Are automatic currency orders worth it?

This calculator is for anyone who earns or saves in one currency and lives in another: euros, pounds or dollars. Many banks and apps let you set up an automatic order: your money converts by itself when the exchange rate reaches a level. Here you can see how that rule would have worked in the past.

You choose your two currencies, how much you want to convert, the period, how far the rate has to move from its average over the last year before the order fires, whether it goes one way or there and back, and what your provider charges to convert. It shows what you would have ended up with using that rule, compares it with converting everything on the first or the last day, how many times the order fired and how long the money sat waiting. It also tests the same rule over every three-year period with data, so you can see whether your result was luck.

The data is the European Central Bank's official reference rates, one per working day since 2010. The levels are measured against the average of the twelve months before each day, so the rule only uses what was known at the time. The pound against the dollar comes from crossing both with the euro.

What it doesn't do

• It does not predict exchange rates or tell you when to convert: these are past figures.
• It does not see moves within the day or at weekends: some orders that would have fired in real life don't fire here.
• It does not use your bank's exact rate: it starts from the official one and takes off the fee you choose.
• It does not count fixed transfer charges, only the percentage.
• It does not work out tax.
• It stores nothing: the calculation runs in your browser.