Weight Simulator
Calculate your TDEE and compare different deficit strategies
AI logs your meals from a photo. Diet & workouts in one app.Get the free appWeight Simulator
Calculate your TDEE and compare different deficit strategies
How to use this weight simulator
Enter your current weight — you can switch between kg and lb — then add your target weight, a daily calorie intake or deficit, and your activity level so the tool can estimate a timeframe. Press calculate and a projected weight trajectory and target date appear instantly, with no sign-up. Change any number and the forecast updates, so you can compare a gentle plan against a more aggressive one in seconds.
How to read your result
The line shows your expected weight over the coming weeks and months, not a fixed promise. A steady loss of about 0.5 kg per week comes from roughly a 500 kcal daily deficit, which is a pace most people can sustain. Faster drops in the first week or two are mostly water and glycogen rather than fat, so the curve usually starts steep and then settles into a slower, more honest slope.
The science behind the projection
The forecast rests on energy balance: burning stored fat releases about 7,700 kcal per kilogram, or roughly 3,500 kcal per pound, so a consistent deficit predicts a broadly linear early loss. But the model is adaptive — as you get lighter your TDEE falls, because a smaller body needs less energy to move and maintain. That shrinking gap between intake and expenditure is why weight loss slows and the curve gradually flattens over time.
Limits and practical tips
Real results vary with water balance, glycogen, diet adherence, sleep and metabolic adaptation, so treat the trajectory as a projection, not a guarantee. Weigh yourself under the same conditions and judge the trend over weeks, not single days. Recalculate as your weight and intake change to keep the plan realistic. To set the numbers you feed in, pair this with CaloNote's TDEE, Calorie Deficit and BMR calculators, and log meals in the CaloNote app to stay on target.
Frequently Asked Questions
- How long does it take to lose 10 kg?
- At a safe ~0.5 kg/week pace, about 20 weeks. A larger deficit is faster but harder to sustain and risks muscle loss.
- Is fast weight loss safe?
- Losing more than ~1 kg per week often means muscle and water loss and a higher rebound risk. Slower loss is more sustainable.
- Why does weight loss slow down over time?
- As you lose weight your TDEE drops, so the same intake becomes a smaller deficit. Recalculate your target as you progress.