Use our Atom Calculator to relate atomic number, mass number, charge, protons, neutrons and electrons. Fast, accurate, ideal for chemistry and physics.

Compute theoretical yield from limiting reagent and stoichiometry. Units auto-convert, live updates, step-by-step, PDF export — by Ajax Calculator.

Convert ppm to molarity and back with molar mass & density. Live syncing, step-by-step derivation, and PDF export. Ajax Calculator.

Free pH calculator that syncs [H+], [OH−], pOH, concentration, and mass/volume. Supports strong/weak acids and bases, unit options, steps, and PDF.

Calculate molarity fast from mass, volume, molar mass, and mass concentration. Live updates, unit conversions, and PDF export. Free online by Ajax Calculator.

Calculate half-life, decay constant, mean lifetime & remaining quantity with unit-aware inputs. Live results and PDF export on Ajax Calculator.

Calculate moles, particles, mass and molar mass using Avogadro’s constant. Real-time results with unit selectors and PDF export; mobile-friendly.