Calculate cross exchange rates by entering any two of A:B, A:C, and B:C to find the missing pair and see calculation steps clearly.

Cross Exchange Rate Calculator

Enter any 2 values to calculate the missing variable

Cross Exchange Rate Formula

A cross exchange rate uses two exchange rates that share a common currency to calculate the exchange rate between the other two currencies. In this calculator, currencies are labeled A, B, and C.

A:B = (A:C) / (B:C)
A:C = A:B × B:C
B:C = (A:C) / (A:B)
  • A:B = the exchange rate between currency A and currency B
  • A:C = the exchange rate between currency A and currency C
  • B:C = the exchange rate between currency B and currency C

The calculator works by taking any two known exchange rates and solving for the missing one:

  • If A:C and B:C are known, it calculates A:B by dividing A:C by B:C.
  • If A:B and B:C are known, it calculates A:C by multiplying A:B by B:C.
  • If A:C and A:B are known, it calculates B:C by dividing A:C by A:B.

Common Cross Rate Setups

The same formulas apply to any currencies as long as the rates are quoted in the same direction.

Known rates Missing rate Formula to use
A:C and B:C A:B A:B = A:C ÷ B:C
A:B and B:C A:C A:C = A:B × B:C
A:C and A:B B:C B:C = A:C ÷ A:B

Interpreting the Rate Direction

Rate format Meaning Example
A:B = 1.2500 1 unit of A equals 1.2500 units of B 1 A = 1.2500 B
A:C = 0.9000 1 unit of A equals 0.9000 units of C 1 A = 0.9000 C
B:C = 0.7200 1 unit of B equals 0.7200 units of C 1 B = 0.7200 C

Example

Example 1: Calculate A:B

Suppose A:C = 1.0800 and B:C = 0.9000.

A:B = (1.0800) / (0.9000) = 1.2000

So, A:B = 1.2000.

Example 2: Calculate B:C

Suppose A:C = 1.3500 and A:B = 1.5000.

B:C = (1.3500) / (1.5000) = 0.9000

So, B:C = 0.9000.

FAQ

What is a cross exchange rate?

A cross exchange rate is the exchange rate between two currencies calculated through a third currency. For example, if you know A:C and B:C, you can calculate A:B because both rates share currency C.

Why does the direction of the exchange rate matter?

The direction matters because A:B is not the same as B:A. If A:B = 1.2500, then 1 A equals 1.2500 B. The reverse rate is B:A = 1 ÷ 1.2500 = 0.8000. Enter each rate in the same direction shown by the calculator labels.

Can a cross exchange rate include fees or spreads?

The formula gives the mathematical cross rate from the exchange rates you enter. If a bank, broker, or exchange service applies a spread or fee, the actual rate offered may be different from the calculated cross rate.