Calorie Deficit Calculator
Find out exactly how many calories to eat per day to reach your weight goal — safely and sustainably.
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What Is a Calorie Deficit?
A calorie deficit means eating fewer calories than your body uses in a day. When you're in a deficit, your body draws on stored fat to make up the energy gap — which is how fat loss happens.
Your total daily energy expenditure (TDEE) is made up of:
- BMR (Basal Metabolic Rate) — calories your body burns at rest (60–70% of TDEE)
- NEAT — non-exercise movement (walking, fidgeting, daily tasks)
- Exercise — deliberate physical activity
- TEF — energy used to digest food (~10%)
How Many Calories Is a Safe Deficit?
| Deficit | Weekly Loss | Best For | Risk |
|---|---|---|---|
| 250 kcal/day | ~0.25 kg | Maintenance phase, first-timers | Low |
| 500 kcal/day ✓ | ~0.5 kg | Most people — sweet spot | Very low |
| 750 kcal/day | ~0.75 kg | Faster results, short-term | Moderate |
| 1,000 kcal/day | ~1 kg | Medical supervision only | High (muscle loss risk) |
How to Track Your Deficit Effortlessly
Knowing your calorie target is only half the battle. The hard part is actually logging every meal — which is where most people give up.
CalRay solves this with AI-powered photo logging. Snap a photo of your meal, and CalRay instantly estimates calories, protein, carbs, and fat — no manual searching, no barcode scanning, no portion weighing.
Calorie Deficit FAQ
What is a calorie deficit?
A calorie deficit occurs when you eat fewer calories than your body burns in a day. Your body then uses stored fat for energy, leading to weight loss. A deficit of 500 calories per day typically results in about 0.5 kg (1 lb) of fat loss per week.
How many calories should I cut to lose 1 kg per week?
To lose 1 kg per week, you need a total deficit of about 7,700 calories — roughly 1,100 calories per day. Most experts recommend a more moderate deficit of 500–750 calories/day for sustainable results and to preserve muscle mass.
What is a safe calorie deficit?
A safe calorie deficit is typically 300–750 calories below your TDEE. Going below 1,200 kcal/day (women) or 1,500 kcal/day (men) is generally not recommended without medical supervision.
How do I calculate my TDEE?
TDEE = BMR × Activity Multiplier. Use Mifflin-St Jeor for BMR: Men = (10 × kg) + (6.25 × cm) − (5 × age) + 5. Women = (10 × kg) + (6.25 × cm) − (5 × age) − 161. Then multiply by your activity factor (1.2 = sedentary, up to 1.9 = very active).
Can I lose weight without counting calories?
Yes, but knowing your numbers helps. CalRay lets you snap a photo of your meal to automatically log calories and macros — no manual counting or database searching. Tracking with photos takes less than 5 seconds per meal.