laboratory
CFU/mL Calculator
Combine replicate plates, dilution factors and plated volumes; flag countable ranges and report mean, SD and CV.
Calculator
Formula
CFU/mL=colonies/(dilution·volume)
Assumptions and limits
- Each colony is treated as one viable colony-forming unit; clumping can bias results.
Example
Editable worked example
The calculator starts with an editable example.
Sources
- Cell Culture Basics Handbook — Thermo Fisher Scientific
Frequently asked questions
Are my inputs uploaded?
No. This calculator runs locally in your browser. Inputs are placed in a URL only when you explicitly copy a share link.
Why are units converted first?
Canonical units prevent scale errors when inputs use mixed units. The result is converted back to your selected output unit afterward.
Does the result replace professional judgment?
No. The result applies only to the stated model and assumptions. Qualified people should review high-risk engineering, medical, or laboratory decisions.