How rollover is calculated for AUD/USD

Direct answer

Rollover (also called the swap or interest adjustment) for AUD/USD is an accounting amount added to or subtracted from an open position to reflect the interest-rate differential between AUD and USD, based on the position’s direction and the rollover timing rules used by the trading account and platform.

Mechanism and definition

What rollover is In spot FX markets, a position is carried forward rather than settled immediately. The “carry” between currencies is typically approximated using interest-rate inputs for AUD versus USD, then converted into a per-day (or per-rollover) amount that depends on your position size.
Direction matters If you are long AUD/USD, you generally receive the carry associated with being long AUD and paying the carry associated with being short USD. If you are short AUD/USD, the sign can reverse. The exact sign convention is account-specific, but the underlying idea is that rollover reflects which currency is treated as “owned” versus “borrowed” in the position.
Common calculation components (conceptual model) A self-check model you can use conceptually is:

Step A: Determine the interest-rate differential between the two currencies (AUD minus USD), typically using daily rates derived from the relevant benchmark rates.
Step B: Convert that differential into a value for your position size. This involves the trade’s notional amount and the conversion mechanics used for the account currency.
Step C: Apply the provider’s swap convention. Many providers quote or compute rollover using a formula that may add or subtract a markup/spread over the underlying theoretical rates.

Timing and the “triple-swap” convention Rollover is not applied continuously; it follows scheduled settlement days. A common market convention is that, on a rollover date that would otherwise skip multiple calendar days (often due to weekend settlement), the swap is charged or credited for multiple days at once. This is often described as a “triple-swap,” meaning an extra day’s amount is included compared with a normal rollover.

Example (using assumptions, not live values)

Assume a provider uses a “daily” rollover amount computed from an AUD/USD interest differential and then multiplied by a factor based on rollover day.

Suppose your long AUD/USD position has a theoretical daily rollover of +X per 1 lot.
On a normal rollover day, you receive +X.
On a special rollover day with a triple-swap, you receive +3X (or an equivalent amount using the provider’s own convention).

Your platform may show the result as “swap” or “rollover” in account currency. Even if the sign matches the conceptual direction, the magnitude can differ across providers because the input rates and markup conventions differ.

Evidence or example to verify on your platform

You can independently verify that rollover for AUD/USD follows the interest-rate differential idea by doing simple comparisons over time without assuming the amounts will be stable:

Compare long vs short Pick the same position size for a short and a long AUD/USD position, and observe whether the rollover sign (credit vs charge) flips. If it flips consistently, that supports the direction-dependence mechanism.
Look for day-type behavior If your platform shows larger rollover on a specific day, that is consistent with a multi-day rollover convention (often called triple-swap). Confirm by comparing two consecutive rollover events: one “normal” day and one “special” day.
Track changes in the displayed swap If your observed rollover changes while your position size stays the same, that indicates the inputs (interest-rate inputs, provider adjustments, or currency conversion assumptions) are being updated.

Limitations and risks (material failure modes)

Provider markup and convention differences: The theoretical interest differential is rarely the full story. Provider-specific adjustments can shift the amount materially. - Changing rates and costs: The interest-rate inputs and any markups can change. Historical rollover patterns do not guarantee future rollover amounts. - Execution timing mismatch: Rollover depends on when the position is held through the provider’s rollover cut-off times. If you open/close around cut-off windows, the applied rollover can differ from what you expected. - Platform reporting differences: Some platforms display rollover per day, others per event; some net out components or show results in account currency, which can obscure direct comparison.