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Calcimator

Cleanroom Classification Calculator

Calculate particle count limits by ISO 14644-1 cleanroom class with EU GMP grade mapping.

Inputs

Results

Max particles/m³

351,676

Max particles/ft³9,958
Limit at 0.5 µm (/m³)351,676
Limit at 5.0 µm (/m³)2,925
Required airflow (CFM)1,177
Compliance margin (%)100
Passes spec (1=yes, 0=no)1
Max At1um83,176.38
Eu Gmp GradeC (in operation)
How to Use This Calculator
  1. Select your ISO class (1–9) and the particle size threshold (µm) to evaluate.
  2. Enter room volume (m³) and your HVAC air changes per hour.
  3. Optionally enter a measured particle count per m³ to check compliance.
  4. Review Max Particles/m³, Required Airflow (CFM), and Compliance Margin (%).
  5. A positive compliance margin confirms your room is within the ISO class limit.

How the result changes with ISO class (1-9)

ISO class (1-9)Max particles/m³
1.84
3.8352
6.235,168
8.23,516,757

What each input means

ISO class (1-9)
ISO 14644-1 class number. Biotech: ISO 5 (aseptic), ISO 7 (controlled), ISO 8 (general).
Particle size (µm)
Particle diameter threshold in micrometers. Common: 0.5 µm and 5.0 µm.
Room volume (m³)
Cleanroom volume in cubic meters for airflow calculations.
Air changes per hour
HVAC air changes per hour. ISO 5: 240-600, ISO 7: 60-90, ISO 8: 10-25.
Measured particle count (/m³)
Your measured particle count per m³ (enter 0 to skip compliance check).

What each result means

Max particles/m³
Maximum allowable particles per cubic meter at specified size for this ISO class.
Max particles/ft³
Equivalent limit per cubic foot (Fed Std 209E reference).
Limit at 0.5 µm (/m³)
Max particles ≥0.5 µm per m³ for this ISO class.
Limit at 5.0 µm (/m³)
Max particles ≥5.0 µm per m³ for this ISO class.
Required airflow (CFM)
Air volume flow rate in cubic feet per minute.
Compliance margin (%)
Margin between your measurement and the class limit. Positive = pass.
Passes spec (1=yes, 0=no)
Whether your measured count is within the ISO class limit.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    ISO class (1-9) = 7, Particle size (µm) = 0.5, Room volume (m³) = 100, Air changes per hour = 20 = 5 input(s) provided
  2. Calculate Max particles/m³
    Max particles/m³ = pow(10, isoClass) * pow(0.1 / particleSizeUm, 2.08)
    351676 = 351676
  3. Calculate Max particles/ft³
    Max particles/ft³ = maxParticlesPerM3 / 35.3147
    9958 = 9958
  4. Calculate Limit at 0.5 µm
    Limit at 0.5 µm = pow(10, isoClass) * pow(0.1 / 0.5, 2.08)
    351676 = 351676

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