Calorie Deficit Calculator
Find a safe, sustainable daily calorie target for weight loss or gain, based on your TDEE and a realistic weekly rate.
Awaiting your TDEE
Enter your maintenance calories and pick a goal to get your daily target.
How a Calorie Deficit Actually Works
A calorie deficit means eating fewer calories than your body burns in a day (your TDEE). When you consistently eat below maintenance, your body draws on stored fat for the missing energy, and you lose weight over time.
Roughly 7,700 kcal equals about 1 kg of body fat. Divide that by 7 days, and a 0.5 kg/week rate works out to a 550 kcal/day deficit:
Daily deficit = (target rate in kg/week x 7,700) / 7
How Big Should Your Deficit Be?
| Rate | Daily deficit | Best for |
|---|---|---|
| 0.25 kg/week | ~275 kcal | Slow, sustainable, minimal muscle loss risk |
| 0.5 kg/week | ~550 kcal | Recommended starting point for most people |
| 0.75 kg/week | ~825 kcal | Faster progress, harder to sustain |
| 1 kg/week | ~1,100 kcal | Only for people with significant weight to lose, ideally supervised |
Deficits larger than 1,000 kcal/day risk muscle loss, fatigue, and rebound overeating. Slower, steadier rates hold up better over months.
Worked Example
A 30-year-old woman has a TDEE of 2,100 kcal and wants to lose 0.5 kg/week.
Daily deficit = (0.5 x 7,700) / 7 = 550 kcal
Target intake = 2,100 - 550 = 1,550 kcal/day
She would eat around 1,550 kcal/day and expect to lose roughly 0.5 kg a week, assuming her TDEE estimate is reasonably accurate.
Don't Know Your TDEE Yet?
This calculator needs your TDEE (maintenance calories) as a starting point. Get it from our Mifflin-St Jeor Calculator or TDEE Calculator first, then come back here to set your target.
Frequently Asked Questions
What's a safe calorie deficit for weight loss?
A deficit of 300-750 kcal/day (roughly 0.25-0.75 kg/week) is considered safe and sustainable for most healthy adults. Larger deficits increase the risk of muscle loss and are harder to maintain.
Should I eat below my BMR?
No. Your deficit should be calculated from your TDEE, not your BMR. Eating below BMR for extended periods is not recommended and can backfire.
Why isn't my weight loss matching the math?
Water retention, measurement error in your TDEE estimate, and natural weight fluctuations all affect short-term results. Track your weekly average over 2-3 weeks rather than day to day.
Ready to plan your macros?
Split your calorie target into protein, carbs, and fat.