Calorie Deficit Calculator — How Many Calories to Lose Weight
Calculate your daily calorie deficit for weight loss free — enter your current weight, goal weight and timeline to get a safe daily calorie target. Based on your BMR and activity level.
Last updated: June 2026
Your plan
- Daily calorie target
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- Daily deficit
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- Weekly deficit
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- Time to target
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- Suggested macros
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This deficit is aggressive (over 1,000 calories/day). Rapid loss can cost muscle and nutrients — consider a gentler rate and consult a healthcare professional.
Medical Disclaimer: This tool provides general health information for educational purposes only. Always consult a qualified healthcare professional for medical advice, diagnosis, or treatment.
About this tool
Planning a safe calorie deficit
Weight loss comes down to one principle: a calorie deficit — taking in less energy than you burn, so your body draws on its stores. The hard part is turning that principle into a daily number you can actually follow. This calorie deficit calculator does exactly that: it estimates how many calories you burn each day, then subtracts the deficit needed for your chosen pace, giving you a clear target intake.
It starts by calculating your Total Daily Energy Expenditure from your weight, height, age, sex and activity level using the trusted Mifflin-St Jeor equation. From there it applies your chosen weekly loss rate — gentle, moderate, fast or aggressive — using the rule of thumb that roughly 7,700 calories equals about a kilogram of fat. The result is your daily calorie goal, your daily and weekly deficit, an estimated timeline to reach your target weight, and a simple macro split to start from.
Pace matters as much as the target. A moderate deficit of around 500 calories a day is sustainable for most people and protects muscle; very large deficits lose weight faster but are harder to stick to and can leave you tired, hungry and short on nutrients. If your chosen rate pushes the daily deficit above 1,000 calories, the tool flags it so you can reconsider — losing slower but keeping it off usually beats a crash.
These are educational estimates, not a prescription. Real results depend on adherence, sleep, stress, training and individual metabolism, and anyone with a medical condition should plan weight loss with a healthcare professional. Everything is calculated privately in your browser. Enter your details above to get your target, and use the BMR calculator to understand the numbers behind it.
How it works
Three quick steps — no account, nothing uploaded to a server.
Enter your stats
Current and target weight, plus age, height and activity.
Pick a pace
Choose how fast you want to lose, from gentle to aggressive.
Follow your target
Get a daily calorie goal, timeline and macro split.
General health information related to this tool is available from the US CDC healthy weight resources. Last checked July 2026.
FAQ
Frequently asked questions
What is a calorie deficit?
A calorie deficit means eating fewer calories than your body burns in a day, which forces it to use stored energy (mostly fat) to make up the difference — and that's how weight loss happens. This calculator works out your daily energy expenditure, then subtracts the deficit needed to hit your chosen rate of loss, giving you a target daily calorie intake.
How big should my calorie deficit be?
A moderate deficit of around 500 calories a day produces roughly a pound (about 0.45 kg) of loss per week, which is widely considered safe and sustainable. Larger deficits lose weight faster but are harder to maintain and risk muscle loss and nutrient gaps. This tool warns you if your chosen rate creates a deficit above 1,000 calories a day.
How fast can I safely lose weight?
Most guidelines suggest 0.25 to 1 kg (about 0.5 to 2 lb) per week. Slower loss is easier to sustain and better preserves muscle; faster loss should generally be done under professional supervision. Pick the rate that feels realistic for your lifestyle rather than the fastest possible.
What about protein and macros?
The calculator suggests a simple macro split — around 30% of calories from protein, 40% from carbohydrates and 30% from fat — as a starting point. Adequate protein is especially important in a deficit to help preserve muscle. Adjust the split to suit your preferences, training and any guidance from a professional.
Is my data private?
Yes. All inputs and calculations stay in your browser and are never uploaded or stored. Your information never leaves your device.
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