RubyMoney/money · error · Money::Bank::UnknownRate

No conversion rate known for '#{from.currency.iso_code}' ->

Error message

No conversion rate known for '#{from.currency.iso_code}' -> '#{to_currency}'

What it means

Error "No conversion rate known for '#{from.currency.iso_code}' -> '#{to_currency}'" thrown in RubyMoney/money.

Source

Thrown at lib/money/bank/variable_exchange.rb:122

      #
      #   # Exchange 100 USD to CAD:
      #   bank.exchange_with(c1, "CAD") #=> #<Money fractional:12451 currency:CAD>
      #
      #   # Exchange 100 CAD to USD:
      #   bank.exchange_with(c2, "USD") #=> #<Money fractional:8031 currency:USD>
      def exchange_with(from, to_currency, &)
        to_currency = Currency.wrap(to_currency)
        if from.currency == to_currency
          from
        elsif (rate = get_rate(from.currency, to_currency))
          fractional = calculate_fractional(from, to_currency)
          from.dup_with(
            fractional: exchange(fractional, rate, &),
            currency: to_currency,
            bank: self,
          )
        else
          raise UnknownRate, "No conversion rate known for '#{from.currency.iso_code}' -> '#{to_currency}'"
        end
      end

      def calculate_fractional(from, to_currency)
        BigDecimal(from.fractional.to_s) / (
          BigDecimal(from.currency.subunit_to_unit.to_s) /
          BigDecimal(to_currency.subunit_to_unit.to_s)
        )
      end

      def exchange(fractional, rate, &)
        ex = fractional * BigDecimal(rate.to_s)
        if block_given?
          yield ex
        elsif @rounding_method
          @rounding_method.call(ex)
        else
          ex

View on GitHub (pinned to 26e2829c34)

When it happens

Trigger: Thrown at lib/money/bank/variable_exchange.rb:122 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of RubyMoney/money@26e2829c34 (2026-08-23). Data as JSON: /api/errors/390f439ec4ee395f. Report an issue: GitHub.