# Calorie Deficit Calculator

- **URL:** https://codeasystem.com/calculators/health/calorie-deficit-calculator/
- **Category:** health
- **Description:** Turn your TDEE into a daily calorie target for fat loss, with expected weekly and monthly progress at your chosen deficit.
- **Primary output:** Daily calorie target: 2,000 kcal/day

## Inputs
- Your TDEE (name: `tdee`, type: number, example: 2500)
- Daily deficit (name: `deficit`, type: select)

## Outputs
- Daily calorie target: 2,000 kcal/day
- Weekly loss at this deficit: 0.45 kg/week
- Estimated monthly loss: 1.98 kg/month

## Formula / methodology
```
Target = TDEE − deficit
Weekly loss ≈ deficit × 7 ÷ 7700 kg
```

Your daily target is simply maintenance minus the chosen deficit. Progress converts through the energy-density convention that one kilogram of body fat stores approximately 7,700 kcal, so a sustained 500 kcal daily deficit yields roughly half a kilogram of loss per week.

Deficits that would push intake below 1,200 kcal/day are rejected; below that threshold meeting micronutrient needs becomes genuinely difficult without medical supervision.

## Assumptions & limitations
- One kilogram of body fat ≈ 7,700 kcal (population-average convention).
- Linear projection ignores metabolic adaptation and water fluctuations.
- Protein intake and resistance training strongly influence how much lost weight is lean mass.

## How to use
1. **Enter your TDEE**; Use the TDEE calculator result, or your empirically tracked maintenance intake.
2. **Choose a deficit size**; Standard advice favors 500 kcal; large enough to see weekly progress, small enough to sustain.
3. **Set your target and track**; Eat near the computed target and compare actual scale trends against the projected rate after three weeks.

## Example
Maintaining on 2,500 kcal/day and cutting 500 creates a 2,000 kcal target; about 0.45 kg of expected loss per week, or roughly 1.9 kg per month.

Result for these inputs:

```
Daily calorie target: 2,000 kcal/day
```

## About this calculator
### Bigger deficits are not better

Beyond roughly 30% below maintenance, hunger hormones rise, training quality drops and lean-mass losses accelerate. Slower cuts preserve muscle and are dramatically easier to adhere to over months.

### Why the scale stalls anyway

Early losses include glycogen-bound water; later, adaptive thermogenesis shrinks true expenditure below predictions. Expect the linear projection to soften; judge progress by the 3-week trend, not daily readings.

### Protecting muscle while cutting

- Keep protein high (see the protein intake calculator).
- Continue resistance training with maintained loads.
- Prefer moderate deficits of 15–25% below TDEE.

## FAQs
### Is 1,200 kcal a magic minimum?

It is a practical floor below which nutrient adequacy gets difficult for most adults, not a biological cliff. Very-low-calorie diets require medical supervision.

### Can I bank deficits across the week?

Yes; weekly energy balance is what matters. Some people prefer larger weekday deficits with higher weekend intake at the same weekly total.

### Does the 7,700 rule account for water weight?

No. It models pure energy balance; short-term scale swings from sodium, carbs and hydration can mask or exaggerate real fat changes.

> **Disclaimer:** This calculator is for general educational purposes only and does not constitute professional advice.

## Related calculators
- [TDEE Calculator](https://codeasystem.com/calculators/health/tdee-calculator/)
- [BMR Calculator](https://codeasystem.com/calculators/health/bmr-calculator/)
- [Macro Calculator](https://codeasystem.com/calculators/health/macro-calculator/)
- [Steps to Calories Calculator](https://codeasystem.com/calculators/fitness/steps-to-calories-calculator/)

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Last updated: 2026-08-23 · Version: 1.0.0 · [HTML version](https://codeasystem.com/calculators/health/calorie-deficit-calculator/)