I'm Nguyen Anh Quan, founder of calculators.im, an open library of 270+ free online calculators covering personal finance, health, math, engineering, and unit conversion. I built calculators.im to give people clean, mobile-first calculator tools — no signup, no paywalls, and clear explanations of every formula. Areas I write about: - Personal finance (mortgages, retirement, taxes, debt) - Health metrics (BMI, calorie needs, body composition) - Practical math and unit conversion - Building free tools at scale I focus on practical, accurate, jargon-free answers.