Free Currency Exchange Calculator: calculate currency exchange instantly with transparent formula, worked examples and tips. No signup.
Converted amount = Source amount × Exchange rate (source → target)
Effective rate after spread = Mid-market rate × (1 − spread%/100)
True cost of conversion = (Mid-market rate − Effective rate) × Amount
Worked example: Converting 10,000 to a foreign currency at mid-market rate of 1.27. Result at mid-market: 12,700. Bank applies 2.5% spread: effective rate = 1.27 × 0.975 = 1.238. You receive 12,380. Hidden cost = 320. Using a specialist app at 0.4% fee: 12,649 received, total fee approximately 40 — a saving of approximately 280 on this transaction.