# Solution Dilution Calculator

> Work out how much stock solution to dilute, the final volume or either concentration with C₁V₁ = C₂V₂, plus the diluent to add and the dilution factor.

Category: Science & engineering · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/solution-dilution-calculator

Diluting does not change the amount of solute, so concentration × volume is the same before and after. Solve for whichever of the four values you do not know.

Also called: C1V1 = C2V2 calculator, Stock dilution calculator.

## Inputs
- Solve for (options: Stock volume needed (V₁), Final volume (V₂), Stock concentration (C₁), Final concentration (C₂); default v1)
- Stock concentration (C₁) (default 1)
- Stock volume (V₁) (unit mL; default )
- Final concentration (C₂) (default 0.1)
- Final volume (V₂) (unit mL; default 250)

## Results
- Answer
- Solvent to add (V₂ − V₁)
- Dilution factor (C₁ ÷ C₂)
- C₁
- V₁
- C₂
- V₂

## Formula

```
C₁ × V₁ = C₂ × V₂;  diluent = V₂ − V₁;  dilution factor = C₁ ÷ C₂ = V₂ ÷ V₁
```

Where:
- C₁, V₁: concentration and volume of the stock used
- C₂, V₂: concentration and total volume after dilution

## Worked example
1. V₁ = C₂ × V₂ ÷ C₁ = 0.1 × 250 ÷ 1 = 25 mL.
2. Solvent to add = 250 − 25 = 225 mL; dilution factor = 1 ÷ 0.1 = 10.

**Result:** To make 250 mL of 0.1 M from 1 M stock, take 25 mL of stock and make it up to 250 mL (about 225 mL of solvent).

## What the result means

In the lab, measure V₁ of stock into a volumetric flask and fill to the V₂ mark rather than adding exactly V₂ − V₁, because volumes are not always additive.

## Assumptions and limits
- The solute amount is conserved and the stock and final concentrations use the same unit.
- Mixing some liquids (for example ethanol and water) changes the total volume, so “diluent to add” is approximate.

## Questions

### What does “1 in 10” dilution mean?

One part stock in ten parts total, a dilution factor of 10: for example 25 mL made up to 250 mL.

### Can I use percentages or mg/mL?

Yes, as long as C₁ and C₂ are in the same unit.

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Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/solution-dilution-calculator