How to Format Currency in C#?

Currency formatting is an important aspect of financial applications, ensuring that financial values are presented clearly and simply. In C#, the developers can use various formatting options provided by the String.Format method or the ToString method of the double and decimal data types. 

Basic Currency Formatting

This method allows developers to specify a format string that defines how the numeric value should be formatted.

using System;

class Program
{
    static void Main()
    {
        double amount = 12345.67;

        // Basic currency formatting
        string formattedCurrency = amount.ToString("C");
        Console.WriteLine("Formatted Currency: " + formattedCurrency);
    }
}

Output:

Formatted Currency: $12,345.67

In this example, the "C" format specifier is used to represent the currency format. The resulting string includes the currency symbol and commas for the thousands separator.

Custom Currency Formatting

Developers often need to customize the currency formatting according to specific requirements. This can be achieved by providing a custom format string. Let's explore some common format specifiers:

• C0: Currency with no decimal places
• C2: Currency with two decimal places
• C3: Currency with three decimal places

using System;

class Program
{
    static void Main()
    {
        double amount = 12345.6789;

        // Custom currency formatting
        string formattedCurrency0 = amount.ToString("C0");
        string formattedCurrency2 = amount.ToString("C2");
        string formattedCurrency3 = amount.ToString("C3");

        Console.WriteLine("Formatted Currency (0 decimal places): " + formattedCurrency0);
        Console.WriteLine("Formatted Currency (2 decimal places): " + formattedCurrency2);
        Console.WriteLine("Formatted Currency (3 decimal places): " + formattedCurrency3);
    }
}

Output:

Formatted Currency (0 decimal places): $12,346
Formatted Currency (2 decimal places): $12,345.68
Formatted Currency (3 decimal places): $12,345.679

These examples provide how to control the number of decimal places in the formatted currency string.

Currency Symbol and Placement

The position and type of currency symbol can be adjusted using format specifiers. The following examples illustrate different scenarios:

• C: Currency symbol before the value
• C0: Currency symbol before the value with no decimal places
• 0:C: Currency symbol after the value with no decimal places

using System;
using System.Globalization;

class Program
{
    static void Main()
    {
        double amount = 12345.67;

        // Currency symbol and placement
        string formattedCurrencyBefore = amount.ToString("C");
        string formattedCurrencyBeforeNoDecimal = amount.ToString("C0");
        string formattedCurrencyAfterNoDecimal = string.Format("{0:C0}", amount);

        Console.WriteLine("Currency Before: " + formattedCurrencyBefore);
        Console.WriteLine("Currency Before (0 decimal places): " + formattedCurrencyBeforeNoDecimal);
        Console.WriteLine("Currency After (0 decimal places): " + formattedCurrencyAfterNoDecimal);
    }
}

Output:

Currency Before: $12,345.67
Currency Before (0 decimal places): $12,346
Currency After (0 decimal places): 12,346$

These examples show how to control the position and type of the currency symbol in the formatted string.

Culture-Specific Currency Formatting

Currency formatting can vary based on cultural differences. In C#, the CultureInfo class provides a way to specify the culture for formatting. Let's explore how to format currency for different cultures:

using System;
using System.Globalization;

class Program
{
    static void Main()
    {
        double amount = 12345.67;

        // Culture-specific currency formatting
        string formattedCurrencyUS = string.Format(new CultureInfo("en-US"), "{0:C}", amount);
        string formattedCurrencyGermany = string.Format(new CultureInfo("de-DE"), "{0:C}", amount);

        Console.WriteLine("Formatted Currency (US): " + formattedCurrencyUS);
        Console.WriteLine("Formatted Currency (Germany): " + formattedCurrencyGermany);
    }
}

Output:

Formatted Currency (US): $12,345.67
Formatted Currency (Germany): 12.345,67 €

These examples show how to format currency according to the cultural conventions of the United States and Germany.

Precision and Rounding

Precision and rounding are important in currency formatting, especially when working with fractional values. The F format specifier can be used to control precision, and rounding can be managed using the Math.Round method.

using System;

class Program
{
    static void Main()
    {
        double amount = 12345.6789;

        // Precision and rounding
        string formattedCurrencyNoRound = amount.ToString("C2");
        string formattedCurrencyWithRound = Math.Round(amount, 2).ToString("C2");

        Console.WriteLine("Formatted Currency (No Round): " + formattedCurrencyNoRound);
        Console.WriteLine("Formatted Currency (With Round): " + formattedCurrencyWithRound);
    }
}

Output:

Formatted Currency (No Round): $12,345.68
Formatted Currency (With Round): $12,345.68

Negative Currency Values

Dealing with negative currency values requires special attention to ensure the proper representation. The N format specifier can be used to format both positive and negative currency values.

using System;

class Program
{
    static void Main()
    {
        double positiveAmount = 12345.67;
        double negativeAmount = -12345.67;

        // Negative currency values
        string formattedPositiveCurrency = positiveAmount.ToString("N2");
        string formattedNegativeCurrency = negativeAmount.ToString("N2");

        Console.WriteLine("Formatted Positive Currency: " + formattedPositiveCurrency);
        Console.WriteLine("Formatted Negative Currency: " + formattedNegativeCurrency);
    }
}

Output:

Formatted Positive Currency: $12,345.67
Formatted Negative Currency: -$12,345.67