Appliances & Utilities calculator
What Dehumidifier Size Do I Need?
Use your measurements for room volume, moisture removal target per room volume, and damp severity factor to find dehumidifier extraction capacity.
Enter your measurements
Use this minimum-capacity calculation when you need to answer “what dehumidifier size do i need?” Enter room volume, moisture removal target per room volume, and damp severity factor and the tool returns dehumidifier extraction capacity using the rule defined for this exact use case.
- Room volume — Required
- Moisture removal target per room volume — Required
- Damp severity factor — Required
Dehumidifier extraction capacity
Enter the measurements above to calculate dehumidifier extraction capacity.
How the calculation works
For this tool, the calculation is requiredDailyRemoval=roomVolume×moistureLoadPerVolume×severityFactor. That produces dehumidifier extraction capacity without borrowing assumptions from unrelated calculators.
Worked example
Example: Room volume = 45000 L; Moisture removal target per room volume = 0.2 L/day per m³; Damp severity factor = 1. Result: Required Daily Removal = 9 L/day.
Before you decide
Enter the dimensions that will exist in real use, not an approximate catalogue category. This page calculates the stated geometry or quantity only; product-specific construction or installation details can still affect the final choice. For what dehumidifier size do i need, the limiting result on this page is dehumidifier extraction capacity.
Direct measurement/geometry calculation. No external reference is required for the arithmetic itself; the result is derived only from the user-entered measurements and the formula stored in calculationLogicJson.
Frequently asked questions
What does the Dehumidifier Size calculator tell me?
It returns dehumidifier extraction capacity from the measurements entered on this page. The calculation is specific to dehumidifier size, so the result should be compared with the exact product or specification you are considering.
Which measurements should I take for dehumidifier size?
Measure room volume, moisture removal target per room volume, damp severity factor. Use clear, usable dimensions rather than nominal room or product labels.
Should I round the dehumidifier extraction capacity?
Keep the calculated value for comparison, then choose a real product that meets or stays within the returned dehumidifier extraction capacity while allowing for the clearances, tolerances or ratings shown by its manufacturer.