A window forward contract fixes an exchange rate now but lets you buy the currency at any point between two agreed dates — the “window” — rather than on one fixed day. It suits a payment you know is coming but cannot yet date precisely, such as an overseas property completion that may slip by a few weeks.
For UK buyers and businesses converting a large sum, that flexibility can be the difference between drawing your money on the day you actually need it and being locked into a date the deal has moved past. This guide explains how a window forward works, when it earns its place over a standard forward, what the flexibility costs, and the mistakes worth avoiding. You can check the live GBP/EUR rate or model an amount on the currency converter before you read on.
What is a window forward contract?
A window forward contract is an agreement to exchange one currency for another at a rate fixed today, with the currency delivered at any time — in one drawing or several — between an agreed start date and an agreed end date. The rate is locked for the whole period, so it does not matter where the market moves in between.
It is a variation on a standard forward contract. A standard forward fixes the rate for one specific future date; a window forward fixes the same kind of rate but gives you a range of dates to draw on. Both differ from a spot deal, which converts at today’s rate for delivery in the next couple of working days. The window is what you pay a little for, and what makes the contract useful when your timing is genuinely uncertain.
How does a window forward contract work?
The mechanics are straightforward. You agree the currency pair, the total amount, the rate and the two dates that bookend your window. From there the process runs in four steps.
- Agree the terms and the window — for example, the right to buy €400,000 at a fixed rate at any point over the next four to seven months.
- Pay a deposit, also called initial margin, to open the contract. The deposit and margin work the same way as on a standard forward.
- Draw down the currency when you need it. You can take the whole amount in one go, or in several stages across the window, paying the balance due on each drawing.
- Complete the contract by the end date. Any amount you have not drawn by the maturity date must be taken then.
When should you use a window forward instead of a fixed-date forward?
A window forward is built for the payment you can see coming but cannot pin to a single day. If you already know the exact date, a fixed-date forward is usually the cleaner and slightly cheaper choice. The window earns its place when the date is a range, not a point.
- Off-plan property abroad. Stage payments on an off-plan purchase fall due as building milestones are hit, and those dates rarely land on schedule.
- A completion that could move. Cross-border conveyancing slips often; a window absorbs the drift without a scramble to re-book. See what happens when an overseas completion is delayed.
- Buying in a single corridor over a period. If you are sending money to Spain across a purchase that runs over several months, one window can cover the whole run at one rate.
- Staged supplier or contractor payments. Businesses with a delivery schedule that could shift use a window as part of their wider FX hedging, drawing funds as invoices are approved.
- Uncertain but committed costs. Tuition instalments, renovation drawdowns and phased investment commitments all fit the same shape: the money is committed, the day is not.
Window forward vs fixed forward vs spot: which suits your payment?
The three tools solve different problems. The table below sets them side by side so you can match the instrument to how certain your payment date is.
| Feature | Spot deal | Fixed-date forward | Window forward |
|---|---|---|---|
| What it fixes | Nothing beyond today | The rate for one future date | The rate across a date range |
| When you take the currency | Now (settles in about two working days) | On one agreed date | Any time between two dates |
| Best when | You need the money now | You know the exact payment date | The payment is coming but the date is uncertain |
| Rate certainty | None after today | Full, to the fixed date | Full, across the whole window |
| Pricing basis | Today’s market | The single chosen date | The least favourable date in the window |
| Deposit | Usually the full amount | Part-payment upfront | Part-payment upfront |
How much does the flexibility of a window forward cost?
A window forward is quoted at a single rate for the entire period, and that rate is set at the least favourable point for you across the window. The provider cannot know when you will draw, so it prices in the possibility that you draw on the date that would otherwise give you the fewest euros (or dollars) per pound. Flexibility, in other words, carries a small, quantifiable premium over a forward to any one date inside the window.
That premium comes from forward points, not from a hidden margin. Forward points are the adjustment added to or subtracted from the spot rate to reflect the gap between each central bank’s policy rate — the Bank of England’s Bank Rate set against the European Central Bank’s key rates in the case of GBP/EUR, a relationship formalised as covered interest parity by the Bank for International Settlements. It is the same mechanism explained in why the forward rate differs from spot. Because the points change over time, a longer window spans a wider spread of possible rates, so the further out the end date, the larger the flexibility premium tends to be.
A worked example. Suppose a buyer needs €400,000 for a property and expects to complete in about six months, though it could slip to eight. At an illustrative spot of 1.1700, a fixed-date forward to month six might be priced at 1.1650, while a window forward covering months five to eight is priced at the least favourable point in that range — say 1.1620.
