AquaVerify

CFU calculator

Calculate CFU/mL from colonies, dilution fraction and plated volume.

CFU calculator

Formula

CFU/mL = colonies / (dilution fraction x plated volume mL)

Variables and units

  • colonies
  • 10^-n, 1:n or decimal dilution
  • mL, µL plated volume
  • CFU/mL

Worked example

Example: 50 colonies, 10^-3 and 0.1 mL gives 500000 CFU/mL.

500000 CFU/mL; log10 result is shown when positive.

How to read the result

Accepts 10^-3, 1:1000 and decimal dilution notation without interpreting compliance.

Validation rules

Inputs must be finite, compatible and within calculation limits. Denominators cannot be zero.

Warnings

This calculator is an educational and workflow aid. It does not replace a validated method, SOP, accreditation decision or regulatory interpretation.

Private by design

Inputs and results stay in your browser. AquaTools Free does not send calculation values to AquaVerify servers.

Sources

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AquaVerify Cloud

Move from a one-off calculation to controlled sample, method and report workflows in AquaVerify Cloud.

FAQ

Are my inputs stored?

Inputs and results stay in your browser. AquaTools Free does not send calculation values to AquaVerify servers.

Can I use this as an official method record?

This calculator is an educational and workflow aid. It does not replace a validated method, SOP, accreditation decision or regulatory interpretation.

Where do saved calculations live?

AquaVerify Cloud keeps the governed workflows: saved calculations, history, traceability, ELN, LIMS review, reports and collaboration.