CSV imports can confuse date-based events with timed meetings when the all-day field and time columns disagree. Review that distinction before importing travel days, closures, or deadlines. An all-day event is a calendar presentation choice and does not automatically establish a precise legal or operational cutoff.
Prepare the intended event type
Keep the required Subject and Start Date headers in English. Google’s CSV guidance documents All Day Event as an optional field using True or False. Check the source’s intended meaning instead of inferring it solely from an empty-looking time cell.
Review dates and times together
Inspect Start Date, End Date, Start Time, and End Time where present. Compare a one-day entry, a multi-day entry, and an ordinary appointment. A spreadsheet’s regional formatting or automatic conversion can make different values look deceptively similar.
Follow the import help’s supported examples and preserve an unchanged copy of the input. Do not apply an ICS end-date convention to a CSV file merely because both formats describe calendar events.
Verify the imported date span
Use a controlled destination calendar and inspect the actual first and last dates shown on the grid. Open the event details to confirm its all-day state. Review a neighboring timed event too, so a file-wide mistake is easier to detect. Avoid repeating the complete import until you know which records were already added. If the event represents a deadline, record the real source’s time zone and cutoff explicitly when needed. A successful CSV import and a correctly understood deadline are separate checks, and neither should be assumed from the appearance of a date block alone.
References
Reviewed against the linked official product guidance on November 4, 2026. Features, limits, screen labels, and access can vary by account, platform, region, and organization policy.