Calorie Deficit Calculator
Calculate the calorie deficit you need to lose weight at your target rate, with mild to aggressive options and the calories each implies from your maintenance.
2133 kcal
Deficit Options (from 2633 kcal maintenance)
| Deficit | Calories | Loss/week |
|---|---|---|
| Mild (−250) | 2383 | 0.25 kg |
| Moderate (−500) | 2133 | 0.50 kg |
| Aggressive (−750) | 1883 | 0.75 kg |
| Very aggressive (−1000) | 1633 | 1.00 kg |
*Below the suggested minimum of 1500 kcal/day for your sex — not recommended without supervision.
Note: Estimates use the Mifflin-St Jeor equation, the most accurate general BMR formula. Real energy needs vary with body composition and genetics — adjust based on 2–3 weeks of weight trend data.
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Calculation Method
A calorie deficit is the gap between the calories you burn and the calories you eat. Sustained over time, it forces your body to draw on stored fat — it is the fundamental driver of weight loss.
How the Deficit Is Calculated
We estimate your maintenance calories (TDEE), then subtract a deficit. About 7,700 kcal equals roughly 1 kg of body fat, so a daily deficit of 500 kcal yields about 0.45–0.5 kg of loss per week.
Deficit Options
| Deficit/day | Weekly loss |
|---|---|
| Mild (−250) | ~0.25 kg |
| Moderate (−500) | ~0.5 kg |
| Aggressive (−750) | ~0.75 kg |
| Very aggressive (−1000) | ~1 kg |
Stay Above the Floor
Don't drop below about 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision. Larger deficits lose weight faster but increase muscle loss, hunger, and the chance of rebound. Keep protein high (1.6–2.2 g/kg) to preserve muscle.
Estimates are a starting point, not medical advice. Adjust based on 2–3 weeks of weight-trend data.
Frequently Asked Questions
A calorie deficit means eating fewer calories than you burn, forcing your body to use stored energy (mostly fat) and lose weight. A deficit of about 3,500 calories roughly equals 0.45 kg (1 lb) of fat.
A deficit of 250–500 calories per day is sustainable and muscle-sparing, yielding about 0.25–0.5 kg of loss per week. Larger deficits lose faster but risk muscle loss and are harder to maintain.
As a general guideline, women should not drop below about 1,200 kcal/day and men below 1,500 kcal/day without medical supervision. The calculator flags deficit options that fall below these floors.
What is a calorie deficit?
How big should my calorie deficit be?
What is the lowest safe calorie intake?
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Calculate your Total Daily Energy Expenditure (TDEE) — the calories you burn per day — from your stats and activity level, plus targets to lose, maintain, or gain.
BMR Calculator
Calculate your Basal Metabolic Rate (BMR) — the calories your body burns at rest — using the Mifflin-St Jeor equation, with a daily-calorie table by activity level.
Maintenance Calorie Calculator
Find your maintenance calories — the daily intake that keeps your weight stable — from your stats and activity, plus targets for cutting and gaining.