Focused purpose
What this tool does
Normalize CSV or TSV dates to ISO 8601 locally after explicitly confirming a day-first or month-first convention. Preview changed cells without an account.
- ✓ Day-first and month-first parsing
- ✓ Explicit ambiguity decision
- ✓ ISO 8601 date output
- ✓ Existing suffix preservation
Workflow
How to use it
- 01
Select the date columns.
- 02
Confirm the calendar order.
- 03
Preview highlighted changes before export.
Available controls
Available options
- Choose DMY or MDY.
- Apply only to selected columns.
- Leave invalid dates unchanged.
- Preserve existing time and offset suffixes.
Ambiguous day and month
Example before and after
One value establishes day-first while another remains ambiguous.
Before
event,date launch,31/08/2026 review,04/05/2026
After
event,date launch,2026-08-31 review,2026-05-04
Expected result: After choosing day-first, both values convert predictably to ISO dates.
Practical scenarios
Common use cases
Prepare API-ready ISO dates.
Unify exports from several regions.
Find invalid dates before database import.
HONEST LIMITS
Important limitations
- iLocale alone cannot resolve every ambiguous numeric date.
- iThis operation preserves timezone suffixes; it does not convert offsets between zones.
FAQ
Questions about this tool
How are DD/MM and MM/DD distinguished?
You must confirm the convention before conversion; the tool does not decide from locale alone.
Are times and timezones preserved?
Yes. Any suffix following the recognized date is copied verbatim; offsets are not converted.
What happens to invalid dates?
They remain unchanged and are never silently rewritten. Use validation to isolate them separately.