Foreign Transaction FX Calculator
Compare which card is cheapest for a foreign purchase after FX spread, foreign transaction fee, and rewards. Enter your own estimated rate — everything is computed client-side.
⚠ Rates are your own estimates. Real issuer/network exchange rates and foreign transaction fees vary daily and by transaction — confirm with your card before relying on these numbers.
The purchase
Mid-market cost ≈ $100.00 before any card fees or rewards.
Cards to compare
Posted cost
$100.00
Fee
$0.00
Reward
$3.00
Net cost
$97.00
Net return
+3.00%
JPY purchase
Posted cost
$103.00
Fee
$3.00
Reward
$2.06
Net cost
$100.94
Net return
-0.94%
JPY purchase
— Add a fee, spread, or reward rate to include this card.
JPY purchase
How the math works
1. Mid-market cost = amount ÷ rate (or your entered USD amount).
2. Converted cost = mid-market × (1 + issuer/network spread).
3. Fee = converted × foreign transaction fee %.
4. Posted to statement = converted + fee.
5. Reward value = posted × reward rate (cashback %, or points/$ × ¢-per-point).
6. Net cost = posted − reward value. The lowest net cost wins.
Net return % = (reward − fee − spread) ÷ mid-market, i.e. how much better or worse than paying mid-market in USD with no fee.
FX rates are user-supplied estimates. Actual issuer/network exchange rates and fees vary daily — verify with your card before relying on these numbers. · Updated June 2026