Updated
Calendar dates use the Gregorian / ISO calendar from 1900 through 2100. Invalid dates and ambiguous date orders are rejected. Date differences count calendar days; elapsed durations measure the UTC timeline.
One pinned Temporal polyfill provides date and zone semantics. Named IANA zones use the host browser’s installed time-zone rules. We cannot identify its exact tzdb version, and future political changes may alter future conversions.
Simple durations use bounded integer seconds. Decimal hours are parsed using exact base-10 rational arithmetic and rounded once to the nearest second, with ties away from zero. Display rounding does not change totals.
Calendar addition combines years and months before applying weeks and days. Month/year overflow clamps unless reject is chosen. Calendar-component differences use Temporal’s years-first decomposition.
Business intervals are half-open [start, end). Open intervals must be ordered, non-overlapping, and within one day. Custom closures are user-entered dates; no legal holidays are inferred. Business calculations are bounded to 1,830 dates.
Meeting suggestions examine actual instants at 15-minute steps over at most 14 days. Every participant must fit the complete duration. Ranking minimizes total local-hour distance from noon, with earliest instant as the tie-breaker. Weekly preview recomputes twelve local anchor occurrences and flags participant changes.
Live clocks and countdowns use the device clock, not a network time service. Timers measure elapsed time with a monotonic clock, so changing the device clock does not add or remove time. Sleep time may be excluded on some devices. Sound is not guaranteed while asleep, suspended or closed.
Conventional Unix/JavaScript time is used; leap-second inputs are rejected. Calculations do not determine payroll compliance, taxes, legal deadlines, or calendar-account availability.
Pay and time-off estimates
Hourly-to-salary multiplies the hourly rate by weekly hours and paid weeks. Salary-to-hourly divides annual salary by that same scheduled-hour total. Neither adds overtime premiums, taxes, benefits, or unpaid time automatically.
Overtime estimates separate one workweek into regular hours up to your chosen threshold and excess hours paid at your chosen multiplier. The pay time card subtracts unpaid breaks and totals seven days before applying those settings. It uses wall-clock shift lengths; use the dated timesheet to check elapsed hours across a clock change.
PTO accrual adds earnings from eligible hours or completed periods, applies an optional balance cap, then subtracts time used. Pay-period dates are inclusive, with a calendar-day lag for payday. Neither tool infers employer rules, bank holidays, carryover, or legal entitlements.
Sources and reference data
Named time zones follow IANA identifiers and the rules available to your browser. The date and time library implements Temporal’s distinction between calendar dates, local clock readings, and exact instants. City names come from GeoNames; the downloadable source record documents attribution and transformations.
These references explain the underlying concepts and data. They do not endorse TrueHour. For a future appointment affected by a recent time-zone change, confirm the local time with the organizer and keep your browser and operating system up to date.
Checking a result and reporting corrections
Start with a small example you can calculate independently, then check the date range, units, time zone, endpoint inclusion, and rounding settings. Two tools can disagree because they answer different questions: calendar days are not always 24 elapsed hours, and decimal hours are not hours-and-minutes notation.
For a suspected error, use the Contact page and include a minimal example, the expected answer, and the actual answer. Replace personal or payroll information with made-up values that reproduce the issue. Content dates change when the relevant page is revised, rather than on every visit or rebuild.