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How to store and output currency values in WordPress

3 min read
Published on 21st March 2024

Managing currency effectively is crucial for any WordPress site dealing with financial transactions, pricing information, or donations. Whether you're running an eCommerce platform, a donation portal for a non-profit, or any site that involves currency, how you store, retrieve, and display these values can significantly impact user experience and accuracy of the data. This article delves into the best practices for handling currency in WordPress, ensuring your site manages financial data efficiently and displays it correctly to your users.

Storing Currency Values in WordPress

The way you store currency values is foundational to accurate financial management. Here are key considerations:

1. Use the Right Data Type

When storing currency values in the database, particularly if you're using custom tables, always use a data type suited for financial calculations. In SQL, for example, this could be DECIMAL or FLOAT. WordPress meta fields, however, store data as strings, so ensure your code accurately converts these values when performing calculations.

2. Store Values in the Smallest Unit

To avoid floating-point errors and simplify calculations, store currency values in their smallest unit (e.g., cents, pence) as integers. For example, store $10.00 as 1000 (cents). This method reduces errors in calculations and makes your financial data easier to work with programmatically.

Retrieving and Calculating Currency Values

When retrieving and performing calculations with currency values, ensure your code correctly handles the data type conversion and accounts for the smallest unit storage.

// Assuming $price is retrieved from a meta field and stored as cents.
$price_in_cents = get_post_meta($post_id, 'price', true);
$price_in_dollars = $price_in_cents / 100;

echo 'Price: $' . number_format($price_in_dollars, 2);

Displaying Currency in WordPress

Displaying currency correctly is vital for user trust and clarity. Here are techniques to ensure currency values are user-friendly:

1. Formatting Currency

Use PHP's number_format() function to format currency values, specifying the desired number of decimal places, decimal point type, and thousands separator.

echo 'Price: $' . number_format($price_in_dollars, 2, '.', ',');

For more complex scenarios or multi-currency sites, consider using the money_format() function (deprecated in PHP 7.4.0) or the NumberFormatter class (part of the Intl extension) for localization.

2. Handling Multiple Currencies

If your site deals with multiple currencies, store the currency code alongside each value. Display the currency appropriately based on the user's preference or locale. WordPress plugins like WooCommerce have built-in solutions for handling currency conversions and formatting.

3. Localization and Internationalization

Consider the locale of your audience when displaying currency values. Utilize WordPress' internationalization functions for formatting and presenting currency, ensuring symbols, position (before or after the value), and formatting match local customs.

$locale = 'en_US';
$fmt = new NumberFormatter($locale . '@currency=USD', NumberFormatter::CURRENCY);
echo $fmt->format($price_in_dollars);

Plugins and Tools for Currency Management

Several WordPress plugins can simplify currency management:

  • WooCommerce: Offers comprehensive solutions for eCommerce sites, including multi-currency support and formatting options.
  • Currency Converter Widget: Useful for sites needing to display values in multiple currencies based on current exchange rates.
  • WPML: While primarily a translation plugin, WPML can handle currency switching for multilingual sites.

You should always try and avoid using plugins wherever possible, as they can often bring about feature-bloat, technical debt, and are the most common attack vector for WordPress attacks.

Properly managing currency in WordPress is essential for sites that engage in financial transactions or display pricing information. By storing currency values accurately, performing precise calculations, and displaying values in a clear and localized format, you can enhance the functionality and user experience of your WordPress site. Always consider the implications of financial data on your site's usability and trustworthiness, and utilize the available tools and plugins to streamline currency management practices.