Dilution Calculator (C1V1 = C2V2)

Enter any three values to calculate the fourth. Private by design—everything runs locally in your browser.

Inputs

Enter initial concentration C1
Result:
Dilution factor
—
Aliquot (stock to pipette)
—
Solvent to add
—

Tips: Ctrl/Cmd + Enter calculates · Esc clears.

Understanding the Dilution Formula (C1V1 = C2V2)

The dilution equation relates a solution before and after dilution. The solute amount stays constant; you only change total volume by adding solvent.

  • C1 — initial concentration (e.g., M, mM, %)
  • V1 — aliquot volume taken from the stock
  • C2 — final concentration
  • V2 — final total volume
Dilution factor (DF): DF = C1/C2 = V2/V1. A DF of 10 is a 10× dilution (1 part stock + 9 parts solvent).

Rearrangements you’ll use

  • V1 = (C2 × V2) / C1 (aliquot to pipette)
  • V2 = (C1 × V1) / C2
  • C2 = (C1 × V1) / V2
  • C1 = (C2 × V2) / V1

Worked example

Goal: Make 500 mL of 0.10 M NaCl from a 1.0 M stock. V1 = (0.10×500)/1.0 = 50 mL. Pipette 50 mL of stock, then add solvent to 500 mL total (10× dilution).

Serial dilutions

Large dilutions are done in steps. For 106, do three sequential 1:100 dilutions (100 × 100 × 100).

For each 1:100: 10 µL stock + 990 µL solvent → 1000 µL total.

Units & compatibility

  • Concentration families must match between C1 and C2 (molarity family or percent family).
  • Volume units must match between V1 and V2.
  • Converting between molarity and percent needs density/MW; this tool treats them separately.

5 Fun Facts about Dilutions

Lemonade logic

Mix 1 part lemon syrup with 9 parts water and you get a 10× dilution. It tastes 10 times less strong—sweet!

Ratio → Strength

Half strength = 1:1

Equal parts stock and water (1:1) cut the strength in half. It’s the quickest way to “make it milder.”

Quick fix

Step-by-step wins

Huge dilutions are easier in steps. Do a small mix, then another, then another—like walking down a staircase instead of jumping.

Serial steps

Match your units

Keep C1 and C2 in the same kind (both molarity or both percent) and V1 and V2 in the same volume units. Apples with apples!

Apples-to-apples

Solute stays, water plays

When you dilute, you add solvent (like water). The amount of solute (the “stuff” in the mix) stays the same—you just spread it out.

Spread it out

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