CFM to CADR Converter
Convert fan speed (CFM) to actual clean air delivery rate (CADR). Understand why airflow doesn't equal air purification and get realistic performance estimates.
Accurate Conversion
Factor in filter efficiency and purifier design for realistic CADR estimates
Performance Analysis
See efficiency ratings and quality tiers for different purifier types
Room Coverage
Calculate actual room size coverage based on converted CADR
Fan & Filter Specifications
Filter type affects particle capture efficiency
Estimated CADR Results
Understanding the Conversion
Current Result:
Good quality air purifier with effective filtration for most home uses.
Why CFM ≠ CADR
- •CFM measures airflow - how much air the fan moves
- •CADR measures clean air - how much purified air is delivered
- •Filter efficiency determines how much dirty air becomes clean
- •Design matters - some air bypasses the filter entirely
Conversion Factors
Efficiency varies by particle type (dust, smoke, pollen)
Room Size Coverage
Important Note
This calculator provides estimates based on theoretical efficiency. Actual CADR can vary significantly based on filter quality, design, air leakage, and testing conditions. Always check manufacturer specifications for verified CADR ratings.
Understanding CFM vs CADR
What is CFM?
CFM (Cubic Feet per Minute) measures the volume of air that a fan moves. It tells you how much air is circulating, but not how clean that air is. A high CFM doesn't guarantee effective air purification.
What is CADR?
CADR (Clean Air Delivery Rate) measures the volume of clean air produced by an air purifier. It accounts for both airflow and filtration efficiency, giving you the actual amount of purified air delivered to your room.
The Conversion Challenge
Converting CFM to CADR isn't straightforward because it depends on filter efficiency, air leakage, and purifier design. A 300 CFM fan might only deliver 200 CFM of clean air if the filter captures 67% of particles.
Factors Affecting Conversion
Filter Efficiency
HEPA filters capture 99.97% of particles, while basic filters may only capture 60-80%
Air Leakage
Poor sealing allows air to bypass filters, reducing actual purification
Particle Type
Filters perform differently for dust, smoke, and pollen particles
Filter Loading
As filters get dirty, efficiency can increase but airflow decreases
How to Use the CFM to CADR Converter
Step-by-Step Instructions
Enter Fan Speed
Input the CFM rating from your air purifier specifications or manual.
Select Purifier Type
Choose between basic filter, True HEPA, or premium HEPA with pre-filters.
Adjust Filter Efficiency
Fine-tune based on your specific filter's rated efficiency.
Review Results
See estimated CADR for dust, smoke, and pollen, plus room coverage.
Interpreting Results
CADR by Particle Type
Different particles have different capture rates - pollen is usually highest, smoke lowest
Conversion Efficiency
Percentage of fan airflow that becomes clean air delivery
Quality Rating
Room Coverage
Conservative, standard, and maximum room sizes based on ACH targets
5 Real-World CFM to CADR Examples
Budget Air Purifier Reality Check
Setup:
- • Fan Speed: 200 CFM
- • Basic non-HEPA filter
- • 70% filter efficiency
- • "Covers 400 sq ft" claim
Reality:
- • Actual CADR: ~120 CFM average
- • Efficiency: 60% (Fair rating)
- • Real coverage: 180-300 sq ft
- • ⚠️ Marketing vs reality gap
🎯 Better Choice:
True HEPA Performance
Setup:
- • Fan Speed: 300 CFM
- • True HEPA filter (99.97%)
- • 85% overall efficiency
- • Well-sealed design
Performance:
- • Dust CADR: 255 CFM
- • Smoke CADR: 240 CFM
- • Pollen CADR: 270 CFM
- • ✅ Excellent 85% efficiency
🎯 Similar Model:
High CFM, Poor Design
Setup:
- • Fan Speed: 400 CFM (impressive!)
- • Cheap pleated filter
- • Poor sealing, air leakage
- • 45% overall efficiency
Reality:
- • Actual CADR: ~180 CFM average
- • Efficiency: 45% (Poor rating)
- • Lots of noise, little cleaning
- • 🚫 Avoid high CFM, low quality
🎯 Reliable Alternative:
Premium Multi-Stage System
Setup:
- • Fan Speed: 350 CFM
- • Pre-filter + HEPA + Carbon
- • Premium sealed design
- • 95% overall efficiency
Excellence:
- • Dust CADR: 333 CFM
- • Smoke CADR: 315 CFM
- • Pollen CADR: 348 CFM
- • ✅ Excellent 95% efficiency
🎯 Premium Pick:
Industrial Powerhouse
Setup:
- • Fan Speed: 600 CFM
- • Medical-grade HEPA
- • Commercial design
- • 90% overall efficiency
Power:
- • Dust CADR: 570 CFM
- • Smoke CADR: 540 CFM
- • Pollen CADR: 585 CFM
- • ✅ Covers 1000+ sq ft easily
🎯 Heavy Duty:
Key Takeaways from Examples
Don't Trust CFM Alone
High airflow doesn't guarantee effective air cleaning - filter quality matters most
HEPA Makes a Difference
True HEPA filters consistently deliver 80-90% efficiency vs 50-70% for basic filters
Design Quality Counts
Premium purifiers achieve 90%+ efficiency through better sealing and multi-stage filtration
Verified CADR Air Purifiers by Efficiency Tier
Budget Efficient (70-80%)
Good value with verified CADR ratings
Premium Efficient (85-90%)
Excellent efficiency and design quality
Ultra-Premium (90%+)
Maximum efficiency and performance
Blueair Blue Pure 211+
Verified 92% efficiency • Swedish design • Ultra-quiet
View on Amazon🎯 Choosing by Efficiency Needs
When 70-80% Efficiency Works
• General air quality improvement
• Dust and pet hair reduction
• Budget-conscious buyers
• Rooms under 400 sq ft
When You Need 85%+ Efficiency
• Allergies or asthma
• Smoke or pollution concerns
• Large rooms (500+ sq ft)
• Maximum air quality standards
Important Disclaimer
This calculator provides estimates based on theoretical efficiency factors. Actual CADR ratings can vary significantly from CFM-based calculations due to:
- • Manufacturing tolerances and quality control
- • Filter aging and loading effects
- • Air leakage around filters and seals
- • Specific testing conditions and standards
Always verify actual CADR ratings from manufacturer specifications or AHAM certification before making purchasing decisions.