RV/Van Ventilation Calculator
Roof fan and intake CFM for a camper van conversion.
Enter your values
Enter the interior length in ft.
Enter the interior width in ft.
Enter the interior height in ft.
Enter the exchanges per minute you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Recommended fan CFM
- 1,560 CFM
- Interior volume
- 390 cu ft
- Passive intake vent area at 400 FPM
- 561.6 sq in
Quick answer
Camper van conversions typically use a roof fan sized for 3-6 air changes per minute of the interior volume for effective cooling.
CFM = volume x exchanges per minute
At a glance
| What it does | Roof fan and intake CFM for a camper van conversion. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Interior length, Interior width, Interior height, Exchanges per minute |
| Main output | Recommended fan CFM |
| Formula | CFM = volume x exchanges per minute |
| Cost | Free — no sign-up, no download |
How to use the RV/Van Ventilation Calculator
- 1Measure the interior volume of the living space.
- 2Apply 3-6 full exchanges per minute — higher for hot climates or cooking.
- 3Provide a passive intake vent (cracked window or roof vent) sized to match the fan's airflow.
Inputs explained
- Interior length(ft)
- Enter the interior length in ft.
- Interior width(ft)
- Enter the interior width in ft.
- Interior height(ft)
- Enter the interior height in ft.
- Exchanges per minute
- Enter the exchanges per minute you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Interior length10 ft
- Interior width6 ft
- Interior height6.5 ft
- Exchanges per minute4
Results
- Recommended fan CFM1,560 CFM
- Interior volume390 cu ft
- Passive intake vent area at 400 FPM561.6 sq in
Frequently asked questions
Why so many exchanges per minute?
Small enclosed spaces heat and humidify fast, especially while cooking or sleeping with the vents closed.
Two fans - intake and exhaust?
A common setup uses one fan pulling air in and another exhausting for effective cross-ventilation.
What do I need to enter into the RV/Van Ventilation Calculator?
Just 4 values: interior length, interior width, interior height, exchanges per minute. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the RV/Van Ventilation Calculator work out the answer?
Camper van conversions typically use a roof fan sized for 3-6 air changes per minute of the interior volume for effective cooling. It applies the formula CFM = volume x exchanges per minute and shows the working so you can check each step by hand.
Is the RV/Van Ventilation Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.