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
| Field | What to enter |
|---|---|
| Maintenance calories | In kcal/day. Use the TDEE from a BMR calculator. |
| Current weight | Units: kg, lb, g, oz, st |
| Goal weight | Units: kg, lb, g, oz, st |
| Weekly weight loss | Units: 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) |
|---|---|
| 1,200 | 650 |
| 1,800 | 1,250 |
| 2,400 | 1,850 |
| 3,000 | 2,450 |
| 3,600 | 3,050 |
| 4,800 | 4,250 |
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.
Formula
Daily deficit = weekly loss (kg) × 7,700 ÷ 7Intake = maintenance − deficitWorked 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.
Frequently asked questions
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.