Dates, clock times and durations

Dates and clock times

Machine dates use YYYY-MM-DD. The date must exist in the calendar. Clock-time inputs support 24-hour HH:MM or explicitly selected 12-hour time with AM or PM. In 12-hour notation, 12:00 AM is 00:00 and 12:00 PM is 12:00. A clock reading is not a duration.

Durations

An HH:MM duration contains hours and a minute part from 00 to 59. Its hours may exceed 24: 27:30 is a 27-hour 30-minute duration. Duration arithmetic can represent signed values where the tool allows them; a negative duration is not a valid ordinary shift length. Follow the field’s label and validation message.

Decimal hours

Use a point for decimal hours in this interface. 7.50 means 450 minutes; 7.30 means 438 minutes, or 07:18. Do not enter grouping or thousands separators; they are not silently removed.

Fractions of a minute

The record model has minute precision. A decimal input that produces a fraction of a minute is rejected by default. If an explicit nearest-minute choice is offered, review that choice before accepting the converted amount. The original precision must not be silently removed.

For example, 0.01 hours is 0.6 minute, not an exact whole-minute record. A two-decimal report may already be rounded, so converting it back cannot always recover the original input.

Correcting an input

An error keeps the value you typed. Read the field-level message, correct the format or date, then check the result again. For a missing end time, saving a draft is different from fabricating an end. The parser does not infer a timezone, a daylight-saving offset or an overnight date from an earlier clock time.

Sources and method

• NIST SP 330, Section 4, Table 8Time-unit definitions only; not a payroll authority or product endorsement.