The supplier quoting 6.7% less that costs you 2.3% more
A quote comparison is usually a comparison of unit prices, because that is the number both suppliers put in front of you. It is also the number that decides least.
Two quotes for the same 1,200 units. Supplier B is further away.
| Supplier A | Supplier B | |
|---|---|---|
| Goods | 18,000.00 | 16,800.00 |
| Freight | 900.00 | 2,600.00 |
| Insurance | 90.00 | 140.00 |
| Duty | 1,170.00 | 1,092.00 |
| Clearance fees | 300.00 | 300.00 |
| Total landed cost | 20,460.00 | 20,932.00 |
| Per unit landed | 17.05 | 17.44 |
On the invoice line that gets compared, B wins by 6.67% — 14.00 a unit against 15.00. Landed, B loses by 2.29%. B even pays less duty, because duty follows the lower goods value; it is the 1,700.00 of extra freight that eats the saving and then some.
Why the duty line misleads on its own
Duty is 5.72% of A's landed cost and 5.22% of B's. Read alone, that says B is the more duty-efficient purchase, and it is — which tells you how little "duty-efficient" is worth as a goal. B has a smaller share of a bigger number. Optimising the duty percentage while the freight line moves underneath it optimises the wrong thing.
The threshold worth carrying
The useful version of this comparison is not "which is cheaper" but "how wrong could the freight estimate be before the answer flips". B needs to get its freight down to about 2,128.00 to draw level with A. If your freight forwarder's quote has more uncertainty in it than the gap between the two suppliers, you do not have a decision yet — you have a freight question wearing a procurement question's clothes.
The same supplier is cheaper at a bigger order, up to a point
Part of a landed cost scales with how much you buy and part does not. Freight and clearance fees are close to fixed for a given shipment; goods, duty and insurance are proportional. So the per-unit figure falls as the order grows, with no negotiation at all. Supplier A's quote at three sizes, at the same 15.00 a unit ex-works:
| Order | Goods | Total landed | Per unit |
|---|---|---|---|
| 600 units | 9,000.00 | 10,830.00 | 18.05 |
| 1,200 units | 18,000.00 | 20,460.00 | 17.05 |
| 2,400 units | 36,000.00 | 39,720.00 | 16.55 |
Quadrupling the order takes 18.05 down to 16.55 — 8.31% off, from spreading the same freight and fees over more units.
The "up to a point" matters. This table holds freight flat, which is only true while the goods still fit the same container. The moment they don't, freight steps up and the curve breaks — which is why this calculation belongs next to the container question rather than after it. Buying to the edge of one container is usually the efficient order; buying slightly past it is the expensive one.
What the per-unit figure still leaves out
It covers everything up to clearance. Several real costs sit after it and none of them is in the 17.05:
Inland delivery from the port to your warehouse, which on a low-value, high-volume line can exceed the international freight.
Storage and demurrage if the container is not collected promptly. These are charged per day and escalate.
Damage and shortage. A 2% rejection rate raises the effective per-unit cost by just over 2%, silently, and it is the number least often tracked.
Payment terms. Paying a deposit six months before the goods sell is a financing cost even when no interest is charged.
Adding those is straightforward once the landed cost exists, and impossible before it — which is the argument for computing this number first rather than last.
Why it settles supplier comparisons
A unit price is a fact about a factory. A landed cost per unit is a fact about a supply chain, and it is the only one of the two you can put next to a selling price. Supplier B quotes 6.67% less on the goods and arrives 2.29% dearer per unit — 17.05 against 17.44 — which is what usually happens when one supplier is further away, ships less densely, or classifies into a higher duty line.
Work it before the negotiation rather than after. A discount argued against the unit price moves the smallest component of the total; the same effort spent on freight density, order quantity or classification moves the parts that are actually large.
Work it for your own shipment
The figures above come from the same code the calculators run, so typing these inputs in reproduces them exactly. Your own numbers are the point though — put both quotes through the landed cost calculator, and estimate each duty line first if you do not have it.
These are estimates, not assessments. Duty rates, the taxable base, and the valuation rules that decide them are set by national law and by how your goods are classified. A customs broker or your national customs authority gives you the binding answer; this site gives you the arithmetic so you know roughly what is coming and which question to ask.