Writing Dates

Every chart type that reads dates — gantt, timeline, event-line, countdown, and pert — shares one date grammar. Write dates however feels natural; Diagrammo normalizes them internally, so the rendered output is identical no matter which form you type.

Formats

All of these mean the same day:

Datetimes work where the chart supports a time: 2026-07-04 14:30. Timeline also accepts era-signed years like 753 BCE and 14 CE.

Numeric dates are US month-first

7/4 is July 4th by default (month-first). Two ways to change that:

• Add date-order dmy once at the top and every numeric slash/dash date reads day-first — 7/4 becomes April 7th.
• Or just use a month name — Jul 4 and 4 Jul are never ambiguous and ignore date-order entirely.

Out-of-range numbers sort themselves out regardless: 13/2 can only be Feb 13.

You rarely need to type the year

Leave the year off a date and Diagrammo fills it in, in this order:

1. A year on the date itself always wins.
2. A year 2026 line anywhere in the chart sets the base year for every bare date below it.
3. A neighbouring dated row. Timeline and event-line carry the year forward from the last full date and roll into the next year when a month falls earlier (a November start followed by a January row lands in the next year). Gantt and PERT anchor every bare date to the project’s start date.
4. This year, as a last resort — only if the chart has no full date at all. You’ll see a gentle hint suggesting you add year 2026 so the chart looks the same next January.

So you only write the year once — one year line covers every bare date below it:

event-line Launch Week
year 2026
  Mar 3 Kickoff
  3/10 Beta opens
  03-24 Press embargo lifts
  Apr 2 Public launch

Directives

These work in any date-bearing chart, and it doesn’t matter whether they appear before or after the dates they affect:

Era, marker, and holiday bands (gantt and timeline) accept the same formats. Existing charts written in ISO keep working unchanged — this is an addition, not a migration.