Dehumidifier Size Calculator
Find the right dehumidifier capacity (pints/day) for a bedroom, basement, or crawlspace. Enter size + humidity and we’ll suggest a common size tier (22 / 35 / 50 / 70 pint).
Updated for 2026 consumer dehumidifier sizing tiers and practical humidity targets.
On this page: Calculator · How to use · Next steps · Equipment · Related calculators · FAQ
Hot + humid climate? Pair this with the portable AC calculator or window AC calculator.
Estimate required pints/day
Use the area of the space you want to control (basement, bedroom, etc.).
Higher ceilings increase air volume and moisture load.
Cool basements often need more capacity to perform well.
Measure with a hygrometer ($10–15).
Most homes aim for ~45–50% RH.
Pick “wet/very wet” for damp basements or seasonal moisture.
Basements and crawlspaces often need more capacity for the same area.
Leaky or stale spaces typically need bigger units.
Adds a small moisture load estimate for multiple people.
Tip: If you don’t know the exact RH, measure it with a digital hygrometer ($10–15) before buying.
How to use this calculator
- Enter your area and current RH.
- Set a target RH (50% is a good default).
- Choose room type + moisture level (basements usually “wet”).
- Use the recommended pints/day and pick the nearest common size tier.
If you’re between sizes or your space is particularly damp, choose the next size up. The unit will cycle less and reach your target faster.
Next steps
Also need cooling?
In hot + humid climates, a dehumidifier alone may not be enough. Use the window AC calculator or portable AC calculator to size cooling equipment. Many portable ACs include a dehumidifier mode.
Size HVAC properly
If you’re sizing equipment for a whole home or large space, start with the advanced BTU calculator for a room-by-room heating and cooling load estimate.
Compare operating costs
Dehumidifiers can add $15–50/month to electricity bills depending on size and run time. Use the energy cost calculator to estimate. Check local electricity rates for your area.
Reduce moisture at the source
Sealing air leaks and fixing drainage issues reduces how hard your dehumidifier has to work. Weatherstripping ($5–15) and spray foam ($10–40) can make a meaningful difference in basements.
Dehumidifier shopping
Dehumidifiers by capacity
22-pint — small rooms. 35-pint — bedrooms, small basements. 50-pint — most basements. 70-pint — very damp or larger spaces. Basement models. Crawlspace models. Browse all dehumidifiers.
Helpful accessories
Digital hygrometer ($10–15) — measure RH accurately before and after. Weatherstripping ($5–15) and spray foam ($10–40) — seal air leaks to reduce moisture infiltration.
All equipment: heating & cooling equipment by BTU range.
Frequently asked questions
What size dehumidifier do I need?
Size is measured in pints/day and depends on room size, humidity, temperature, moisture sources, and ventilation. Use the calculator above to estimate pints/day and choose the nearest common size tier (22, 35, 50, or 70 pint).
What humidity level should I target?
Most homes aim for about 45–50% relative humidity. Basements often do well around 50% to reduce musty odors and mold risk while staying comfortable.
Should I buy the next size up?
If you’re between sizes, or you have a damp basement or crawlspace, choosing the next size up can pull humidity down faster and reduce run time. A slightly oversized dehumidifier is generally preferable to an undersized one.
Do I need a dehumidifier or better ventilation?
Often both. Ventilation can help, but if outside air is humid, ventilation alone may not reduce indoor RH. A dehumidifier removes moisture reliably — especially in basements and crawlspaces where ventilation options are limited.
How do I measure my current humidity?
Use a digital hygrometer ($10–15). Place it in the room at waist height, away from direct airflow, and read it after 30 minutes for an accurate measurement.