How Currency Conversion Works on Card Payments

One of the most common questions we hear from NRIs and Indian travellers is some version of this: "The exchange rate on my phone showed one number. My bank charged a different number. Where did the difference go?"

The short answer is: several places at once. Currency conversion on card payments is not a single calculation.

It is a chain of steps, each involving a different party, each adding a small cost. By the time the transaction settles, four or five layers have touched your money.

Understanding how this chain works helps you make better decisions about which card to use, when to convert, and when to avoid card payments entirely.

Step One: You Swipe the Card

When you use a debit or credit card in a foreign currency, the merchant's point-of-sale terminal captures the transaction amount in the local currency of the country you are in.

At this point, no conversion has happened. The terminal simply records the amount in, say, AED or USD or GBP.

The transaction request is then sent to the card network - Visa, Mastercard, or RuPay - for authorisation.

Step Two: The Card Network Converts the Amount

This is where the first conversion happens.

Visa and Mastercard each maintain their own exchange rates, updated daily. These rates are based on wholesale interbank rates but include a small spread - typically around 1% - which is the card network's own margin.

The card network converts the foreign currency amount to the currency of your card's home country.

For an Indian cardholder, that means converting from AED or USD or GBP to INR at the network's rate.

Most cardholders assume the rate they see on Google is what their card uses. It is not. Google shows the mid-market rate, which is the midpoint between buy and sell rates in the wholesale market.

The card network's rate is close to this but not identical. For how this spread affects NRE account holders specifically, see NRE account exchange rates.

Step Three: Your Bank Applies Its Own Markup

After the card network converts the amount, your bank receives the INR equivalent and applies its own forex markup before debiting your account.

This markup is the bank's margin on the transaction and typically ranges from 1.5% to 3.5% depending on the card type and bank.

This markup is separate from the card network's spread. Both apply on the same transaction.

So by the time the final debit hits your account, you have paid the card network's spread plus the bank's markup - on top of a rate that was already not the best available rate.

For a full breakdown of what different Indian bank accounts charge in cross-border fees, the NRE account fees and charges and NRI account charges pages are worth reviewing side by side.

Step Four: GST Is Applied on the Forex Service

For transactions processed through Indian cards, GST at 18% applies on the forex conversion service.

This is not charged on the full transaction amount. It is charged on the forex markup component specifically.

So if your bank charges a 2% markup on a Rs 1 lakh transaction, the GST is 18% of Rs 2,000, which adds Rs 360 to your cost.

It appears as part of the total debit, not as a separate line item. Most people never notice it.

This is one reason the actual cost of an international card transaction is consistently higher than the stated forex markup percentage suggests.

👉 When comparing cards, the forex markup percentage alone does not tell the full story. Add the card network spread, GST on markup, and any flat transaction fee to get the real cost per transaction.

Step Five: The Settlement Happens Later

Card authorisation and card settlement are two different events. When you swipe your card, the amount is authorised and a hold is placed on your account.

The actual settlement - when the money moves between banks - happens one to three business days later.

During this window, exchange rates move. Most banks apply the rate at the time of settlement, not the time of purchase.

For most transactions, the difference is small. For large transactions made at times of high currency volatility, this timing gap can work in your favour or against you.

This is a detail most cardholders are completely unaware of. It also explains why the amount shown when you swipe occasionally differs slightly from the amount finally debited.

The NRI banking hidden fees resource covers this and other timing-related charges in detail.

What Dynamic Currency Conversion Does to This Chain

Dynamic Currency Conversion (DCC) is an option offered by some merchant terminals abroad. It presents the transaction amount in your home currency at the point of sale, so you see the INR amount before you approve.

What actually happens when you accept DCC is that the merchant's payment processor applies its own conversion rate - which is almost always worse than the card network rate - and locks in the INR amount.

Your bank then still processes this as a cross-border transaction and may apply additional charges on top.

Accepting DCC means you pay the merchant processor's margin and then your bank's charges too.

Always decline DCC. Always pay in the local currency of the country you are in. Let your card network handle the conversion rather than the merchant's processor.

How This Affects NRIs Differently

If you are an NRI in the UAE using an Indian card for local purchases, the conversion chain above applies to every transaction.

