Forex Swap/Rollover Cost Calculator

What Is a Swap (Rollover)?

In forex, positions held past the end of the trading day (5 PM New York time) are “rolled over” to the next day. This involves a charge or credit called a swap — reflecting the interest rate differential between the two currencies in the pair.

If you are long a currency with a higher interest rate than the currency you borrowed, you receive a positive swap (you earn interest). If you are long the lower-rate currency, you pay a negative swap.

The Formula

Swap cost per night: Swap Per Night = Swap Rate (pips) × Pip Value ($) × Number of Lots

Total swap for holding period: Total Swap = Swap Per Night × Effective Nights

Effective Nights accounts for the triple-swap Wednesday:

• Regular night: 1 night counted
• Wednesday night: 3 nights counted (covers Saturday + Sunday, when markets are closed)

So if you hold for 10 nights and one of them is a Wednesday: Effective Nights = 9 regular nights + 1 Wednesday (×3) = 9 + 3 = 12 effective nights

The Carry Trade Strategy

A carry trade involves borrowing a low-interest-rate currency and investing in a high-interest-rate currency — earning the interest differential (positive swap) overnight.

Classic carry trade pairs:

• AUD/JPY — Australian dollar (historically higher rates) vs Japanese yen (near-zero rates)
• NZD/JPY — New Zealand dollar vs Japanese yen
• USD/TRY — US dollar vs Turkish lira (very high rates, but high risk)

Carry trades can be highly profitable in stable markets — but dangerous when risk sentiment shifts suddenly. A sharp JPY rally can wipe out months of carry income overnight.

Positive vs Negative Swap

Your broker publishes a swap table showing rates for each pair, for both long and short positions. Rates are typically expressed in pips or in the account currency per lot per night.

• Positive swap: You earn money for holding the position overnight.
• Negative swap: You pay money for each night the position stays open.

For longer-term trades, swap costs can significantly erode profitability — or add to it.

Triple Swap Wednesday Explained

Forex markets are closed on weekends (Saturday and Sunday), but swap charges still accrue for those two days. Because the settlement cycle for spot forex is T+2 (trade date + 2 days), positions opened on Wednesday settle on Friday — and rolling them over means they now need to settle the following Monday, covering the weekend.

As a result, Wednesday’s swap is charged at 3× the normal rate to cover Friday, Saturday, and Sunday.

Important: The triple swap applies regardless of whether you think you are “holding over the weekend.” If your position is open at 5 PM New York on any Wednesday, you pay the triple rate.

Broker Swap Tables

Swap rates change constantly — they are linked to central bank interest rates. When the Fed raises rates, USD-denominated swap rates shift. Always check your broker’s current swap table before calculating long-term holding costs.

Worked Example

• Position: 1 standard lot EUR/USD (long)
• Swap rate: −0.35 pips per night (negative = you pay)
• Pip value: $10.00
• Days held: 10 nights
• Wednesday included: Yes (1 Wednesday in the period)

Swap per night = 0.35 × $10 = $3.50/night Regular nights = 9 (at $3.50 each) = $31.50 Wednesday (triple): $3.50 × 3 = $10.50 Total swap cost = $31.50 + $10.50 = $42.00

Without knowing about the Wednesday triple swap, you might have expected only 10 × $3.50 = $35.00 — but the actual cost is $42.00.

Pro Tips

• Always check the swap table before holding a position overnight.
• For day traders: close before 5 PM New York to avoid all swap charges.
• For swing traders: factor swap into your expected P&L — especially for trades lasting 1–4 weeks.
• A positive swap can boost your return on long-held trending positions — align your direction with carry where possible.