i What this calculator does
This calculator works out the forward exchange rate for a currency pair, based on today's spot rate and the interest rate differential between the two currencies, using covered interest rate parity.
Enter the spot rate, both currencies' interest rates, and the number of days, and the calculator returns the forward rate, closely related to how carry trade strategies work in practice.
This calculator is for educational purposes only and uses simplified covered interest rate parity. Not financial advice.
How to use the Forward Rate Calculator
There is no blank form to complete. The inputs arrive with working values, and changing one at a time is what shows you the effect.
- 1. Spot Rate e.g. USD/ZAR spot rate
- 2. Base Currency Interest Rate (%)
- 3. Quote Currency Interest Rate (%)
- 4. Number of Days
The result panel reports:
- Difference From spot rate
- Contract Period
Alongside the headline figures, the calculator reports forward rate, forward points, difference, contract period. Those are the numbers that usually explain why the headline result came out where it did.
Below the figure, the calculation is shown in full, so you are not asked to take it on faith.
The value in a calculation like this is less the figure than the sensitivity. Move each input in turn and the one that shifts the answer most is the one worth being careful about.
Frequently asked questions
Why does the forward rate differ from today's spot rate?
The forward rate reflects the interest rate differential between the two currencies over the contract period, known as covered interest rate parity, a currency with a higher interest rate typically trades at a forward discount, one with a lower rate at a forward premium, this isn't a market prediction of future spot price.
Who actually uses forward rate contracts in practice?
Forward contracts are primarily used by businesses and institutions hedging future foreign currency exposure, for example, an exporter expecting Dollar payment in 90 days can lock in today's forward rate to remove exchange rate uncertainty from that future transaction.
Does a forward premium mean the currency will actually strengthen?
No, a forward premium purely reflects the interest rate differential, not a market forecast of future spot price direction, forward rates and actual future spot rates frequently diverge, since the forward calculation is a mathematical relationship, not a prediction.
How does this connect to the swap rate on my trading platform?
Your broker's overnight swap or rollover rate is conceptually related to forward pricing, both derive from the same interest rate differential concept, though your specific broker's swap rate includes their own markup, distinct from a pure institutional forward rate.
What time periods are forward contracts typically quoted for?
Common standard periods include 30, 60, 90, and 180 days, though genuinely customised periods are also available in institutional markets, this calculator lets you enter any number of days for your specific scenario.
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