Our displayed price is allowed to be wrong in one direction only, and Intl decides how many decimals it is wrong by

The displayed price on Notifio can be inaccurate, but it will never be lower than the actual cost. The one rule governing this discrepancy is that the displayed price must always be an upper bound. Prices are shown in an approximate local currency to help visitors decide if a product is worth purchasing. This introduces a margin of error, but the rule ensures the displayed price is never less than what the customer will actually be charged.

The pricing system uses the mid-market exchange rate as the basis, but actual conversion fees from banks or card issuers can add 2 to 4 percent to the total. These fees are applied after the price is displayed. To avoid under-quoting the price, a buffer of 1.04 is used, which ensures the displayed price is always an upper bound.

Not all currencies use decimal places, so the system determines how many decimal places each currency uses based on the visitor's locale. For example, Japanese Yen (JPY) doesn't use decimals, while currencies like Icelandic Króna (ISK) and Hungarian Forint (HUF) also don't. If a price is already an exact retail price, no additional rounding is applied.

Zero is passed through without modification, ensuring free tier prices remain at £0. The function that converts the price for display first checks for finite values, then rounds the result to the appropriate number of decimal places based on the currency's format.