How do you calculate the total size of all files in a directory (including subdirectories)?

Question

ICSM Computer · Answer

To calculate the total size of all files in a directory, including
all subdirectories, you can use DirectoryInfo and recursively enumerate files using
EnumerateFiles() with the SearchOption.AllDirectories option.
Example: Calculate total size (in bytes)
using System;
using System.IO;
using System.Linq;
class Program
{
    static void Main()
    {
        string path = @"C:\MyFolder";
        long totalSize = GetDirectorySize(path);
        Console.WriteLine($"Total size: {totalSize} bytes");
        Console.WriteLine($"Total size: {totalSize / 1024.0 / 1024.0:F2} MB");
    }
    static long GetDirectorySize(string folderPath)
    {
        if (!Directory.Exists(folderPath))
            return 0;
        return Directory.EnumerateFiles(folderPath, "*", SearchOption.AllDirectories)
                        .Select(f =andgt; new FileInfo(f))
                        .Sum(fi =andgt; fi.Length);
    }
}
Notes:
Directory.EnumerateFiles(...) is memory-efficient compared to 
GetFiles(...) because it streams results.This method handles deep nested folders and hidden files.If you want to ignore certain file types, you can filter them with
.Where(...).
Optional: Handle exceptions (e.g., permission errors)
Wrap file access in try-catch if you expect restricted folders:
long safeSize = 0;
foreach (var file in Directory.EnumerateFiles(path, "*", SearchOption.AllDirectories))
{
    try
    {
        safeSize += new FileInfo(file).Length;
    }
    catch { /* Ignore inaccessible files */ }
}
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How do you calculate the total size of all files in a directory (including subdirectories)?

ICSM Computer

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1 Answers

Example: Calculate total size (in bytes)

Notes:

Optional: Handle exceptions (e.g., permission errors)

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