Calorie Deficit Calculator
Find your daily calorie target to lose weight at your desired pace.
<250 kcal Moderate
250–500 Aggressive
500–750 Extreme
>750 kcal
Calorie Breakdown
How to Use This Calorie Deficit Calculator
Enter your age, sex, weight, height, and activity level. Then choose your weekly weight loss goal and optionally set a target weight. Hit "Calculate" and you'll instantly see your Total Daily Energy Expenditure (TDEE), recommended daily calorie intake, and an estimated timeline to reach your goal.
Why This Matters
Weight loss fundamentally comes down to energy balance — consume fewer calories than you burn, and your body draws from fat stores to make up the difference. A calorie deficit calculator removes the guesswork from this equation.
Consider someone who is 35 years old, moderately active, and weighs 90 kg. They might estimate they need 2,000 calories/day, when in reality their TDEE is closer to 2,600. Without this knowledge, they could accidentally eat at maintenance while thinking they're in a deficit — and wonder why the scale won't budge.
A safe, sustainable deficit is typically 300–500 kcal/day, producing roughly 0.3–0.5 kg (0.6–1 lb) of fat loss per week. Going too aggressive (750+ kcal deficit) can cause muscle loss, fatigue, nutrient deficiencies, and metabolic adaptation — making long-term success harder, not easier.
This calculator is useful for anyone starting a weight loss journey, people who've hit a plateau, athletes cutting for a competition, or anyone who simply wants a more accurate, science-backed calorie target than a generic "eat 1,200 calories" recommendation.
How It's Calculated
We use the Mifflin-St Jeor equation — considered the most accurate for general populations:
Women: BMR = (10 × weight_kg) + (6.25 × height_cm) − (5 × age) − 161
BMR (Basal Metabolic Rate) is then multiplied by your activity factor to get TDEE. Your chosen weekly loss goal is converted to a daily deficit (1 kg fat ≈ 7,700 kcal, so 0.5 kg/week = 550 kcal/day deficit). The result is capped at no less than 1,200 kcal/day (women) or 1,500 kcal/day (men) as a safety floor.
Daily Deficit = (Weekly Goal kg × 7,700) ÷ 7
Tips & Common Mistakes
- Don't over-estimate activity level. Most people are "lightly active" at best — desk job + 3 gym sessions/week is not "very active."
- Weigh yourself consistently — same time, same conditions (morning, after bathroom). Fluctuations of 1–2 kg daily are normal due to water and food weight.
- Don't slash calories overnight. Start with a mild deficit and increase gradually. Drastic cuts often lead to bingeing and yo-yo dieting.
- Protein is your best friend in a deficit. Aim for 1.6–2.2g/kg of body weight to preserve muscle while losing fat.
- Re-calculate every 4–6 weeks. As you lose weight, your TDEE decreases — your calorie target should too.
Frequently Asked Questions
What's the maximum safe calorie deficit per day?
Most nutrition experts recommend staying within 500–750 kcal/day below TDEE. Beyond 1,000 kcal/day, the risk of muscle loss, nutrient deficiencies, and metabolic adaptation increases significantly. Always stay above 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision.
Why am I not losing weight in a calorie deficit?
Several factors can stall weight loss: overestimating calorie burn, underestimating calorie intake (liquid calories, cooking oils, sauces), water retention from sodium or stress, or metabolic adaptation over time. Track food accurately with a food scale for 1–2 weeks to identify the issue.
Should I eat back exercise calories?
If your activity factor already accounts for your exercise (e.g., "Moderately Active"), then no — eating back exercise calories would erase your deficit. If you chose a lower activity level and track workouts separately, you can eat back 50–75% of estimated burn to account for tracker inaccuracies.
How accurate is this calculator?
The Mifflin-St Jeor equation has a margin of error of roughly ±10% for most adults. It's less accurate for very muscular individuals (underestimates) and those with hormonal conditions like hypothyroidism (overestimates). Use the result as a starting point, track for 2–3 weeks, then adjust based on real-world results.