Working with Currency in Rails: Mastering Rails

Three Best Practices with Code Examples

When developing financial applications in Rails, handling currency correctly is paramount to ensure accuracy and user trust. Here, we explore three essential best practices: using BigDecimal for precision, storing currency in the smallest unit, and utilizing money gems, complete with Ruby code examples.

Use BigDecimal for Precision

Precision in financial calculations cannot be compromised. Ruby’s BigDecimal class is designed to avoid floating-point errors, which are common with standard floating-point types. Rails automatically uses BigDecimal for decimal columns in the database, providing high precision for financial calculations.

Example:

Suppose you need to calculate the total amount for a list of prices. Using BigDecimal ensures precision.

Store Currency in the Smallest Unit

Storing currency values in their smallest unit (like cents for USD) as integers is a standard practice. It simplifies the arithmetic and avoids the issues related…