The customs value rate is monthly

A declaration can use a rate that is correct in itself and still be wrong. That happens when the customs value is converted at the rate of the day.

The rate is monthly

For converting the customs value, the rate used is not the daily one but a monthly one: it is set before the start of the month and applies for the whole of the following calendar month. This is a provision of EU customs law, and it differs from the way currency is converted everywhere else in your accounts.

The practical consequence: in the middle of the month, when the market rate drifts away from the monthly one, a declaration at the rate of the day produces a different customs value than one at the monthly rate. In which direction depends on how the rate moved. If the customs value came out higher, more duty was paid.

The error does not come from not knowing, it comes from automation: the accounting or declaration system converts at the daily rate, because that is what is required everywhere else.

The error works twice — but the loss is single

The customs value is the base for both the duty and the import VAT. One rate error therefore distorts both.

But that does not mean the loss is double. Import VAT is deductible in most cases, so overpaid VAT is not your loss — it is an inaccuracy in the declaration. The real loss is in the duty.

This matters, because if someone presents you with a finding in which the duty and the VAT are added into a single amount, the finding looks roughly twice as large as it is. Ask for them to be separated.

The time limit is three years

Here is the reason why this check deserves attention before the carriers' invoices do.

EU customs law sets a three-year time limit for the repayment of overpaid duty. That is a long window: declarations lodged two years ago can still be reviewed.

The time limit for disputing a carrier's currency margin is contractual, and in forwarding contracts it is often weeks from receipt of the invoice. So when you check backwards, some of the findings in carriers' invoices can no longer be disputed, while those in customs declarations still can.

The practical order that follows from this: start with the declarations.

Who files the application

The application for repayment of overpaid duty is filed by the declarant or by their representative in the customs procedure. That is a defined person, and a third party cannot take their place, however complete the substantiation.

In practice this means that the analysis and the substantiation can be prepared externally, but the application is filed by you or by your customs agent. If someone offers to file it on your behalf, it is worth asking on what basis.

What to check

Take ten declarations from different months in which the invoice was not in euros. In each of them find the rate that was used and compare it with the customs rate for that month.

If in at least two out of the ten the rate was the daily one rather than the monthly one, that is a matter of system configuration, not chance — and then the whole three-year window is worth reviewing.