Solution Dilution Calculator
Work out exactly how much stock solution and diluent you need. Enter any three values and leave the one you want to find blank — the calculator solves it using C1V1 = C2V2.
Leave exactly one field blank to solve for it.
How it works
A dilution keeps the amount of solute constant while increasing the volume, so the product of concentration and volume is conserved: C1 × V1 = C2 × V2. Here C1 and V1 are the concentration and volume of the concentrated stock, and C2 and V2 are the concentration and volume of the final, diluted solution.
Enter any three of the four values and leave the unknown blank — the calculator rearranges the equation and solves it. Concentration units (M, mM, µM, nM) and volume units (L, mL, µL) can be mixed freely; conversions are handled internally, and the answer is shown in the unit you selected for the blank field.
Examples
- 10 M stock → 1 M final in 100 mL: V1 = (1 M × 100 mL) / 10 M = 10 mL of stock, topped up to 100 mL.
- 0.5 M stock, use 25 mL in 500 mL final: C2 = (0.5 M × 25 mL) / 500 mL = 0.025 M.
- Need 250 mL of 2 mM from a 50 mM stock: V1 = (2 mM × 250 mL) / 50 mM = 10 mL.
Frequently asked questions
- What does C1V1 = C2V2 mean?
- It is the dilution equation. Because diluting a solution does not change the number of moles of solute, concentration multiplied by volume is equal before and after dilution.
- Can I mix different units?
- Yes. Choose any concentration unit (M, mM, µM, nM) and volume unit (L, mL, µL) per field. The calculator converts everything internally and returns the answer in the unit you picked for the blank field.
- How much diluent do I add?
- The diluent volume is the final volume minus the stock volume (V2 − V1). For the 10 mL of stock into 100 mL example, you add 90 mL of solvent.
- Why is the result blank?
- Make sure exactly one field is empty and the other three contain valid numbers. If a solve would require dividing by zero, there is no valid result.