If you invoice clients in another country or pay overseas suppliers, currency conversion is not just a technicality. It is a cost centre that can silently erode your margins if you do not manage it deliberately.
Most small business owners know exchange rates fluctuate. Fewer realise how much of that fluctuation is compounded by bank fees and conversion margins, or how easy it is to reduce the impact with the right tools and a basic risk management approach.
This guide covers the mid-market rate versus what you actually get, the real cost of converting currencies, how to decide whether to invoice in your currency or the client's, and practical steps to reduce FX risk. Use the Currency Converter to check current rates and calculate conversion amounts.
The Mid-Market Rate: What It Is and Why It Matters
When you look up GBP/USD or EUR/GBP on Google, you see the mid-market rate. This is the midpoint between the buy price and the sell price on global currency markets. It is the rate that financial news websites quote and the rate that services like Wise use as a benchmark.
It is not the rate your bank gives you.
Banks and many payment processors add a margin to the mid-market rate before they apply it to your conversion. This margin is how they make money on foreign exchange. It is usually not shown as a separate fee. It is simply baked into the rate they quote you.
The typical margin for a UK high street bank on a business account is 2% to 4% above mid-market. On a £10,000 invoice converted from USD, that is £200 to £400 you lose before the money reaches you. On larger sums, or across many transactions over a year, this is a significant cost.
Credit cards commonly charge 1.5% to 2.75% as a foreign transaction fee on top of an already marked-up exchange rate. If you are paying overseas suppliers on a business credit card, calculate what that is actually costing you annually.
Calculating the Real Cost of Currency Conversion
To understand what a conversion is actually costing you, you need to compare the rate you received against the mid-market rate on the same day.
Say the mid-market rate for USD/GBP is 0.8000 (meaning $1 buys £0.80). Your bank converts your $10,000 payment at 0.7720, giving you £7,720 instead of the £8,000 you would get at mid-market. The difference is £280, which represents a 3.5% margin on top of mid-market.
If you receive 20 such payments per year, that is £5,600 in annual conversion costs that you might never have consciously noticed. Those costs show up only as "the exchange rate was not great" rather than as a line item on a bill.
Make it a habit to check the mid-market rate on the day of conversion, calculate what you received, and note the effective margin. This makes the cost visible and motivates you to find better alternatives.
Should You Invoice in Your Currency or the Client's?
This is one of the more consequential decisions for a business that works internationally, and there is no single right answer.
Invoicing in your own currency (GBP for UK businesses) means you know exactly what you will receive. There is no FX risk for you. The client carries the exchange rate risk and the conversion cost. This is the simpler option and gives you predictable income.
The downside is that it adds friction for the client. If they are comparing you to a local provider who quotes in their currency, your GBP quote requires them to do a conversion calculation and carry uncertainty about the final cost. In competitive sales situations, this can work against you.
Invoicing in the client's currency makes your pricing cleaner for the client and removes one barrier to saying yes. But it introduces risk for you. If the client's currency weakens between when you agree a price and when you collect payment, you receive less than you planned for.
For a US client on a 30-day payment term, the USD/GBP rate can move by 1% or more in that time. On a $5,000 invoice, that is $50 of variance, which may be acceptable. On a $50,000 project, a 2% currency move is a £1,000 swing. That is worth managing.
A practical middle ground is to invoice in the client's currency but build a buffer into your pricing to absorb moderate exchange rate movement. If you target £4,000 for a piece of work and the current rate is 0.80, you might invoice $5,100 rather than $5,000 to give yourself a 1-2% buffer.
FX Risk: What It Is and When It Matters
FX risk (also called currency risk or exchange rate risk) is the possibility that a change in the exchange rate between invoicing and collection reduces the value you receive.
For small, frequent transactions, the risk is manageable and random. Sometimes you benefit from a favourable rate move; sometimes you do not. Over a large number of transactions, the effects roughly cancel out.
For large, infrequent transactions, the risk is more concentrated. A single contract worth £50,000 that takes 6 months to deliver and collect can be significantly affected by rate movements over that period.
FX risk is also relevant on the cost side. If you pay a supplier in a foreign currency, a weakening GBP makes those payments more expensive. Businesses that source materials or services overseas can see their cost base change substantially when exchange rates shift.
Practical Options for Managing FX Risk
You do not need sophisticated financial instruments to manage basic currency risk. Here are the options available to small businesses.
Use a specialist foreign exchange service. Services like Wise Business, Revolut Business, and Airwallex typically offer rates close to the mid-market rate with transparent, low fees. Compared to a high street bank, the saving on a £10,000 conversion can easily be £200 to £300. If you convert foreign currency regularly, switching from a bank to a specialist service is the single highest-impact step you can take.
Open a multi-currency account. Many FX services let you hold balances in multiple currencies. Instead of converting USD to GBP the moment it arrives, you hold it in USD and convert when the rate is favourable or when you have accumulated enough to make a conversion worthwhile. This also reduces the number of conversion events and therefore the total fees.
Set rate alerts. Most FX platforms let you set alerts for when a currency pair reaches a specific rate. If you know you need to convert $20,000 and you are comfortable with today's rate, set an alert for 1% better than today. You may or may not achieve it, but it costs nothing to try.
Use forward contracts for large amounts. A forward contract locks in today's exchange rate for a conversion you will make in the future. If you have a large confirmed contract in a foreign currency and you want to know exactly what you will receive in GBP when you collect, a forward contract eliminates the uncertainty. You give up the chance of benefiting from a favourable rate move, but you also protect against an unfavourable one. Forward contracts are offered by specialist FX brokers such as Moneycorp and WorldFirst, typically for amounts from £5,000 upwards.
Tips Specifically for Freelancers with International Clients
If you work independently and bill clients in the US, Europe, or elsewhere, currency management is part of your financial admin. A few practical points:
Quote rates that include a conversion buffer. If you work in GBP but quote in USD, base your USD price on a slightly less favourable rate than today's mid-market. This protects you from rate movements during the project.
Get paid via a specialist service, not a bank transfer. Bank-to-bank international transfers often apply poor rates at both ends. Receiving USD via Wise into a USD account, then converting only when needed, is much more efficient.
Track what you actually received in GBP. Your income for tax purposes is the GBP amount you received, not the original foreign currency invoice amount. Keep records of both, and note the date of conversion for accurate bookkeeping.
Consider your pricing frequency. If you work with a client on a retainer and rates are agreed annually, review your rates against exchange rate movements annually. A GBP/USD rate shift from 0.80 to 0.75 over a year means your USD-denominated retainer is worth 6.25% less in GBP terms. Factor this into annual rate reviews.
Use the Currency Converter before quoting or invoicing to see current mid-market rates and calculate your expected GBP receipts. This takes 30 seconds and prevents the unpleasant surprise of collecting less than you expected.
Making Currency Conversion a Non-Issue
The goal is to reduce currency conversion from a source of invisible cost and stress to a predictable, manageable part of your business finances.
For most small businesses, the biggest gain comes from switching away from bank conversions to a specialist FX service. The second gain comes from using multi-currency accounts to batch conversions rather than converting on every receipt. The third gain, for larger and more predictable amounts, is planning ahead rather than converting reactively.
Currency conversion does not need to be complicated. But it does need to be deliberate.