Calorie Deficit Calculator
Set Your Weight-Loss Plan
Estimate maintenance calories, the deficit needed for a goal, target calorie intake, and a simple weight-loss timeline from your body details and activity.
Quick presets
Calculation mode
Body details
Goal plan
Changing days and weeks preserves the same actual duration.
Enter only exercise beyond what is already represented by the selected activity multiplier.
Calorie Deficit Results
Target calorie intake
2,452 kcal
Estimated BMR
1,749 kcal
Maintenance TDEE
2,711 kcal
Total daily deficit
458 kcal
Moderate deficit
Food deficit
258 kcal
Additional exercise deficit
200 kcal
Estimated weekly loss
0.42 kg
Estimated monthly loss
1.79 kg
Estimated time to goal
84 days · 12.0 weeks
Weekly Weight Estimate
This is a simple estimate using 7,700 kcal per kilogram, not a prediction of actual body-weight change.
| Week | Elapsed | Estimated weight |
|---|---|---|
| 0 | 0 days | 80.0 kg |
| 1 | 7 days | 79.6 kg |
| 2 | 14 days | 79.2 kg |
| 3 | 21 days | 78.8 kg |
| 4 | 28 days | 78.3 kg |
| 5 | 35 days | 77.9 kg |
| 6 | 42 days | 77.5 kg |
| 7 | 49 days | 77.1 kg |
| 8 | 56 days | 76.7 kg |
| 9 | 63 days | 76.3 kg |
| 10 | 70 days | 75.8 kg |
| 11 | 77 days | 75.4 kg |
| 12 | 84 days | 75.0 kg |
This calculator uses BMR, an activity multiplier, and a simple 7,700 kcal-per-kilogram estimate for general planning. Do not treat it as a prescription during pregnancy, breastfeeding, growth, eating-disorder history, chronic disease, medication use, or medically restricted diets.
Weight-Loss Energy Model and Limits
Reference date and last reviewed: July 11, 2026
Calculation Basis
Estimates daily deficit and intake from Mifflin-St Jeor BMR, the selected activity multiplier, a simplified 7,700 kcal/kg conversion, and separately entered exercise.
Reference Limits
Water, glycogen, lean mass, metabolic adaptation, and tracking error make actual weight change differ from a linear schedule. Exercise-device calorie values are estimates as well.
When to Confirm Officially
Before applying the plan, seek qualified medical or nutrition guidance for pregnancy, breastfeeding, minors, eating disorders, diabetes, kidney disease, treatment, or a calculated intake that is unusually low.
Usage Tips
Start with a Moderate Calorie Deficit and Adjust Gradually Based on Progress
Setting a drastic daily deficit (e.g., 1,000 kcal or more) from the start can lead to severe hunger, chronic fatigue, muscle loss, and a drop in workout performance, eventually causing you to quit. The most sustainable approach is to begin with a modest deficit of 300 to 500 kcal below your daily maintenance calories (TDEE). Monitor your weight trend, muscle retention, and overall physical energy level for 2 to 4 weeks, and then make small, flexible adjustments to find the sweet spot that works best for your body.
What is Calorie Deficit Calculator?
The Calorie Deficit Calculator estimates BMR and TDEE maintenance calories from sex, age, height, weight, and activity, then uses a goal timeline or a directly entered daily deficit to estimate target calorie intake and a simple weight-loss schedule. It asks for only additional exercise beyond the selected activity multiplier to reduce double counting. Results are general planning references, not an individual diet prescription or a guarantee of weight loss.
How to Use
- 1Enter sex, age, height, current weight, and the activity level that represents a typical week.
- 2Enter a goal weight lower than or equal to current weight. An equal value is treated as maintenance.
- 3Choose a target timeline or enter a total daily deficit directly.
- 4Enter only additional exercise that is not already represented by the activity multiplier.
- 5Review target intake, BMR, TDEE, food and exercise deficits, estimated rate, and the simple weekly table.
