Rename Files (bulk)
Preview a consistent sequence-based filename rule and package renamed copies of selected files into one local ZIP archive.
Use the Rename Files (bulk)
Preview a consistent sequence-based filename rule and package renamed copies of selected files into one local ZIP archive.
File processing and generation happen locally in your browser; this batch does not require an external processing service.
File operations create browser-side copies/downloads and do not modify source files in place. Keep originals until you have checked the generated package or extracted files.
How to use it
Start with the realistic worked example, replace it with your own data or local file, inspect the generated result, and verify the important assumptions before using the output.
How the Rename Files (bulk) works
The Bulk Rename tool creates a predictable sequential filename pattern from a prefix, separator, starting number and zero-padding width, while preserving each original file extension.
Calculation breakdown
ToolLott will explain the current inputs and displayed result here.
How the bulk rename pattern is assembled
ToolLott validates the prefix for common cross-platform filename safety, pads each sequence number to the chosen digit width, inserts the selected separator and keeps the original extension so a batch can be renamed consistently.
prefix + separator + zeroPad(start + index, digits) + original extensionThe sequence increments once for each selected file.
| Symbol / input | Meaning | Unit |
|---|---|---|
prefix | Text placed before the sequence number | text |
start | First sequence number | integer |
digits | Minimum width of zero-padded number | digits |
Step-by-step method
- Select the files to rename and enter a filesystem-safe prefix.
- Choose the separator, starting sequence number and number width.
- Generate one new basename per file using zero-padded sequential numbering.
- Preserve each original extension and package/download the renamed files according to the tool workflow.
Worked example
Ethan, a operations coordinator, A site inspector has dozens of camera filenames and needs renamed copies such as NORTHPUMP_2026-08-10_001.jpg through the final sequence while preserving the original files.
Example inputs
- prefix = NORTHPUMP_2026-08-10
- separator = _
- start = 1
- digits = 3
Calculation / processing
Prefix = NORTHPUMP_2026-08-10, separator = underscore, start = 1, digits = 3.Sequence 1 padded to three digits becomes 001.The first pattern is NORTHPUMP_2026-08-10_001.ext, then 002, 003 and onward.
The preview shows the naming rule before it is applied. This helps users verify ordering and padding rather than discovering an unwanted pattern after a large batch is renamed.
Assumptions
- The selected file order is the order used for numbering.
- Original extensions are retained.
Limitations
- The tool does not infer semantic filenames from file content.
- Characters considered unsafe on common file systems are rejected in the prefix.
Common questions
Does the tool change file extensions?
No. The rename pattern changes the basename while preserving the existing extension.
Why use zero padding such as 001?
Fixed-width numbers sort more predictably in many file browsers and document-management systems.
Can I start at 20 instead of 1?
Yes. The starting sequence number is configurable.
Methodology sources
This page uses basic mathematical or ToolLott implementation logic that does not require an external factual source. The worked result is still tied to the production tool and QA example.
Related ToolLott tools
A realistic way Ethan could use this tool
Ethan is a operations coordinator.
A site inspector has dozens of camera filenames and needs renamed copies such as NORTHPUMP_2026-08-10_001.jpg through the final sequence while preserving the original files.
Ethan runs the example with prefix = “NORTHPUMP_2026-08-10”; separator = “_”; start = 1; digits = 3. Processing that specific set gives Rename pattern: NORTHPUMP_2026-08-10_001.ext onward, making the result reproducible instead of relying on a generic claim about what the tool should do.
For this scenario, Rename pattern: NORTHPUMP_2026-08-10_001.ext onward. Ethan can use that specific result to renamed copies such as NORTHPUMP_2026-08-10_001, while keeping the stated assumptions separate from the calculation itself. The page also keeps this limitation explicit: No new external service or backend is introduced.
Fictional scenario using realistic example data. For Ready tools, the worked result is tied to the tested example shown in the tool. Replace the figures with your own inputs and independently verify important professional, financial, legal, health or safety decisions.
What this tool is for
Use it to create renamed copies of selected files with a prefix and numbered sequence while preserving their extensions.
It sits within ToolLott’s File Utilities collection, where you can also convert CSV and Excel files, HEIC photos and audio/video formats, clean spreadsheets, ZIP or unzip files, and batch-rename files.