PC Case Pressure Balance Calculator
Intake vs exhaust airflow balance for a PC build.
Enter your values
ⓘ Live results
Results
- Pressure balance
- 25%
- Verdict
- Positive pressure (less dust, slightly warmer)
- Net airflow
- 30 CFM
- Recommended target
- +10% to +20% intake for dust control
Quick answer
A PC case with 10-20% more intake than exhaust airflow runs mildly positive, which reduces dust buildup on unfiltered panels.
Balance % = (intake - exhaust) / exhaust x 100
How to use the PC Case Pressure Balance Calculator
- 1List the rated CFM of every intake fan.
- 2List the rated CFM of every exhaust fan.
- 3Compare the two — slight positive pressure is usually the best trade-off.
Worked example
Using the values the calculator loads with:
Inputs
- Total intake fan CFM150 CFM
- Total exhaust fan CFM120 CFM
Results
- Pressure balance25%
- VerdictPositive pressure (less dust, slightly warmer)
- Net airflow30 CFM
- Recommended target+10% to +20% intake for dust control
Frequently asked questions
Is negative pressure bad?
Not for temperatures, but it pulls dust through every unfiltered gap in the case.
Do fan curves matter?
Yes — rated CFM assumes free air; restriction from filters and radiators lowers real airflow.
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.