How Does Customs Valuation Work?
Customs valuation determines the number that duty and VAT rates are actually applied to — get it wrong, and every downstream calculation is wrong too.
The transaction value method
Most countries, following the WTO Customs Valuation Agreement, primarily use the "transaction value" — the price actually paid or payable for the goods, adjusted for certain additions.
What gets added to the price
- Freight and insurance up to the port or place of importation (this is why customs value is often described as a "CIF-equivalent" value even under other Incoterms)
- Packing costs paid by the buyer
- Royalties or license fees the buyer must pay as a condition of sale
- Commissions paid to buying agents (in some jurisdictions)
When transaction value can't be used
If there's no sale (e.g., goods sent for repair), or the buyer and seller are related parties whose relationship affected the price, customs may use alternative methods: value of identical goods, value of similar goods, or a computed/deductive value based on resale price.
Frequently asked questions
Does my declared invoice value automatically become the customs value?
Not always — customs will add freight and insurance if they weren't part of your Incoterm's included costs, and can challenge the value if it looks understated compared to market prices.
What happens if customs disagrees with my declared value?
They can request supporting documentation (purchase contracts, payment proof) or reassess the value using an alternative method, which can delay clearance and change your duty bill.
Related tools and reading
Conclusion
Understanding customs valuation isn't just theory — it's the difference between an accurate duty estimate and an unpleasant reassessment at the border. Always declare the full transaction value, including freight and insurance where required.
Estimate your duty on the correct value: Use the Customs Duty Calculator →
Last updated: July 25, 2026