Considerations for changing billing from USD to GBP

When changing your AWS billing currency from USD to GBP, there are several important considerations:

1. Currency changes only affect future bills - When you change the payment currency in your AWS Billing preferences, it only applies to future invoices and bills. The change cannot be applied retroactively to bills that have already been issued and paid.

2. Invoice currency importance - The payment currency you select is the currency that your default payment method will be charged in and is displayed on your invoices. It's important to ensure your payment currency is accurate, as some organizations cannot process invoices issued in the wrong currency.

3. AWS Marketplace private offers - For AWS Marketplace, you can receive private offers in GBP (among other currencies like EUR, AUD, and JPY) with no foreign exchange variability. At offer acceptance, AWS converts the non-USD pricing to USD and locks the exchange rate for the entire subscription.

4. Local currency display options - If you need to view your AWS spend in local currency for reporting purposes, you can customize the AWS Cloud Intelligence Dashboards to display costs in local currencies. This involves creating a currency conversion CSV file with monthly averages of conversion rates from USD to your local currency.

Regarding your specific questions about the FX rate URL and testing capabilities:

Currently, AWS does not provide a public API or URL to access the Bloomberg FX rates used for currency conversion. The ability to preview the cost impact before switching currencies is also not available as a standard feature. For accurate forecasting of the impact, you would need to manually calculate using current exchange rates or work with your AWS account team to understand potential implications.

If you need historical billing information in a different currency for accounting purposes, you may need to manually convert the amounts using applicable exchange rates at the time of the original transactions.
Sources
Change invoice currency of paid bills | AWS re:Post
AWS Spend in Local Currency - Cloud Intelligence Dashboards on AWS
Pay for a private offer with foreign currencies - AWS Marketplace
Reviewing your monthly billing best practices - AWS Billing
Customizing your AWS payment preferences - AWS Billing