About the Forex Swap & Rollover Calculator
When you hold a spot forex position past the daily rollover time (usually 5 p.m. New York), the position is rolled to the next value date and you either pay or receive interest. You effectively borrow one currency and lend the other, so the swap depends on the interest rate differential between them, the size of the position and the broker’s markup. This forex swap and rollover calculator estimates that overnight charge or credit and the total for as many nights as you plan to hold.
It is useful for carry traders looking for positive swap, swing traders who hold for days or weeks, and anyone puzzled by a swap line on their statement. Enter the two currencies’ interest rates, choose long or short, add the broker’s markup and the number of nights, and convert the result into your account currency.
The result is an estimate: brokers set swap rates from interbank tom-next forward points plus their own markup, and publish them in points or currency per lot. Remember that most brokers charge three nights’ swap on Wednesday (to cover the weekend) — include those extra nights in the night count.
With the default inputs, the swap per night (account currency) is −$6.78. Change any value above to recalculate instantly.
How to use the forex swap & rollover calculator
- 1Choose long or short and enter the position size in base currency units.
- 2Enter the current exchange rate and the policy or overnight interest rate for each currency.
- 3Add your broker’s markup and pick the day-count basis.
- 4Enter the number of nights, counting Wednesday as three.
- 5If your account currency differs from the quote currency, enter the conversion rate.
Formula and method
A long position borrows the quote currency to hold the base currency, so it earns the base rate and pays the quote rate; a short position does the opposite. The net annual rate is that differential minus the broker’s markup. Multiplying by the notional value in the quote currency (units × exchange rate) and dividing by the day-count basis (360 for most currencies, 365 for sterling, yen and several Commonwealth currencies) gives the swap per night in the quote currency.
That figure is converted into your account currency with the conversion rate you enter, then multiplied by the number of nights held. Real swap rates come from tom-next forward points, which track the interest differential closely but not exactly, so treat this as an estimate and compare it with your broker’s published swap table.
- Units
- Position size in base currency units
- Price
- Exchange rate, quote currency per 1 base unit
- r_long
- Interest rate of the currency you are long (base if buying)
- r_short
- Interest rate of the currency you are short
- Basis
- Day-count basis, 360 or 365
- FX
- Quote-to-account currency conversion rate
Worked examples
Long 1 lot EUR/USD overnight
Long 100,000 EUR at 1.0850 is a $108,500 notional. Earning 2% on euros and paying 4% on dollars, minus a 0.25% markup, nets −2.25% a year: 108,500 × −2.25% ÷ 360 ≈ −$6.78 per night.
Short 1 lot EUR/USD for a week (with triple Wednesday)
Short EUR/USD earns the 4% dollar rate and pays the 2% euro rate; after the 0.25% markup that is +1.75%. 108,500 × 1.75% ÷ 360 ≈ $5.27 a night, and five trading days with a triple Wednesday make 7 nights, about $36.92.
AUD/JPY carry trade, USD account
Long 50,000 AUD at ¥98.50 is a ¥4,925,000 notional. A 3.1% differential minus 0.5% markup leaves 2.6%, or ¥350.82 a night on a 365-day basis. At about ¥150 per dollar (0.0066667) that is roughly $2.34 credited each night.
Frequently asked questions
What is a forex swap or rollover fee?+
It is the interest adjustment applied when a spot forex position is held past the daily cut-off (normally 5 p.m. New York time). You receive interest on the currency you hold and pay interest on the one you borrowed, adjusted by the broker’s markup.
Why is swap charged three times on Wednesday?+
Spot trades settle two business days later. A position rolled on Wednesday moves its value date from Friday to Monday, so it covers Saturday and Sunday too. Most brokers therefore apply three days of swap on Wednesday night.
Can I earn positive swap?+
Yes. Buying a higher-yielding currency against a lower-yielding one (a carry trade) can earn a daily credit, as long as the interest differential exceeds the broker’s markup. Exchange-rate moves can easily outweigh the swap, though.
Do I pay swap on intraday trades?+
No. Positions opened and closed before the daily rollover time incur no swap. Islamic (swap-free) accounts also avoid it, but brokers often charge a fixed administration fee instead.
Why does my broker’s swap differ from this estimate?+
Brokers base swap on interbank tom-next forward points and their own markup, which can be wider for short positions or exotic pairs. Many quote swap in points per lot; check the broker’s contract specifications for the exact current figure.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.