How do I work out the cost per unit of a material I buy in bulk?
Last updated October 1, 2026
Divide the total you paid by the quantity you bought. That gives the cost per unit, such as per ounce of wax or per bead. To find what one item uses, multiply the cost per unit by the amount that item needs.
What is the formula?
Cost per unit = total paid / quantity bought
Cost in one item = cost per unit x amount used
Use the total you actually paid for that purchase. If shipping on your supplies was charged separately, adding it to the total gives a cost per unit that reflects what the material really cost you.
How does it work for wax bought by the pound?
A 10 lb bag of soy wax costs $35. A candle recipe measures wax in ounces, so record the purchase in ounces too: 10 lb is 160 oz.
$35 / 160 oz = $0.21875 per oz, which is about $0.22. An 8 oz candle uses 8 x $0.21875 = $1.75 of wax.
Keep the unrounded figure when you multiply. Rounding to $0.22 first gives $1.76, a cent off on every candle.
This is an illustrative example, not data from a real shop.
How does it work for a beaded bracelet?
| Material | Bought | Paid | Cost per unit | Used | Cost |
|---|---|---|---|---|---|
| Seed beads | 500 beads | $12.00 | $0.024 each | 24 beads | $0.58 |
| Stretch thread | 100 yards | $6.00 | $0.06 per yard | 0.5 yards | $0.03 |
| Clasp | 10 clasps | $12.00 | $1.20 each | 1 clasp | $1.20 |
| Materials | $1.81 |
This is an illustrative example, not data from a real shop. The bead cost is $0.576 before rounding.
Which unit should I use?
Record the purchase in the same unit your recipe uses. If you buy wax by the pound but pour it by the ounce, convert the pound figure to ounces before you divide.
MakerKit lets you choose a unit for each material: yards, meters, oz, lb, grams, kg, pieces, sheets, sq ft, ml, liters, bottles, jars, sticks or bags. It does not convert between units, so the amount a recipe uses has to be in the material's unit.
Doing this in MakerKit
- When you add a material, enter how much you bought and what you paid in total. MakerKit divides the two to get the cost per unit.
- MakerKit keeps the full cost per unit when it adds up a recipe, and rounds only what it shows you.
- Remaining stock starts at the quantity you bought and goes down when you log a production run that uses the material.