benri-ni
Language: English

Switching the language does not keep what you entered or the file you selected.

Compare two folders

Compare an original folder with its copy and list missing files, files with different content, and matches. Nothing is copied or deleted.

The files you choose are only read on this device and are never sent anywhere.

Original folder

or drop a folder here

Copy folder

or drop a folder here

Up to 20,000 files and 64 GiB in total per side.

How to compare

How to compare

File contents are not read. This is fast, but files with the same size and modified date may still differ.

Choose both the original and the copy to compare them.

How the comparison works

  • Pairing: files in the original and the copy are paired by their path relative to the chosen folder, without the folder’s own name (for example docs/quote.pdf).
  • Size and date (quick): file contents are not read; only size and modified date are compared. Different sizes mean “Different content”. The same size and modified date mean “Same size and date”. Dates up to 2 seconds apart count as the same, because FAT and exFAT drives store dates in 2-second steps. Pairs with the same size but a different date are “Not checked”.
  • Content (SHA-256): for pairs of the same size, both files are read in full and their SHA-256 hashes are compared. Pairs of different sizes are marked “Different content” without reading.

“Same size and date” does not confirm that the contents are identical.

Path rules

  • Upper and lower case: treated as different by default (they are different files on Linux, for example). With this on, Photo.JPG and photo.jpg end up in “Missing from the copy” and “Only in the copy”, and a notice shows how many such pairs exist. Turn it off to pair them as the same path.
  • Character encoding: macOS and other systems may store an accented letter such as “é” as two characters. By default, names that look the same are treated as the same path (normalized to Unicode NFC).
  • If two or more files on the same side map to the same path under these rules, they cannot be paired and are listed as “Not checked”.

What this tool does not do

  • It never copies, overwrites, deletes or syncs files.
  • Symbolic links, hidden files and files without permission are compared only if the browser provides them. Some browsers leave them out.
  • Files that cannot be read (for example deleted or moved after choosing) are listed as “Not checked”, and the rest of the comparison continues.

Limits and saving

  • Up to 20,000 files and 64 GiB in total per side. The list shows up to 500 items per category; the CSV contains everything.
  • “Save results as CSV” saves folder-compare.csv in UTF-8 (with BOM) and CRLF. Dates are ISO 8601 in UTC and sizes are in bytes. Paths that spreadsheet apps might treat as formulas are not changed; a notice shows how many there are.
  • Your folders, files and results are not saved. Only the comparison settings are remembered.

This tool processes your input and files on this device (in your browser) and does not send them to a server. See Privacy and ads for details.

  • Open a ZIP and extract files

    See what is inside a ZIP file and extract only the files you need, one at a time or together. Nothing to install, and the file is not uploaded.

  • Batch rename files

    Add prefixes, suffixes, or sequence numbers, or replace text in file names, then save renamed copies as a ZIP. Your original files are not changed or deleted.

  • Split CSV by rows

    Split a CSV file into several files with a set number of data rows each. The header row is added to every file, values stay unchanged, and you can save all files as a ZIP.

  • Find duplicate files

    Find files with identical content in a folder or files you choose, and list them. Nothing is deleted or moved.