UV Sterilizer Calculator
Calculate UV dose, sterilization effectiveness, and recommended exposure time for bacteria, viruses, and mold based on your room size, lamp power, distance, and exposure duration.
How the UV Sterilizer Calculator works
This calculator estimates the UV dose delivered to a surface based on lamp power, distance, and exposure time, then compares it to the dose required to inactivate common pathogens. The UV dose (mJ/cm²) = Irradiance (µW/cm²) × Time (seconds) ÷ 1000. Irradiance decreases with the square of the distance from the lamp, so placement is critical.
Enter your room dimensions, lamp power, distance, exposure time, and select a target pathogen. The calculator will show the delivered UV dose, sterilization effectiveness, and whether the exposure meets the recommended dose for that pathogen.
Step 1: Room & Lamp
Understanding UV Dose
UV dose is the product of irradiance and exposure time. Higher lamp power, closer distance, and longer exposure all increase the dose. Most pathogens require 5–40 mJ/cm² for 99.9% inactivation.
Step 2: Exposure & Pathogen
Safe UV Sterilization Guidelines
For effective sterilization, aim for a UV dose that meets or exceeds the required dose for your target pathogen. Always follow manufacturer guidelines and never expose skin or eyes to UVC light.
UV Sterilization Results
UV Dose Delivered
Pathogen UV Dose Requirements
| Pathogen | Required Dose (mJ/cm²) | Your Dose | Effectiveness |
|---|
UV Dose Breakdown
UV Dose Calculation Formula
UV Dose = Irradiance × Time
Irradiance (µW/cm²) = (Lamp Power × Efficiency) / (4π × Distance²). The calculator assumes 15% UVC efficiency for low-pressure mercury lamps. Dose is then compared to pathogen-specific requirements.
Frequently Asked Questions
What is UV sterilization?
UV sterilization uses ultraviolet light, specifically UVC light at 254 nm wavelength, to inactivate microorganisms by damaging their DNA or RNA, preventing them from reproducing and causing infection.
What is the UV dose required to kill bacteria?
Most bacteria require a UV dose of 5–20 mJ/cm² for 99.9% inactivation. For example, E. coli needs about 6 mJ/cm², while more resistant organisms like Bacillus subtilis require around 15 mJ/cm².
What is a safe UV dose for sterilization?
For effective sterilization, a UV dose of 20–40 mJ/cm² is generally recommended for most pathogens. Higher doses (40–100 mJ/cm²) may be needed for more resistant microorganisms or when a higher log reduction is required.
How is UV dose calculated?
UV dose (mJ/cm²) = Irradiance (µW/cm²) × Exposure Time (seconds) ÷ 1000. Irradiance depends on the UV lamp power and the distance from the lamp to the target surface, following the inverse square law.
What factors affect UV sterilization effectiveness?
Key factors include UV dose (irradiance × time), distance from the UV source, lamp age and cleanliness, temperature, humidity, and the type of microorganism being targeted. Shadowing and surface material also play a role.
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