Free Scientific Weight Loss Calculators & Journey Hub

BMI (Body Mass Index) is a ratio of weight to height used to screen body composition categories. While useful as a starting baseline, it does not account for muscle mass or fat distribution. Our BMI calculator includes WHO 2004 Asian-adjusted thresholds and senior-specific ranges for greater clinical accuracy than the standard 18.5–25 scale.

Start with BMI and Ideal Weight to establish your baseline, then calculate TDEE to understand your daily calorie needs. Next, use the Calorie Deficit and Macro calculators to plan your approach. Use the Weight Loss % and Body Fat % calculators to track body composition over time. Finally, use the Goal Weight Calculator to project your exact arrival date. If you walk for exercise, add the Walking Weight Loss or Daily Steps Weight Loss calculators to model how your activity contributes to your daily deficit — the combined diet-plus-movement approach produces the best long-term results.

All formulas are evidence-based and verified against clinical nutritional protocols. The TDEE calculator supports three formulas: Mifflin-St Jeor (default — most validated for the general population), Harris-Benedict (the classic widely-used alternative), and Katch-McArdle (most precise when body fat percentage is known). Body fat uses the US Navy circumference method. Results are population-level estimates and should be treated as starting baselines, not medical diagnoses.

Yes, with caution. BMI overestimates body fat in muscular individuals. For athletes, prioritise the Body Fat % calculator over BMI for an accurate picture of body composition. TDEE activity multipliers can also be adjusted to reflect higher training volumes.

Clinical guidelines recommend 0.5–1 kg (1–2 lbs) per week as safe and sustainable. Faster loss risks muscle loss, metabolic adaptation, and nutritional deficiencies. Our Calorie Deficit Calculator flags deficits that exceed safe thresholds, and the Weight Loss % Calculator warns when your weekly rate is too aggressive.

A deficit greater than 1,000 kcal/day or projected loss exceeding 1 kg per week is generally considered aggressive. Our Calorie Deficit Calculator highlights this threshold and suggests a more conservative, sustainable alternative to preserve lean muscle and metabolic rate.

Both are effective, and research suggests tracking both together produces better body composition outcomes than either alone. Start with total calories (via TDEE and Deficit calculators), then layer in macros — particularly protein — to preserve muscle mass during a calorie deficit.

Verify you are using consistent units (metric or imperial) across all calculators. All results are population-level estimates — individual variation is expected and normal. If results consistently seem inaccurate, consult a registered dietitian for a personalized clinical assessment.

Yes — walking is one of the most effective and sustainable forms of fat-loss exercise because it has a low injury risk, requires no equipment, and can be done daily without recovery time. A 45-minute brisk walk burns around 275 kcal for a 70 kg person. Combined with a modest 300 kcal dietary reduction, that creates an approximately 575 kcal daily deficit — enough to lose roughly 0.5 kg (just over 1 lb) per week. Use the Walking Weight Loss Calculator to project your exact calorie burn and fat loss timeline based on your pace, duration, and body weight.

10,000 steps per day burns roughly 256 kcal above resting metabolism for an average 70 kg person at moderate pace — enough to contribute, alongside a modest dietary deficit, to 0.5–1 lb of weekly fat loss. The exact number depends on your body weight and height: heavier and taller people cover more ground per step and burn more. Use the Daily Steps Weight Loss Calculator to get a personalised calorie burn, weekly weight loss rate, and projected milestone dates based on your specific step goal and measurements.