How TimeBridge thinks about time

One instant, many local times

Internally there is only ever one thing: an absolute instant. Each city converts that same instant into its own local wall-clock time using real IANA rules for the date in question. Absolute instant, local time and timezone identifier are kept as three separate ideas, which is what stops the classic bugs — a meeting that silently shifts an hour, or a date that slides backwards because the browser is in a different zone.

Planning dates are handled as calendar dates, never as instants, so 2026-09-15 stays the fifteenth no matter where you open it.

Daylight saving is not an afterthought

Offsets are never hardcoded. Dublin is UTC+1 in July and UTC+0 in January; New York is UTC−4 and then UTC−5, and the two regions change on different dates. TimeBridge calculates the correct offset for the exact date being viewed, which is also why the timeline for a clock-change day is genuinely twenty-three or twenty-five hours long instead of pretending to be twenty-four.

Local times that occur twice, or never occur at all, are named rather than guessed. The converter will tell you which one you have hit and let you choose.

How a slot is scored

Every candidate meeting is scored for each person from the hours they configured:

• Inside preferred meeting hours scores highest
• Inside working hours scores well
• Just outside, but within their stated flexibility, scores modestly
• Further outside decays steadily
• Very early, late evening and night are capped regardless of configured hours
• A non-working day is heavily penalised; an unavailable window removes the slot entirely

A meeting is sampled across its whole duration, not just its start, so a two-hour meeting that runs into someone’s evening is scored as what it is.

Why fairness is separate from quality

The obvious approach — pick the largest overlap — reliably produces meetings that are excellent for most people and miserable for one. So the ranking blends three things: the average comfort, the score of the worst-off participant, and how evenly the discomfort is spread. A slot that is perfect for two and impossible for a third loses to a slot that is merely good for all three.

For standing meetings, Fair Rotation goes further. It tracks how much inconvenience each city has accumulated and steers later occurrences away from whoever has borne the most, so the same team is not taking the 06:00 call every single week.

What TimeBridge refuses to assume

It does not know when your team eats lunch, which days count as a weekend where you are, or whether an 08:00 start is early. Defaults are generic — 09:00 to 17:00, Monday to Friday — and every one of them is yours to change. Explanations only ever reference the hours you configured and neutral clock times.

What it is not

There is no account, no calendar connection, no server-side record, and no model making judgements. See the privacy note for the specifics.