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Sample & Dummy File Generator — Any Size, Any Format

Create valid test files of an exact size in 22 formats — text, data, code, images, audio, PDF and ZIP.

A sample file generator creates valid, openable test files at a size you choose. Pick a format — text, CSV, JSON, XML, SQL, code, PNG, GIF, WAV, PDF or ZIP — set the target size and how many files you need, and each one is built in your browser to that exact byte count.

Runs in your browser
Formats
22 — TXT, MD, LOG, CSV, TSV, JSON, NDJSON, XML, YAML, SQL, HTML, JS, TS, PY, ENV, PNG, BMP, GIF, WAV, PDF, ZIP and raw BIN
Size range
1 byte to 64 MB per file, up to 256 MB per batch
Batch size
Up to 200 files per run, optionally varied around the target
Validity
Real encoders — every image, audio file, PDF and archive opens normally
Privacy
Runs entirely in your browser — nothing is uploaded
Cost
Free, unlimited, no sign-up

Frequently asked questions

Are the generated files actually valid?

Yes. PNG, BMP and GIF are encoded pixel by pixel, WAV contains real audio samples, PDFs are built with a proper PDF writer and ZIPs are real archives. They all open in ordinary software.

Why is my ZIP not exactly the size I asked for?

Archive size depends on how well the contents compress. The generator stores entries uncompressed to keep it predictable, but the central directory adds a small fixed overhead per entry.

What are the three content options for?

Random bytes are incompressible and represent the worst case for a compression or storage test. Zeros compress almost perfectly and represent the best case. Realistic content sits between the two, matching what real uploads do.

Is anything uploaded?

No. The files are assembled in your browser and handed straight to the download — they never touch a server, which is also why there is no size cap beyond your device memory.

How to use the sample file generator

  1. 1Choose the file format.
  2. 2Set the how many files.
  3. 3Choose the size driven by.
  4. 4Set the pages per document.
  5. 5Set the target size.
  6. 6Choose the size unit.
  7. 7Set the size variance.
  8. 8Choose the content.
  9. 9Choose the archive contents.
  10. 10Enter or paste your file name pattern.
  11. 11Enter or paste your seed.
  12. 12Turn "Download batch as one ZIP" on or off as needed.
  13. 13Press Run, then download the result when it is ready.

Embed this tool

Put the working sample file generator on your own site. It runs in your visitors' browsers exactly as it does here — free, no account, nothing uploaded.

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