How is the forex markup calculated?

The converted rupee amount is the foreign amount times the INR rate you enter. Markup is that amount times your markup percent. GST is calculated on the markup only, at the GST percent you enter. The reward line is the converted amount times your reward percent, and it is subtracted only as an assumption that those rewards are eligible and realizable.

Does this use a card's published forex rate?

No. You type the markup. Card pages on Money Matters show a published rate when one is verified. This calculator does not read those rates.

Is GST included in the markup percent?

Not unless you set GST to 0 because the percentage you entered already includes it. The default is 18% of the markup fee, the residual rate in the GST Council schedule for services not listed elsewhere. The markup percent and the GST percent stay separate.

What if the terminal charges me in rupees?

That is dynamic currency conversion. The merchant's rate replaces this calculation, and this tool does not estimate that rate. Paying in the local currency leaves the conversion to the card network.

Why might my statement differ?

The card network's exchange rate can differ from the rate you assumed. A statement can also include a cash-withdrawal fee, or interest if you revolve the balance. Those are outside this illustration.

Tool · Forex

Credit card forex cost calculator

Estimate what a foreign-currency card spend costs in rupees from assumptions you type. The markup, the GST on that markup, and a reward value stay on separate lines.

JavaScript is off, so the figures stay on the worked example: 1,000 units at ₹85, scenario A at 2% markup and 1% reward value, scenario B at zero, GST at 18% of the markup.

The spend

Foreign amount Assumed INR per 1 unit Your assumption. This is not a live rate and not the card-network rate. GST on the markup (%) Applied only to the markup fee. Set 0 to see the markup before tax.

Who converts the amount? The card converts a foreign-currency amount The merchant already charged INR

Converted amount ₹85,000

Scenario A

Forex markup (%) Eligible reward value (%)

Markup ₹1,700

Markup less rewards, before GST ₹850

GST on markup: ₹306
Assumed reward value: ₹850
Markup including GST, less rewards: ₹1,156

Scenario B

Forex markup (%) Eligible reward value (%)

Markup ₹0

Markup less rewards, before GST ₹0

GST on markup: ₹0
Assumed reward value: ₹0
Markup including GST, less rewards: ₹0

On these assumptions, scenario A costs ₹1,156 more than scenario B after markup, GST and the reward values entered.

Rewards are assumed eligible and realizable at the percent you enter. The two scenarios are your assumptions, not a ranking of cards.

Worked example

1,000 units of foreign currency at an assumed ₹85 each is ₹85,000. A 2% markup is ₹1,700. GST at 18% of that markup is ₹306. A reward worth 1% of the converted amount is ₹850, if it is eligible and you can realize it at that value. Markup less rewards, before GST, is ₹850. Markup including GST, less that reward, is ₹1,156. Scenario B at 0% markup and 0% reward value adds nothing on these lines.

What the arithmetic leaves out

Exchange-rate spread. You supply the INR rate. A card network publishes its own rate, and the gap between that rate and a mid-market quote is not estimated here.
Dynamic currency conversion. If you accept rupees at the terminal, the merchant sets the conversion. This formula does not price that offer.
Other charges. Cash-withdrawal fees, interest on a revolved balance, and a reward that is capped, excluded, or hard to redeem are outside the percent you type.

Common questions

How is the forex markup calculated?: The converted rupee amount is the foreign amount times the INR rate you enter. Markup is that amount times your markup percent. GST is calculated on the markup only, at the GST percent you enter. The reward line is the converted amount times your reward percent, and it is subtracted only as an assumption that those rewards are eligible and realizable.
Does this use a card's published forex rate?: No. You type the markup. Card pages on Money Matters show a published rate when one is verified. This calculator does not read those rates.
Is GST included in the markup percent?: Not unless you set GST to 0 because the percentage you entered already includes it. The default is 18% of the markup fee, the residual rate in the GST Council schedule for services not listed elsewhere. The markup percent and the GST percent stay separate.
What if the terminal charges me in rupees?: That is dynamic currency conversion. The merchant's rate replaces this calculation, and this tool does not estimate that rate. Paying in the local currency leaves the conversion to the card network.
Why might my statement differ?: The card network's exchange rate can differ from the rate you assumed. A statement can also include a cash-withdrawal fee, or interest if you revolve the balance. Those are outside this illustration.

Sources

GST Council: schedule of GST rates for services , opens external site — row 36, services not specified elsewhere at 18%; checked 15 October 2026

The GST default is the Council schedule's residual 18% on services not listed elsewhere. Notification No. 12/2017-Central Tax (Rate), dated 28 June 2017, exempts some financial services, including interest on deposits and loans other than interest involved in credit card services, and some acquiring-bank settlement fees. It is not a forex-markup table. Your statement is the record of the tax charged.