# WeightLoss Calculators

> All the math you need to get in shape. Free, evidence-based weight-loss and fitness calculators built on peer-reviewed formulas (Mifflin–St Jeor, ISSN, WHO, AHA, IOM).

WeightLoss Calculators (weightloss-calculators.com) is a free, no-signup site offering 10 evidence-based health calculators plus accompanying knowledge pages. Each calculator runs entirely client-side, returns multiple goal-based scenarios, and cites peer-reviewed primary sources. Formulas used include Mifflin–St Jeor, Harris–Benedict, Katch–McArdle, Devine/Robinson/Miller/Hamwi (IBW), WHO BMI categories, ISSN protein guidance, IOM fiber AI, IOM water AI, and AHA/DASH sodium thresholds.

## Calculators

- [TDEE Calculator](https://www.weightloss-calculators.com/tdee-calculator/): Total Daily Energy Expenditure via Mifflin–St Jeor BMR × PAL multiplier.
- [BMR Calculator](https://www.weightloss-calculators.com/bmr-calculator/): Basal Metabolic Rate with Mifflin–St Jeor, Harris–Benedict, and Katch–McArdle.
- [BMI Calculator](https://www.weightloss-calculators.com/bmi-calculator/): Body Mass Index with WHO categories and healthy weight range.
- [Calorie Deficit Calculator](https://www.weightloss-calculators.com/calorie-deficit-calculator/): Daily calorie target for weight loss with multiple pace scenarios.
- [Maintenance Calories Calculator](https://www.weightloss-calculators.com/maintenance-calories-calculator/): Calories needed to hold weight steady.
- [Ideal Weight Calculator](https://www.weightloss-calculators.com/ideal-weight-calculator/): Devine, Robinson, Miller, Hamwi, and healthy-BMI ranges with frame-size adjustment.
- [Protein Calculator](https://www.weightloss-calculators.com/protein-calculator/): Daily protein target in grams using ISSN goal-based multipliers.
- [Fiber Intake Calculator](https://www.weightloss-calculators.com/fiber-intake-calculator/): Daily fiber target using IOM Adequate Intake values.
- [Water Intake Calculator](https://www.weightloss-calculators.com/water-intake-calculator/): Personal hydration target accounting for weight, exercise, climate.
- [Sodium Intake Calculator](https://www.weightloss-calculators.com/sodium-intake-calculator/): AHA/DASH-aligned sodium target with athlete sweat-loss top-up.

## Knowledge & guides

- [How to Track Calories Accurately](https://www.weightloss-calculators.com/how-to-track-calories/): Step-by-step practical guide with sources.
- [Mifflin–St Jeor Equation](https://www.weightloss-calculators.com/knowledge/mifflin-st-jeor/): The most accurate BMR predictive equation.
- [Harris–Benedict Equation](https://www.weightloss-calculators.com/knowledge/harris-benedict/): Original and revised formulas.
- [BMI Formula Explained](https://www.weightloss-calculators.com/knowledge/bmi-formula/): History, formula, limitations.
- [Activity Multipliers (PAL)](https://www.weightloss-calculators.com/knowledge/activity-multipliers/): How to pick honestly.
- [Protein Requirements](https://www.weightloss-calculators.com/knowledge/protein-requirements/): ISSN/ACSM evidence-based intakes.
- [Macronutrients 101](https://www.weightloss-calculators.com/knowledge/macronutrients/): Protein/carbs/fat calories and splits.

## Primary sources cited site-wide

- Mifflin MD, et al. *A new predictive equation for resting energy expenditure in healthy individuals.* Am J Clin Nutr. 1990;51(2):241–7.
- Frankenfield D, et al. *Comparison of predictive equations for resting metabolic rate.* J Am Diet Assoc. 2005;105(5):775–89.
- FAO/WHO/UNU. *Human Energy Requirements.* 2001.
- WHO. *Obesity: preventing and managing the global epidemic.* Technical Report 894, 2000.
- Hall KD. *What is the required energy deficit per unit weight loss?* Int J Obes. 2008;32(3):573–6.
- Jäger R, et al. *ISSN Position Stand: protein and exercise.* JISSN. 2017;14:20.
- Morton RW, et al. *Protein supplementation on resistance training–induced gains: meta-analysis.* BJSM. 2018;52:376–84.
- Helms ER, et al. *Dietary protein during caloric restriction in resistance trained lean athletes.* IJSNEM. 2014;24(2):127–38.
- Institute of Medicine. *Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids.* 2005.
- Institute of Medicine. *DRIs for Water, Potassium, Sodium, Chloride, and Sulfate.* 2005.
- American Heart Association. *Sodium and salt guidance.*