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Air Purifier CADR Chart
Use this air purifier CADR chart to compare calculated clean air delivery targets by room size at four or five air changes per hour. Use the chart as a quick planning reference, then use Air Purifier Size Calculator when you need exact numbers for your own inputs.
At a glance
- Coverage
- 5 reference rows
- Default schedule
- See assumptions below
- Data effective
- Not stated
- Published
- Not stated
- Updated
- Not stated
- Author
- EverydayCalc.org
- Reviewer
- EverydayCalc editorial review
Chart values
| Room floor area | Volume at 8 ft | 4 ACH target | 5 ACH target |
|---|---|---|---|
| 150 sq ft | 1,200 cu ft | 80 CADR | 100 CADR |
| 250 sq ft | 2,000 cu ft | 134 CADR | 167 CADR |
| 300 sq ft | 2,400 cu ft | 160 CADR | 200 CADR |
| 400 sq ft | 3,200 cu ft | 214 CADR | 267 CADR |
| 500 sq ft | 4,000 cu ft | 267 CADR | 334 CADR |
Calculated from the existing air purifier size calculator using room floor area, an 8 ft ceiling, and either 4 or 5 air changes per hour.
How to use this chart
Find the room's floor-area row, then choose the four- or five-air-changes column. If the ceiling is not 8 ft or the room sits between rows, open the calculator and enter the actual length, width, height, and ACH target.
When to use the calculator instead
Use the calculator when your measurements, rates, room conditions, local prices, tank setup, loan terms, or classroom routine do not match the simple chart rows. The calculator lets you adjust the inputs instead of forcing your situation into a rough example.
Examples from this chart
Worked example
A 300 sq ft room with an 8 ft ceiling has 2,400 cu ft of volume. The formula gives 160 CADR at 4 ACH or 200 CADR at 5 ACH, so the exact target changes with the air-change rate you choose.
Limitations and assumptions
Every row uses an 8 ft ceiling and CADR = room volume × air changes per hour ÷ 60, rounded up to a whole number. These are calculated sizing targets, not product certifications or health guidance. Verify the purifier's published CADR, filter type, noise, and operating speed before buying.
Save or share this chart
You can print this page, save the tall image for planning, or link to the page from a blog post, classroom resource, forum answer, or project checklist so readers can open the calculator too.
Chart questions
Chart questions
How do I read an air purifier CADR chart?
Match the closest room-size row, choose an ACH target, and use the listed CADR as a minimum planning target. Use the calculator for the room's actual dimensions.
Does ceiling height change the CADR target?
Yes. A taller ceiling increases room volume, so it increases the CADR needed for the same number of air changes per hour.
Should I buy a purifier with exactly the listed CADR?
Treat the chart as a starting target. Compare the product's published CADR, fan speed, noise, filter replacement cost, and the room where it will actually run.