Conversion hub
Scientific & Concentration Calculators
Tools for ppm, percentage, nanomoles, and BAC unit conversion that require the correct denominator or molecular context.
How these calculators are built
Every calculator shows its conversion formula, includes a searchable 1–1000 reference table where meaningful, links to related tools in the same silo, and states any density or concentration assumptions.
Written by Qudoos
Calculator publisher and site editor. Formula logic is shown on-page so results can be independently checked.
Last updated: October 7, 2026