Currency conversion explained: how rates apply

Start with what an exchange rate actually is

An exchange rate expresses how much of one currency you get for one unit of another. GBP/USD at 1.27 means one pound buys 1.27 US dollars. That number moves constantly during market hours, driven by supply and demand across a global market that never really closes from Monday morning in Wellington to Friday evening in New York. When people talk about "the rate", they usually mean the mid-market rate — the theoretical midpoint between what buyers are willing to pay and what sellers are willing to accept. You will rarely transact exactly at the mid-market rate; more on that below. See our exchange rate glossary entry for the formal definition.

Why the rate you're quoted isn't the rate you saw online

Currency comparison sites and banking apps often display the mid-market rate because it's a useful, neutral reference point. But any actual conversion — whether it's a bank, a card provider or an FX broker — applies a spread around that mid-market rate. The spread is effectively the cost of the service: it covers the provider's own risk in holding or sourcing that currency, their operational costs, and their margin. A wider spread means a worse rate for you; a tighter spread means you keep more of the value of the transaction. This is why two providers quoting "the same currency pair" can hand you meaningfully different amounts for the same transfer.

Spot conversion versus forward-dated conversion

A spot conversion happens at (or close to) today's market rate, usually settling within one to two business days. A forward contract fixes a rate today for a conversion that will actually happen on a specified date in the future — useful when you know you'll need to convert a certain amount later and want to remove the uncertainty of where the rate will be by then. See our full explainer on forward contracts for how that works in practice.

What actually moves exchange rates

Exchange rates respond to interest-rate expectations, inflation data, trade flows, political events and overall risk sentiment, among other factors. No provider — including TimeFX — can predict where a rate will move next, and any supplier who implies they can should be treated with caution. What a good process can do is remove the guesswork from *when* you convert and *how much spread* you pay, which is a controllable cost even though the underlying rate is not.

Reading a rate you've been quoted

When you receive a quote for a transfer, it typically includes: the amount you're sending, the currency pair, the rate being applied, and the amount the recipient will receive (sometimes before third-party deductions, which is why international payment fees matter separately from the rate itself). Compare quotes on the actual amount that arrives, not just the headline rate — a slightly worse rate with no downstream fees can beat a slightly better rate with several deductions along the way.

Practical steps for businesses converting regularly

• Understand your typical volumes per currency pair so you can judge whether the spread you're being offered is competitive for your size of business.
• Ask what happens between quote and execution — some providers guarantee the quoted rate for a short window, others reprice on execution.
• Separate the conversion decision from the payment decision. You can convert GBP to EUR today and hold the EUR balance in a multi-currency account until you need to pay it out, which is useful if your payment date and your preferred conversion timing don't line up.

Where TimeFX helps

We provide UK businesses with FX conversion, with rates and costs explained clearly before you commit to anything. If you'd like a walkthrough of how conversion would work for your typical volumes, make an enquiry or read about our currency risk management service.