Parse Dates in Excel Files Online
Parse and convert date columns in Excel files between formats and timezones directly in your browser. Supports ISO 8601, US/EU dates, Unix timestamps, and custom patterns — no upload required.
How to parse Dates in Excel files
- Drop your file. The first column is preselected, and the output name defaults to that column name plus _parsed.
- Pick the column to parse. The list shows each column's detected type, so you can see whether it is already a DATE or TIMESTAMP or still text.
- Choose the input format: Auto-detect, ISO 8601, US date (MM/DD/YYYY), EU date (DD/MM/YYYY), Unix epoch in seconds or milliseconds, or a custom strptime pattern.
- Leave both timezones on UTC unless you need a conversion, then pick an output format: ISO 8601, date only, US date, EU date, Unix epoch seconds, or a custom strftime pattern.
- Click Parse Dates, check the preview, and download. The parsed column replaces the original column in the same position. A message tells you how many values could not be parsed.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
A hotel booking system exports check-in times as ISO-style timestamps. The UK finance team wants plain DD/MM/YYYY dates, and one booking still has "TBC" instead of a date.
Input (Excel)
Excel workbook, first sheet (Sheet1)
| booking_ref | guest_country | check_in | nights |
|---|---|---|---|
| HB-5520 | IE | 2026-09-14 15:00:00 | 3 |
| HB-5521 | DE | 2026-09-15 11:30:00 | 1 |
| HB-5522 | FR | TBC | 2 |
| HB-5523 | GB | 2026-10-02 18:45:00 | 5 |
Settings
- Column to parse: check_in
- Output column name: check_in_parsed (the default)
- Input format: Auto-detect
- Source and target timezone: UTC (no conversion)
- Output format: EU date (15/01/2024 style)
Result
| booking_ref | guest_country | check_in_parsed | nights |
|---|---|---|---|
| HB-5520 | IE | 14/09/2026 | 3 |
| HB-5521 | DE | 15/09/2026 | 1 |
| HB-5522 | FR | NULL | 2 |
| HB-5523 | GB | 02/10/2026 | 5 |
check_in is replaced by check_in_parsed in the same position, and the other columns are untouched. Auto-detect reads the timestamps and the EU output keeps only the date. "TBC" is not a date, so it becomes NULL instead of stopping the run, and the tool reports 1 value that could not be parsed. The new column is text, because DD/MM/YYYY is a display format rather than a date type.
Working with Excel files
Excel stores dates as serial numbers with a display format. When a cell has a date format, the loader writes it as ISO text such as 2026-03-02, or 2026-03-02 09:45:00 when it holds a time. The column then arrives as DATE or TIMESTAMP whatever style it showed, so there is often nothing to parse. The time part is kept even if the cell format hides it. Check the type shown for the column before running this tool.
Parse Dates is still the right tool for dates stored as text, from a leading apostrophe, a paste or an export. Text like 1-Jun-26 stays VARCHAR, so parse it with a pattern such as %d-%b-%y. A text column like 3/2/26 may be detected as dates, but the order is guessed. If no day is above 12 it reads day-first, so 3/2/26 becomes 3 February. A date in General format arrives as a serial like 46083 and needs a date format in Excel. The parsed values are written to a new workbook as text cells, not Excel dates. They look right, but formulas treat them as text until you convert them. ISO output is the easiest to convert back later with DATEVALUE.
Frequently Asked Questions
Do I need Parse Dates for a normal Excel date column?
Usually not. Cells with an Excel date format load as DATE or TIMESTAMP whatever their display style, and the time part is kept even if the cell hides it. Parse Dates is for dates stored as text, such as 1-Jun-26 typed with a leading apostrophe.
Are the parsed values saved as real Excel dates?
No. They are written as text cells in the format you chose. Use DATEVALUE, or Text to Columns with a date column type, in Excel if you need date serials.
What happens to values that cannot be parsed?
They become empty (NULL) in every mode, and the rest of the column is parsed. After the run the tool tells you how many values failed, so you can check them. Empty cells are not counted as failures.
How does the time zone conversion work?
The source zone is where the times were recorded, and the target zone is the one you want. 14:00 US/Eastern in July becomes 18:00 UTC, and 14:00 in January becomes 19:00 UTC, because daylight saving time is applied. Unix epoch values are always read as UTC, whatever the source zone says.
Does the tool keep the original column?
No. The parsed values replace the source column in the same position, under the output column name. Keep a copy of the original file if you need both.
What type is the parsed column?
Text for every output format except Unix epoch seconds, which is a whole number. ISO 8601 output looks like 2026-09-14T15:00:00 and date-only output like 2026-09-14. Cast the column to DATE or TIMESTAMP afterwards if you need a typed column.
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