Filename Rename Planner
Plan sequential filenames and export an old-to-new mapping without changing files.
How to use
- Paste one original filename per line, without folder paths.
- Set the prefix, starting number, and minimum digit width. Names retain input order.
- Review and download the CSV mapping. Validate it in a separate file-management tool before performing any rename.
When to use this tool
Review old-to-new filename mappings before adopting a naming convention for photos or documents. The tool uses a pasted list and does not select, upload, or rename actual files.
Inputs and settings
Result
Example input and actual output
- Original filenames (one per line): photo.jpg scan.png
- New name prefix: project-
- Starting number: 1
- Minimum number width: 3
original,planned photo.jpg,project-001.jpg scan.png,project-002.png
The example produces project-001.jpg and project-002.png. The suffix after the final dot is retained unless that dot is at the first position: .env is extensionless, while .config.json retains .json. CSV cells may receive a leading apostrophe to prevent spreadsheet formula interpretation. This is a CSV safety prefix, not a character to add to the intended filename.
Scope and limitations
Does not rename files. Preserves extensions and outputs a CSV mapping. A leading dot alone is not an extension boundary: .env is extensionless, while .config.json keeps .json.
Next step and alternatives
CSV Viewer & Formatter — Inspect the exported mapping as a table.
Frequently asked questions
Will the CSV rename my files automatically?
No. It is a planning table. Back up original files and check the import format required by your rename utility.
What happens when a number exceeds the chosen width?
The width is a minimum. With three digits, 999 is followed by 1000 without truncation. Windows reserved names, path characters, and trailing spaces are rejected.
Is a leading apostrophe in the CSV part of the intended filename?
It may be added to prevent spreadsheet formula interpretation. It is a CSV safety prefix, not a character to add to the intended filename.
Related tools
Share this tool
Share only the tool name and public URL. Your input and results are not included.