Why a higher freight bill can also mean more import tax

Your supplier keeps the goods price the same. The forwarder quotes more for shipping. You expect the landed cost to rise by the difference in freight, then discover the import tax has gone up too.

That can be correct. The first thing to check is the value the tax was applied to.

One shipment can have several tax bases

The goods price is a starting point. Customs value may include adjustments. Import VAT or GST can use another base that includes duty and transport costs.

For example, HMRC's import VAT guidance starts with customs value and adds duty and relevant incidental expenses. Australian Border Force includes customs value, duty and relevant transport and insurance in its GST calculation, with wine tax where applicable.

So “the rate is 10%” does not tell you the amount. You still need to know what that 10% is charged on.

A controlled example

We calculated nine import-tax scenarios for the US, Great Britain and Australia. Each uses goods worth 10,000 illustrative currency units and a hypothetical 5% duty rate. The Great Britain example uses 20% VAT, and Australia uses 10% GST. The scenarios exclude fees, extra tariffs, reliefs and recoverable-tax effects.

Moving freight and insurance from zero to 2,000 increases the modeled taxes by 520 in Great Britain and 200 in Australia. US modeled duty stays unchanged. That is an arithmetic comparison with fixed assumptions, not a claim about the cheapest country to import into. The zero-freight scenario is a baseline for the calculation, not a declaration value to copy.

The report gives the formulas, sources and downloadable spreadsheet data. You can see exactly which input caused the change.

Read the freight line before adding it again

An invoice total may already include freight or insurance. If the broker starts from that total and adds the same costs again, the calculation can overstate the base.

The opposite mistake is assuming that a goods-only price includes every cost customs requires. HMRC's transaction-value guidance includes transport to the place of introduction, while CBP's CIF guidance explains why the US treatment differs. Delivery terms are useful context, but the supporting amounts still matter.

Ask for the goods value, freight, insurance, duty base and consumption-tax base as separate figures. Keep the invoice and transport evidence together so the broker can explain any adjustment.

What to ask when the bill looks wrong

• Which commodity code, origin and duty rate were used?
• What was included in the customs value?
• Were freight or insurance already included in the supplier's total?
• Was duty added to the VAT or GST base?
• Are brokerage and carrier fees being shown separately from government charges?

A landed cost worksheet helps keep the numbers together. It does not choose the correct legal tax base for you. Establish that first, then enter the figures. For the full assumptions and jurisdiction-specific sources, use the comparison report.