Calculate your calorie deficit and daily target in seconds.
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Calorie deficit calculator
Results are estimates. Use as a starting point and adjust based on real-world progress over two to three weeks.
Takes about 10 seconds. No signup required.
What this calculator does
LeanCalc estimates your maintenance calories (TDEE), subtracts the deficit you choose, and shows a daily calorie target with protein, carb, and fat grams. You also get a simple 12-week weight trend and optional check-ins saved on this device.
- Inputs: age, sex, height, current weight, goal weight, activity level, and deficit preset (250 to 1000 kcal per day).
- Limitations: Formulas cannot capture hormones, medications, sleep stress, or logging error. If your target is very low, consider a smaller deficit and judge progress over two to three weeks of consistent data.
- Who it is for: adults who want a structured starting point for fat loss. It is not a substitute for medical nutrition therapy.
Learn the concepts in our weight loss guide or blog overview; refine maintenance with the TDEE calculator.
Medical disclaimer: This site does not provide medical advice. Consult a qualified professional before major diet or exercise changes.
Your results
…
over the next 12 weeks
Your numbers are above. Adjust your inputs anytime, or use tracking to stay close to your daily target.
What is a calorie deficit?
A calorie deficit happens when you consume fewer calories than your body burns in a day. Your body's total daily energy expenditure (TDEE) includes everything it burns: breathing, digestion, movement, and exercise. When your intake falls below this number, your body turns to stored fat for fuel, resulting in weight loss.
The most sustainable deficits sit between 300 to 500 calories per day, producing roughly 0.3 to 0.5 kg (0.7 to 1 lb) of fat loss per week. Larger deficits accelerate loss but increase the risk of muscle breakdown and nutrient deficiency.
How many calories should I eat to lose weight?
There is no universal answer; it depends on your height, weight, age, sex, and activity level. That is why calculators like this one use the Mifflin St Jeor equation, widely considered the most accurate formula for estimating your resting metabolic rate (BMR). Your BMR is then multiplied by an activity factor to give your TDEE, and your target is TDEE minus your chosen deficit.
A common starting point is eating at a 500 calorie deficit per day, which targets approximately 0.5 kg (1 lb) of fat loss per week.
What is a safe calorie deficit?
Most nutrition experts consider a deficit of 250 to 750 calories per day safe for healthy adults. Going below 1,200 kcal per day (women) or 1,500 kcal per day (men) is not recommended without medical supervision; it risks muscle loss, fatigue, and nutritional deficiencies.
If you are new to dieting, start small (250 to 300 kcal per day) and increase gradually as your body adjusts.
How to calculate your calorie deficit manually
- Calculate BMR with Mifflin St Jeor: (10 × kg) + (6.25 × cm) − (5 × age) + 5 (men) or −161 (women)
- Multiply BMR by your activity factor (1.2 sedentary → 1.9 athlete) to get TDEE
- Subtract your target deficit. That is your daily calorie goal.
Example: 30-year-old man, 180 cm, 85 kg, moderately active → TDEE ~2,750 kcal. A 500 kcal deficit = 2,250 kcal/day target.
Calorie deficit vs calorie restriction
Calorie restriction is a blanket food reduction with no individual baseline. Calorie deficit is targeted: you calculate exactly what your body burns, then eat a specific amount less. The deficit approach is more precise and sustainable because it is based on your actual metabolism.
What macros should I eat on a calorie deficit?
Protein is the most important macro when cutting. A higher intake (about 40% of calories) preserves muscle mass during a deficit. LeanCalc uses 40% protein, 35% carbs, 25% fats, a well-researched split for fat loss while maintaining strength and energy.
Frequently asked questions
Can I lose weight without counting macros?
Yes. Macros help with structure and muscle retention, but a calorie deficit is the main driver of fat loss. Tracking macros simply makes the process easier to manage.
Why does my projected timeline look long?
Because slower, sustainable fat loss works better over time. Bigger deficits look faster on paper but are harder to maintain and increase the risk of muscle loss.
Should I eat back exercise calories?
Most people overestimate calories burned during exercise. Monitor real-world progress over two to three weeks before adjusting your target upward.
How accurate is this calculator?
LeanCalc uses the Mifflin St Jeor equation, the most validated BMR formula for healthy adults. Treat results as a strong starting estimate, then adjust based on real progress tracking.