How to use (3 steps)
- Choose a mode: from solid reagent, from stock solution (C1V1 = C2V2) or serial dilution series.
- Enter the solute name, molar mass, target concentration and volume, or the stock concentration, factor and tube count.
- Read off the required mass/volumes and numbered recipe steps, then copy the URL to share the setup.
Default examples use NaCl so you can see realistic recipes immediately and adjust them to your own solutes.
Key formulas (for review)
This calculator is built around a small set of concentration formulas. Reviewing them helps you connect what you see on screen with the algebra.
- Molarity: C = n / V
- C is concentration in mol/L, n is amount in mol and V is volume in L. From this you can move between moles, mass (via molar mass M in g/mol) and volume.
- Dilution: C₁V₁ = C₂V₂
- For simple dilutions, the moles before and after are equal. C₁ and V₁ are the stock concentration and volume; C₂ and V₂ are the diluted concentration and final volume.
- Percent solutions (% w/v and % w/w)
- % w/v means grams of solute per 100 mL of solution. % w/w means grams of solute per 100 g of solution (here we approximate aqueous solutions using 1 g/mL for water).
As you read the calculation steps, try to match each line to one of these formulas.
Practice examples
Example 1 — NaCl solution from solid
You need 0.20 M NaCl and 250 mL of solution. Roughly how many grams of NaCl are required? Hint: use C = n/V with C = 0.20 mol/L and V = 0.250 L, then m = n·M with M = 58.44 g/mol. The calculator should give about 2.9 g.
Example 2 — Dilution from a stock solution
You have a 2.0 M HCl stock and want 100 mL of 0.50 M HCl. Use C₁V₁ = C₂V₂ with C₁ = 2.0, C₂ = 0.50 and V₂ = 0.100 L to find V₁. The calculator should suggest pipetting about 25 mL of stock and diluting to 100 mL.
Results
Mode: From solid reagent
These values show what to weigh or pipette; use the calculation steps below to see how the formulas are applied.
Preparation steps
- Recipe steps will appear here after calculation.
Serial dilution table
How it's calculated
- Steps will appear here after calculation.
How to use this calculator
Pick the mode that matches your bench task: weigh from a solid, dilute from a stock, or build a serial dilution series. Enter the common solute information once, then use the generated recipe as a checklist for weighing, transferring, rinsing, and filling to the final mark.
How to choose a concentration type
Use molarity when your target is in mol/L. Use % w/v when the protocol is written as grams per 100 mL of final solution, and use % w/w only when a mass-based formulation is acceptable and the water-density approximation is reasonable for your workflow.
How to verify the recipe
Check the final volume unit, the glassware or flask name, and whether the result assumes an approximate aqueous density. For stock dilutions, confirm that the stock concentration is stronger than the target concentration before you start pipetting.
Recommended next checks
- Compare the calculated mass or transfer volume with the resolution of the balance or pipette you actually have.
- Keep units consistent between stock concentration, target concentration, and final volume.
- When making serial dilutions, verify that each tube volume stays practical for the tubes and pipettes in your workflow.
FAQ
What kinds of solution recipes can this tool generate?
The calculator covers three common lab tasks: preparing a solution from a solid reagent at a chosen concentration and volume, diluting a concentrated stock to a target concentration using C₁V₁ = C₂V₂, and building a serial dilution series with a fixed dilution factor and number of tubes.
Does this replace good lab practice or safety checks?
No. The tool provides idealised recipes based on simple concentration formulas and assumes routine aqueous solutions. You should still follow your lab’s safety rules, check units and significant figures, and adapt the volumes or glassware to the available equipment and your protocol.
Related calculators
- Concentration & pH calculatorConvert concentration units before you choose a solid-reagent recipe or a stock-dilution setup.
- Reagent table plannerTurn one recipe into a bench-ready reagent list when you have several solutions or repeats to prepare.
- Limiting reagent & theoretical yieldUse this after preparing solutions when the next step is a stoichiometric reaction or yield estimate.
- Stoichiometry & limiting reactantCheck balanced mole ratios when your preparation recipe feeds into a reaction worksheet or lab calculation.
- Buffer pH (Henderson-Hasselbalch)Move here when the next question is how the prepared solution will behave in a buffer system.
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