Paint Booth Air Changes Calculator
Booth airflow from cross-draft velocity.
Enter your values
ⓘ Live results
Results
- Booth airflow
- 12,600 CFM
- Cross-section
- 126 sq ft
- Air changes
- 250
- Makeup air
- 12,600 CFM tempered
- Filter face area needed
- 50.4 sq ft
Quick answer
Paint booths are sized on cross-draft velocity, typically 100 FPM for cross-flow and 50-100 FPM for downdraft.
CFM = booth cross-section x design velocity
How to use the Paint Booth Air Changes Calculator
- 1Measure the booth's internal width and height for the cross-section.
- 2Use 100 FPM for cross-draft booths; downdraft booths often run 50-75 FPM.
- 3Supply an equal amount of filtered, tempered makeup air.
Worked example
Using the values the calculator loads with:
Inputs
- Booth width14 ft
- Booth height9 ft
- Design velocity100 FPM
- Booth length24 ft
Results
- Booth airflow12,600 CFM
- Cross-section126 sq ft
- Air changes250
- Makeup air12,600 CFM tempered
- Filter face area needed50.4 sq ft
Frequently asked questions
Why is velocity regulated?
It keeps solvent vapour below 25% of the lower explosive limit and carries overspray away from the finish.
Does more airflow improve finish?
Only up to a point — excessive velocity dries the paint before it flows out.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.