000 | 1,500 | 1,250 | 40 weeks | 27 weeks |
| 2,200 | 1,700 | 1,450 | 40 weeks | 27 weeks |
| 2,500 | 2,000 | 1,750 | 40 weeks | 27 weeks |
| 2,800 | 2,300 | 2,050 | 40 weeks | 27 weeks |
| 3,000 | 2,500 | 2,250 | 40 weeks | 27 weeks |
*Below 1,200 calories is generally not recommended without medical supervision.
Based on the 3,500 cal/lb approximation. Actual results vary due to metabolic adaptation.
Key Considerations for Weight Loss
Metabolic Adaptation
As you lose weight, your TDEE decreases for two reasons: you weigh less (smaller body burns fewer calories) and your body actively reduces energy expenditure in response to the deficit. Research shows this "adaptive thermogenesis" can reduce your TDEE by an additional 5–15% beyond what weight loss alone would predict. This is why progress stalls — you need to recalculate your TDEE every 10–15 lbs lost.
Protein During a Deficit
When eating below your TDEE, protein intake becomes critical. Without adequate protein (1.6–2.2 g/kg of body weight), up to 25% of weight lost can come from muscle instead of fat. Higher protein intake preserves muscle, keeps you fuller, and has a higher thermic effect of food (your body burns more calories digesting protein than carbs or fat).
When to Adjust Your Deficit
If your weight loss stalls for more than 2–3 weeks, recalculate your TDEE at your new weight. Alternatively, increase activity rather than cutting calories further — adding 30 minutes of walking burns approximately 150 calories and is easier to sustain than eating less.
Frequently Asked Questions
Subtract 500 from your TDEE for a moderate deficit that produces about 1 pound of fat loss per week. For example, if your TDEE is 2,200 calories, aim for 1,700 calories per day. Never go below 1,200 calories (women) or 1,500 calories (men) without medical supervision.
The most common reasons are: inaccurate calorie tracking (most people underestimate intake by 20–50%), overestimating exercise calories burned, metabolic adaptation reducing your TDEE below what you calculated, water retention masking fat loss, or your deficit being too small. Recalculate your TDEE and track food more precisely for 2 weeks.
Most health organizations recommend 1–2 pounds per week as a safe rate of weight loss. Losing faster than this increases risk of muscle loss, gallstones, nutritional deficiencies, and metabolic adaptation. People with more weight to lose (BMI 35+) may safely lose 2–3 lbs/week initially.
Generally, no — or eat back only half. Exercise calorie estimates (from watches, machines, apps) are notoriously inaccurate, often overestimating by 30–50%. If your TDEE already accounts for your activity level, those exercise calories are already included. Only add calories back if you do significantly more exercise than your selected activity level.
Sources & References
- Hall KD, et al. "Quantification of the effect of energy imbalance on bodyweight." The Lancet, 2011.
- Trexler ET, et al. "Metabolic adaptation to weight loss." Journal of the International Society of Sports Nutrition, 2014.
- Helms ER, et al. "A systematic review of dietary protein during caloric restriction." International Journal of Sport Nutrition and Exercise Metabolism, 2014.
- U.S. Department of Agriculture. Dietary Guidelines for Americans, 2020–2025.
This content is for informational purposes only and does not constitute medical advice. Consult a healthcare provider for personalized recommendations.