DOS 8.3 Filename Generator

Validate and convert filenames to DOS 8.3 format. Batch process lists, handle collisions, and export a clean mapping.

Input

Single filename

Type a filename to validate and convert instantly.

Batch list (one per line)

Paste a list to generate a collision-safe 8.3 mapping.

Space handling

Accents and diacritics

Case

Tilde collisions

Avoid reserved DOS device names (CON, PRN, AUX, NUL, COM1–9, LPT1–9, CLOCK$, CONFIG$)

Single filename result

Original

Valid 8.3

8.3 name

Reason / notes

Batch results

#	Original	Valid 8.3	8.3 name	Reason / notes

If two names collide, a tilde suffix is added, for example REPORT~1.TXT, REPORT~2.TXT.

What counts as DOS 8.3

Up to 8 characters for the name, up to 3 for the extension.
Only one dot, used to separate the extension.
Allowed characters are letters, digits, and these: ! # $ % & ' ( ) - @ ^ _ ` { } ~
Disallowed include spaces (commonly), and characters like . " / \ [ ] : ; | = , + ? * < >
Reserved device names are not allowed: CON, PRN, AUX, NUL, COM1–COM9, LPT1–LPT9, CLOCK$, CONFIG$.

This tool normalises your names to match these rules, strips accents if you choose, and applies a tilde number when two names would clash.

Tips

When preparing files for disk images or retro PCs, export the CSV and keep it with your project so others can track the mapping.

If you need a strict “no spaces ever” policy, set spaces to Remove. If you want readability, pick underscores.

Related tools

Why 8.3 still matters

Short names are still useful when working with legacy systems, old games, firmware updaters, and bootable tool disks. If a name is longer than 8.3 or contains disallowed characters, you can hit errors when writing to FAT12 or FAT16 media. This tool gives you a clear, repeatable mapping from modern filenames to safe 8.3 names.

How collisions are handled

If two names would become the same after cleaning, the base is shortened and a tilde number is appended, for example REPORT~1.TXT, then REPORT~2.TXT. The base never exceeds eight characters once the tilde and digits are added.