Batch File Renamer

How do I rename many files at once in the browser?

Open AnyTool Batch File Renamer, add your files (drag-and-drop, the file picker, or a whole folder on Chromium), then build a rules pipeline. Stack as many rules as you like — find & replace (plain text or regex), add a prefix or suffix, sequential numbering (start, step, padding, before/after the name), change case (UPPER, lower, Title, Sentence, camelCase, snake_case, kebab-case), remove characters by pattern, replace spaces with _ - or . , change the extension, insert the file’s modified date or today’s date, and trim whitespace. A live preview shows every old → new name and flags duplicate names, empty names and illegal characters. Then export: Download as ZIP works everywhere, or Save to folder writes the renamed copies into a folder you pick (Chromium, with your permission). Everything runs in your browser — nothing is uploaded.

Stackable, reorderable rules pipeline applied to every filename in order
Find & replace (plain or regex), prefix, suffix, numbering, case, remove chars, replace spaces, change extension, insert date, trim
Live old → new preview with duplicate, empty-name and illegal-character warnings
Export: Download as ZIP (every browser) or Save to folder via the File System Access API (Chromium)
Produces renamed copies — originals are untouched; 100% in your browser, nothing uploaded

What is

Batch File Renaming

Batch (or bulk) file renaming is applying one or more transformation rules to the names of many files at once instead of editing each by hand. Typical rules include find-and-replace (often with regular expressions), adding a prefix or suffix, inserting an incrementing counter with configurable start, step and zero-padding, changing letter case, removing characters, normalising spaces, changing the extension and stamping a date. A good renamer previews the results and detects name collisions before committing, since two files in the same folder cannot share a name.

Generators

Related terms

Rules pipelineRegular expressionSequential numberingFile System Access APIName collision

Frequently Asked Questions

AnyTool Batch File Renamer uses an ordered rules pipeline, so you add as many rules as you need and they apply top-to-bottom to every filename. The rules are: find & replace, either as plain text or a regular expression and optionally case-insensitive; add a prefix or a suffix; sequential numbering with a configurable start value, step increment, zero-padding, a separator and a position before or after the name; change case to UPPER, lower, Title Case, Sentence case, camelCase, snake_case or kebab-case; remove characters matching a regex pattern; replace spaces with an underscore, hyphen, dot or nothing; change or normalise the file extension; insert the file’s modified date or today’s date using YYYY/MM/DD/HH/mm/ss tokens; and trim, which collapses repeated spaces and strips leading and trailing spaces and dots. Each rule can be reordered, toggled on or off, and removed.

Find & replace (plain or regex), add a prefix or suffix, sequential numbering with start, step and padding, change case, remove characters, replace spaces, change the extension, insert a date, and trim whitespace — stacked in any order.

For privacy and broad browser support, the tool generates renamed copies rather than renaming your original files in place. The universal route bundles all the renamed copies into a single ZIP you download, which works in every modern browser. On Chromium browsers an optional Save to folder button uses the File System Access API, with your explicit permission, to write the renamed copies straight into a folder you pick — but it still writes copies, because browsers deliberately cannot silently rename arbitrary files on your drive. Your originals are never moved, modified or deleted, so you should always keep a backup and check the preview for name collisions before exporting.

No — for safety it produces renamed copies. The universal path zips them for download; the optional Save-to-folder path writes copies into a folder you choose. Your originals are never modified.

Because two files in one folder cannot share a name, the renamer checks for collisions as you type. Any filename that would be produced more than once is highlighted in the live preview alongside warnings for empty names and characters that are illegal in a filename. When you export, duplicates are made unique automatically by appending a numeric suffix in parentheses — name.txt, name (1).txt, name (2).txt — so no file is lost or overwritten. Empty names fall back to the original, and the preview lets you adjust your rules before committing.

The live preview flags any duplicate name, and on export the tool automatically makes them unique by appending (1), (2) and so on, so nothing is silently overwritten.

