File Renamer

2. How to Bulk Rename Files Online in Four Steps

No account, no email and no cap on the number of files. To batch rename files with the tool above:

To bulk rename files from several folders with one pattern, add them all at once; if each needs its own prefix, press Clear and run separate batches.

3. The Rules, in the Order They Run

The rules apply in a fixed sequence. Each works on the base name; the extension is split off at the last dot and reattached at the end.

How to add a prefix to multiple file names is therefore one field. How to add a suffix to file names in bulk is the other box — “_v2”, “_final” — and it lands before the extension. Change Extension swaps the part after the dot, which is how you change the file extension of multiple files at once: .jpeg to .jpg, .txt to .md. If the rules would leave nothing at all, the original name is kept.

4. Web-Safe Names: kebab-case, snake_case and lowercase

This is the job the tool was built for. If your file names have spaces breaking upload forms, image links or CMS imports, the cause is that a space is not a legal character in a web address. The URI syntax in IETF RFC 3986 allows a small set of characters unencoded; everything else must be percent-encoded, which is why “Hero Banner.png” becomes “Hero%20Banner.png” in one place and a broken link in another. Many web servers also treat Hero.png and hero.png as different files.

The Letter Case menu solves both at once. To convert file names to kebab-case, pick that mode: the name is trimmed and lowercased, spaces and underscores become single hyphens, and runs of hyphens collapse. “Hero Banner FINAL.png” becomes hero-banner-final.png. To rename files to snake_case in bulk — what Python projects and data pipelines expect — choose snake_case and the same happens with underscores. Either is the quickest way to remove spaces from file names across multiple files. If you only need to make all file names lowercase at once and keep the punctuation, choose lowercase; to rename files to Title Case in bulk, every word gets a capital first letter and the rest is lowercased.

A full recipe to rename files for web upload with no spaces and lowercase names: Find “FINAL” and replace with nothing, Letter Case kebab-case, Prefix with the campaign slug, and Change Extension to settle .JPG and .jpeg into one .jpg. If the images also need to be smaller, use the image compressor first and rename the output.

5. Sequential Numbering and Duplicate Handling

The classic camera problem: photos all named IMG_ and no idea how to rename them in order. Find “IMG_”, Replace with nothing, Prefix “wedding-”, tick Sequential Numbering, and IMG_4471.jpg becomes wedding-4471_01.jpg. That is how to rename files sequentially here: queue order is number order, first added is _01. The numbers are two digits, start at 1, step by 1, and sit at the end of the base name with an underscore.

What happens when two names collide

Apply lowercase to Report.pdf and report.pdf and you have two files with one name. A tool that lets that through either fails or silently keeps one file. Here the check is always on and case-insensitive: the first file keeps the clean name, the second becomes report-1.pdf, the third report-2.pdf, with the counter before the extension. You see it in the preview, which is what people mean when they search for a way to rename duplicate file names automatically. Nothing is ever lost inside the archive.

6. Chromebook, iPad, Mac and Locked-Down Work PCs

People look for a batch file renamer with no signup because the desktop option is unavailable to them.

• Rename files on a Chromebook, multiple at once. The Files app renames one item at a time. Open this page, add the files, and take the ZIP back.
• Batch rename files on an iPad. Same one-at-a-time limit in the Files app. The picker here accepts a multi-select, and Files can unpack the ZIP.
• You cannot add renaming software to a work computer. No admin rights, a locked software policy. Open this page instead; nothing about your files is stored or retained afterwards.
• Bulk rename files on a Mac without writing a workflow. Finder can add and replace text but offers no kebab-case, snake_case or lowercase mode.

The same applies to a teacher who needs to rename student submissions files in bulk: Find the platform’s junk prefix, replace it with nothing, Title Case the rest, add a suffix like “_Wk3”, and the cohort is consistent in one pass. If the export arrived as one archive, unpack it first; this tool does not rename files inside a ZIP.

7. What This Renamer Does Not Do

A bulk file renamer earns trust by being clear about its edges.

• No regular expressions. Find is plain text and case-sensitive. For wildcards, a desktop renamer or a shell is the right instrument.
• No numbering options. Start at 1, step by 1, two digits, underscore, suffix position.
• No sorting. Files are numbered in the order you added them; there is no sort by name, date or size.
• No folders. Every file lands in the root of the ZIP.
• No per-file edits. One rule set applies to the whole batch; a single output name cannot be hand-typed in the preview, and there are no saved presets or undo history.
• No stated size cap, but no guarantee either. A very large batch may fail with an “Export error” message; if that happens, split it into smaller batches.
• No metadata. Dates taken, ID3 tags and dimensions cannot appear in a name; there are no {name} or {date} tokens.
• Changing an extension does not convert the file. photo.png renamed to photo.jpg is still a PNG. For a real format change use the image converter, audio converter or the file converter hub, then rename the output.

8. Why Cortexis Is the Best Free File Renamer

It sits alongside a wider set of free file tools on the same terms, so you can build an archive, resize a batch of images or merge the renamed PDFs without paying for any of it.

9. Frequently Asked Questions (FAQ)