What is a dummy file?

A dummy file is a file of a set size with no meaningful content. It's for tests where only the size matters, such as upload limits, download speeds, disk quotas and progress bars. Need to check that your form rejects anything over 25 MB? Make a file that's one byte bigger.

Tool description

This tool creates a file of an exact size, with any name and extension. Enter the size in B, KB, MB or GB. Here 1 KB is 1,024 bytes and 1 MB is 1,048,576 bytes, so the file matches the size your system shows. Then pick what to fill it with:

  • Zero bytes (0x00), the fastest option
  • Full bytes (0xFF)
  • Random bytes, which don't compress, so they're good for upload tests
  • Repeated text, any text you type, repeated until the file is full

The bytes are generated in your browser, with a progress bar, and the file downloads when it's ready. The extension only changes the name, so a .pdf or .mp4 made here won't open in a viewer.

Examples

  • A 10 MB .bin file to test an upload limit
  • A 1 GB file of random bytes to measure transfer speed
  • A 0 byte file to check how an app handles an empty upload

Features

  • Exact sizes from 0 bytes up to 2 GB
  • Any file name and extension
  • Zero bytes, full bytes, random bytes or repeated text

Limitations

The largest file is 2 GB. If your browser can't create a file that big, the tool asks you to try a smaller size.