Calculate safe calorie deficits, TDEE, and project your weight loss timeline.
Male
Female
Required for BMR calculation (Mifflin-St Jeor equation).
Please enter a valid age (18-100).
Weight must be greater than goal weight.
Sedentary (little or no exercise)
Lightly active (exercise 1-3 days/week)
Moderately active (exercise 3-5 days/week)
Very active (exercise 6-7 days/week)
Extra active (very hard exercise/physical job)
Determines your Total Daily Energy Expenditure (TDEE).
Slow & Sustainable (0.25 kg / 0.5 lb per week)
Moderate (0.5 kg / 1 lb per week)
Aggressive (0.75 kg / 1.5 lb per week)
Very Aggressive (1.0 kg / 2 lb per week)
Higher rates require larger calorie deficits.
Daily Calorie Target
2,050 kcal
Eat this amount daily to reach your goal.
Estimated Time to Goal30 Weeks
Target DateOct 15, 2024
Maintenance Calories (TDEE)2,550 kcal
Daily Deficit-500 kcal
Projected weight loss trajectory over time.
Monthly Milestones
Month
Date
Projected Weight
Total Loss
What is an Ideal Weight Loss Per Week Calculator?
An ideal weight loss per week calculator is a specialized digital tool designed to help individuals determine a safe, sustainable, and mathematically accurate pace for reducing body mass. Unlike generic advice that suggests arbitrary calorie cuts, this calculator uses your specific physiological data—including age, gender, height, current weight, and activity level—to compute your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE).
By establishing these baselines, the calculator identifies the precise caloric deficit required to achieve a specific weight loss goal, typically ranging from 0.5 to 2 pounds (0.25 to 1 kg) per week. This tool is essential for anyone looking to lose weight without compromising metabolic health or muscle mass.
Ideal Weight Loss Formula and Mathematical Explanation
The core logic behind the ideal weight loss per week calculator relies on the laws of thermodynamics, specifically the energy balance equation. The calculation follows a three-step process:
1. Calculating BMR (Mifflin-St Jeor Equation)
First, we calculate the energy your body needs just to exist at rest. The Mifflin-St Jeor equation is widely considered the most accurate for healthy individuals:
Men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
2. Calculating TDEE
We then multiply the BMR by an activity factor to find your Total Daily Energy Expenditure (TDEE):
Activity Level
Multiplier
Description
Sedentary
1.2
Desk job, little to no exercise
Lightly Active
1.375
Light exercise 1-3 days/week
Moderately Active
1.55
Moderate exercise 3-5 days/week
Very Active
1.725
Hard exercise 6-7 days/week
3. The 3,500 Calorie Rule
To lose 1 pound of fat, you generally need to create a deficit of approximately 3,500 calories. To lose 1 kg of fat, the deficit is approximately 7,700 calories.
Profile: John, 35 years old, male, 180cm, 95kg. Goal: 85kg. Activity: Sedentary (1.2 multiplier). Goal Pace: 0.5 kg per week.
Calculation: John's TDEE is approx 2,300 kcal. To lose 0.5kg/week, he needs a daily deficit of 550 kcal (0.5 × 7700 / 7). Result: John should eat 1,750 kcal/day. He will reach his goal in approximately 20 weeks.
Example 2: The Active Professional (Moderate)
Profile: Sarah, 28 years old, female, 165cm, 70kg. Goal: 60kg. Activity: Moderately Active (1.55 multiplier). Goal Pace: 0.5 kg per week.
Calculation: Sarah's TDEE is approx 2,200 kcal. To lose 0.5kg/week, she needs a daily deficit of 550 kcal. Result: Sarah should eat 1,650 kcal/day. She will reach her goal in approximately 20 weeks.
How to Use This Ideal Weight Loss Per Week Calculator
Select Your Units: Choose between Metric (kg/cm) or Imperial (lbs/ft) using the toggle at the top.
Enter Personal Details: Input your gender, age, height, and current weight accurately.
Set Activity Level: Be honest about your activity level. Overestimating activity is a common reason for stalled weight loss.
Choose Loss Rate: Select how much weight you want to lose per week. We recommend 0.5kg to 1kg (1-2 lbs) for sustainability.
Review Results: The calculator will display your daily calorie budget and the date you will reach your goal.
Key Factors That Affect Ideal Weight Loss Results
While the math is straightforward, biological reality is complex. Several factors influence your actual results:
Metabolic Adaptation: As you lose weight, your body requires less energy to move. Your TDEE will decrease, meaning you may need to adjust your calories downward over time.
Macronutrient Composition: Protein has a higher thermic effect than fats or carbs, meaning your body burns more calories digesting it. High-protein diets often yield better results.
Sleep Quality: Poor sleep increases cortisol and ghrelin (hunger hormone), making adherence to a deficit harder and potentially reducing fat oxidation.
Water Retention: Sodium intake, carbohydrate intake, and hormonal cycles can cause temporary water weight fluctuations that mask fat loss.
Non-Exercise Activity Thermogenesis (NEAT): This is the energy burned by fidgeting, walking, and standing. Dieting often subconsciously reduces NEAT, lowering your TDEE.
Medical Conditions: Thyroid issues (hypothyroidism) or PCOS can lower BMR, requiring a more tailored approach than standard calculators provide.
Frequently Asked Questions (FAQ)
What is a safe amount of weight to lose per week?
General medical guidelines suggest losing 0.5% to 1% of your total body weight per week. For most people, this translates to 1-2 pounds (0.5-1 kg). Losing weight faster than this risks muscle loss and nutritional deficiencies.
Why is my weight loss stalling?
Plateaus are common. They often occur because your TDEE has dropped as you've lost weight, or because of water retention masking fat loss. Recalculate your numbers every 5-10 pounds lost.
Can I target fat loss in specific areas?
No. "Spot reduction" is a myth. A calorie deficit causes the body to burn fat systemically. Genetics determine where fat is lost first.
Should I eat back my exercise calories?
Generally, no. Fitness trackers often overestimate calories burned. It is safer to consider your activity level in your TDEE calculation rather than adding back calories daily.
What is the minimum calorie intake I should not go below?
As a general rule, women should not eat fewer than 1,200 calories and men fewer than 1,500 calories per day without medical supervision to ensure nutrient sufficiency.
Does muscle weigh more than fat?
A pound is a pound. However, muscle is much denser than fat. Replacing fat with muscle may result in the scale not moving, but your body measurements shrinking.
How accurate is the BMR calculation?
The Mifflin-St Jeor equation is accurate to within 10% for most people. However, individual metabolism varies. Use the result as a starting point and adjust based on real-world progress.
Does age affect weight loss speed?
Yes. Metabolism generally slows with age due to a natural loss of muscle mass. Strength training can help mitigate this decline.
Related Tools and Internal Resources
BMI Calculator – Check if your weight falls within a healthy range.
Macro Calculator – Determine the best split of protein, carbs, and fats.