Calorie Deficit Calculator
A calorie deficit occurs when you consume fewer calories than your body expends, forcing it to draw on stored fat for energy. By knowing your Total Daily Energy Expenditure (TDEE) — the number of calories you burn each day — you can set a precise daily intake target to lose a specific amount of weight within a chosen timeframe.
The standard energy equivalents are 7,700 kcal per kilogram of body fat (or 3,500 kcal per pound). Dividing your total required deficit by the number of days in your plan gives your daily deficit. Health experts generally recommend keeping the deficit below 1,000 kcal/day and your daily intake above 1,200 kcal to avoid muscle loss, nutrient deficiencies, and metabolic slowdown.
How it works
Total deficit (kcal) = target weight loss × 7,700 (kg) or × 3,500 (lb). Daily deficit = Total deficit ÷ (weeks × 7). Daily intake = TDEE − daily deficit.
Use cases
- Planning a structured weight-loss program with a specific goal date
- Checking whether a proposed diet is medically safe before starting
- Adjusting calorie targets after a plateau or change in activity level
- Comparing outcomes for different timeframes (e.g., 8 vs. 16 weeks)
- Estimating how many calories to cut per day to lose 1–2 kg per month
Frequently asked questions
How many calories should I cut to lose 1 kg per week?
One kilogram of body fat is roughly equivalent to 7,700 kcal, so losing 1 kg per week would require a deficit of about 1,100 kcal per day. That exceeds the commonly recommended maximum of 1,000 kcal/day, so for most people a slower pace — such as 0.5 kg per week (about 550 kcal/day) — is safer and more sustainable.
What is a safe daily calorie deficit?
Health experts generally recommend keeping the deficit below 1,000 kcal per day and total daily intake above 1,200 kcal. Larger deficits increase the risk of muscle loss, nutrient deficiencies, and metabolic slowdown. If the calculator shows your plan requires a bigger deficit, extend the timeframe instead of cutting further.
How do I find my TDEE to use in this calculator?
Your Total Daily Energy Expenditure (TDEE) is the number of calories you burn each day, including exercise and everyday movement. It is typically estimated by calculating your basal metabolic rate (BMR) from age, sex, height, and weight, then multiplying by an activity factor. Once you know your TDEE, subtract the daily deficit from it to get your daily intake target.
Why am I not losing weight in a calorie deficit?
Common reasons include underestimating how much you actually eat, overestimating your TDEE, and temporary water retention that masks fat loss on the scale. Metabolism also adapts as you lose weight, so a deficit that worked initially may shrink over time. Track intake carefully for a few weeks and recalculate your targets after a plateau or a change in activity level.
Is 3,500 calories really equal to one pound of fat?
The 3,500 kcal per pound (7,700 kcal per kg) figure is a standard planning approximation based on the energy content of body fat. In practice, real-world weight loss is not perfectly linear because the body adapts and some weight change comes from water and lean tissue. It remains a useful rule of thumb for setting initial targets, which you should adjust based on actual progress.