Date format converter — mm/dd/yyyy, dd/mm/yyyy & ISO online

The same calendar day can look completely different depending on locale and software defaults. A US export might show 03/15/2024 while a European report lists 15/03/2024 for the identical moment. APIs and databases often insist on yyyy-mm-dd, the ISO standard that sorts lexicographically and avoids ambiguity in JSON.

When you format date values for a migration, a customer ticket, or a one-off script, a dedicated date format converter saves time compared to hand-editing cells or writing brittle spreadsheet formulas. This tool handles bulk lines — paste a column from Excel, convert every row, and paste the result back without sending data to a server.

mm/dd/yyyy is the default US short date: month first, then day, then four-digit year. dd/mm/yyyy and dd/mm/yy follow the day-month-year order common in the UK, India, Australia, and much of Europe. The dd/mm yyyy variant with spaces appears in government forms and legacy mainframe printouts.

yyyy-mm-dd is the ISO 8601 date portion used in PostgreSQL, MySQL strict mode, JavaScript Date.parse hints, and most REST APIs. yyyy/mm/dd mirrors ISO with slashes. dd-mm-yyyy and mm-dd-yyyy swap separators while keeping regional ordering.

Oracle date formats frequently use DD-MON-YYYY, such as 15-MAR-2024, in SQL*Plus listings and TO_CHAR output. Date time formats add clock fields: yyyy-mm-dd hh:mm:ss for logs, mm/dd/yyyy hh:mm for US dashboards, and dd/mm/yyyy hh:mm for European reports.

Knowing which token order a file uses prevents silent data corruption. A dd/mm/yyyy format label on a CSV header does not guarantee Excel imported it correctly — always verify a few known dates before bulk conversion.

Choose a source format or leave Auto-detect when your paste mixes patterns. Select the target format from the dropdown — for example dd/mm/yyyy format to mm/dd/yyyy format when preparing a US vendor file from EU source data.

Paste dates one per line, or drag and drop a .txt or .csv file onto the input panel. Conversion starts immediately; there is no convert button. The output panel updates live as you type or after import. Copy the full block or download a .txt file for re-import into Excel.

Lines that do not match the chosen source format are left unchanged so you can spot outliers. The stats row below the panels shows how many lines converted, how many were skipped, and which formats auto-detection found.

Inside Excel, right-click a column, choose Format Cells, and pick Date to change display locale. That only changes how Excel renders the value — the underlying serial may stay the same. When you need a different string pattern in a CSV export, convert here first, then paste into a new column.

Excel date format confusion often comes from opening a CSV in the wrong regional setting: 03/04/2024 might mean March 4 or April 3. Export the column as plain text, paste into this tool with Auto-detect, confirm the detected pattern in the toolbar, then output yyyy-mm-dd before sharing internationally.

For recurring ETL jobs, note the target pattern in your runbook — excel date formats in documentation should name the exact token order (dd/mm/yyyy vs mm/dd/yyyy) so engineers do not swap month and day during imports.

To format date in Oracle SQL you typically use TO_CHAR(column, 'DD-MON-YYYY') or similar masks. When you copy query results into a spreadsheet, the display may differ from what TO_CHAR produced. Paste raw strings here to normalize them to yyyy-mm-dd for comparison with application logs.

PostgreSQL accepts ISO dates natively. MySQL STR_TO_DATE requires the correct format string — verify with a few rows in this converter before running UPDATE statements on millions of records. Snowflake and BigQuery loads often specify date/time formats in the load job; use this page to prototype the pattern.

Date oracle format searches usually mean DD-MON-YYYY or similar NLS-dependent output. Select Oracle as source or target to translate between MON abbreviations and numeric months without memorizing the full NLS_DATE_FORMAT table.

Payroll dates, contract deadlines, and customer birth dates stay on your device. Clear the input on shared workstations when finished.

Use Unix Time to Date when your source column is epoch integers. Use Date to Unix Timestamp when an API expects seconds instead of formatted strings. Use Time Zone Converter when the same instant must be shown in two regional clocks.