How the Weight Loss Calculator Works

This tool uses the Mifflin-St Jeor equation, widely regarded as one of the most accurate methods for estimating basal metabolic rate (BMR). Your BMR is multiplied by an activity factor to estimate total daily energy expenditure (TDEE).

The tool then applies a 500 kcal/day deficit from your TDEE — a level many health experts associate with roughly 0.5 kg of fat loss per week. The timeline estimate divides the gap between your current and target weight by this weekly rate.

What the Numbers Mean

Your TDEE is the number of calories your body needs to maintain its current weight. Eating below that creates a deficit. A 500 kcal/day deficit equals approximately 3,500 kcal/week, commonly associated with around 0.5 kg of fat loss. Your estimated timeline is based on this rate — actual progress depends on consistency, sleep, stress, hormones, and other individual factors.

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Understanding Your Weight Loss Timeline

A realistic timeline is one of the most useful tools you can have. Without one, it’s easy to feel like progress isn’t happening fast enough — leading to frustration and giving up prematurely.

At a moderate pace of 0.5 kg per week, losing 10 kg takes approximately 20 weeks (about 5 months). That might feel slow, but people who lose weight gradually are significantly more likely to maintain their results long-term.

Which Pace Is Right for You?

The slow pace (0.25 kg/week) is ideal for those already fairly active or with a small amount to lose. The moderate pace is recommended for most beginners — achievable through diet changes alone. The faster pace (0.75 kg/week) typically requires both dietary changes and regular exercise.

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What Are Maintenance Calories?

Your maintenance calories (TDEE — Total Daily Energy Expenditure) represent the number of calories your body burns in a day when your weight stays the same. Eating above this leads to weight gain; eating below it leads to weight loss.

How Many Calories Do You Need to Lose Weight?

A typical starting point is reducing your maintenance calories by 300–500 kcal per day. This creates a calorie deficit without being so low that it causes fatigue, muscle loss, or unsustainable hunger. The calculator applies a 500 kcal deficit for the “lose weight” goal, and a gentler 200 kcal reduction for “improve consistency.”

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What Is the Waist-to-Height Ratio?

The Waist-to-Height Ratio (WHtR) compares your waist circumference to your height. Research suggests it can be a useful general indicator of central fat distribution at a population level. A ratio below 0.5 is generally considered in the healthy range for most adults.

Why Does Belly Fat Matter?

Visceral fat — stored around internal organs in the abdominal area — has been associated in research with various metabolic concerns. Reducing central fat through improved diet, regular movement, and better sleep is generally considered beneficial. Use this tool as a general awareness check, not a medical assessment.

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What Affects Your Metabolism?

Your metabolism is influenced by age, gender, genetics — and by highly controllable lifestyle factors including activity level, sleep quality, daily routine consistency, and overall energy balance. Contrary to popular belief, most people don’t have a “slow” metabolism, but many have habits that make it harder for their body to function efficiently.

How to Support Your Metabolism

The most effective approaches are the most consistent ones: regular physical activity (even walking), prioritising 7–9 hours of quality sleep, eating regular meals, staying hydrated, and managing stress. Supplements may provide additional support alongside these foundations.

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