How to Use an Essential Oil Diffuser: Drops, Timing and Cleaning

It is easy to use too much oil and run the diffuser too long. The result is a headache-strength smell for an hour and then nothing, because your nose stops noticing. Less oil, shorter sessions and a clean tank work better.

These steps are for ultrasonic diffusers, the common kind with a water tank. Waterless diffusers are different; see the note at the end.

How to use a diffuser, step by step

1. Put it in the right spot. On a flat, water-safe surface, at least a little above the floor, away from wood furniture the mist would dampen and out of reach of children and pets.
2. Fill with room-temperature water up to the line inside the tank. Not above it: overfilling is a common reason a diffuser stops misting.
3. Add the oil. Start with 3 to 5 drops in a small diffuser. If you can barely smell it after ten minutes, add one or two more next time. More than that rarely helps.
4. Put the lid back on and choose a setting. Use the timer or the intermittent mode if yours has one.
5. Run it for 30 to 60 minutes, then give it a break of 30 to 60 minutes. This is the pattern the Tisserand Institute recommends: your sense of smell gets used to the scent, so continuous diffusion does not give you more.
6. Empty what is left when you are done for the day. Old water with oil in it is what makes a diffuser smell stale.

How many drops of essential oil in a diffuser?

These are our starting points, not rules. Your diffuser's manual comes first. If you want recipes, our diffuser blends list exact drop counts.

Which oils to use

Any pure essential oil works in an ultrasonic diffuser. Lavender and eucalyptus are easy starting points. Fragrance oils are a different product from essential oils; check your manual before putting them in a diffuser.

A simple first set

Handcraft Blends Lavender & Eucalyptus Set

Two 4 oz bottles: lavender for the evening, eucalyptus for the morning. Big enough to find out how much you actually use.

Lavender + Eucalyptus set on Amazon →(paid link)

If you want an oil whose batch test you can look up, see our essential oil brands ranking.

How to clean a diffuser

After each use: empty the tank, wipe it with a soft dry cloth, and leave the lid off to dry.

About once a week if you use it daily:

1. Unplug it.
2. Fill the tank halfway with clean water and add a small splash of white vinegar.
3. Run it for a few minutes so the mixture reaches the ultrasonic plate.
4. Empty it. Wipe the inside and the small disc at the bottom gently with a cotton swab dipped in vinegar.
5. Rinse with plain water and dry it.

Do not scrub the ultrasonic disc with anything hard, and do not put the base under a tap. If your manual gives different cleaning steps, follow the manual.

If you need a diffuser

InnoGear Ultrasonic Diffuser

A small, basic ultrasonic diffuser. Easy to fill, easy to clean. For bigger rooms and for waterless options, see diffuser vs humidifier and waterless diffusers.

InnoGear Diffuser on Amazon →(paid link)

If your diffuser is waterless

Waterless and nebulizing diffusers use pure oil with no water, so there is no drop count: you attach the bottle or fill the oil chamber and set the intensity. Start at the lowest setting and the shortest cycle. The same on-and-off timing applies. See our nebulizing diffuser guide.