Ant Renamer is a batch renamer for files and folders on Windows, written by a single developer, released under the GNU GPL version 2 or later, with the source code open. The project description makes a point of saying this is an old tool, started in 2003 and still maintained today, and that it handled Unicode filenames back then, which meant Chinese and Japanese names came through without turning into garbage. For the era, that was a notable piece of engineering rather than a footnote.

Renaming broken into separate actions

The design does not ask you to fill in a naming template. It asks you to pick actions and then stack them. The documented list runs: change the extension, replace one run of characters with another, insert characters, move characters, delete characters, number files in sequence, build a name from the ID3 tags of an audio file, build one from the file's last-modified date and time, generate a random name, convert case, take names from a prepared list or a file, read EXIF information, and use a regular expression. When several things need to happen at once, several actions are queued and run in order, each one acting on the result the previous one produced.

That arrangement suits the case the tool is actually bought for: one rule applied to a whole pile. Several hundred photographs sorted into shooting order, or a batch of downloaded documents given a common prefix, stop needing to be touched one at a time. What the program changes is the name, and only the name; the contents of the files are never rewritten, which is the reason a mis-typed rule costs a rename rather than a recovery job.

Building names out of what the file already carries

A few of those actions take the file's own metadata as raw material. Photographs are read through EXIF, music through ID3, and the regular expression action handles files whose names already follow a predictable pattern but need the parts reshuffled. The release notes show the pattern matching being moved onto a new regular expression engine in 2.13, and both the date-and-time action and the EXIF action gaining an offset option, which exists to correct a timezone or a clock that drifted.

Version 2.13 also carries a change that only makes sense on Windows: more sensible handling of daylight saving time for file timestamps, so that names built from a modification date agree with what newer Windows releases report. The notes say the option is on by default from Windows 7 upward. In the same release, the table used for multiple string replacement learned to copy and paste, which sounds minor until you have typed forty substitutions by hand.

Version, size, and where it comes from

The current version is 2.13.0, with a program date of 2024-12-14 and a package last updated on 2025-09-20. Two forms are offered: a full installer at 1.15 MB, and a portable ZIP at 1.19 MB. The size stays that small because the program draws a native Windows interface and bundles neither a runtime library nor an installer shell around itself. One thing worth knowing: the 2.12.0 that circulates online is not the current build. That release is dated 2015-07-04, almost nine years earlier than this one.

On compatibility, the documentation states the program has been tested from Windows 98 and NT4 all the way up to the current Windows 10 and Windows 11. Unicode filename support is limited to NT-kernel systems, which happens to cover every modern Windows. The interface is translated into roughly twenty-five languages, Simplified and Traditional Chinese among them, so a Chinese-speaking user can start without translating menu items in their head first.

The position Ant Renamer takes is modest: free, open source, extremely small, and willing to list each action a batch rename might need and let you combine them. The project has run from 2003 to 2.13, the interface style stopped somewhere in the past, but the capabilities keep getting patched, with the regular expression engine, the EXIF offset and the daylight saving handling all still moving.