Dust Particle Settling Calculator

Calculate particle settling velocity and time using Stokes' law with Cunningham slip correction.

Particle Diameter (μm)

Particle Density (kg/m³)

Room / Settling Height (m)

Tab to move between fields

Settling Velocity (mm/s)

7.52

Settling Time (hours)0.11

Particle Reynolds Number0.01

Cunningham Slip Factor1.02

Corrected Velocity (mm/s)7.65

Corrected Settling Time (hours)0.11

How to Use This Calculator

Enter Particle Diameter (μm), Particle Density (kg/m³), and Room / Settling Height (m).
Review the Settling Velocity (mm/s) result.
Use Settling Time (hours) and Particle Reynolds Number to inform your decision.

How the result changes with Particle Diameter (μm)

Particle Diameter (μm): Particle diameter in micrometers. PM2.5 = 2.5 μm, PM10 = 10 μm, pollen ~25 μm, fine sand ~100 μm.
Particle Density (kg/m³): Density of the particle material. Dust/quartz ~2,500,iteite ~5,200, water droplet ~1,000.
Room / Settling Height (m): Height from which the particle settles. Typical room ceiling ~3 m.

Settling Velocity (mm/s): Terminal settling velocity from Stokes' law (without slip correction).
Settling Time (hours): Time to settle the full room height at Stokes velocity.
Particle Reynolds Number: Re < 1 means Stokes' law is valid for this particle.
Cunningham Slip Factor: Correction factor for sub-micron particles (approaches 1.0 for large particles).
Corrected Velocity (mm/s): Settling velocity with Cunningham slip correction applied.
Corrected Settling Time (hours): Settling time with slip correction — more accurate for fine particles.

Identify Input Parameters
Particle Diameter (μm) = 10, Particle Density (kg/m³) = 2500, Room / Settling Height (m) = 3 = 3 input(s) provided
Calculate Settling Velocity
Settling Velocity = Number((vs * 1000).toFixed(6))
7.523936 = 7.523936
Calculate Settling Time
Settling Time = settlingTimeSec / 3600
0.11 = 0.11
Calculate Particle Reynolds Number
Particle Reynolds Number = Number(re.toFixed(6))
0.005092 = 0.005092