What Fir Oil Costs Per Candle and Soap Batch: The Math
The cost of fir oil in a batch is three numbers multiplied together: the weight of your wax or oils, the percentage of oil you add, and the price of one gram of oil. Most of the confusion about "bulk versus bottle" disappears once you work in grams. Our fir needle oil is sold undiluted, so the whole calculation is yours to do, and this page shows how, with a stand-in price you replace with the live one.
Fir Needle Essential Oil
Our own Fir Needle Essential Oil, in sizes from 0.5 oz to bulk.
From $10.99
Shop Now →Step one: put the price in grams
Prices on the shop page are per size, and bulk is quoted per pound. Convert everything to cost per gram before comparing anything. A pound is 16 ounces, 453.6 g; an ounce is 28.35 g.
To keep this article honest, it never states our prices (they change, and you should read them off the shop page). The examples below use a stand-in: say the oil costs two dollars per ounce. This is a made-up round number, not our price. Two dollars per 28.35 g is about 7.05 cents per gram. Replace it with the live figure for the size you are considering: price divided by grams in that size.
Step two: oil weight is wax weight times load
For candles, the formula is: oil (g) = wax (g) x load (%). The load is the oil's share of the wax weight, not of the finished candle. One soy container-wax data sheet (version 5.0, revised August 2020) says that wax may be used with fragrance at levels up to 10 to 12%, and it adds that the maker's own tests decide suitability and that the wax maker recommends fragrance oils developed for natural waxes. That sheet is for one soy wax and one fragrance category (fragrance oils), not for fir essential oil, so treat the 10 to 12% as a ceiling for that wax, not a target for ours. Reasoning from that ceiling, a load well below it leaves room to adjust.
A worked example on an 8 oz (227 g) wax fill, with the stand-in price of about 7.05 cents per gram:
| Load | Oil per candle (g) | Volume at density 0.924 (ml) | Drops (about 20 per ml) | Oil cost per candle (stand-in price) |
|---|---|---|---|---|
| 6% | 13.6 | 14.7 | about 295 | about 96 cents |
| 8% | 18.2 | 19.7 | about 393 | about 1.28 dollars |
| 10% | 22.7 | 24.6 | about 491 | about 1.60 dollars |
The volume column divides grams by the density on the COA we publish (relative density 0.924 at 20 C, batch FIRAIUABUNC010A), so a scale and a measuring syringe agree. The drop column uses about 20 drops per ml, which follows from our skin-dilution copy (3 drops per ounce of carrier at 0.5%); it is arithmetic, not a measurement, and drop sizes vary with the dropper. Weigh the oil in grams. At 400 or so drops per candle, nobody should be counting drops.
Step three: the same sum for soap
For cold-process soap the base is the weight of the oils in the recipe, not the batch. A 1,000 g batch of oils at a 3% use rate takes 30 g of fir oil (about 2.12 dollars at the stand-in price); at 5% it takes 50 g (about 3.53 dollars). These rates are placeholders to show the arithmetic, not recommendations: the right rate depends on your recipe, the oil's documented limits and your own trial. Our soap article covers the process side.
Where the bulk break really sits
A bigger size lowers the price per gram. Whether that pays depends on one ratio: how much of the container you finish before the oil gets old. If the larger size is a fraction d cheaper per gram, buying N pounds beats buying only the u pounds you need whenever u/N is greater than (1 minus d). Take a purely hypothetical 20% discount (not a figure for our sizes): you break even only if you use more than 80% of the bulk container, and you lose if you use less.
The shelf life is the clock on that ratio. Our product pages say conifer oils typically keep 1 to 2 years; another supplier's data sheet for a Canadian fir needle oil lists 1 year from the date shipped and says to store it in full, tight containers away from light. Plan on the shorter figure.
| Annual use (8 oz candles at 8%) | Oil used per year | Fraction of a 25 lb container |
|---|---|---|
| 100 candles | 1.82 kg (4.0 lb) | 16% |
| 300 candles | 5.45 kg (12.0 lb) | 48% |
| 625 candles | 11.3 kg (25 lb) | 100%, about 12 a week |
Even the 100-candle maker has a clear answer: a 25 lb container is the wrong size. At the hypothetical 20% discount, 16% use is nowhere near the 80% breakeven. The 625-candle maker uses all of it inside a year and still has to decant, as explained in storing bulk essential oil.
Why the discount matters less than the load
Position: at small volumes, fixing the load saves more than hunting the lowest price per gram. At the stand-in price, going from 10% to 8% saves about 32 cents per candle. A hypothetical 20% discount on the 8% candle saves about 26 cents. Over 100 candles that is 32 dollars versus 26 dollars. Whether either is real depends on your wax and your wick, which is why a small test batch comes first. For the load itself, see how much essential oil in candles.
Oil is also not the whole cost. Wax, wick, jar, label and your time sit beside it, and we sell none of them; get them from a candle-supply shop. Divide your oil cost per candle by your all-in cost per candle to see its share, and decide on the bulk question only after you know it.
Waste you should price in
- Test batches. Three 8 oz test candles at 8% use 54.5 g of oil. At the stand-in price that is about 3.84 dollars before you have made a candle you can sell.
- Residue. Oil clings to beakers and syringes. Weigh a beaker before and after pouring to measure your own loss, and add it to the load.
- Decanting loss. Each transfer leaves a film in the old container. Fewer, larger transfers lose less.
We have not poured these candles or made these soaps; the tables above are arithmetic from the sources cited, not results. Run a small batch and weigh what you use.
Who should not buy bulk
- Anyone who will not finish the container inside the shelf life, per the ratio above.
- Anyone without a cool, dark place and smaller amber bottles for decanting.
- Anyone still choosing a load. Buy a retail size first; the same oil is sold from 0.5 oz to 400 lb, so the oil does not change when you scale up.
- Anyone who needs documents we have not published. We publish a COA but no SDS or IFRA certificate; ask via the wholesale page before ordering.
Read the live price per size on the shop page or the bulk page, divide by grams, and rerun the tables with your numbers. For the pricing context, see our price guide.
Fir Needle Essential Oil
Fir Needle Essential Oil from our own shop, in sizes from 0.5 oz to bulk.
From $10.99
Shop Now →Sources & Further Reading
- Soy container wax maker, 2020. Technical Data Sheet, Soy Wax Container, version 5.0 (revised 26 August 2020). cdn.shopify.com/Soy_Wax_Container_Technical_Data_Sheetv5.0.pdf
- The Lebermuth Company, 2022. Technical Data Specification, Fir Needle Canadian Oil, 50-6125-02. docs.lebermuth.com/50-6125-02