- Fixed forward at 1.1650: €400,000 costs £343,347.64.
- Window forward at 1.1620: €400,000 costs £344,234.08.
- The flexibility premium is £886.44 — about 0.26% of the sterling cost.
Set that against what it removes. A 2% move in GBP/EUR on €400,000 is €8,000, and a completion date can easily drift far enough for the market to move by more than the premium. The window fixes your rate for every date you might realistically draw on, for a known cost decided upfront.
What if your payment date falls outside the window?
Set the end date with a buffer. It is better to give yourself a window that runs a little beyond your worst-case date than to have the contract mature before the money is needed. Forward contracts can be arranged up to 12 months ahead, which covers most property and business timelines.
If the date still slips past the end of the window, a forward can usually be extended, but the extension is re-priced at the forward points that apply at the time. If the market has moved against you in the meantime, carrying the position forward can cost more than the original flexibility premium would have. As an illustration, a buyer who had instead booked a fixed forward to month six and then had to roll it to a much weaker level of 1.1400 would pay about £350,877 for the same €400,000 — roughly £7,530 more than the fixed rate they started with. Building enough room into the window from the outset is the simpler protection.
Do you pay a deposit, and is a window forward regulated?
Yes, opening a window forward normally means paying a deposit, and you can be asked to top it up if the market moves sharply before you draw. The deposit and margin call mechanics are the same as on a standard forward, because a window forward is simply a forward with a flexible delivery date.
On the regulatory side, a deliverable forward booked to make a genuine commercial payment — buying a home, settling an invoice, funding a purchase — is treated as a means of payment rather than a speculative financial instrument, and sits outside the MiFID financial-instruments regime under the Financial Conduct Authority’s perimeter guidance in PERG 13.4. Cambridge Currencies operates with FCA-authorised partners Currencycloud and ScioPay, and client funds are safeguarded at a credit institution.
Common mistakes to avoid with a window forward
- Setting the window too short. A window that ends on your expected date leaves no room for a delay — the most common reason people need one in the first place.
- Choosing a window when the date is firm. If you know the exact day, a fixed-date forward is usually priced a touch more keenly.
- Overlooking the margin. A large adverse move before you draw can trigger a request to top up the deposit; keep some liquidity in reserve.
- Forgetting the maturity obligation. Whatever you have not drawn by the end date must be taken then, so plan your drawings.
- Comparing only the headline rate. The window rate looks slightly worse than a single-date forward by design; the fair comparison is against the risk of being unhedged on a moving completion.
Window forward contracts: frequently asked questions
What is the difference between a window forward and a flexible forward?
The terms are often used interchangeably. Both fix a rate now and let you draw the currency across a date range rather than on one fixed day. Some providers reserve “flexible forward” for a window that starts immediately, so it is worth confirming the exact start and end dates when you book.
Can you draw down a window forward in several payments?
Yes. You can take the full amount in one drawing or split it into several within the window, at the same fixed rate each time. This makes a window forward well suited to staged payments, such as off-plan property instalments or scheduled supplier settlements.
Is a window forward more expensive than a standard forward?
Usually by a small amount. Because the rate is set at the least favourable point across the window, the quoted rate is typically a little less generous than a forward to any single date inside it. That difference is the price of the flexibility, and it tends to grow the longer the window.
How far ahead can a window forward be arranged?
Forward contracts, including window forwards, are generally available up to 12 months ahead. That horizon covers most overseas property completions, phased investment commitments and business payment schedules.
What happens if you do not use the full amount by the end date?
Any currency not drawn by the maturity date must be taken then, settling the remaining balance. If your need has changed, speak to your specialist before the end date to discuss the options, which may include extending the contract at the prevailing forward points.
Is my money protected on a window forward?
Cambridge Currencies works with FCA-authorised partners, and client funds are safeguarded at a credit institution rather than held as a bank deposit. Safeguarding is a different framework from the protection that applies to money held in a UK bank account; our safeguarding page explains how it works.
Fix a flexible rate for your overseas payment
If a payment is on the horizon but the date is still moving, a window forward can hold your rate steady until you are ready to draw. Speak to a Cambridge Currencies specialist about the right window for your property purchase, business schedule or investment commitment — every transfer is arranged by phone with a dedicated specialist who explains the pricing before you commit. Request a quote and a callback to talk it through.
