Bmiweight Loss Calculator
Estimate your bmiweight loss with our free bmi calculator. See reference ranges, risk factors, and next-step guidance.
Formula
Target Weight = Target BMI x height(m)^2 | Weeks = Weight to Lose / Weekly Rate
First calculate the target weight from your desired BMI and height. Then divide the total weight to lose by your planned weekly loss rate to get the timeline. Daily calorie deficit is calculated as (weekly loss in kg x 7700) / 7 calories per day.
Worked Examples
Example 1: Weight Loss Plan for Overweight Man
Problem: A 35-year-old man weighs 90 kg, is 170 cm tall, and wants to reach a BMI of 24. He plans to lose 0.5 kg per week.
Solution: Current BMI = 90 / (1.70)^2 = 90 / 2.89 = 31.14 (Obese)\nTarget weight = 24 x (1.70)^2 = 24 x 2.89 = 69.4 kg\nWeight to lose = 90 - 69.4 = 20.6 kg\nWeeks needed = 20.6 / 0.5 = 41.2 weeks (~10 months)\nBMR = 10(90) + 6.25(170) - 5(35) + 5 = 1,793 cal\nTDEE (moderate) = 1,793 x 1.55 = 2,779 cal\nDeficit needed = 0.5 x 7700/7 = 550 cal/day\nTarget intake = 2,779 - 550 = 2,229 cal/day
Result: Lose 20.6 kg in ~41 weeks | Eat ~2,229 cal/day | Target: 69.4 kg
Example 2: Moderate Weight Loss for Woman
Problem: A 40-year-old woman weighs 75 kg, is 165 cm, and targets BMI 23. She plans 0.75 kg/week loss.
Solution: Current BMI = 75 / (1.65)^2 = 75 / 2.7225 = 27.55 (Overweight)\nTarget weight = 23 x 2.7225 = 62.6 kg\nWeight to lose = 75 - 62.6 = 12.4 kg\nWeeks = 12.4 / 0.75 = 16.5 weeks (~4 months)\nBMR = 10(75) + 6.25(165) - 5(40) - 161 = 1,420 cal\nTDEE (moderate) = 1,420 x 1.55 = 2,201 cal\nDeficit = 0.75 x 7700/7 = 825 cal/day\nTarget intake = 2,201 - 825 = 1,376 cal/day
Result: Lose 12.4 kg in ~16.5 weeks | Eat ~1,376 cal/day | Target: 62.6 kg
Frequently Asked Questions
How does BMI relate to weight loss goals?
BMI provides a framework for setting evidence-based weight loss targets. Rather than choosing an arbitrary goal weight, you can use BMI to determine a target weight that falls within the healthy range (18.5-24.9). To find your target weight from a desired BMI, multiply the target BMI by your height in meters squared. For example, a person 1.70 m tall targeting a BMI of 24 would aim for 24 x (1.70)^2 = 24 x 2.89 = 69.4 kg. This approach ensures your goal is medically appropriate and achievable. Health benefits begin with just a 5-10% reduction in body weight for those who are overweight, so even partial progress toward a healthy BMI brings meaningful improvements in blood pressure, blood sugar, and cholesterol levels.
What is a safe rate of weight loss per week?
Medical professionals generally recommend losing 0.5 to 1.0 kg (1-2 lbs) per week for safe, sustainable weight loss. This rate requires a daily caloric deficit of approximately 550 to 1,100 calories. Losing weight faster than 1 kg per week can lead to muscle loss, nutritional deficiencies, gallstone formation, and metabolic slowdown. Very rapid weight loss (more than 1.5 kg per week) is associated with rebound weight gain as the body's metabolism adapts to severe calorie restriction. For people with BMIs above 35, slightly faster initial weight loss of up to 1.5 kg per week may be appropriate under medical supervision. The most important factor is sustainability: a modest deficit maintained consistently over months produces better long-term results than aggressive dieting followed by regaining.
What is TDEE and why does it matter for weight loss?
Total Daily Energy Expenditure (TDEE) represents the total number of calories your body burns in a day, including basal metabolic rate, physical activity, and the thermic effect of food. TDEE is the foundation of any weight loss plan because you must consume fewer calories than your TDEE to lose weight. TDEE is calculated by multiplying your Basal Metabolic Rate (BMR) by an activity factor: sedentary (1.2), lightly active (1.375), moderately active (1.55), very active (1.725), or extremely active (1.9). A common approach is to eat 500-750 calories below TDEE to lose approximately 0.5-0.75 kg per week. Importantly, TDEE decreases as you lose weight because a smaller body requires less energy, so calorie targets should be recalculated periodically throughout a weight loss journey.
How does sleep affect weight loss and BMI?
Sleep deprivation significantly undermines weight loss efforts and BMI management through multiple hormonal and behavioral pathways. Getting fewer than 7 hours of sleep increases ghrelin (hunger hormone) by up to 15 percent and decreases leptin (satiety hormone) by similar amounts, leading to increased appetite, particularly for high-calorie, carbohydrate-rich foods. Sleep-deprived individuals consume an average of 300-400 extra calories per day. Insufficient sleep also elevates cortisol levels, promoting visceral fat storage and insulin resistance. Research shows that dieters who sleep 5.5 hours versus 8.5 hours lose 55 percent more lean mass and 60 percent less fat, even at the same caloric deficit. Poor sleep reduces motivation for exercise and impairs recovery from workouts. For optimal weight loss, aim for 7-9 hours of quality sleep in a cool, dark room with consistent bedtime and wake times.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.
What formula does Bmiweight Loss Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.