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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.

Dilution Calculator: Make Accurate Solutions with C1V1 = C2V2

Whether you are preparing a lab buffer, mixing a disinfectant, or scaling a flavor concentrate, dilution is the everyday math that turns a strong stock into a usable solution. This calculator helps you find the missing value in the classic dilution equation, so you can confidently measure how much stock and solvent to combine without guessing.

The idea is simple: when you dilute, the amount of solute stays the same, but the total volume changes. That relationship is captured by C1V1 = C2V2. It links the concentration and volume before dilution (the stock) to the concentration and volume after dilution (the final mix).

  • C1 — initial concentration of the stock (for example, M, mM, %, or ppm)
  • V1 — the volume you take from the stock
  • C2 — target concentration after dilution
  • V2 — final total volume of the diluted solution
Dilution factor (DF): DF = C1/C2 = V2/V1. A DF of 10 is a 10× dilution (1 part stock + 9 parts solvent).

How to use this calculator

  1. Decide which value you need to solve for: C1, V1, C2, or V2.
  2. Enter the three known values using consistent units (same concentration family and same volume units).
  3. Review the result and the dilution factor to confirm the scale makes sense.
  4. If you solved for V1, subtract it from V2 to get how much solvent to add.

For example, to make 500 mL of a 0.10 M NaCl solution from a 1.0 M stock, the equation gives V1 = (0.10 × 500) / 1.0 = 50 mL. Measure 50 mL of stock, then add solvent until you reach 500 mL total for a 10× dilution.

Where this is useful

Dilution calculations show up in chemistry and biology labs (buffers, reagents, standard curves), in food and beverage preparation (syrups, extracts, concentrates), and in everyday tasks such as mixing cleaning solutions, aquarium additives, or garden treatments. If a label gives a target ratio or concentration, this tool converts that instruction into precise volumes.

Serial dilutions and unit tips

Very large dilutions are often done in stages, called serial dilutions. Three 1:100 steps produce an overall 1:1,000,000 dilution, which is easier to measure accurately than a single massive step.

  • Match concentration families between C1 and C2 (molarity with molarity, percent with percent).
  • Match volume units between V1 and V2 (mL with mL, L with L).
  • Converting between % and molarity requires density and molecular weight, so treat them separately here.

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

About this tool

This calculator solves one unknown in C1V1 = C2V2, shows dilution factor, and estimates aliquot and solvent volumes with unit consistency checks.

Release Updates

v1.1 (February 5, 2026)

Added stricter concentration safety checks: percent inputs now require matching types (% v/v with % v/v, or % w/v with % w/v).

Improved reliability with validation that requires positive values for concentrations and volumes, plus a mobile layout fix for cleaner stacked input rows.

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