C# Academy · Lesson

TimeSpan and Durations

Measure spans of time.

Lesson 3 of 413 steps

TimeSpan and Durations 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.

What Is a TimeSpan

While DateTime is a point in time, TimeSpan represents a length of time, like 2 hours or 90 minutes.

It is a duration with no calendar attached. You use it for stopwatch results, timeouts, and the gap between two dates.

Creating a TimeSpan

One constructor takes hours, minutes, and seconds: new TimeSpan(hours, minutes, seconds).

So new TimeSpan(1, 30, 0) is one hour and thirty minutes. The value prints in a clear h:mm:ss layout.

using System;

class Program
{
    static void Main()
    {
        TimeSpan span = new TimeSpan(1, 30, 0);
        Console.WriteLine(span);
    }
}

Factory Methods

Often it reads better to use a factory method. TimeSpan.FromMinutes(90) builds a span of 90 minutes.

There are matching helpers: FromHours, FromSeconds, FromDays, and FromMilliseconds.

using System;

class Program
{
    static void Main()
    {
        TimeSpan span = TimeSpan.FromMinutes(90);
        Console.WriteLine(span);
    }
}

Total vs Component Values

TimeSpan has two families of properties. Hours, Minutes, and Seconds are the broken-down components.

The Total... versions like TotalMinutes express the whole duration in one unit, as a decimal.

using System;

class Program
{
    static void Main()
    {
        TimeSpan span = TimeSpan.FromMinutes(90);
        Console.WriteLine(span.Hours);
        Console.WriteLine(span.TotalMinutes);
    }
}

Component vs Total Explained

For 90 minutes, Hours is 1 and Minutes is 30, because the duration breaks into 1 hour and 30 minutes.

But TotalHours is 1.5 and TotalMinutes is 90, since those count the entire span in a single unit.

using System;

class Program
{
    static void Main()
    {
        TimeSpan span = TimeSpan.FromMinutes(90);
        Console.WriteLine(span.TotalHours);
    }
}

Subtracting Two Dates

When you subtract one DateTime from another, the result is a TimeSpan.

This is the everyday way to find how much time passed between two moments, such as the length of an event.

using System;

class Program
{
    static void Main()
    {
        DateTime start = new DateTime(2024, 3, 5, 9, 0, 0);
        DateTime end = new DateTime(2024, 3, 5, 11, 30, 0);
        TimeSpan diff = end - start;
        Console.WriteLine(diff.TotalHours);
    }
}

Adding TimeSpans

You can add or subtract TimeSpan values with the normal + and - operators.

Combining two durations gives a longer one, which is useful for summing several intervals.

using System;

class Program
{
    static void Main()
    {
        TimeSpan a = TimeSpan.FromMinutes(45);
        TimeSpan b = TimeSpan.FromMinutes(15);
        Console.WriteLine((a + b).TotalMinutes);
    }
}

Negative Durations

A TimeSpan can be negative if the end is before the start, or after a subtraction.

The Duration method returns the absolute value, and Negate flips the sign. These help when you only care about magnitude.

using System;

class Program
{
    static void Main()
    {
        TimeSpan span = TimeSpan.FromHours(-3);
        Console.WriteLine(span.Duration().TotalHours);
    }
}

Comparing Durations

TimeSpan values compare with <, >, and == just like numbers.

This lets you check whether one duration is longer than another, for example to enforce a maximum allowed time.

using System;

class Program
{
    static void Main()
    {
        TimeSpan limit = TimeSpan.FromHours(2);
        TimeSpan used = TimeSpan.FromMinutes(150);
        Console.WriteLine(used > limit);
    }
}

Zero and Constants

TimeSpan.Zero represents no elapsed time, a handy starting point for sums.

There are also TimeSpan.MinValue and TimeSpan.MaxValue for the extreme bounds of a duration.

using System;

class Program
{
    static void Main()
    {
        TimeSpan total = TimeSpan.Zero;
        total += TimeSpan.FromMinutes(10);
        Console.WriteLine(total.TotalMinutes);
    }
}

Formatting a TimeSpan

You can format a TimeSpan with a custom string. For example @"hh\:mm" shows hours and minutes.

The backslashes escape the colon so it appears literally. For quick output, the default ToString is usually enough.

using System;

class Program
{
    static void Main()
    {
        TimeSpan span = new TimeSpan(2, 5, 0);
        Console.WriteLine(span.ToString(@"hh\:mm"));
    }
}

Quick Check

You have a TimeSpan of 90 minutes. Which property returns the value 1.5?

Answer it in the interactive lesson

Recap

A TimeSpan is a duration. Build it with new TimeSpan(...) or factory methods like FromMinutes.

Component properties (Hours) differ from Total... properties. Subtracting two DateTimes yields a TimeSpan, and you can add, compare, and format durations.

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Measure spans of time. 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.

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