Purpose and scope
What this technical calculator produces
Convert a UTC timestamp into Julian Date and Modified Julian Date.
The Julian Date and Modified Julian Date Converter creates a readable value from UTC timestamp and Decimal places; Save Decimal places beside the copied output.
Instructions
How to use this calculator
Confirm UTC timestamp and Decimal places from the Julian Date and Modified Julian Date Converter reference data, then evaluate Decimal places with the required technical convention.
- Confirm UTC timestamp and Decimal places exactly as supplied by the reference data.
- Create the Julian Date and Modified Julian Date Converter conversion and evaluate Decimal places with the copyable output.
Calculation
Method used
Julian Date is derived from the Unix epoch relationship and Modified Julian Date subtracts 2400000.5.
The Julian Date and Modified Julian Date Converter relates UTC timestamp and Decimal places to the converted value; save the Decimal places precision or unit convention.
Calculation method last reviewed: June 21, 2026.
Worked scenario
Example calculation
Evaluate the Julian Date and Modified Julian Date Converter worked value with Decimal places, then trace its precision and format.
Interpretation
Validating the generated output
The conversion treats the input as UTC and does not substitute TT, TDB, or UT1 astronomical scales.
Trace the Julian Date and Modified Julian Date Converter output against Decimal places before sending its unit, epoch, or syntax elsewhere.
The Julian Date and Modified Julian Date Converter handles this calculation; the GPS Week and Time-of-Week Converter can then convert UTC time into GPS week and seconds-of-week using an entered offset.
Boundaries
Important edge cases and limitations
The input is treated as UTC; TT, TDB, UT1, and leap-second handling are not represented.
Replace the Julian Date and Modified Julian Date Converter convention when Decimal places uses another epoch, precision, or syntax rule.
Input audit
Checklist for this calculation
- Trace the Julian Date and Modified Julian Date Converter unit or epoch in UTC timestamp and Decimal places.
- Evaluate Decimal places with the Julian Date and Modified Julian Date Converter copyable output.
Questions
Frequently asked questions
Why does a Julian Date change at noon UTC?
The traditional Julian day begins at noon, while Modified Julian Date begins at midnight.
Should UTC timestamp be compared with the raw julian date and modified julian date converter output before copying it?
Compare the Julian Date and Modified Julian Date Converter human-readable result with its raw unit, epoch, or syntax form. A correct-looking Julian Date and Modified Julian Date Converter label can still be unsuitable under the Decimal places convention.
What should be saved with a julian date and modified julian date converter result?
Attach Decimal places to the saved Julian Date and Modified Julian Date Converter result and retain UTC timestamp and Decimal places from the same run; units and calculation date complete the audit trail.