CFM Per Person Calculator
Enter any two Total CFM, Number of People, or CFM Per Person, and the calculator will finds the the required values.
CFM Per Person Calculator
Contents
How To Calculate CFM Per Person
When setting up a ventilation system, it’s important to figure out how much air each person actually needs. This straightforward tool helps you calculate one of three key things
- How many people the system can support
- How much airflow (CFM) you need
- Or how much air each person gets
Example 1: Find Out CFM Per Person
Let’s say you’re handling the air circulation for a small conference room with 10 people, and your system is pushing 800 CFM.
Step-by-step:
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You enter 800 as the Total CFM.
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You enter 10 as the Number of People.
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Leave the CFM Per Person box empty.
What you’ll get:
➤ 800 ÷ 10 = 80 CFM per person
That means each person is getting 80 cubic feet of air per minute.
Example 2: Find Out How Many People the System Supports
If your HVAC system supplies 1200 CFM, and the building code requires 60 CFM per person.
Steps:
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Enter 1200 as Total CFM.
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Enter 60 as CFM Per Person.
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Leave the Number of People box empty.
What you’ll get:
➤ 1200 ÷ 60 = 20 people
So your current system can support up to 20 people comfortably.
Example 3: Find Out Total CFM Needed
If you’re designing ventilation for 15 people, and you want to give each one 50 CFM.
Steps:
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Enter 15 as Number of People.
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Enter 50 as CFM Per Person.
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Leave the Total CFM box blank.
What you’ll get:
➤ 15 × 50 = 750 CFM
That’s the amount of airflow you’ll need from the system.
Quick Reference
| Scenario | What to Enter | What You’ll Get |
|---|---|---|
| Find CFM per person | Total CFM + Number of People | CFM per person = Total CFM ÷ People |
| Find how many people system fits | Total CFM + CFM per person | People = Total CFM ÷ CFM per person |
| Find total airflow (Total CFM) | Number of People + CFM per person | Total CFM = People × CFM per person |
| Best for | Small rooms, offices, classrooms | Easy HVAC setup and quick checks |
| Key Benefit | Saves time with quick, clear calculations | Supports safe and comfortable airflow |
FAQs
1. What does this calculator do?
It figures out how much airflow is needed per person, how many people a system can handle, or how much total airflow is required.
2. Do I need to enter all three values?
No, just enter any two values — the calculator will find the third one for you automatically.
3. Who should use this tool?
Anyone working on indoor air systems, including HVAC installers, building managers, and ventilation planners.
4. Is this tool suitable for big buildings?
Yes, but for large-scale systems, it’s best used as a quick estimate. For exact planning, pair it with professional guidelines.