Calorie deficit and timeline calculation
Last reviewed: July 11, 2026Timeline-mode formula
daily total deficit = (weight loss kg × 7,700 kcal) ÷ target days
The tool estimates TDEE by multiplying Mifflin-St Jeor BMR by an activity factor, then subtracts separately entered exercise calories from the total deficit to find the food deficit. The 7,700 kcal/kg constant is a simplified planning model.
Example: 80 kg to 75 kg in 12 weeks
- • Male, age 30, 175 cm, 80 kg
- • Moderate activity 1.55 and 75 kg goal
- • 12 weeks (84 days) and 200 exercise kcal/day
- 1. 5 kg × 7,700 = 38,500 kcal total deficit
- 2. 38,500 ÷ 84 = 458.33 kcal/day total deficit
- 3. food deficit = 458.33 − 200 = 258.33 kcal/day
- 4. 2,710.56 TDEE − 258.33 = 2,452.23 kcal/day
Estimated target intake is about 2,452 kcal/day, with a simplified weekly loss of about 0.42 kg.
How to read the result
- A shorter timeline requires a larger daily deficit for the same weight change.
- Exercise calories cover part of the total deficit and should not be subtracted twice from food intake.
- If multi-week weight trends differ from the estimate, reassess measured intake and activity instead of forcing the schedule.
Conditions that change the result
- The 7,700 kcal/kg model does not represent water, glycogen, lean-mass change, or metabolic adaptation.
- Do not use this general adult model for pregnancy, breastfeeding, growth, eating-disorder recovery, or medical treatment.
- The activity factor already includes usual training; enter only exercise beyond that baseline.
Common input mistakes
- Entering 12 days instead of 12 weeks or pounds in a kilogram field changes the result substantially.
- Treating a wearable calorie estimate as exact and subtracting it again from food creates double counting.
- A goal weight above current weight or an unrealistically short timeline does not fit this loss model.
Reference Knowledge
- ●The Mifflin-St Jeor BMR formula uses 10×weight (kg) + 6.25×height (cm) - 5×age + 5 for men and -161 as the final constant for women.
- ●TDEE equals BMR multiplied by sedentary 1.2, light 1.375, moderate 1.55, high 1.725, or very high 1.9.
- ●Timeline mode calculates total required deficit as weight to lose × 7,700 kcal, then divides it by target days.
- ●Food deficit equals total daily deficit minus additional exercise, and target intake equals TDEE minus the food deficit.
- ●The activity multiplier already represents usual lifestyle and training. Enter only exercise beyond that baseline to reduce double counting.
- ●The 7,700 kcal-per-kilogram conversion is a simple planning model and does not include metabolic adaptation, water, glycogen, lean mass, or changing activity.
- ●Compare the estimate with several weeks of consistent intake, weight trends, and wellbeing, then adjust with qualified guidance when needed.
FAQ
Q.How is a calorie deficit calculated?
A calorie deficit is the difference between daily calories used and calories eaten. This tool converts the goal weight difference using about 7,700 kcal per kilogram and divides by the target duration, or uses the total daily deficit entered directly.
Q.How much weight could a 500 kcal daily deficit represent?
The simple conversion is about 0.45 kg per week or 1.95 kg per 30 days. Actual scale weight can differ because of water, glycogen, food volume, activity, and metabolic adaptation.
Q.How are exercise calories included?
Usual exercise is already represented by the activity multiplier. Enter only additional exercise beyond that baseline. The value is used to divide the total deficit into food and additional-exercise portions.
Q.What should I do if target calorie intake is too low?
The calculator does not silently raise the value. It warns below 1,000 kcal, below sex-based reference levels, below estimated BMR, or above a 1,000 kcal daily deficit. Do not use these values as a sustained target without qualified medical or nutrition guidance.
Q.Why can actual weight change differ from the estimate?
The equations cannot directly measure body composition, hormones, water, glycogen, sleep, stress, medication, illness, or metabolic adaptation over time. Use the estimate as a starting point and adjust from a multi-week real trend.