You are converting AED to INR at each step, even though your income is already in AED.

Many NRIs carry Indian cards for familiarity or for making payments back home. But using an Indian card for UAE purchases means paying the full conversion cost stack on everyday spending.

Over a month of regular use, this adds up to a meaningful amount. See common financial mistakes NRIs make in Dubai for how this pattern plays out in practice.

For remittances, the card payment conversion chain is one of the most expensive routes available.

Direct bank transfers and dedicated remittance platforms bypass most of this chain and offer rates much closer to the interbank rate. See how to transfer money from Dubai to India, cheap ways to send money to India, and best money transfer apps in UAE for specific comparisons.

👉 If you are an NRI sending Rs 2 lakh a month to India, switching from a card-based transfer to a direct remittance channel can save Rs 4,000 to Rs 8,000 per month depending on your current card's cost stack. See NRI money transfer mistakes to understand the most common errors.

What Resident Indians Should Know

If your financial life is in India and you travel internationally or make purchases on foreign websites, the same conversion chain applies.

Every foreign-currency transaction on an Indian card goes through the card network conversion, bank markup, and GST stack.

For resident Indians beginning to invest globally under the Liberalised Remittance Scheme (LRS), understanding currency conversion costs matters at the investment level too.

Each time money moves from INR to a foreign currency for investment purposes, conversion costs reduce the effective amount invested. Platforms and structures that minimise this friction improve long-term outcomes.

Cards That Short-Circuit Part of the Chain

Zero-forex markup cards remove the bank's own spread from the chain. The card network conversion still applies, and GST may still apply depending on how the card is structured.

But the total cost drops significantly.

For NRIs, best debit cards for NRIs and best credit cards in UAE cover current options with lower cross-border costs.

Cross-referencing with NRI account charges helps you see the full picture before switching.

The GIFT City Structure Avoids This Chain Entirely

For NRIs investing in India through GIFT City, the conversion chain described above does not apply. Investments go in as USD and returns come back as USD.

There is no retail card conversion at any stage. The FEMA framework governing GIFT City transactions, detailed in the FEMA guidelines resource, ensures this structure is fully compliant and repatriable.

For resident Indians, GIFT City mutual funds allow USD-denominated global investing without triggering repeated LRS conversion overhead on every transaction.

The GIFT City mutual funds tool lets you compare available funds. The GIFT City AIF explorer and GIFT Nifty tracker provide market context.

For fixed deposit comparisons, the NRI FD rates tool shows current GIFT City bank rates.

Funds worth evaluating include the DSP Global Equity Fund, Tata India Dynamic Equity Fund, Edelweiss Greater China Equity Fund, and Sundaram India Mid Cap Fund.

For NRIs interested in IPO access through GIFT City, the GIFT City IPO guide and IPO products page are useful starting points.

At Belong, we help both NRIs and resident Indians structure their investments so that currency conversion is a deliberate, cost-efficient decision - not a silent tax on every transaction.

FAQs

Does the exchange rate lock in at the time of purchase or settlement?

Most banks apply the rate at settlement, which happens one to three business days after the purchase. The rate at the time you swipe and the rate at settlement may differ slightly.

Why does my card show one exchange rate but my statement shows another?

The rate shown at the point of sale is often an estimate. The final rate applied at settlement, plus the bank's markup and fees, produces the number on your statement.

Is the card network conversion rate the same for Visa and Mastercard?

Both use rates based on wholesale interbank rates but calculated independently. Rates are generally similar but not identical on any given day.

Do these conversion steps apply to contactless and online card payments too?

Yes. The conversion chain is the same regardless of how the card is used, whether tap, chip, swipe, or online. The foreign currency amount triggers the same process.

Can I check what rate my bank will apply before making a transaction?

Most banks publish their card exchange rates on their website, updated daily. This rate includes the bank's markup. The card network's spread is applied before this and is not separately disclosed by most banks.

Disclaimer: This article is for informational purposes only and does not constitute financial or tax advice. Fee structures and exchange rate practices mentioned are indicative and subject to change by individual banks and card networks. Verify applicable charges with your card issuer.