Calorie Deficit Calculator
Plan your daily calorie target and the time to reach your goal weight.
The Calorie Deficit Calculator connects the three numbers that drive weight loss: your maintenance calories, how fast you want to lose, and your goal weight. It computes your daily calorie target, the deficit behind it, and the weeks it will take — turning 'I want to lose 5 kg' into a concrete, trackable plan.
The math is transparent: roughly 7,700 kcal of stored energy per kilogram of fat. Lose at 0.5 kg per week and that is a 550 kcal daily deficit; the calculator lets you pick a slow, moderate or aggressive pace and shows the trade-off between speed and sustainability.
Estimates only — loss slows as you get lighter because your maintenance drops with your weight, so re-run the numbers every few kilograms. Never force extreme deficits without professional guidance. Everything runs in your browser.
Daily calorie target
1,850 kcal
maintenance 2,400 − deficit 550
Daily deficit
550 kcal
≈ 1 kg of fat = 7,700 kcal
To lose
5 kg
6.25% of body weight
Time to goal
10 weeks
≈ 70 days at this pace
Estimates assume 7,700 kcal per kg of fat. Loss slows as you shrink — re-run this calculator as your weight and maintenance change, and never force extreme deficits without professional guidance.
How to use the Calorie Deficit Calculator
- Enter your current weight and goal weight.
- Enter your maintenance calories (see the TDEE calculator).
- Choose a loss pace from slow to aggressive.
- Read your daily calorie target, deficit and time to goal.
- Re-run every few kilograms as your maintenance changes.
Frequently asked questions
How many calories is a kilogram of fat?
Approximately 7,700 kcal. A daily deficit of 550 kcal therefore yields about 0.5 kg per week; 1,100 kcal daily yields roughly 1 kg per week — the calculator uses exactly this relationship.
What is a safe calorie deficit?
Deficits of 300–500 kcal daily (0.25–0.5 kg per week) are sustainable for most people and preserve more muscle. Aggressive cuts above ~1,000 kcal daily raise hunger, muscle loss and rebound risk — use them only with professional supervision.
Why does weight loss slow down?
As you lose weight your maintenance calories fall (smaller body, less energy to move), so the same intake becomes a smaller deficit. That is why the calculator should be re-run every few kilograms rather than treated as a fixed plan.
Related tools
View all health & fitness calculators →BMI Calculator
Calculate your Body Mass Index and see the healthy weight range for your height.
HealthBMR Calculator
Find your Basal Metabolic Rate — the calories your body burns at rest.
HealthTDEE Calculator
Total Daily Energy Expenditure — the calories you need to maintain your weight.
HealthMacro Calculator
Split your daily calories into protein, carbs and fat targets.
HealthBody Fat Calculator
Estimate body fat percentage from tape measurements — no special equipment.
HealthIdeal Weight Calculator
Ideal body weight by formula plus the healthy BMI range for your height.