Dilution Calculator
Solve C₁V₁ = C₂V₂ for any unknown. Enter the three values you know, leave the one you want blank, and get the answer instantly — with the solvent volume to add.
Fill in any three values — the fourth is solved automatically. (3 more to go.)
All dilution & concentration calculators
A focused toolkit for the lab bench, classroom and workshop. Every tool is free and shows the formula it uses.
Find molarity from mass and molecular weight, or the mass needed for a target molarity.
Convert between moles, volume, and molar concentration (mol/L) in any direction.
Turn a 1:N ratio into exact stock + solvent volumes for any final amount.
Dilute a stock solution to a target concentration with full unit switching.
Convert mg/mL to molarity (and back) using molecular weight — both directions.
Parts per million ⇆ mg/L ⇆ percent, plus the mass of solute for a target ppm.
Work out % w/v and % v/v solutions — grams or mL of solute for any volume.
Build a fold-dilution series with concentration and transfer volumes per tube.
How the dilution calculator works
Diluting a solution means lowering its concentration by adding more solvent while keeping the amount of solute the same. Because the moles of solute do not change, the product of concentration and volume is conserved:
C₁ and V₁ are the concentration and volume of the concentrated stock; C₂ and V₂ are the concentration and volume after dilution. Rearranging lets you solve for whichever value you are missing — the calculator above does this automatically when you leave one field empty.
Worked example
You have a 10 M stock and need 50 mL of a 1 M working solution. Set C₁ = 10 M, C₂ = 1 M, V₂ = 50 mL, leave V₁ blank: V₁ = (1 × 50) / 10 = 5 mL of stock, topped up with 45 mL of solvent to reach 50 mL.
Choosing the right tool
- Need molarity from a mass? Use the molarity calculator.
- Working from a ratio like 1:10? Use the dilution ratio calculator.
- Making a tenfold series? Use the serial dilution calculator.
Frequently asked questions
›What is the dilution formula?
The core dilution equation is C₁V₁ = C₂V₂, where C₁ and V₁ are the concentration and volume of your stock solution, and C₂ and V₂ are the concentration and volume after dilution. Because it is a balance, you can solve for any one of the four values when you know the other three.
›How do I dilute a stock solution to a lower concentration?
Enter your stock concentration (C₁), the final concentration you want (C₂), and the final volume you need (V₂). Leave V₁ blank. The calculator returns the volume of stock to take, and the amount of solvent to add equals V₂ minus V₁.
›Do the units have to match?
Yes — C₁ and C₂ must share the same concentration unit, and V₁ and V₂ must share the same volume unit. The equation is a ratio, so as long as each pair matches, the result is correct in those units. Use the unit selectors to keep them consistent.
›Is this dilution calculator free?
Yes. Every calculator on DilutionCalc is free, runs entirely in your browser, needs no sign-up, and never sends your numbers to a server.