How to use Calorie Deficit Calculator
A calorie deficit calculator turns a weight-loss goal into a concrete daily number: how many calories to eat each day to lose weight at the rate you want. Weight loss happens when you consistently consume fewer calories than your body burns — your maintenance level, or TDEE. This tool takes your maintenance calories and your target rate of loss per week, then works out the daily deficit required and the target intake that produces it, using the well-known figure of roughly 7,700 calories per kilogram of body fat. Seeing both numbers makes a vague goal like "lose some weight" into an actionable daily calorie target you can plan meals around.
- Find your maintenance calories (TDEE) — use a TDEE calculator if unsure.
- Choose metric or imperial for your weekly target.
- Enter how much weight you want to lose per week.
- Read the daily deficit and your target daily intake.
- Adjust the rate to find a sustainable, safe target.
Your data never leaves your device — 100% private processing.
How calorie deficits create weight loss
Your body uses energy every day to stay alive and to move — the total is your Total Daily Energy Expenditure, or TDEE. If you eat exactly that amount you maintain your weight; eat less and your body makes up the shortfall by burning stored energy, mostly fat. The widely used conversion is that a kilogram of body fat stores about 7,700 calories (a pound about 3,500), so to lose half a kilo a week you need a weekly deficit of around 3,850 calories, or roughly 550 a day. This calculator does that arithmetic for you: it multiplies your weekly target by 7,700, divides by seven for the daily deficit, and subtracts that from your maintenance to give the calories you should actually eat. The result is an estimate — water weight, glycogen and muscle changes mean the scale rarely moves in a perfectly straight line.
| Weekly loss | Weekly deficit | Daily deficit |
|---|---|---|
| 0.25 kg | ~1,925 kcal | ~275 kcal |
| 0.5 kg | ~3,850 kcal | ~550 kcal |
| 1 kg | ~7,700 kcal | ~1,100 kcal |
Choosing a sustainable rate
Faster is not better when it comes to fat loss. Very large deficits do strip weight quickly, but much of the early drop is water, and aggressive dieting tends to burn muscle alongside fat, slow your metabolism and leave you hungry enough to rebound. For most people a deficit of 500–750 calories a day, producing around 0.5–0.75 kg of loss per week, is the sweet spot between results and sustainability. The calculator flags target intakes below about 1,200 calories because eating that little makes it hard to get enough protein and micronutrients and is rarely advisable without professional supervision. Pair your deficit with adequate protein and resistance training to protect muscle, and recalculate every few weeks, since your maintenance calories fall as you lose weight.
Worked examples
Moderate cut
Inputs: 2,500 TDEE · 0.5 kg/wk
Result: ~550 deficit · eat ~1,950 kcal
Gentle cut
Inputs: 2,200 TDEE · 0.25 kg/wk
Result: ~275 deficit · eat ~1,925 kcal
Glossary
- Calorie deficit
- Eating fewer calories than your body burns, which drives weight loss.
- TDEE
- Total Daily Energy Expenditure — the calories you burn in a day, your maintenance level.
- Maintenance calories
- The intake at which your weight stays the same.
- Target intake
- The calories to eat each day to achieve your chosen deficit.
- 7,700 rule
- The approximation that one kilogram of body fat equals about 7,700 calories.
Related reading
Frequently Asked Questions
Why use Calorie Deficit Calculator?
- Turn a weekly weight-loss goal into a daily calorie target
- See the exact daily deficit your goal requires
- Plan a sustainable rate rather than crash dieting
- Get a warning when your target intake is dangerously low
- Runs privately in your browser with no sign-up
Common use cases
- Set a daily calorie target for a cutting phase
- Check whether a desired loss rate is realistic
- Compare a 0.25 kg versus 0.5 kg per week plan
- Plan calories around a known TDEE figure
- Understand how deficits translate into weight change
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