Short answer
Fragrance load is the amount of fragrance in a product expressed as a percentage — but of what depends on the product and the habit of the trade. Candle makers usually quote it as a percentage of the wax, soap makers as a percentage of the oils, and lotion and diffuser makers as a percentage of the whole batch. A "10% load" in a candle (100 g of fragrance per 1,000 g of wax) is 9.09% of the finished candle. Before comparing a load with a supplier's maximum or an IFRA limit, convert it to the basis that limit uses; IFRA limits are always a percentage of the finished product.
Three different denominators
| Product | Load usually quoted as % of… | Converting to % of the finished product |
|---|---|---|
| Container candle | Wax weight (sometimes total) | fragrance ÷ (wax + fragrance) × 100 |
| Cold-process soap | Weight of oils and butters | fragrance ÷ whole batch × 100, which then changes as water evaporates in curing |
| Lotion, cream, body oil | Total batch | Already on the finished basis |
| Reed diffuser, room spray | Total of fragrance plus base | Already on the finished basis |
| Fine fragrance | Total — the "concentration" | Already on the finished basis |
The habits are not universal; some candle suppliers quote loads as a percentage of the total. When you read a figure, ask "percent of what?" before you use it. The same question is the root of many errors in perfume batch calculation errors.
Candles
A container candle with 500 g of wax at an "8% load" by the wax convention:
- fragrance = 500 × 0.08 = 40.0 g;
- finished candle = 540.0 g;
- fragrance as a share of the finished candle = 40 ÷ 540 = 7.41%.
To hit a target share of the finished candle instead, divide: for 8% of the finished candle with 500 g of wax, fragrance = 500 × 8 ÷ (100 − 8) = 43.48 g.
The maximum load is set by the wax (how much oil it can hold without "sweating") and by the fragrance (its supplier's maximum for candles and its IFRA certificate). More fragrance is not always more scent; wicking and burn quality matter as much.
Soap
Cold-process soap recipes usually state fragrance as a percentage of the oils and butters. With 1,000 g of oils at 5%, the fragrance is 50 g. The finished batch also contains the lye solution, so the fragrance is a smaller share of the soap than of the oils. In one illustrative recipe with 140 g of sodium hydroxide dissolved in 330 g of water, the batch weighs 1,000 + 140 + 330 + 50 = 1,520 g and the fragrance is 50 ÷ 1,520 = 3.29% of the fresh soap — rising slightly as water evaporates during curing. For a restriction check, use the finished-product basis and be conservative about curing. Some materials also behave badly in soap: vanillin-rich fragrances discolor it, and some materials speed up the soap's set. Your fragrance supplier's soap notes are the first source here.
Lotions, body oils and other leave-on products
These are quoted on the whole batch, so the arithmetic is direct: 2 g of fragrance in a 200 g batch is 1%. Leave-on products usually carry far less fragrance than a perfume, because they cover more skin and stay there, and restrictions for these categories are typically tighter than for fine fragrance. Moving a fragrance from one product type to another is its own task; see adapting a fragrance to a different product base.
Diffusers and room sprays
Quoted on the total of fragrance plus base. A 100 g reed diffuser at 20% is 20 g of fragrance and 80 g of diffuser base. A room spray containing alcohol is, like perfume, a flammable liquid.
Comparing a load with a limit
IFRA Standards set maximum levels of restricted materials in the finished product, by product category, and suppliers' IFRA certificates translate that into a maximum percentage of their fragrance oil per category. Two checks follow:
- Convert your load to the finished-product basis, as above.
- Compare it with the certificate's figure for the right category — candles, soap, a leave-on body product and a fine fragrance are different categories with different limits.
If you are using your own concentrate rather than a purchased oil, you calculate each restricted material's level in the finished product yourself; the method is in how to calculate IFRA compliance, and certificates are explained in how to read an IFRA certificate.
A worked conversion, both directions
| You know | You want | Formula | Example |
|---|---|---|---|
| % of wax | % of finished | L ÷ (100 + L) × 100 | 8% of wax → 7.41% |
| % of finished | % of wax | F ÷ (100 − F) × 100 | 8% of finished → 8.70% of wax |
Every figure in this article is illustrative; recipes, waxes and soaps vary. What does not vary is the method: name the denominator, convert before comparing. The broader arithmetic is collected in the perfume dilution and calculations guide.
Frequently asked questions
Can I use my fine-fragrance concentrate in a candle?
Sometimes, but check it as a new product: a different IFRA category, a flash-point question for hot wax, and materials that may not burn or throw well. Many perfume materials perform poorly in wax.
Does a higher load always mean a stronger product?
No. Above the base's capacity, a candle sweats oil and may burn badly, soap may set too fast, and lotion may separate. Find the useful range by testing.
Written and reviewed by the RUŌOD Lab team. This article is general education about perfume formulation and record-keeping; it is not legal, regulatory or safety advice, and the examples are illustrations, not validated commercial formulas. How we write and check these guides.