Introducing Bulk File Renamer: Rename Hundreds of Files at Once, No Upload
Bulk File Renamer is a browser-based tool for renaming a batch of files — any type, any number — without installing software or uploading anything. Drop in your files, pick a rename rule, preview the exact result for every file, then download a zip with everything renamed.
Why Not Just Use the OS?
Windows and macOS both support renaming multiple selected files at once, but the built-in tools are limited: usually just "append a number" or a single find-and-replace. They also rename files in place, with no live preview and no easy way to undo a mistake across hundreds of files. Bulk File Renamer keeps your originals untouched — it reads each file into memory, computes new names based on your rules, and packages the renamed copies into a zip you download. If the result isn't what you wanted, your source files were never modified.
Two Ways to Rename
Quick Edits
For everyday cleanup, Quick Edits chains together a set of simple operations: trim a fixed number of characters from the start or end of each filename, add a prefix or suffix, run a find-and-replace (plain text or regex), switch the case (lowercase, UPPERCASE, or Title Case), replace or strip spaces, and optionally swap the file extension. Every field updates the preview table instantly, so you can stack several edits — say, remove a camera's "IMG_" prefix, replace underscores with dashes, and lowercase the result — and see exactly what each file will be called before committing.
Full Pattern Rename
For building a numbered sequence from scratch, Pattern mode uses a small token language: {name} for the original filename without its extension, {ext} for the extension, {n} for an incrementing counter, and {date} for today's date in YYYY-MM-DD form. A pattern like invoice-{n} with a start number and zero-padding turns a folder of arbitrarily named PDFs into invoice-001.pdf, invoice-002.pdf, and so on — useful for archiving, batch uploads, or any workflow that expects sequential filenames.
Live Preview and Collision Detection
Every file gets its own row showing the original name next to the computed new name, updated on every keystroke. If two files would end up with the same name — easy to do with an aggressive find-and-replace — the colliding rows are flagged in red and the download button is disabled until you fix the rule. That check runs before any zip is generated, so you never end up silently overwriting one renamed file with another inside the archive.
How the Zip Is Built
Downloading reads each file's raw bytes with the browser's File API, adds them to an in-memory archive under the newly computed name using JSZip, and compresses the whole thing to a single .zip blob that's handed to the browser's normal download mechanism. File type doesn't matter — images, PDFs, spreadsheets, videos, anything — since the tool only ever touches the filename, never the file contents.
Privacy
Nothing is uploaded. Files stay in browser memory from the moment you drop them to the moment the zip downloads — there's no server component to this tool at all, so there's nothing to send your files to even if you wanted to.