Weight Loss Calculator

Project how long a goal will take at your current calorie intake.

Please note: For general information only. This is not medical advice — speak to a doctor or registered dietitian before changing your diet, training or medication.

What the Weight Loss Calculator does

This projects your timeline from the gap between what you burn and what you eat. It is a linear model, so treat the later weeks as optimistic — your maintenance drops as you get lighter, which flattens the curve.

Formula

Daily deficit = TDEE − Intake
Days = (Weight to lose in kg × 7,700) ÷ Daily deficit

Inputs explained

Input	Unit	Required	Notes
Units	one of 2 options	Yes	—
Current weight	kg or lb	Yes	Accepts 1 or more.
Goal weight	kg or lb	Yes	Accepts 1 or more.
Maintenance calories (TDEE)	cal	Yes	Accepts 800 or more.
Daily calorie intake	cal	Yes	Accepts 500 or more.

How to use it

Choose Units.
Enter Current weight, Goal weight, Maintenance calories (TDEE) and Daily calorie intake.
Select Calculate.

Worked example

Going from 95 kg to 85 kg with a 2,700 TDEE and eating 2,200.

Current: 95
Goal: 85
TDEE: 2700
Intake: 2200

500 calorie deficit, 154 days, about 22 weeks at 0.45 kg a week.

Frequently asked questions

Why is real progress slower than projected?

Because TDEE falls as body mass drops, and because activity often declines subtly in a deficit. Recalculate every few kilos.

Method and sources

Method. Projects weight over time from the gap between maintenance calories and intake, converted at the conventional energy-per-kilogram figure.

Assumptions

Maintenance stays constant, and the deficit is sustained exactly as entered.
The conversion between energy deficit and mass lost is uniform over the period.

Limitations

A straight-line projection overstates later loss. Metabolic adaptation and the smaller body both reduce expenditure as weight falls, so real curves flatten while this one does not.
Weight is not fat. Water, glycogen and gut contents move the scale by more than a day of dieting does, which is why short-term readings mislead.
A projected date is arithmetic, not a plan, and says nothing about whether the intake behind it is adequate.

Sources

Caloric equivalents of gained or lost weight — The American Journal of Clinical Nutrition 6(5):542–546 (Max Wishnofsky), 1958. The energy-per-unit-mass conversion, and its status as an approximation rather than a constant.