What does C1V1 = C2V2 mean?

It expresses the conservation of solute: the amount of solute before dilution (C1 × V1) equals the amount after dilution (C2 × V2). Because you only add solvent, the solute quantity does not change.

Do the units have to match?

No. You can select different volume units (e.g., mL and L) and different metric prefixes for concentration (e.g., M and mM). The calculator automatically converts between compatible units, provided C1 and C2 share the same category (molar, mass concentration, or percent).

Can I use this for percent solutions?

Yes. Enter C1 and C2 as percent values (e.g., 70 and 10) and the volumes in any consistent unit. The formula is the same regardless of the concentration unit type.

What if my result is larger than the final volume?

If V1 > V2 (or the required initial volume exceeds the target volume), the dilution is not physically possible — you cannot dilute a larger volume into a smaller one. Re-check your inputs or reconsider the target concentration.

Is this calculator accurate enough for lab work?

The formula itself is exact. Accuracy depends on the precision of the values you enter. For critical assays, always verify with calibrated pipettes and balances.

Dilution Calculator (C1V1 = C2V2)

Solve the dilution equation C1V1 = C2V2 for any one unknown — enter the other three values and get the answer instantly.

Solve For

Select the unknown variable, then enter the three known values.

C₁ × V₁ = C₂ × V₂

C₁ — Initial Concentration

V₁ — Initial Volume

C₂ — Final Concentration

V₂ — Final Volume

Select a variable to solve for, enter the known values, then click Calculate.

Quick Reference

Find C1

C1 = (C2 × V2) / V1

Find V1

V1 = (C2 × V2) / C1

Find C2

C2 = (C1 × V1) / V2

Find V2

V2 = (C1 × V1) / C2

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Summary

This dilution calculator solves the standard laboratory equation C1V1 = C2V2, where C1 is the initial concentration, V1 is the initial volume, C2 is the final concentration, and V2 is the final volume. Select which variable you need to find, enter the other three values with their units, and the calculator returns the result immediately. It automatically converts between compatible units (e.g., M to mM, µL to mL) within the same concentration category.

How it works

Select which variable you want to solve for: C1, V1, C2, or V2.
Enter the three known values in the corresponding input fields.
Choose appropriate units for each concentration and volume field.
Click Calculate to apply the C1V1 = C2V2 formula.
Read the result and copy it with one click.
Use the Reset button to clear all fields and start over.

Use cases

Prepare a working solution from a concentrated stock in a chemistry lab.
Calculate how much stock solution is needed to make a diluted sample.
Determine the final concentration after adding diluent to a known volume.
Verify serial dilution steps in biological or analytical protocols.
Teach or learn solution preparation in high school or university chemistry.
Quick sanity check before running an experiment or assay.

Frequently Asked Questions

Last updated: 2026-06-04 · Reviewed by Nham Vu