How the dilution calculator works
When you dilute a solution, the amount of solute stays the same; only the volume grows. So concentration times volume before equals concentration times volume after.
V₁ = C₂ × V₂ ÷ C₁
Diluent = V₂ − V₁
The concentrations can be in molarity, percent, mg/mL or any unit, as long as C₁ and C₂ match. The volumes can be in any unit too; the result is in the same unit as V₂ (labelled mL here). The dilution factor is C₁ ÷ C₂. For acids, always add acid to water, not water to acid, to control the heat released.
Worked example
To make 500 mL of 1 M hydrochloric acid from a 12 M stock, V₁ = 1 × 500 ÷ 12 = 41.67 mL of stock. Add it to about 400 mL of water, then top up to 500 mL (about 458.3 mL of water in total). The dilution factor is 1:12.
Frequently asked questions
What does C1V1 = C2V2 mean?
The amount of solute is conserved during dilution: initial concentration × volume equals final concentration × volume.
Can I use percentages?
Yes, if both concentrations are percentages of the same kind (w/v or v/v).
What is a 1:10 dilution?
One part stock in ten parts total, such as 1 mL stock plus 9 mL diluent.
Why not add the stock to the full volume of water?
Then the final volume would be larger than intended. Add stock, then fill to the target volume.
Updated October 2026. Results are estimates for education, not financial or medical advice. All math runs in your browser; nothing you type is sent anywhere.