Common questions
Everything you need to know about CalcBrew and our health calculators.
What formula do you use for BMI?
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We use the standard BMI formula referenced by the World Health Organization (WHO): BMI = weight (kg) ÷ height² (m²). For imperial inputs, we convert values accurately before calculating. BMI categories (Underweight, Normal, Overweight, Obese) also follow WHO guidelines.
Are these calculators completely free?
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Yes, 100% free — no hidden fees, no premium tier, no credit card, no signup required. All CalcBrew tools are and always will be free to use.
How accurate are online health calculators?
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Our calculators use clinically established formulas used by health professionals worldwide. They provide strong population-level estimates, though individual results may vary due to factors like muscle mass, bone density, and genetics. Always consult a healthcare professional for medical decisions.
What is TDEE and why does it matter?
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TDEE stands for Total Daily Energy Expenditure — the total calories your body burns each day including activity. Knowing your TDEE helps you set accurate calorie goals: eat below it to lose weight, at it to maintain, or above it to gain.
How often should I check my BMI or TDEE?
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BMI changes slowly, so monthly is enough. Recalculate your TDEE whenever your activity level, weight, or lifestyle changes significantly — or every 2–3 months as a habit.
Can I request a calculator that doesn't exist yet?
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Absolutely! Use the "Request a Calculator" section above. We review all submissions and prioritize the most requested tools. It's the best way to influence what we build next.