Why this projection is different
Most weight-loss calculators do one division: total weight ÷ weekly rate = weeks. That math quietly assumes your body burns the same at 70 kg as it did at 90 kg — and it doesn't. Every kilogram lost lowers your TDEE by roughly 10–12 kcal/day via the Mifflin-St Jeor equation, so a fixed food intake produces a shrinking deficit and a slowing rate of loss.
This calculator simulates your loss week by week and charts it: it fixes your starting intake from the rate you choose, then recalculates your TDEE at each new weight. The timeline chart under your results plots the honest curve against the straight line other calculators promise — watch the gap widen as the loss gets bigger — with orange markers showing the weeks where your falling TDEE means it's time to adjust intake to hold your pace. The result is three numbers — the linear date other calculators give you, the realistic date from body-size math alone, and a third date adding an estimated ~7.5% of metabolic adaptation, the measured tendency of metabolism to drop slightly more than body size predicts during a diet.
The plateau warning
If your goal is far below your current weight and your chosen rate is gentle, the simulation may find that your TDEE falls to meet your intake before you reach the goal. Instead of a fictional date, it shows you the projected plateau weight — and that's the honest answer: getting past it requires lowering intake again, raising activity, or a staged plan with diet breaks.
Using the result
- Get the daily calories that drive the projection from the deficit calculator, and split them with the meal calculator.
- Re-run with real data every 4–5 kg — your actual trend beats any simulation.
- Keep protein high throughout (protein calculator); it's the main defense against losing muscle along with fat.
Frequently asked questions
Why does this calculator give a later date than others?
Because the others are wrong in your favor. Linear calculators assume your burn rate never changes; in reality TDEE falls as you shrink, the deficit narrows, and the final kilograms come off slower than the first. The realistic date models that decline week by week.
What is metabolic adaptation?
A measured tendency for energy expenditure during dieting to drop a bit more than body size alone predicts — commonly 5–10% — driven by reduced NEAT and hormonal shifts. It's real but usually modest, and it largely reverses at maintenance. The third date in the results adds ~7.5% phased in over your loss.
Why does it say I'll plateau before my goal?
At your chosen intake, your shrinking TDEE would eventually equal what you eat — and loss stops there. That's physics, not failure. The fix is a planned second phase: a further intake reduction, more activity, or a maintenance break before continuing.
Is the linear estimate useless then?
It's a fine first sketch for small losses (under ~5 kg), where TDEE barely moves. The gap between linear and realistic grows with the size of the loss — for 20+ kg goals it can be months.
More calculators
TDEE Calculator
Work out your Total Daily Energy Expenditure
Calorie Calculator
Get a daily calorie target matched to your goal
BMR Calculator
Estimate the calories your body burns at complete rest, compared across the three standard equations
Calorie Deficit Calculator
Choose a weekly weight-loss rate and see the exact daily calories that achieve it
Macro Calculator
Split your daily calories into protein, carbs and fat
Maintenance Calorie Calculator
Find the daily calories that keep your weight stable
Sources
- Hall KD, Sacks G, Chandramohan D, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011. [link]
- Leibel RL, Rosenbaum M, Hirsch J. Changes in energy expenditure resulting from altered body weight. N Engl J Med. 1995. [link]
- Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr. 1958. [link]
- Trexler ET, Smith-Ryan AE, Norton LE. Metabolic adaptation to weight loss: implications for the athlete. J Int Soc Sports Nutr. 2014. [link]