Batch rename files by date and number, offline

Give a folder of camera-named files like IMG_4023.jpg clean, sortable names like 20260926_1.jpg in one run. 1FileTool's Rename by Pattern renames files in place using {name}, {index}, {date} and {ext} tokens — no uploads, no command line.

What you'll need

• 1FileTool 1.10.0 or later on macOS (Apple Silicon or Intel), Windows, or Linux.
• A folder of files to rename.

The ZIP holds 40 synthetic JPGs named the way cameras and phones name them (DSC_*.jpg, IMG_*.jpg, PXL_*.jpg). Extract it to a scratch folder and follow along.

This one matters here: Rename by Pattern renames files in place — there's no output copy to fall back on. When Replace source is on, a rename run can even revert itself and leave your files with their old names. Keep it off.

Steps

1. Open Rename by Pattern

Launch 1FileTool, click Files in the sidebar, and choose Rename by Pattern from the Rename group.

2. Drop in the files

Drag the 40 sample JPGs (or your own folder's contents) onto the drop zone.

3. Write the pattern

In the Pattern field, type:

{date}_{index}

The field's hint lists the tokens: {name} (the original base name), {index} (position in the list), {date} (today's date as YYYYMMDD), and {ext} (the file extension). {date}_{index} yields names like 20260926_1.jpg.

Two details worth knowing:

• The extension is kept automatically. Leave {ext} out and 1FileTool appends the original extension for you.
• {index} counts from 1 with no padding — 1, 2, 3…. For zero-padded numbers like 001, use the Number Sequentially tool instead.

4. Check the order

{index} numbers files in the order they appear in the file list. Sort your folder the way you want it before dropping it in — oldest to newest, say, if you're stamping dates.

5. Run it

Click Run on 40 files. The result card reports the batch, and every file is renamed in place inside the folder it came from.

The result

The 40 sample files went from this:

IMG_4023.jpg  DSC_8062.jpg  PXL_20411.jpg  IMG_4092.jpg …

to this:

20260926_1.jpg  20260926_2.jpg  20260926_3.jpg  20260926_4.jpg …

One run renamed the whole set — each file counts individually against the free plan's 8 files per day, so this batch of five used five.

Want to preview before committing? Rename by Pattern has no live preview. For prefix/suffix renames, the separate Preview Rename tool shows the old name next to the new one before anything changes.

If it didn't work

• Files kept their old names after "ready". Replace source was on — it can silently undo a rename. Turn it off and run again.
• Wrong order. {index} follows the file list order, not the filesystem's. Drop the files already sorted.
• A name collides. If the pattern produces two identical names in the same folder, the rename fails for the collision — include {index} or {name} to keep names unique.
• On Linux, clicking the drop zone opens a folder picker. A known quirk — drag the files onto the window instead.

Try next

Try a prefix/suffix rename in the browser first — Preview Rename shows the old name next to the new one before anything changes:

Related

• Batch rename reference
• Where results land: output folder and Replace source
• Rename by Pattern tool page
• Preview Rename and Number Sequentially