# Calorie Deficit Calculator

URL: https://speedycalculator.com/calculators/health/calorie-deficit/
Last updated: 2026-10-25

> The calorie deficit calculator sets a daily calorie target for a chosen rate of weight loss, assuming about 7,700 kcal per kilogram of body fat. It also estimates how many weeks it will take to reach your goal weight.

## Inputs

- Maintenance calories (kcal/day) — Use the TDEE from a BMR calculator.
- Current weight (kg, lb, g, oz, st)
- Goal weight (kg, lb, g, oz, st)
- Weekly weight loss (kg, lb)

## Results

- Daily calorie deficit
- Daily calorie target
- Time to goal

## Formula

```
Daily deficit = weekly loss (kg) × 7,700 ÷ 7
Intake = maintenance − deficit
```

## Explanation

Losing about 0.5–1% of body weight per week is a common, sustainable target. Very large deficits are hard to maintain and can cost muscle.

### How to use the Calorie Deficit Calculator

- **Maintenance calories** — Use the TDEE from a BMR calculator.
- **Current weight**
- **Goal weight**
- **Weekly weight loss**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

The weekly loss in kilograms is converted to calories and spread over seven days, then subtracted from maintenance calories.

### Inputs explained

FieldWhat to enterMaintenance caloriesIn kcal/day. Use the TDEE from a BMR calculator.Current weightUnits: kg, lb, g, oz, stGoal weightUnits: kg, lb, g, oz, stWeekly weight lossUnits: kg, lb

### What each result means

- **Daily calorie deficit** = [Weekly weight loss] × 7700 ÷ 7
- **Daily calorie target** = [Maintenance calories] - [Daily calorie deficit]
- **Time to goal** = ([Current weight] - [Goal weight]) ÷ [Weekly weight loss]

### Example values

How the main result changes when **Maintenance calories** changes and everything else stays at the example values above:

Maintenance calories (kcal/day)Daily calorie target (kcal/day)1,2006501,8001,2502,4001,8503,0002,4503,6003,0504,8004,250
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Maintenance calories: 2,400 kcal/day; Current weight: 85 kg; Goal weight: 75 kg; Weekly weight loss: 0.5 kg.

Results — Daily calorie deficit = 550 kcal; **Daily calorie target = 1,850 kcal/day**; Time to goal = 20 weeks.

## FAQ

**Is 7,700 kcal per kg exact?**
It is a rule of thumb; weight loss usually slows as your body adapts.

**How low should calories go?**
Most adults should not go below about 1,200–1,500 kcal without medical supervision.

**What formula does the Calorie Deficit Calculator use?**
Daily deficit = weekly loss (kg) × 7,700 ÷ 7.


## Sources

- [NHS – Losing weight](https://www.nhs.uk/live-well/healthy-weight/managing-your-weight/)