Standardize Excel Dates Online
Convert mixed text dates, serial numbers, and conflicting date formats into clean, database-ready ISO YYYY-MM-DD.
Drop Excel (.xlsx, .xls) or CSV here
Supports up to 100,000 rows. Files are never stored or trained on.
Stop Fighting Mixed Excel Date Formats
When spreadsheets combine US dates (04/05/2024), European dates (05/04/2024), and Excel serial integers, database imports crash.
ISO 8601 Uniformity
Standardize inconsistent strings like '15/03/2024' and '2024.03.15' into database-compliant '2024-03-15'.
Serial Date Recovery
Automatically identifies 5-digit raw Excel timestamps and converts them back to genuine calendar dates.
Zero Destructive Loss
Verify every date transformation in the Before/After Diff table before exporting the result.
Frequently Asked Questions
Frequently asked questions about standardizing and fixing Excel dates.
Why does Excel store dates as random 5-digit numbers like 45321?
Excel internally stores dates as serial numbers counting days since January 1, 1900. When formatting is lost during CSV export or copy-paste, they appear as numbers. Our engine recognizes serial dates and restores readable ISO calendar dates.
How does it handle ambiguous US (MM/DD) vs European (DD/MM) dates?
The Agent analyzes the distribution across the entire column to determine the predominant date convention before executing standardization.
Can I choose my desired output date format?
Yes. You can output to ISO standard YYYY-MM-DD (recommended for databases and CRM imports), DD/MM/YYYY, or MM/DD/YYYY.
Does this repair dates that Excel misclassifies as text?
Yes. Text-based dates like '2024.03.15', '15-Mar-2024', or '2024/03/15 14:00' are parsed and standardized into clean date values.
Are blank or invalid dates overwritten?
No. Blank cells remain blank, while unparseable anomalies are flagged in the health scorecard for your inspection.
What file types can I upload?
Excel (.xlsx, .xls) and CSV spreadsheets up to 100,000 rows.
Is the date conversion preview free?
Yes. The diagnostic scan and Before/After Diff table are 100% free to inspect.
How much does it cost to download the repaired spreadsheet?
$4.90 for a Single Clean Job or $1.49/file with a 10-Job Pack.