How Much Fragrance Oil per 100 ml of Reed Diffuser Base?

The most common question from people making their own reed diffusers: how much oil goes in? Here is the ratio, why it's measured by weight, and a gram chart you can use with a kitchen scale.

If you make your own reed diffusers, one number decides whether the room smells beautiful or barely at all: how much fragrance oil goes into the base.

The short answer

Use 15 to 25% fragrance oil by weight, and the rest base. 20% is the best place to start.

• 15%: a soft scent for a small room, a bedroom or a bathroom.
• 20%: the everyday strength for a living room or entrance.
• 25%: a strong scent for a large, open or busy space.

Always stay within the limit your oil's maker gives for reed diffusers (the IFRA limit). Our Cold-Air Concentrates are made to be blended at 20 to 25% into our Reed Diffuser Base.

Why by weight, not by volume?

Because the base and the oil are different densities. Our base is heavier than water (150 ml weighs 158.5 g), and fragrance oils vary from one scent to the next. A "20% by volume" mix can come out anywhere from 18 to 22% in reality, and change from batch to batch. Weighing is also easier: put the bottle on a kitchen scale, zero it, pour the base, zero it again, then pour the oil.

Gram chart (20% blend)

• 100 ml bottle: 84 g base + 21 g fragrance oil
• 200 ml bottle: 168 g base + 42 g fragrance oil
• 250 ml bottle: 208 g base + 52 g fragrance oil
• 500 ml bottle: 416 g base + 104 g fragrance oil

For a 15% blend, use about three-quarters of the oil; for 25%, add about a quarter more. The totals are approximate: fill to just below the neck.

How to mix it

1. Weigh the base into a clean, dry glass jug.
2. Weigh in the fragrance oil and stir slowly for a minute.
3. Pour into a clean vessel, cap it, and let it rest for a day so the blend settles.
4. Add fresh reeds, and flip them after an hour and then once a week.

Quick answers

Can I just add more oil for a stronger scent? Up to 25%. Beyond that the blend wicks unevenly and the bottle empties faster without smelling much stronger. More reeds is the better fix.

Which oils can I use? Fragrance oils made for home fragrance that dissolve clearly in the base. We explain what to look for in Not All Fragrance Oils Are Equal.

Want the full walkthrough? Read how to make a reed diffuser at home, the clean way.

Explore: the Scaldera Arch · Shop the collection · Take the Scent Quiz · Membership · Refill subscription

More from the Journal

• Reed Diffuser Base: Why the Cheapest One Costs You More — Most people pick a reed diffuser base on price. But the base is most of what's in the bottle, and it decides how far the scent travels and how long it lasts.
• How to Refill a Reed Diffuser (and How Long a Refill Lasts) — A good reed diffuser should outlive its first bottle of scent. Here is how to refill one properly, how long each refill lasts, and the one mistake that ruins the scent.
• Refill or Buy New? What a Reed Diffuser Really Costs per Month — A beautiful reed diffuser shouldn't be a one-time purchase. Here is what it actually costs per month to keep one going, and when refilling saves the most.