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Per piece, per thousand, per kilo: making two quotes comparable

Suppliers quote in whatever unit suits their machine. Converting them all to a cost per finished unit is the only way to compare — and the arithmetic has two traps.

Updated September 21, 2026·4 min read

You have three quotes. One says $18.50 per kg. One says $142 per thousand pieces. One says $0.96 per unit. Which is cheapest is not a question you can answer yet, and the reason is not arithmetic — it is that two of those prices are not about the same object.

Why suppliers quote in different units

Each quotes in the unit their machine measures. A contract manufacturer mixes formula in a vessel and thinks in kilos or litres, because that is what the batch record says. An injection moulder runs a mould with a cycle time and thinks in thousands of pieces, because that is what a shift produces. A label printer thinks in thousands too, because that is how the web is counted. Only a supplier making the whole finished item naturally quotes per unit.

None of them is being awkward. Your job is the conversion, because you are the only person in the chain who cares about the finished unit.

The conversion

Every quote becomes a cost per finished unit by answering one question: how much of this goes into one finished unit?

Added together, the first three come to $0.79 per unit against the fourth at $0.96 — but the fourth includes filling and assembly and the first three do not, so the comparison still is not fair until filling is priced in. That is the second trap, and it is the one that catches people.

Trap one: fill volume is not fill weight

A 30 ml bottle does not contain 30 g of product unless the formula happens to have a density of 1.0. An oil is nearer 0.92, a thick cream can exceed 1.0, a sugar syrup is well above it. At $18.50 a kilo the difference between assuming and knowing is a few cents a unit — small until you multiply it by a batch, and embarrassing when the supplier's invoice uses their number rather than yours.

Ask for the density, or ask them to quote the bulk cost per finished unit at your fill volume and let them do the conversion. The second is better: it puts the arithmetic on the person who knows the formula.

Trap two: comparing different scopes

The most expensive mistake in quote comparison is not a unit error. It is comparing a quote that includes filling against one that does not, or one with a carton against one without. The prices are both correct and the comparison is meaningless.

The fix is a fixed list. Write down the lines your finished unit is made of, and place every quote against a line. Ours is seven: manufacturing, packaging, filling, cartons, freight and duties, setup, testing. A quote that covers three of them fills three rows, and the empty rows are visible rather than forgotten — the seven lines, with a worked example.

Minimums need converting too

A supplier's minimum arrives in their unit as well. A 50 kg minimum batch of a formula that goes 30 ml into each bottle is about 1,650 finished units — a perfectly reasonable first run. A 10,000-piece minimum on the bottle is 10,000 finished units. Converted to the same unit, the two constraints can be compared, and the binding one is usually the component rather than the formula.

That conversion is what turns a wall into a plan: you buy 10,000 bottles, make 3,000 units now and hold the rest, or you find a stock bottle with a lower minimum. Neither option is visible while the minimums are still in different units. More on where those numbers come from: MOQ.

Do it before you negotiate, not after

Founders routinely negotiate hard with the supplier whose number looked highest and turn out to have been arguing with the cheapest one. Convert first. The conversion takes ten minutes and it reorders the list more often than not.

Then make each converted number whole by adding the part that never appears on any quote — landed cost — and check what the quote quietly left out — line by line.