Calorie Deficit Calculator
Daily calories to eat and fat loss from your deficit. Free, private and instant.
How to use the Calorie Deficit
- Pick metric (cm, kg) or imperial (ft, in, lb) units.
- Choose sex: Male or Female.
- Enter age.
- Enter height.
- Enter weight.
- Choose activity level: Sedentary (little or no exercise), Lightly active (1-3 days/week), Moderately active (3-5 days/week), Very active (6-7 days/week) and more.
- Enter daily calorie deficit (kcal/day).
- Press Calculate to get an instant result with a colour scale, chart and plain-English explanation.
About the Calorie Deficit
A calorie deficit means eating fewer calories than you burn. This calculator turns a daily deficit, for example 500 kcal, into expected weekly fat loss and a 12-week weight projection, and rates how aggressive it is.
Also known as: deficit calculator, fat loss calculator, how big a calorie deficit.
Worked example
- Sex: Male
- Age: 30 years
- Height: 170 cm
- Weight: 70 kg
- Activity level: Lightly active (1-3 days/week)
- Daily calorie deficit: 500 kcal/day
Daily calories to eat: 1,724 kcal/day (22% below maintenance). A 500 kcal daily deficit means about 0.5 kg of fat loss per week, or 2.0 kg per month.
- Maintenance (TDEE): 2,224 kcal
- Daily deficit: 500 kcal
- Loss per week: 0.5 kg
- Loss in 12 weeks: 5.1 kg
Formula and cut-offs
Deficit % = deficit / TDEE x 100. Weekly loss = deficit x 7 / 7,700 kg. TDEE = Mifflin-St Jeor BMR x activity factor.
Frequently asked questions
How big should my calorie deficit be?
A deficit of 10 to 25% of maintenance, around 300 to 700 kcal a day for most people, is sustainable.
Does a 500 calorie deficit equal 0.5 kg a week?
Yes, roughly. 500 kcal x 7 days = 3,500 kcal, about 0.45 kg of fat, though results vary.
Can I eat below 1,200 calories?
Very low intakes should only be used under medical supervision because they can cause nutrient gaps and muscle loss.
What are the daily calories to eat for a 30-year-old man, 170 cm, 70 kg and a daily calorie deficit of 500 kcal/day?
Daily calories to eat: 1,724 kcal/day (22% below maintenance). A 500 kcal daily deficit means about 0.5 kg of fat loss per week, or 2.0 kg per month. Enter your own numbers above for a personal result.
Sources and references
- World Health Organization - Obesity and overweight fact sheet
- World Health Organization - Healthy diet fact sheet
- NHS - BMI healthy weight calculator
Written and checked by the MediHub editorial team against the sources above. Read how we build and review our calculators.
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Last updated . This calculator is for education only and is not medical advice. See the medical disclaimer.