How to Build a Hair Oil Formula Using Percentages
HAIR OILS
Patricia Ofori | Abby Ofori | Janelle Ofori
9/26/20262 min read
One of the biggest upgrades you can make as a DIY formulator is to stop thinking only in tablespoons, teaspoons, and drops.
Start thinking in percentages.
Why?
Because percentages make formulas scalable.
Make Formulation Easier
I've created a Hair Oil Formulation Calculator for exactly this process.
Enter the batch size and formula percentages, and the calculator can determine the required ingredient quantities for you.
That makes it much easier to move from:
“I want to make this formula”
to:
“I know exactly how much of each ingredient I need.”
A Formula Should Equal 100%
Suppose we create a simple hair-length oil:
59.5% base oil
39% supporting oil
1% antioxidant
0.5% optional aromatic phase
Together:
59.5 + 39 + 1 + 0.5 = 100%
Now the formula can be scaled to almost any batch size.
The Calculation Is Simple
Use:
Total batch size × ingredient percentage ÷ 100
For a 100 g batch, 59.5% base oil is:
100 × 59.5 ÷ 100 = 59.5 g
For a 250 g batch:
250 × 59.5 ÷ 100 = 148.75 g
The percentages don't change.
Only the ingredient amounts change.
That is the beauty of percentage-based formulation.
Why I Prefer Grams
Volume measurements are convenient, but oils don't all have the same density.
That means 10 grams of one oil will not necessarily occupy exactly the same volume as 10 grams of another.
For repeatable formulation, weighing ingredients in grams is generally more useful.
If you need volume measurements, you can calculate them when you know the ingredient's density:
mL = grams ÷ density in g/mL
Then:
U.S. fluid ounces = mL ÷ 29.5735
What About Fragrance?
Fragrance should be treated as optional.
An example formula containing a 0.5% aromatic phase does not mean 0.5% is a universal safe-use level for every essential oil or fragrance material.
The appropriate amount depends on the specific material, supplier guidance, intended use, applicable IFRA restrictions, and the person using the product.
And remember: Fragrance does not preserve an oil or prevent rancidity.
A fragrance-free formula is completely valid—and may be preferable for some users.
