Auto currency conversion

Auto currency conversion is a currency conversion feature that enables automatic funding of card payments from your designated primary currency. This feature simplifies multi-currency card spending by eliminating the need to manually convert currencies before each transaction.

How auto currency conversion works

Auto currency conversion enables you to designate a primary currency in your Airwallex Wallet that serves as a fallback funding source for card transactions.

The funding logic depends on whether the transaction uses a direct or indirect billing currency:

• For direct billing currency transactions: Airwallex first attempts to utilize funds from the wallet denominated in the transaction currency. If there are insufficient funds in that wallet, Airwallex then attempts to utilize funds from the wallet denominated in the primary currency, performing the necessary currency conversion in real-time.

• For indirect billing currency transactions: Airwallex always attempts to utilize funds from the wallet denominated in the primary currency, regardless of whether funds exist in other currency wallets.

This automated approach offers two key advantages:

• Reduced transaction declines: Card transactions can proceed even when the specific transaction currency balance is insufficient, preventing payment failures.
• Flexible fund management: You can maintain a primary currency as a safety net without needing to pre-fund every currency wallet before each transaction.

Currency terminology

Understanding the different currency types in the auto currency conversion flow helps clarify how transactions are processed:

• Transaction currency: The currency in which the merchant charges the card (for example, THB for a purchase from a merchant in Thailand).
• Primary currency: The currency you designate in your Airwallex account settings to serve as the primary funding source for auto currency conversion.
• Billing currency: The currency from which funds are debited in your wallet. For direct billing currency transactions, this is the transaction currency when sufficient funds exist, or the primary currency when auto currency conversion applies. For indirect billing currency transactions, this is always the primary currency.

Billing currency

The funding logic for auto currency conversion depends on whether the transaction currency is classified as a direct or indirect billing currency.

Direct billing currencies

Direct billing currencies are specific currencies that allow Airwallex to directly debit your wallet in the transaction currency. For the complete list of direct billing currencies by region, see Supported regions and currencies.

For direct billing currencies, Airwallex first attempts to utilize funds from the wallet denominated in the transaction currency.

If there are insufficient funds in the transaction currency wallet and auto currency conversion is enabled, Airwallex converts the transaction amount to your primary currency using Airwallex FX rates and an applied auto currency conversion markup.

If auto currency conversion is not enabled, the transaction is declined with failure reason INSUFFICIENT_FUNDS.

Indirect billing currencies

All Visa-supported currencies not listed as direct billing currencies are considered indirect billing currencies.

For indirect billing currencies, Airwallex always utilizes funds from the wallet denominated in your primary currency. Airwallex converts the transaction amount to your primary currency using Airwallex FX rates and an applied auto currency conversion markup.

Auto currency conversion is always applied for indirect billing currencies, regardless of whether the setting is enabled.

Transaction processing logic

Auto currency conversion operates at both the authorization and clearing stages of a transaction, with potential variations in the conversion amounts due to exchange rate fluctuations.

Authorization stage

When a card transaction is authorized, Airwallex immediately places a hold on funds in the billing currency wallet.

The held amount appears in your reserve balance until clearing occurs.

Clearing stage

Clearing usually happens 1 day (up to 31 days for certain merchant categories) after authorization. At clearing, Airwallex receives the final amount for the transaction and debits the funds from the billing currency wallet.

If auto currency conversion was applied:

1. Airwallex recalculates the billing amount using the FX rate at the time of clearing.
2. Airwallex releases the authorization hold.
3. Airwallex then debits the final billing amount from the billing currency wallet.

As FX rates fluctuate between authorization and clearing, the final debited amount may differ slightly from the initially held amount. This variation reflects market movements in the relevant currency pair.

Currency conversion calculations

Auto currency conversion uses Airwallex's FX rates with an applied markup to calculate the amount deducted from your primary currency wallet.

Direct billing currencies

For direct billing currencies, the calculation converts the transaction amount directly to your primary currency:

Converted amount in primary currency = Transaction amount in transaction currency × FX rate from Airwallex FX engine × (1 + Auto currency conversion markup)

Indirect billing currencies

For indirect billing currencies, the calculation converts the Visa billing amount in USD to your primary currency:

Visa billing amount in USD = Transaction amount in transaction currency × Visa FX rate

Converted amount in primary currency = Visa billing amount in USD × FX rate from Airwallex FX engine × (1 + Auto currency conversion markup)

View conversion details in transactions

When you retrieve transaction details using the Get transactions API endpoint, the response includes the billing_amount and billing_currency fields. These fields represent the actual amount and currency that was deducted from your wallet.

For example, if a transaction was processed in THB but auto currency conversion was applied:

• The transaction_amount shows the original amount in THB
• The billing_amount and billing_currency show the converted amount that was actually debited from your primary currency wallet

This allows you to track exactly how much was deducted from your wallet for each transaction, regardless of whether auto currency conversion was applied.

See also

To understand how auto currency conversion fits into the broader context of Issuing transactions, refer to:

• Concepts:
  • Transaction lifecycle
  • How Airwallex Issuing works
• How-to guides:
  • Fund your Issuing balance
  • Retrieve card transactions