How LabCalc calculates

One calculation engine

Every calculator uses the same core: values are converted to canonical SI-based units (grams, litres, moles, mol/L, g/L), the calculation is performed there, and the result is converted back into the unit you selected. This avoids rounding drift and makes unit handling identical across the app.

Atomic weight data

IUPAC conventional atomic weights (abridged), values in g/mol.

Formula masses are the sum of the conventional atomic weights of every atom in the formula unit. Isotopic composition, monoisotopic masses and charge states are not modelled.

What is never assumed

• No density is ever assumed, including that of water.
• Mass and volume percentages are not converted into one another without an explicit density.
• Amount ↔ mass conversions require the molecular weight; the calculator asks rather than guesses.
• Volume contraction on mixing, temperature effects and activity coefficients are not modelled.

Validation

The calculation engine is covered by an automated unit test suite with worked examples for each calculator. Invalid input — negative volumes, zero concentrations, impossible dilutions, malformed formulas — is rejected with a specific message rather than producing a silently wrong number.

Responsibility

LabCalc is a calculation aid. You remain responsible for verifying results, units, chemical compatibility and all applicable safety requirements before laboratory use.