Calorie Deficit Calculator for Weight Loss
Calculate your daily calorie deficit needed to lose weight at your target rate.
About this calculator
Losing weight comes down to eating fewer calories than you burn. This calculator works out your maintenance calories and then the daily deficit needed to lose weight at the pace you choose: a quarter, half, three quarters or a full kilogram a week.
It also shows the target daily intake and warns when a goal is too aggressive. A rate of 0.25 to 0.5 kg a week is easy to sustain. One kilogram a week demands a 1,100-calorie deficit and usually costs muscle.
How to use it
- Enter your Age, Gender, Weight and Height.
- Choose your Activity Level.
- Choose your Weekly Loss Goal.
- Press Calculate to see BMR, maintenance, the deficit and your target.
Deficit calculation
Deficit per day = Weekly loss (kg) × 7,700 ÷ 7. One kilogram of body fat holds about 7,700 kcal. Target intake = TDEE − Deficit, where TDEE comes from the Mifflin-St Jeor BMR times your activity factor.
Worked example
Man, age 30, 75 kg, 170 cm, moderately active, 0.5 kg a week
| BMR | 1,668 kcal |
| Maintenance (TDEE) | 2,585 kcal |
| Daily deficit | 550 kcal |
| Target intake | 2,035 kcal |
A deficit of 550 a day for 12 weeks should take off about 6 kg. Real results are uneven because water weight shifts.
This tool gives general information, not medical advice. Talk to a doctor or dietitian before making changes to your diet, exercise or medication.
Tips and common mistakes
- Choose the smallest deficit that keeps you motivated. Slow loss is easier to keep off.
- Combine a modest food deficit with more walking and strength training, instead of cutting food only.
- Eat enough protein, around 1.6 g per kg, to keep muscle.
- Plan a diet break at maintenance every 8 to 12 weeks if the deficit is long.
- Do not go below the minimum safe intake. Seek advice if you need to lose more than 1% of body weight a week.
Frequently asked questions
How big a calorie deficit should I have?
About 300 to 500 calories a day is a sensible range for most people.
How many calories make 1 kg of fat?
About 7,700. It is an approximation, since real weight change also includes water and muscle.
Is a 1,000-calorie deficit safe?
It can be too aggressive for many people, and is better done under medical supervision.
Why did my weight loss stall?
As you lose weight your maintenance falls, so the same intake gives a smaller deficit. Recalculate.
Do I need to count calories?
Counting helps at first. Many people move to portion habits after learning the numbers.
Does exercise change the deficit?
Yes, exercise raises TDEE. Choose an activity level that matches your real week.