Why file10 sorts before file2, and how to add leading zeros to file names

Your slides, scans or video frames look fine in one window, then a zip listing, an upload form or a script shows them as 1, 10, 11, 2, 3. Nothing is broken: two different kinds of sorting are disagreeing.

Two kinds of sorting

Because you cannot choose how every other program sorts, the dependable answer is to make the two sorts agree. When every number has the same number of digits, character order and number order are the same.

How many digits?

Use enough digits for the largest number you will ever reach: 2 for up to 99 files, 3 for up to 999, 4 for up to 9,999. Padding further costs nothing, but going back later to add one more digit means renaming everything again.

Pad the numbers in the browser

1. Load the names into the batch rename tool (choose the files or paste a list).
2. Turn on natural sort so page2 stays before page10.
3. Choose numbering, set the mode to replace the name or add a prefix, start at 1 and set digits to 3. Add a prefix such as page- if you like.
4. Check the before/after table, then copy the bash or PowerShell script and run it in the folder.

Or pad them in a terminal

bash, for names like file7.jpg:

for f in file*.jpg; do
  n=${f#file}; n=${n%.jpg}
  case $n in (*[!0-9]*|'') continue;; esac
  mv -n -- "$f" "$(printf 'file%03d.jpg' "$((10#$n))")"
done

PowerShell:

Get-ChildItem -File file*.jpg | ForEach-Object {
  if ($_.BaseName -match '^file(\d+)$') {
    Rename-Item -LiteralPath $_.FullName -NewName ('file{0:D3}{1}' -f [int]$Matches[1], $_.Extension)
  }
}

The 10# in bash stops a number like 08 being read as octal. To list files in number order without renaming, use ls -v or sort -V.

Related

Number files in the order you choose · How to batch rename files safely (without uploading them) · Why a batch rename overwrites or skips files (name collisions) · Renaming a file when only the upper/lower case changes · Windows names you cannot use: CON, NUL, AUX, COM1 · Remove spaces and special characters from file names · Batch rename tool (names only, in your browser) · Compress many photos at once · Invisible characters in text

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Published 8 November 2026 · updated 9 November 2026.