DIY Cost Tools
Dilution Calculator
Find the final volume and ideal diluent addition needed to reduce a stock solution to a lower target concentration. Concentration units must match.
How to use this calculator
- Enter every quantity in the unit printed beside its field.
- Select Calculate or press Enter.
- Read the labeled results and compare them with the assumptions below.
Formula and method
Conservation of solute gives C₁V₁ = C₂V₂; diluent added = V₂ − V₁.
The calculation runs locally in your browser. If any entry is invalid or a mathematical condition is undefined, the prior result is hidden so it cannot be mistaken for a new answer.
Worked example
Using Stock concentration C₁ = 2, Stock volume V₁ (mL) = 100, Target concentration C₂ = 0.5, the formula returns Final volume V₂ (mL) = 400, Diluent to add (mL) = 300. The displayed default result is generated from these same inputs.
Limitations and safety
Assumes volumes are additive and the solute amount is conserved. Real mixtures can contract or expand, and reactive or hazardous chemicals require an approved laboratory procedure. Results use floating-point arithmetic and are displayed to about 10 significant digits; measurement uncertainty usually supports fewer. Verify units before relying on a result.
Frequently asked questions
Can this calculate a stronger target?
No. Adding diluent cannot make a solution more concentrated, so the target must not exceed the stock concentration.
Why might a measured result differ?
The formula isolates the stated model. Real systems can add uncertainty, losses, changing properties, geometry or forces that are not among the inputs.
How should I handle units?
Convert every value to the unit shown beside its field before calculating. A numerically valid value in the wrong unit will still produce a wrong result.
Review notes and reference
Reviewed October 3, 2026. The default example and an independent edge or scaling case were checked against expected values. The live script was also checked for blank, text, comma-formatted, non-finite and out-of-range entries. Method reference. Constants use the values stated in the formula. This page’s explanation and example are original.
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