OANDA

Many of the online travel agents offer their own currency conversion features, but OANDA's traveller currency cheat sheet makes the visitor feel like a professional currency trader-in-training. It's very easy to use, even by the most numerically illiterate.

The best money-saving feature is the choice of rates: unlike bureaux de change, you can choose to view the official, typical credit card, or typical cash rate.

SPECIAL FEATURES

Get my Cheat Sheet brings up a neat chart listing the exchange rate between your chosen currencies of values between £1 to £5,000.

Reverse Cheat Sheet reveals the same conversions the opposite way round, with the foreign currency first. These can be printed out and popped in a wallet, meaning that shop-a-holics no longer have any excuse for making mistakes in how much things cost.