Laboratory Calculators

The laboratory bench runs on a handful of concentration calculations, and getting them wrong wastes reagents and ruins experiments. This collection covers solution preparation from first principles — every tool shows its formula, works through real numbers, and cites where the method comes from.

Molarity & Concentration

Molarity is the workhorse concentration unit: moles of solute per litre of final solution. The molarity calculator solves in four directions, so you can go from a weighed mass to a concentration, or backwards from a target molarity to the mass you need to weigh. The molar mass calculator turns any chemical formula into the grams-per-mole value those conversions depend on. If you want the concept first, what is molarity explains the definition, the M vs mM relationship, and why temperature changes the answer.

Dilution

Diluting a stock is the most repeated action at the bench. The dilution calculator solves a single step in three directions — final concentration, dilution factor, or the stock and diluent volumes — while the C1V1 calculator handles the same C₁V₁ = C₂V₂ relation when you think in concentrations and volumes. For very large factors, the serial dilution calculator plans a step-wise series and prints the concentration in every tube. The how to calculate molarity guide covers the mole and volume conversions underneath all of them.

Solution Preparation

Preparing a stock means converting a target concentration and volume into a mass to weigh, then dissolving and bringing to volume. The stock solution calculator does exactly that with an optional purity correction, and the percent solution calculator keeps the % w/v, % v/v and % w/w conventions distinct so a recipe is never ambiguous.

Trace & Unit Conversion

Below the percent scale, concentration is quoted in parts per million. The PPM calculator converts between ppm, mg/L, µg/mL and percent, and works out the solute mass for a target ppm. Across the whole set the tools convert between mol/L, mmol/L, µM and nM, and between g, mg, µg and ng, so you can match whatever unit your protocol uses without doing the arithmetic by hand.

Which calculator do I need?

Start from what you are holding, not from the tool name:

• A weighed solid and a target volume → molarity calculator in mass mode. If you only have the chemical formula, run the molar mass calculator first to get grams per mole.
• A concentrated stock and a weaker working solution → dilution calculator for one step, or the C1V1 calculator when your protocol states C₁V₁ = C₂V₂ with mixed units.
• A very large dilution factor (1:100 or more) → serial dilution calculator, which plans the step-wise series and reports every tube.
• A recipe that says “make a 1 M stock” or “% w/v” → stock solution calculator for molar stocks (with purity correction) or percent solution calculator for % w/v, % v/v and % w/w.
• A specification in ppm, mg/L or µg/mL → PPM calculator.
• A target concentration and you need the mass to weigh → molarity or stock solution calculator in mass mode; both return grams, milligrams or micrograms.

When two tools seem to fit, prefer the one whose inputs match what you actually measured — a balance reading goes to a mass-mode tool, a pipette volume goes to a dilution tool.

Popular Lab Calculators

• Molarity Calculator — solve molarity, mass, volume or amount of substance.
• Dilution Calculator — final concentration, dilution factor or stock and diluent volumes.
• C1V1 Calculator — solve C₁V₁ = C₂V₂ for any unknown, with mixed units.
• Serial Dilution Calculator — tube-by-tube concentrations and the overall factor of a step-wise series.
• Molar Mass Calculator — molar mass from any formula, with percent composition.
• Stock Solution Calculator — grams to weigh for a molar or % w/v stock.
• Percent Solution Calculator — solute amounts for % w/v, % v/v and % w/w.
• PPM Calculator — ppm, mg/L, µg/mL and percent conversions.