Forex Swap Rate Calculator
Calculate the daily interest credited or debited for holding a position overnight.
Daily Swap Amount:
0.00
Total for Period:
0.00
Position Type:
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How to Calculate Swap Rates in Forex
A swap rate, also known as a rollover rate, is the interest rate differential between the two currencies of a pair that a trader is holding overnight. Depending on whether you are long or short, you will either earn or pay interest.
The Mathematical Formula
The standard formula to calculate the daily swap value is:
Swap = (Notional Value × (Base Rate – Quote Rate – Broker Fee)) / (365 × 100)
- Notional Value: This is your trade size (Lots) multiplied by the contract size (typically 100,000 units).
- Base Rate: The interest rate of the first currency in the pair.
- Quote Rate: The interest rate of the second currency in the pair.
- Broker Fee: The markup the broker takes for managing the overnight position.
Example Calculation
If you are trading 1 lot (100,000 units) of a pair where the Base currency has a 5% interest rate and the Quote currency has a 1% interest rate, and your broker charges a 0.5% markup:
- Net Interest = 5% – 1% – 0.5% = 3.5% annually.
- Annual Value = 100,000 × 0.035 = 3,500 units.
- Daily Swap = 3,500 / 365 = 9.58 units per day.
Important: The 3-Day Swap Rule
Most brokers charge a triple swap on Wednesdays (or Fridays for some instruments). This is to account for the weekend when the markets are closed, but interest still accrues on the underlying capital. Always check your broker's rollover schedule to avoid unexpected costs.