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FREE RESEARCH CALCULATOR

Stock Solution Calculator

Calculate compound mass for a target molar stock using molecular weight, volume, and optional purity correction.

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CORE EQUATIONmass = M × V × MW ÷ purity
Unit-awarePractical checksLocal processingHow results are handled →
READY TO CALCULATEExample values are included so you can test the workflow immediately.
COMPOUNDS

Stock solution

Prepare a molar stock from powder with an optional purity correction.

mass = M × V × MW ÷ purity
BENCH RECIPE✓ READY
5mgcompound to weigh
→
1mL10 mM final

Dissolve fully, then adjust to 1 mL final volume — do not simply add 1 mL solvent.

10 µmol total
WHAT IT DOES

From formula to a bench-ready decision.

Convert a target stock concentration into the mass of powder to weigh and final volume to prepare.

Tossora Lab keeps units, intermediate values, and practical preparation checks visible so a mathematically correct answer is easier to translate into an experimental workflow.

BUILT-IN CHECKS

What Tossora Lab checks.

  • Supports molar concentration and volume units.
  • Corrects weighed mass for entered assay or purity.
  • Warns when the calculated mass is very small.
BENCH NOTES

Before you use the result.

  • Use the reagent certificate value when purity correction is required by your protocol.
  • Dissolve first, then bring the solution to its final volume.

Research use only. Verify critical calculations, reagent specifications, route or instrument limits, and procedures against your approved protocol and institutional requirements.

COMMON USES

When this calculator is useful.

  • Calculating how much compound to weigh for a molar stock.
  • Correcting weighed mass for a reagent assay or purity value.
  • Checking whether the required mass is realistic for the available balance.
WORKED CONTEXT

Example: preparing a 10 mM small-molecule stock

Enter target concentration, molecular weight, final volume and the assay/purity shown for the material. The result reports the corrected mass to weigh and reminds you to dissolve before bringing the solution to final volume.

Try it with your values ↑
FAQ

Questions researchers often ask.

Why does purity change the mass to weigh?

If the material contains less than 100% active compound by mass, more material is required to provide the requested molar amount.

Which molecular weight should I enter?

Use the molecular weight for the exact material form used in the experiment, including salt or hydrate form when applicable to the stated reagent specification.

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