The Batch File Renamer is 100% client-side. Your files are read in the browser only to copy their bytes into the ZIP, or into the folder you pick with the File System Access API, and the rename rules are pure string transformations that never touch a server. There is no upload, no CDN round-trip, no analytics on your file names and no storage — close the tab and everything is discarded, and the tool keeps working offline once it has been cached.

No. Reading your files, applying the rules and building the ZIP all happen in your browser. There is no server, no CDN upload, and nothing is logged or stored.

Bulk-rename many files with a stackable rules pipeline — find/replace, regex, numbering, prefix/suffix, case, dates and more — with a live preview and collision check, then download as ZIP. 100% in your browser.

Features

Ordered, reorderable rules pipeline applied to every filename
Find & replace (plain or regex), prefix, suffix, numbering (start/step/padding/position)
Change case, remove characters, replace spaces, change extension, insert date, trim
Live old → new preview with duplicate, empty-name and illegal-character flags
Export as ZIP (all browsers) or Save to folder via File System Access API — renamed copies, nothing uploaded

PriceFree

CategoryGenerator

PlatformAll (browser-based); Save to folder needs a Chromium browser

PrivacyFiles are read, renamed and zipped locally; nothing is uploaded, logged or stored

Input: Any files (drag-and-drop, file picker, or folder)

Output: ZIP of renamed copies, Renamed copies written to a chosen folder

Detailed Explanation

Methodology

A Stackable Rules Pipeline for Filenames

AnyTool Batch File Renamer renames many files at once by running an ordered pipeline of rules over every filename, entirely in the browser. You add files by drag-and-drop, the file picker, or (on Chromium) a whole folder, and then stack as many rules as you need; each one is reorderable, can be toggled on or off, and is applied top-to-bottom so order matters. The rule set covers the common bulk-rename operations: find and replace as plain text or a regular expression with an optional case-insensitive flag; add a prefix or a suffix; sequential numbering with a configurable start value, step, zero-padding, separator and position before or after the name; change case to UPPER, lower, Title, Sentence, camelCase, snake_case or kebab-case; remove characters matching a regex; replace spaces with an underscore, hyphen, dot or nothing; change or normalise the extension; insert the file’s modified date or today’s date with YYYY/MM/DD/HH/mm/ss tokens; and trim, which collapses repeated spaces and strips leading and trailing spaces and dots. The file extension is preserved unless the Change Extension rule is used.

Ordered, reorderable, toggleable rules applied to every filename
Find/replace (plain or regex), prefix, suffix, numbering, case, remove chars, replace spaces, change extension, insert date, trim
Numbering supports start, step, zero-padding, separator and before/after position
Extension preserved unless the Change Extension rule is added
Runs entirely client-side — no server, no CDN, no upload

Technical Details

Live Preview, Collision Handling and Two Export Modes

Every change re-renders a live preview table showing each file’s old name and resulting new name, with running counts of how many files will change. Because two files in one folder cannot share a name, the tool detects collisions as you type and highlights any duplicate result, alongside warnings for names that would be empty or that contain characters illegal in a filename. On export, duplicates are made unique automatically by appending a parenthesised counter — name.txt, name (1).txt, name (2).txt — so nothing is silently overwritten, and empty names fall back to the original. There are two execution modes that share this pipeline: a universal Download as ZIP that bundles all the renamed copies using a lazily-imported JSZip and works in every modern browser, and an optional Save to folder that uses the File System Access API on Chromium to write the renamed copies into a directory the user picks, with explicit permission. Both modes write renamed copies; the originals on disk are never modified.

Live old → new preview updates on every keystroke
Detects and flags duplicate names, empty names and illegal characters
Duplicates auto-suffixed (1), (2)… on export so nothing is overwritten
Export as ZIP (all browsers, via lazy-loaded JSZip) or Save to folder (Chromium, File System Access API)
Both modes produce renamed copies — originals are untouched

Privacy & Security

Why It Renames Copies, and Why That Is Private

The renamer is deliberately 100% client-side: your files are read in the browser only to copy their bytes into the ZIP or into the folder you choose, the rename rules are pure string transformations, and nothing is uploaded, logged or stored. It is honest that, for both privacy and compatibility, it produces renamed copies rather than renaming originals in place — browsers cannot silently rename arbitrary files on a user’s drive, so even the Chromium Save to folder path writes copies with the user’s permission rather than mutating the source files. The guidance is therefore to keep a backup and to review the live preview for collisions and invalid names before exporting. Closing the tab discards everything, and the tool keeps working offline once cached.

