BasisFile guide
Standardise Date Formats in Excel Automatically — A 30-Second Fix
You've got a CSV where some dates look like '15/01/2026' and others look like '2026-01-15' or 'Jan 15, 2026'. Excel won't sort them properly until they're all the same format. Doing it manually means TEXT, DATEVALUE, MONTH, DAY, and YEAR functions in some unholy nest — and you'll still get the UK/US ambiguity wrong on a few rows.
How BasisFile fixes this in 30 seconds
- 1
Upload your CSV (or Excel file)
Drag and drop. BasisFile reads the date column even if dates are stored as text.
- 2
AI detects every date format used
It shows you each format it found — DD/MM/YYYY, MM/DD/YYYY, ISO, written-out — and how many rows use each. You confirm UK vs US for ambiguous dates like '03/04/2026'.
- 3
Pick a target format and download
Recommended is ISO YYYY-MM-DD (sortable, universal). Or pick UK, US, or written-out. You get a clean file in seconds.
Before vs after
One column, four formats → one tidy ISO column.
Before
| Order ID | Order date |
|---|---|
| 1001 | 15/01/2026 |
| 1002 | 2026-01-16 |
| 1003 | Jan 17, 2026 |
| 1004 | 18-Jan-2026 |
| 1005 | 19/01/26 |
After BasisFile
| Order ID | Order date |
|---|---|
| 1001 | 2026-01-15 |
| 1002 | 2026-01-16 |
| 1003 | 2026-01-17 |
| 1004 | 2026-01-18 |
| 1005 | 2026-01-19 |
Most users go straight to Pro
The free tier is enough for occasional cleanup. If you do this weekly, Pro pays for itself the first Monday.
Pro
- Unlimited file cleans
- Up to 100,000 rows per file
- No watermarks on output
- Save merge & cleaning templates
- Cancel anytime
Frequently asked questions
What date formats does it recognise?
UK (DD/MM/YYYY), US (MM/DD/YYYY), ISO (YYYY-MM-DD), written-out forms ('Jan 15, 2026', '15 January 2026'), short-year forms ('15/01/26'), and most others. Ambiguous dates are flagged for you to confirm.
Will it convert dates that are stored as text?
Yes. Most exported CSVs store dates as text, which is why Excel won't sort them. BasisFile parses the text and outputs proper ISO dates that Excel and any BI tool will recognise as real dates.
Can I keep dates as text vs Excel dates?
Yes — configurable in download options. Output as plain text strings (for systems that need a specific string format) or as Excel-recognised date values.
Does it handle timezones?
It preserves UTC by default. If your dates include timezone offsets, you can convert to a specific timezone (Europe/London, America/New_York, etc.) on the way out.
What about dates spread across multiple columns?
If your file has separate Year/Month/Day columns, BasisFile combines them into one ISO date column. Same for Date + Time pairs.
Stop wasting Mondays on data hygiene
Drop your file, get a clean one back in 30 seconds. No signup needed for the free tier.
Try free — no signup required