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Julian Date Converter

Convert between Julian ordinal dates (YYDDD, YDDD, YYYYDDD) and Gregorian calendar dates — essential for payment settlement, batch processing, and mainframe systems

📅 Conversion

Enter a Julian date in YYDDD (5-digit), YDDD (4-digit), or YYYYDDD (7-digit) format.

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📖 About This Tool

What is the Julian Date Converter?

The Julian Date Converter translates between Julian dates (YYDDD format) and Gregorian calendar dates. Julian dates are used in ISO 8583 Field 13 (Date, Local Transaction) and settlement file naming.

🛠️ How to Use
  1. Select the conversion direction.
  2. Enter a Julian date (YYDDD) or Gregorian date.
  3. View the converted result.
❓ FAQ

Where are Julian dates used in payments?

Julian dates appear in ISO 8583 date fields, settlement and clearing file names, batch processing timestamps, and HSM audit logs in YYDDD format (2-digit year + 3-digit day of year).