This guide shows a repeatable workflow to convert csv to excel cleanly (preserve columns, dates, and leading zeros) using browser‑based tools. All processing happens locally in your browser (no uploads), which is especially useful for sensitive documents.
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Why Excel breaks CSVs
Excel guesses data types. That can convert IDs into scientific notation, remove leading zeros, and misinterpret dates.
Safe conversion approach
Use a dedicated converter so each field remains intact and columns are preserved.
Workflow
1) Convert CSV to XLSX. 2) Review columns with IDs (postal codes, product IDs). 3) If you need to share again, export XLSX back to CSV with consistent formatting.
Pro tip for submissions
If the portal is strict about file size, compress the final Office file (or remove embedded objects) before upload.
Quick checklist (before you download)
- Open the output at 100% zoom and check the most important page.
- Confirm page order and page count are correct.
- If you will email or upload the file, verify size limits first.
- Keep a “submitted” copy unchanged once you send it.
Recommended next steps
These internal links help you complete the full workflow faster:
Tools
- CSV to Excel — Convert CSV to XLSX in your browser.
- Excel to CSV — Export a clean CSV back out.
- JSON to CSV — Convert JSON datasets to CSV.
- CSV to JSON — Convert CSV to JSON for apps/APIs.