The calculator gives an estimate. Pint ratings depend on the test used, so check the label and the maker’s notes.
A dehumidifier that is too small never catches up, and one that is too big wastes power. Use the calculator below to find the pint size for your space.
Slightly to Moderately Damp: musty smell only in humid weather. Very Damp: always feels damp, persistent odor. Wet: damp spots on walls or floor, standing water or a flooding history.
Dehumidifier capacity you need
Square footage
500 sq ft
Dampness level
Very Damp
ENERGY STAR range
25-40 pints/day
Table of Contents
Real dehumidifiers that clear this pint rating
How This Dehumidifier Pint Calculator Works
A dehumidifier is rated in pints of water it can pull from the air per day. The calculator uses ENERGY STAR’s sizing guide, which gives a range of pints per day by room size and how damp the space is.
Rule: pints = ENERGY STAR range for your room size and dampness, using the top of the range for a heavy load
- Dampness levels: slightly to moderately damp, very damp and wet, the three levels ENERGY STAR uses. Rooms up to 2,000 sq ft get a range, and larger rooms get a minimum.
- Heavier load: if several people use the room, laundry dries there, or the ceiling is above 8 ft, the calculator shows the top of the range, because ENERGY STAR says it is better to oversize than undersize.
Results are shown in steps of 5 pints.
Here is where dehumidifiers are heading: more Wi-Fi control, built-in pumps and inverter compressors that run quieter and use less power. Ratings are also changing, so the same pint number on an older box and a newer box does not mean the same thing.
Worked Examples
- 500 sq ft, slightly to moderately damp, normal use. ENERGY STAR’s range is 20 to 30 pints. The calculator shows 20.
- 1,000 sq ft, very damp. The range is 25 to 40 pints, so it shows 25. Tick laundry in the room and it shows 40.
- 1,500 sq ft, wet, many people and laundry. The range is 30 to 50 pints. With a heavy load it shows 50.
- 2,500 sq ft, very damp. Over 2,000 sq ft ENERGY STAR gives a minimum of 40 pints. The calculator shows 40+, and you should size up if you can.
What Do the Dampness Levels Mean?
- Slightly to moderately damp: the space feels humid in summer and smells a bit stale.
- Very damp: always clammy, with a musty smell and damp spots on walls or floors.
- Wet: visible water or condensation on walls and floors, seepage, standing water or frequent flooding. ENERGY STAR notes that heavy loads such as drying laundry can fall in this level.
If you are standing in water, a dehumidifier is not the fix. Fix the leak or drainage first.
Check Which Rating Test the Label Uses
Before 2019, pint ratings were measured at warmer, more humid conditions. The newer test uses cooler air, so the numbers dropped. A 50-pint unit from the old test is closer to a 35-pint unit under the new one. Look for the test conditions on the box or listing, and be careful when comparing models.
Pick the Target and Check It
Most guides suggest keeping indoor humidity between 30 and 50 percent. Above 60 percent for long stretches, mold and dust mites do well. A cheap hygrometer shows if your unit is keeping up. If it runs all day and cannot get below 55 percent, size up or fix the moisture source. See how to get rid of mold spores in the air if mold is already present.
The downside is mislabeled size and mold risk. Since the 2019 federal test change, pint ratings are measured at cooler conditions, so a unit labeled 35 pints today pulls about as much as a unit once labeled 50 pints. Compare labels carefully. A unit that is too small never dries the room, and damp air breeds mold and dust mites. Expect more confusion when old and new labels share the shelf. Check which test the rating uses, and add a humidity meter.
Where to Go Next
For more on picking a size, read how to choose the right size dehumidifier. Going to a basement? See the best dehumidifiers for basements. Need to treat a whole home? Browse the best whole-house dehumidifiers. If the tank stays empty, read dehumidifier not collecting water.
FAQ
What size dehumidifier do you need for a damp basement?
A 1,000 sq ft very damp space needs about 20 pints a day by this calculator. Wetter spaces need more.
Does ceiling height matter?
Yes. Taller rooms hold more air, so the calculator scales the answer by ceiling height compared with 8 feet.
Is a bigger dehumidifier better?
Bigger dries faster but costs more and uses more power. Pick the size the room needs.
What humidity should you aim for?
About 30 to 50 percent relative humidity indoors.
Final Word
Pick the size, then check the result with a humidity meter. If the room stays above 50 percent, fix the moisture source or size up.
What comes next: smarter humidistats, better drain options and more models for crawl spaces. Size with the math below, then confirm with a meter that you land under 50 percent.
Related Guides
Keep going with how to choose the right size dehumidifier, best dehumidifiers for basements, best whole-house dehumidifiers, dehumidifier not collecting water and how to get rid of mold spores in the air.
