Weight Loss Calculator
Estimate your daily calories, safe calorie deficit, and realistic timeline to reach your goal weight. Switch between weekly loss and goal-date planning in one tool.
Weight loss planner
Most guidelines recommend 0.25–1 kg (0.5–2 lb) per week for safe, sustainable loss.
Choose a realistic date. The calculator will estimate the required weekly loss and calorie deficit.
Your weight loss plan
How this weight loss calculator works
This calculator estimates how many calories you burn per day and how long it may take to reach your goal weight with different calorie deficits. It is based on the Mifflin–St Jeor equation for basal metabolic rate (BMR) and standard activity multipliers for total daily energy expenditure (TDEE).
1. Basal metabolic rate (BMR)
Your BMR is the energy your body needs at rest to keep you alive (breathing, circulation, cell maintenance).
For men:
\(\text{BMR} = 10 \times \text{weight(kg)} + 6.25 \times \text{height(cm)} - 5 \times \text{age} + 5\)
For women:
\(\text{BMR} = 10 \times \text{weight(kg)} + 6.25 \times \text{height(cm)} - 5 \times \text{age} - 161\)
2. Total daily energy expenditure (TDEE)
TDEE is your BMR multiplied by an activity factor. For example, if your BMR is 1500 kcal and you are lightly active (×1.375), your TDEE is about 2060 kcal/day.
3. Calorie deficit and expected weight loss
A calorie deficit means eating fewer calories than you burn. A common rule of thumb is that a deficit of about 7700 kcal corresponds to ~1 kg of body fat (or 3500 kcal per pound), though real-world results vary.
\(\text{Weekly loss (kg)} \approx \dfrac{\text{daily deficit} \times 7}{7700}\)
\(\text{Daily deficit} \approx \dfrac{\text{weight to lose (kg)} \times 7700}{\text{weeks}}\)
4. Safe ranges and limits
- Typical safe loss: 0.25–1 kg (0.5–2 lb) per week.
- The calculator warns you if your plan requires a very large deficit or drops below a conservative minimum intake.
- Very low-calorie diets should only be done under medical supervision.
How to use this weight loss calculator
- Enter your age, sex, height, current weight, and goal weight.
- Select your usual activity level (not what you wish it were).
- Choose whether to plan by weekly loss or by a goal date.
- Click Calculate plan and review the suggested calorie target and timeline.
- Adjust the weekly loss slider or goal date until the plan looks realistic and safe.
Frequently asked questions
Is this weight loss calculator medically approved?
The formulas and ranges are based on widely used equations and public health guidelines, but this tool does not replace personalized advice from a doctor or registered dietitian. Always consult a professional if you have medical conditions, take medications, are pregnant, or have a history of eating disorders.
Why is my recommended calorie intake higher than other calculators?
Different tools use different equations (Mifflin–St Jeor, Harris–Benedict, Katch–McArdle) and activity factors. Small differences of 100–200 kcal/day are normal. What matters most is how your body responds over several weeks—use the number as a starting point and adjust based on your actual weight trend.
What if my plan requires fewer calories than the minimum?
That usually means your goal or timeline is too aggressive for your current size and activity level. The calculator will suggest a slower weekly loss or a later goal date. In some cases, increasing your activity (if safe) can allow a slightly higher intake for the same rate of loss.
How often should I recalculate?
As you lose weight, your calorie needs decrease. Recalculating every 4–6 weeks with your new weight helps keep your plan realistic and prevents plateaus.
Can I gain muscle while losing fat?
Some people, especially beginners or those returning after a break, can gain muscle while losing fat. However, the scale weight may change more slowly. Focus on strength, measurements, and how you feel—not just the number on the scale.
Disclaimer: This calculator is for educational purposes only and does not provide medical advice. Always consult your healthcare provider before starting any diet or exercise program.