A column with 03/04/2026, 2026-04-03 and 'April 3, 2026' looks fine until you sort it or build a monthly pivot. Some of those values are real dates, some are text, and some may be read as March 4 instead of April 3. Fixing dates means finding which is which before converting.
Plumb is built on a simple idea: the data your business runs on should be trustworthy before anyone draws conclusions from it. Cleaning, checking and reshaping data should not need macros, scripts or a weekend. Plumb keeps your files private, shows every change it proposes, and lets you approve fixes instead of hunting for problems by hand.
How Plumb helps: Data transformation
Plumb's data transformation detects every date pattern in a column, flags ambiguous values (like 03/04 that could be either day-first or month-first), infers the most likely format from the rest of the column, and converts everything to one standard such as ISO 8601 (YYYY-MM-DD).
How It Works
The core idea: turn every value into a real Excel date (a number), then format it however you like.
- Spot text dates: =ISNUMBER(A2) returns FALSE for dates stored as text. Left-aligned dates are usually text.
- Convert simple text dates with =DATEVALUE(A2), then format the cell as a date.
- For a whole column, use Data > Text to Columns > Delimited > Finish, choosing the column format DMY or MDY to match the source.
- Resolve day/month ambiguity by checking values above 12 in the first position: if any exist, that position is the day.
- Apply one display format with Format Cells > Custom, for example yyyy-mm-dd.
- In Plumb: upload the file, review the detected date patterns and ambiguous cells, confirm the source format, and export with one consistent format.
Where This Helps
Multi-region exports
Combine US (MM/DD) and European (DD/MM) system exports without swapping days and months.
Time-series reports
Make monthly and weekly pivots work by converting text dates into real dates.
System imports
Prepare dates in ISO format before loading them into a database or BI tool.
Try Plumb in early access
Plumb is in early access. Join the waitlist on tryplumb.pro to get an invite. Early access covers Excel (.xlsx), CSV and JSON files, and we are adding more sources as people ask for them. Your files are processed privately and are never used to train models.
One column, one date format
Now you have a repeatable way to do it, by hand or with Plumb. Join the waitlist and tell us what your data looks like; we read every reply.
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