Tudo Cálculo – 20 free calculators for finance, health and math

Immediate, no-friction calculators in Portuguese — IMC, juros compostos, juros simples and 70+ more — with instant results, a theme toggle and an articles/news section. It’s useful and accessible, but ultimately derivative; to feel more than another utility hub it needs exportable outputs, transparency about formulas, or an API for integrations.