C# Academy · Lesson

Numeric and Date Format Specifiers

Control how numbers and dates render.

Lesson 3 of 413 steps

Numeric and Date Format Specifiers is a free C# Academy lesson on CoddyKit. This is lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C# Academy learning path, and your progress syncs across the web and the CoddyKit app. The C# Academy course includes 4 lessons in total.

Standard Numeric Formats

Format specifiers are short codes that shape how numbers display. Common ones are N, C, P, F, and D.

using System;

class Program {
    static void Main() {
        double n = 1234.5;
        Console.WriteLine($"{n:N2}");
    }
}

Number Format: N

N2 formats a number with thousands separators and two decimal places.

using System;

class Program {
    static void Main() {
        Console.WriteLine($"{1234567.891:N2}");
    }
}

Currency Format: C

C formats a number as currency using the current culture symbol and grouping.

using System;
using System.Globalization;

class Program {
    static void Main() {
        Console.WriteLine(19.99m.ToString("C", CultureInfo.GetCultureInfo("en-US")));
    }
}

Percent Format: P

P multiplies by 100 and appends a percent sign. 0.25 becomes 25 percent.

using System;
using System.Globalization;

class Program {
    static void Main() {
        Console.WriteLine((0.25).ToString("P1", CultureInfo.InvariantCulture));
    }
}

Fixed-Point: F

F3 shows a fixed number of decimal places without thousands separators.

using System;

class Program {
    static void Main() {
        Console.WriteLine($"{3.14159:F3}");
    }
}

Padded Integers: D

D5 pads an integer with leading zeros to at least five digits.

using System;

class Program {
    static void Main() {
        Console.WriteLine($"{42:D5}");
    }
}

Hexadecimal: X

X formats an integer as hexadecimal; X4 pads to four hex digits.

using System;

class Program {
    static void Main() {
        Console.WriteLine($"{255:X}");
        Console.WriteLine($"{255:X4}");
    }
}

Custom Numeric Patterns

Use a custom pattern like 0.00 or #,##0 for precise control over digits and grouping.

using System;
using System.Globalization;

class Program {
    static void Main() {
        Console.WriteLine((1234.5).ToString("#,##0.00", CultureInfo.InvariantCulture));
    }
}

Date Format Specifiers

Dates also have specifiers: d short date, D long date, t short time, and custom patterns like yyyy-MM-dd.

using System;
using System.Globalization;

class Program {
    static void Main() {
        var date = new DateTime(2026, 5, 30);
        Console.WriteLine(date.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture));
    }
}

Custom Date Patterns

Compose patterns from tokens: dd day, MM month, yyyy year, HH:mm time.

using System;
using System.Globalization;

class Program {
    static void Main() {
        var dt = new DateTime(2026, 5, 30, 14, 5, 0);
        Console.WriteLine(dt.ToString("dd/MM/yyyy HH:mm", CultureInfo.InvariantCulture));
    }
}

Specifiers in Interpolation

All these specifiers work after a colon inside interpolated strings too.

using System;

class Program {
    static void Main() {
        double total = 1999.5;
        Console.WriteLine($"Total: {total:N2}");
    }
}

Quick Check

Test your knowledge of format specifiers.

Answer it in the interactive lesson

Recap

Standard numeric specifiers shape output: N grouped number, C currency, P percent, F fixed decimals, D zero-padded integer, and X hex. Custom patterns like #,##0.00 offer fine control.

Date specifiers (d, D, yyyy-MM-dd) work the same way, and all of them apply after a colon in interpolation or string.Format.

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Frequently Asked Questions

Is the “Numeric and Date Format Specifiers” lesson free?

Yes — the full text of “Numeric and Date Format Specifiers” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C# Academy course, upgrade to CoddyKit PRO. The C# Academy course includes 4 lessons in total.

What will I learn in “Numeric and Date Format Specifiers”?

Control how numbers and dates render. You practise C# Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start C# Academy?

No prior experience is required. C# Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 3 of 4.

How long does the “Numeric and Date Format Specifiers” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this C# Academy lesson?

Yes. Every C# Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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