Collect the receipt and the settled charge
Note the original amount and currency on the receipt, the billing amount and currency on the statement, and the transaction and posting dates. Use a settled charge for reconciliation rather than treating a pending amount as final.
Also record any separately stated foreign currency fee. If the receipt already shows your home currency, check whether the merchant converted the amount. Your card network’s conversion may not apply in that situation.
Calculate the implied rate
Imagine a fictional receipt for 80 EUR and a settled purchase amount of 88 USD, with no fee included in that 88 USD amount. Calculate 88 ÷ 80 = 1.10 USD per EUR.
That tells you how many billing currency units correspond to each transaction currency unit for this record. It does not prove which underlying rate source was used or establish that the same quote is available today.
If a 2 USD fee is separately charged, the total outlay becomes 90 USD. Dividing 90 by 80 gives 1.125 USD per EUR as an effective cost including that known fee. Keep the purchase only rate and total cost calculation clearly labeled.
Check timing and who performed the conversion
Mastercard explains that its applicable rate generally relates to authorization timing, with processing time used in some circumstances. It also states that the bank may apply different rates or additional fees. If the merchant or ATM performs the conversion, Mastercard’s rates do not apply. See the official Mastercard converter and notes.
Other cards and issuers can have different conditions. Use your issuer’s transaction details and terms to establish what applies to your purchase. A converter using today’s reference data cannot reconstruct an earlier transaction by itself.
Use a reference as context
Open the Lineium converter to understand the scale of an amount and check the displayed data timestamp. Do not expect a current reference result to match an older settled charge exactly.
If you have a relevant historical reference from another source, compare the same currency direction and explain whether fees are included. Our percentage difference guide helps with the arithmetic, but a difference alone does not establish an error.
Ask the issuer a specific question
If something still looks unexpected, ask which original currency, rate, conversion date, and charges were applied. Keep the receipt and statement available through the issuer’s own support process.
When contacting Lineium about the calculator, a fictional example and the currency codes are enough. Do not send us card numbers, bank credentials, or a full statement. Lineium provides reference calculations and cannot investigate or change a card charge.
For payments at a terminal, also read local currency or home currency.
Written by Lineium, publisher of Worldwide Currency Converter. Examples are fictional. Provider references were checked on October 15, 2026.