Batch File Renamer

Renaming a batch is rarely hard because of one file; it is hard because two files end up with the same name, an extension gets eaten, or nobody remembers what the originals were called. This tool turns renaming into a rule you can inspect row by row: drop the files in, adjust the template and see every new name before anything is written.

• Name template: {name} for the base name, {n} for the sequence number, {ext} for the extension, {date} for today, {time} for the current time, {mtime} for the file's modified date and {size} for its size; common templates are one-click buttons
• Sequence controls: start, step and zero padding are set separately, so a start of 10, a step of 5 and four digits give 0010 / 0015 / 0020; switching a row off takes it out of the numbering and later rows move up
• Regex find and replace: with regex on, $1 and $2 back-references work, so ^(\w+)\s(\d+) replaced with $2_$1 turns "DSC 0421" into "0421_DSC"; a bad pattern flags the row and keeps the original name instead of blanking the column
• Case and cleanup: the base name can go lower case, upper case, sentence case or title case; spaces can become -, _ or nothing; characters such as \ / : * ? " < > | are stripped by default, repeated separators collapse, leading and trailing dots and spaces are trimmed, and reserved Windows names such as CON, NUL and LPT1 get an underscore prefix
• Four extension modes: keep, lower case, upper case or force a specific one. If {ext} appears in the template it is placed exactly where you put it; otherwise the original extension is reattached automatically so renamed files still open
• Collision handling: when a new name is taken, the tool appends (2) and (3), or you can choose to keep the original name; names that differ only in case count as collisions because Windows and macOS are case-insensitive by default
• Per-row edits and exclusions: any row in the preview can be edited by hand; a hand-edited row stops following later rule changes, and a restore button puts it back. Rows you do not want to touch can be excluded, and a row can be removed entirely
• Sort decides the numbering: order by insertion, name, size or modified time before numbering. Sort by modified time newest first, then apply {n}, and you get a sequence in shooting order
• Three ways to finish: download a ZIP of the renamed copies, flat or preserving the original folders; copy the list of new names; or copy an original to new name mapping for your records
• Rename scripts: PowerShell, batch and Shell output, with one Rename-Item, ren or mv -n per file and quoting handled. Copy the script into the target folder and run it

Why a script as well

A browser cannot rename files on your disk for security reasons, so the ZIP is a set of copies with new names. To rename in place, the generated script is the safer route: it only changes names, leaves contents, permissions and timestamps alone, and never loads gigabytes of files into memory.

When to use it

• Phone exports full of names like IMG_2043 copy (1).JPG that you want in shooting order as IMG_0001
• Downloads with spaces and brackets that break on a server or in Git and need safe characters
• Meeting recordings or interview transcripts filed as date plus number so they line up with notes
• Scans named scan0001.pdf that should read like contract-20261020-01.pdf
• A folder where some images end in .JPG and others in .jpg, breaking case-sensitive web references
• One batch renamed to a shared prefix with continuous numbers, plus a mapping table for later reference

Template cheat sheet

Common questions

• Can it damage files?No. Rules only touch names; the ZIP is built from the original bytes, and the page never writes to your disk
• How many files at once?Up to 2000. The preview draws the first 400 rows, but numbering, collision handling, scripts and the ZIP cover all of them
• Why is the ZIP stored without compression?Photos, video and installers are already compressed, so a second pass saves little and costs time. Stored entries are faster and avoid large memory use in the browser. If a single file or the total approaches 4GB the tool refuses and suggests the script instead
• Does dropping a folder keep its structure?The default is flat in the ZIP root, with collisions resolved automatically; choose the folder-preserving option to keep the original layout
• What should I watch in the scripts?The script contains bare filenames, so run it from the folder that holds the files. Batch ren stops on a name clash, while mv -n skips instead of overwriting. Try it on a copy the first time
• How are dotfiles treated?A name like .gitignore counts as having no extension, and the leading dot is preserved rather than becoming an empty base name
• Can the extension get lost?It is reattached by default. Only two cases are yours to manage: the template contains {ext}, or the replace-extensions option is on, in which case the whole name goes through replacement and nothing is appended
• Can I rename only some file types?Switch off the rename toggle on the rows you want to leave alone, or sort by name or modified time first so similar files sit together
• Is anything uploaded?No. Reading, rule evaluation, zipping and script generation all happen in the browser; no request is sent and a refresh clears everything

To inspect files before renaming, use the file info reader; for a plain list of names, use the filename extractor; to split base names from extensions or change extension case on its own, use the filename and extension splitter and the extension case converter; to confirm renamed copies match the originals, run them through the file hash tool; to build matching folders, use the folder batch creator.