Unit converters
Our unit conversion tools use conversion constants compliant with the International System of Units (SI) and official definitions of imperial units. Sources: BIPM, NIST.
ConvertBase.app
How our tools work
Every tool on ConvertBase.app is based on publicly available formulas, standards, or algorithms. Here's where our data comes from and how we maintain accuracy.
Health calculators (BMI, calories)
The BMI calculator uses the Quetelet formula (weight in kg / height in m²) as defined by the World Health Organisation (WHO). Category ranges follow WHO 2000 guidelines.
Financial calculators
Loan and instalment calculations use standard financial mathematics formulas (equal instalments - annuity method; decreasing instalments - capital method). These tools are for informational purposes only and do not constitute financial advice.
Construction calculators
Material estimates are based on standard industry norms and coefficients used in construction practice. We always recommend adding a waste margin - the suggested percentage is shown next to each calculator.
Developer tools
All data operations (Base64 encoding, hashing, JSON formatting) use algorithms defined by IETF, W3C, or NIST. All operations run locally in your browser - no data is sent to our servers.
Reporting errors
Spotted a calculation error or an outdated formula? Contact us - every report is reviewed and fixed.