How to Show Order Totals with Decimals in WooCommerce REST API Response

I'm working on a WooCommerce store with a multi-currency setup. My store's default currency is Japanese Yen, and I have the price decimal setting in the WooCommerce dashboard set to 0 to avoid showing decimals for JPY prices. However, I also sell in other currencies (e.g., USD), and I need the WooCommerce REST API to return order totals with 2 decimal places for those currencies.

The issue is that when I retrieve order data via the WooCommerce REST API (e.g., /wp-json/wc/v3/order/{id}), the total fields are rounded up to integers for all currencies, even for currencies like USD, where decimals are important.

What I’m Trying to Achieve:
Keep the WooCommerce dashboard and storefront displaying prices without decimals for JPY. Ensure the WooCommerce REST API returns order totals with 2 decimal places for currencies that require it (e.g., USD).

What I’ve Tried:
I attempted to use the woocommerce_rest_prepare_shop_order_object filter to modify the total field in the API response. Here’s the code I’ve used:

add_filter( 'woocommerce_rest_prepare_shop_order_object', 'modify_order_total_in_api', 10, 3 );

function modify_order_total_in_api( $response, $order, $request ) {

    // Check if the total exists
    if ( isset( $response->data['total'] ) ) {
        // Format the total with 2 decimals
        $response->data['total'] = number_format( $order->get_total(), 2, '.', '' );
    }

    return $response;
}

What Happens:

• The API does add the 2 decimals to the amount.

• It still returns rounded order totals (e.g., 26.00 instead of 25.99 for USD).

Additional Context:

• Amounts for currencies other than JPY (like USD) are displayed correctly with decimals in both the storefront and the WooCommerce order dashboard.

• If I change the decimal setting in the WooCommerce dashboard from 0 to 2, the API starts returning the correct order totals with decimals for all currencies. However, this also causes decimals to show on the storefront for JPY, which is not desirable.

Questions:

• How can I ensure the API respects the currency’s decimal settings (e.g., 2 for USD) while keeping the dashboard and storefront settings at 0 decimals for JPY?

• Are there other filters, actions, or methods I should consider for this use case?

• Is there anything else I might be missing?

Any help would be greatly appreciated!

The issue might arises when a product's price is rounded and stored in an order, making it challenging to replicate the same rounding method in an external system.

Instead you can do the following:

1. Go to your store settings and set decimals to 2.
2. Use the filter woocommerce_price_trim_zeros

You can use below code in your functions.php file to trim your decimals on the price in your store, while maintaining the 2 decimals for your API:

/* Hide trailing zeros on prices */
add_filter( 'woocommerce_price_trim_zeros', '__return_true' );

You can read more about the woocommerce_price_trim_zeros filter in the woocommerce documentation

This way you ensure the API respects the currency’s decimal settings, while keeping the dashboard and storefront settings at 0 decimals.

If you need to apply this to only 1 currency like the JPY, you can use conditional check within the filter. Example:

add_filter( 'woocommerce_price_trim_zeros', 'trim_zeros_for_jpy' );

function trim_zeros_for_jpy( $trim ) {
    $currency = get_woocommerce_currency();
    if ( $currency === 'JPY' ) {
        return true;
    }
    return false;
}