Files read locally only to copy bytes into the ZIP or chosen folder
Rename rules are pure string transforms; nothing is uploaded or stored
Produces renamed copies; originals are never modified, moved or deleted
Even Save to folder writes copies — browsers cannot silently rename disk files
Works offline once cached; closing the tab discards everything

Bulk renaming: in-browser (AnyTool) vs typical online / desktop renamers
Capability	AnyTool	Typical alternatives
Processing	Runs entirely in your browser	Online tools often upload; desktop apps need install
Rules	Stackable pipeline: find/replace, regex, numbering, prefix/suffix, case, date, trim	Varies; online tools often offer a small fixed set
Live preview	Old → new for every file, updates instantly	Often absent on simple online tools
Collision handling	Flags duplicates; auto-suffixes (1), (2)…	Frequently silent overwrite or error
Export	ZIP of copies, or Save to folder (Chromium)	Per-file download or server-side processing
Privacy	Files never uploaded; works offline	Online tools may transmit or retain files
Cost / signup	Free, no signup	Often gated, ad-heavy or paid desktop apps

AnyTool reads, renames and zips files locally and uploads nothing; it produces renamed copies, leaving originals untouched.

Cite This Page

Title: Batch File Renamer (stackable rules pipeline — find/replace, regex, numbering, prefix/suffix, case, date — with a live preview, collision handling and ZIP download, 100% client-side)
Author: AnyTool
Published: January 1, 2026
Modified: February 8, 2026
Section: Generators
URL: https://www.anytool.tech/batch-file-renamer

Formatted Citation

AnyTool. "Batch File Renamer (stackable rules pipeline — find/replace, regex, numbering, prefix/suffix, case, date — with a live preview, collision handling and ZIP download, 100% client-side)." AnyTool, January 1, 2026. https://www.anytool.tech/batch-file-renamer

A privacy-first, 100% client-side batch file renamer that bulk-renames many files by running an ordered, reorderable, toggleable pipeline of rules over every filename entirely in the browser with no server round-trip, no CDN and no upload. Files are added by drag-and-drop, the file picker, or a whole folder on Chromium, and the rule set covers find and replace (plain text or regular expression with an optional case-insensitive flag), add prefix, add suffix, sequential numbering (configurable start value, step increment, zero-padding, separator and position before or after the name), change case (UPPER, lower, Title, Sentence, camelCase, snake_case or kebab-case), remove characters by regex, replace spaces (with an underscore, hyphen, dot or nothing), change or normalise the extension, insert the file’s modified date or today’s date using YYYY/MM/DD/HH/mm/ss tokens, and trim (collapsing repeated spaces and stripping leading and trailing spaces and dots); the extension is preserved unless the Change Extension rule is used. A live preview table shows each file’s old → new name and updates on every keystroke, detecting and flagging duplicate results, empty names and characters illegal in a filename; on export duplicates are made unique automatically by appending a parenthesised counter so nothing is silently overwritten and empty names fall back to the original. Two execution modes share the pipeline: a universal Download as ZIP that bundles all renamed copies using a lazily-imported JSZip and works in every modern browser, and an optional Save to folder that uses the File System Access API on Chromium to write the renamed copies into a directory the user picks with explicit permission. The tool is explicit that, for privacy and compatibility, it produces renamed copies rather than renaming originals in place — browsers cannot silently rename arbitrary files on a drive, so even the Save to folder path writes copies rather than mutating the source files — and it advises keeping a backup and reviewing the preview for collisions and invalid names before exporting. Files are read locally only to copy their bytes into the ZIP or chosen folder, the rename rules are pure string transformations, nothing is uploaded, logged or stored, closing the tab discards everything, and the tool works offline once cached.