Calorie Deficit Calculator
Time to reach a target weight at a chosen daily calorie deficit, and the intake it implies.
Results
Days
108
Weeks
15.4
Daily intake
1900
kcal
Weight lost per week
0.455
kg
Percentage
20.83
%
What this tool does
A deficit of around twenty percent of maintenance is a common, sustainable target; much more and you lose muscle along with fat and struggle to hold the diet. Get your maintenance figure from a BMR calculation multiplied by your activity level rather than guessing it.
Formula
≈ 7700 kcal per kilogram of body fat
Variables
| Symbol | Meaning | Unit |
|---|---|---|
cl | Current weight | kg |
tg | Target weight | kg |
df | Daily calorie deficit | kcal |
md | Maintenance calories | kcal |
D | Days | — |
WK | Weeks | — |
TI | Daily intake | kcal |
WW | Weight lost per week | kg |
PC | Percentage | % |
Worked example
- Current weight85 kg
- Target weight78 kg
- Daily calorie deficit500 kcal
- Maintenance calories2400 kcal
- Days108
- Weeks15.4
- Daily intake1900 kcal
- Weight lost per week0.455 kg
- Percentage20.83 %
Limitations
- This tool is informational only. It does not diagnose, treat or replace a qualified health professional. Speak to a doctor before making decisions about your health.
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- The default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.
Frequently asked questions
Will the weight really come off at that rate?
Rarely in a straight line. The 7700 kcal per kilogram figure describes fat tissue, but early weight change is largely water, and maintenance calories fall as you get lighter, so the same deficit slows down over time. Treat the result as an order of magnitude and expect the last kilograms to take longer than the first.