> So they’ll have to be calculated in that currency Yes. > therefore invoices in that currency. No, the value of the foreign currency in the local currency a

> So they’ll have to be calculated in that currency Yes. > therefore invoices in that currency. No, the value of the foreign currency in the local currency at the tax date of the invoice is used to calculate the applicable local taxes. It's 100% A-OK for a Canadian company to invoice its Canadian customers in USD (or EUR) and pay taxes in CAD using GAAP rules for currency valuation (e.g. using the daily published interbank rates). Many accounting or billing packages just do it the simple & dumb way though, so you end up with situations like the OP's.