Weight Loss Calculator
Calculate your timeline to reach your goal weight based on your daily calorie deficit and starting weight.
The weight loss timeline is the number most people want but rarely calculate correctly. One pound of fat is roughly 3,500 calories. A 500-calorie daily deficit produces about 1 pound per week — not 2, not 0.5. The math is linear at the start but slows as you lose weight, because a lighter body burns fewer calories and the deficit effectively shrinks unless you adjust intake or activity.
1 lb of fat = approximately 3,500 calories. A 500 cal/day deficit = 3,500 cal/week = 1 lb/week loss. This is the most reliable simple formula. Real results vary by individual, water retention, muscle changes, and dietary adherence.
Why weight loss slows over time
Metabolic adaptation works against sustained deficits. As body weight decreases, basal metabolic rate decreases proportionally. A deficit of 500 calories at 195 lbs produces a smaller effective deficit at 175 lbs because your maintenance calories are lower. Beyond this mechanical effect, adaptive thermogenesis (the body becoming more efficient during caloric restriction) further reduces the actual deficit below the calculated one. This is why recalculating your TDEE and adjusting intake every 10-15 pounds lost produces better results than keeping intake constant throughout.
Rate of loss and muscle preservation
Faster deficits (1,000+ cal/day, 2+ lbs/week) increase the proportion of weight lost from muscle rather than fat, especially without resistance training. Slower deficits (500 cal/day, 1 lb/week) combined with strength training preserve more lean mass. The goal for most people is not just weight loss but fat loss with muscle preservation, which generally means a moderate deficit with adequate protein and resistance training.
Frequently asked questions
Why am I not losing weight despite a deficit?
Common reasons: food tracking underestimates actual intake by 20-40% on average, activity level is lower than assumed, water retention masks fat loss (especially early in a diet or around menstruation), or adaptive thermogenesis has reduced actual TDEE below the estimated level. Weighing daily and tracking the 7-day average provides a clearer picture than single weigh-ins.
What is a realistic weekly rate of loss?
0.5-1% of body weight per week is the most commonly cited sustainable rate. At 195 lbs, that is about 1-2 lbs/week. Faster rates are possible early in a diet due to water weight, but sustained loss exceeding 1% of body weight weekly usually includes significant muscle loss without structured resistance training and high protein intake.