Meeting Planner Time Zone Converter

The Meeting Planner Time Zone Converter computes meeting planner time zone from the relation destination hour = (source hour + (destination UTC offset - source UTC offset)) mod 24. It takes 3 inputs (meeting hour in source zone 0 to 23 in h, source utc offset in h, destination utc offset in h) and returns the meeting planner time zone. These are for anyone working to a fixed calendar or clock: people setting deadlines and milestones, teams and travelers coordinating across regions, administrators counting notice or waiting periods, and anyone planning a personal date or a daily routine, and the result gives you the specific date, time, count or label you can put on a calendar or confirm to someone else. Enter your values below and the result updates instantly, and you can share a permalink that pre-fills the exact calculation. Enter each date or time exactly as it is recorded, note the time zone and stick to a single clock convention (24-hour, or 12-hour with AM and PM) whenever a value carries a time of day, and where a span is involved decide up front whether the start day or start time counts toward the total, since an inclusive versus exclusive endpoint and an unnoticed daylight saving shift are the usual reasons two people get different answers from the same starting point. For example, with meeting hour in source zone 0 to 23 = 9 h, source utc offset = 0 h, destination utc offset = 9 h, the meeting planner time zone works out to 18, and the worked example further down the page shows every step so you can follow the arithmetic and reproduce it by hand. The method is the standard form documented by NIST Time and Frequency Division, and the figure above each result carries the date it was last verified. This is arithmetic over the calendar and clock, so it reports what the dates and times themselves add up to rather than what a particular deadline or routine requires: an employer or institution that counts business days, public holidays and cut-off times by its own rules, a region that shifts its clocks or observes different holidays, and ordinary variation in what a personal schedule has to accommodate can all move the practical answer away from the calculated one.

With Meeting hour in source zone 0 to 23 = 9 h, Source UTC offset = 0 h, Destination UTC offset = 9 h, the result is 18.

Formula: destination hour = (source hour + (destination UTC offset - source UTC offset)) mod 24. Source: NIST Time and Frequency Division, as at 2026-06-23.

Meeting Planner Time Zone18

Applies to: any numeric inputs. Method source: NIST Time and Frequency Division, checked 2026-06-23.

The formula

destination hour = (source hour + (destination UTC offset - source UTC offset)) mod 24

Worked example

With Meeting hour in source zone 0 to 23 = 9 h, Source UTC offset = 0 h, Destination UTC offset = 9 h:

  1. offset difference: 9 - (0) = 9
  2. shift source hour: 9 + 9 = 18
  3. wrap into 0 to 23: 18
  4. Meeting Planner Time Zone = 18

This worked example is one of the automated golden-value tests this calculator must pass before it can publish.

What this assumes

  • Inputs are real numbers in the units shown.
  • The result is the exact value of destination hour = (source hour + (destination UTC offset - source UTC offset)) mod 24; general information, not professional advice.

Frequently asked questions

What formula does this use?

destination hour = (source hour + (destination UTC offset - source UTC offset)) mod 24, the standard form documented by NIST Time and Frequency Division.

Does the result ever change over time?

No. This is a pure formula with no external rate, so the same inputs always give the same result.

Official sources and verification

Reviewed by the CalculatorHub team, edited by James Graham, 2026-06-23. See our methodology. General information, not professional advice.