Compare instants, not clock faces
A fictional shift starts at 01:30 with an offset of +10:00 and ends at 03:30 with +11:00. The wall clock advances two hours, but only 60 minutes elapse. At A$80 per hour with no entered break, the reference amount is A$80. The example illustrates offset arithmetic; it is not confirmation of a roster, location or billable entitlement.
Enter the offset for each endpoint
Use dated records with an explicit offset at the start and end. An overnight shift needs different dates when it crosses midnight. The checker does not look up a city, daylight-saving calendar or time-zone history. If either offset is uncertain, verify it before using the result. A positive interval of up to seven days is supported.
Separate time measurement from billing
Deduct only the breaks that your billing agreement excludes. Remaining elapsed time is a calculation input, not a payroll award, overtime determination or NDIS claiming rule. Review the agreement and put the service date, period and agreed amount into the invoice tool manually. The checker does not start a timer or change an existing draft.
Keep a review record
Run the check again whenever an input changes. Invalid or incomplete input clears the previous live result and disables download, so an old answer is not presented as current. Downloads contain the check table only; they are not a tax invoice, payment receipt or successful invoice export. They do not update drafts, history, login or payment status.
Bureau of Meteorology: time zones and daylight saving · Reference for the underlying recordkeeping or calculation concept; not an endorsement of this helper.