How to sample
Pick 3-5 files at random from each batch of 50+. Open the Markdown output and check: heading hierarchy intact, tables rendered as pipe tables, no garbled characters, code blocks preserved. If one sample fails, inspect the full batch.
What to look for
Systematic defects show up in every sample: missing headings, broken tables, encoding errors. Random defects (one garbled page in an otherwise clean file) are usually source-file issues, not converter bugs.
When to use getmarkitdown.com
MarkItDown Online handles batch conversion with ZIP export and side-by-side preview. Use sampling for large batches where opening every file is impractical. Typical conversions finish in 2-5 seconds per file.