What is the dilution equation C1V1 = C2V2?

C1V1 = C2V2 is the dilution equation where C1 is the initial concentration, V1 is the initial volume, C2 is the final concentration, and V2 is the final volume. This equation is based on the principle that the amount of solute remains constant during dilution - you're only adding solvent. It's fundamental in chemistry, biology, and laboratory work.

How do I calculate how much solvent to add?

First, use C1V1 = C2V2 to find the final volume (V2) needed. Then subtract the initial volume from the final volume: Solvent to add = V2 - V1. For example, if you need 100 mL total (V2) and you're starting with 20 mL of concentrated solution (V1), you need to add 80 mL of solvent.

Do concentration units matter in dilution calculations?

The units for C1 and C2 must be identical (both M, both g/L, both %, etc.), and V1 and V2 must have the same volume units (both mL, both L, etc.). The actual units don't matter as long as they're consistent because the equation is based on ratios. You can't mix M with % or mL with L without converting first.

What's the difference between dilution ratio and dilution factor?

Dilution ratio expresses how much solute compared to solvent (like 1:10 means 1 part solute + 9 parts solvent). Dilution factor is the ratio of final volume to initial volume (V2/V1). If you dilute 1 mL to 10 mL total, the dilution ratio is 1:10 and the dilution factor is 10. The concentration decreases by the dilution factor: C2 = C1/dilution factor.

Can I use the dilution equation for serial dilutions?

Yes, for serial dilutions (multiple successive dilutions), apply C1V1 = C2V2 to each step. The final concentration after multiple dilutions is C(final) = C(initial) × (dilution factor 1) × (dilution factor 2) × ... For example, two 1:10 dilutions give a final dilution of 1:100, reducing concentration by a factor of 100.

Math

Dilution Calculator

Calculate dilution ratios and volumes using the C1V1 = C2V2 formula.

Solve For

Initial Concentration (C1)

Initial Volume (V1)

Final Concentration (C2)

Final Volume (V2)

How to Use This Calculator

Enter Known Concentration and Volume

Input your initial concentration (C1) and volume (V1) of the stock solution you're starting with. Make sure you're using consistent units - if concentration is in M (molarity), keep it in M; if volume is in mL, keep it in mL.

Enter Your Target

Specify either your desired final concentration (C2) or your desired final volume (V2). The calculator will solve for the unknown variable using the C1V1 = C2V2 equation.

Calculate Dilution Requirements

Click calculate to see your results. The calculator will show the missing value and, importantly, how much solvent (water or other diluent) you need to add to achieve your target dilution. Follow the recommended dilution procedure for accurate results.