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Molarity & Solution Dilution Calculator

Solve stock concentration dilutions using the fundamental chemistry equation C1V1 = C2V2.

Quick Answer:Select which variable to solve for (V1, C1, V2, or C2). Enter the known values; the calculator computes the answer and volume of solvent to add.

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How to Use the Dilution Calculator: Stock Solutions (C1V1 = C2V2)

1Select which variable you need to solve for (typically V1: stock volume needed).
2Enter the stock solution concentration (C1).
3Enter the target desired working concentration (C2) and target final volume (V2).
4Review the exact stock volume required and volume of solvent/water needed to reach target volume.

Formula & How It Works

Law of Conservation of Mass in Solutions

C₁ × V₁ = C₂ × V₂; Solvent to Add = V₂ - V₁

Calculates aliquot and diluent quantities based on molar mass preservation.

Worked Examples

Diluting 10M Stock HCl to 100mL of 1M HCl

Input: C1 = 10M, C2 = 1M, V2 = 100mL

Explanation: V1 = (1M × 100mL) / 10M = 10mL stock HCl. Add 90mL distilled water to achieve 100mL total.

Result: V1 = 10mL, Solvent to Add = 90mL

Frequently Asked Questions

What units must be used for C1V1 = C2V2?▼

Any concentration (M, mM, %, mg/mL) and volume (mL, L, μL) units work, as long as C1 matches C2 units and V1 matches V2 units.

Why is it important to add acid to water instead of water to acid?▼

Adding water to concentrated acid generates rapid exothermic heat that can cause boiling and dangerous acid splatter.

What is a dilution factor?▼

The dilution factor is the ratio of final volume to initial stock volume (V2 / V1), representing the fold reduction in concentration.

Can this formula be used for serial dilutions?▼

Yes, apply the formula sequentially across each dilution step in the series.

Quick Reference & Conversion Table

Stock Conc (C1)	Target Conc (C2)	Final Vol (V2)	Stock Aliquot (V1)	Solvent Added
10.0 M	1.0 M	100 mL	10 mL	90 mL
5.0 M	0.5 M	500 mL	50 mL	450 mL
1.0 M	0.1 M	250 mL	25 mL	225 mL
20× Buffer	1× Buffer	1,000 mL	50 mL	950 mL

⚠️ Common Pitfalls to Avoid

•Mixing up units (e.g. entering milliliters for V1 and liters for V2 without converting).
•Adding the full final volume of water instead of subtracting the stock aliquot volume.