Interpret Dates, Times and Time Zones
Avoid mixed-up days, months and time zones in activity dates
Overview
Dates are one of the most common causes of import errors. "04/05/2026" can mean 4 May or 5 April, and "10:00 IST" can refer to several time zones. The Studio never guesses when a date is ambiguous. It asks you to clarify, then prepares timestamps in a consistent format HubSpot can trust.
Where date settings apply
The Date and timezone settings in Details apply to:
- Note activity dates.
- Marketing event timestamps: Registered at, Attended at and Left at.
- Custom event Occurred at timestamps.
Values mapped to other company or contact date properties are exported as prepared. Make sure they use a consistent format before importing.
Choose a date interpretation
Date interpretation tells the Studio how to read dates written with numbers:
- Detect; block ambiguous dates: The default. Dates are read when unambiguous. Dates that could be read either way are flagged for clarification.
- Day / month / year: For example, 04/05/2026 is 4 May 2026.
- Month / day / year: For example, 04/05/2026 is 5 April 2026.
- ISO only: Only values such as 2026-05-04 are accepted.
ISO dates and dates stored natively in Excel are recognised automatically.
When the Studio finds ambiguous values, Clarify dates shows an example and asks which order the file uses.
Choose a time zone
Timezone for date-only / local values sets the time zone for dates and times without a time zone, such as 2026-05-04 or 2026-05-04 14:30.
- Timestamps with an explicit offset, such as +01:00 or Z, keep their exact moment in time.
- Times that don't exist or occur twice because of daylight saving changes must be corrected or given an explicit offset.
- Each date field has its own time for date-only values, such as 09:00.
Clarify time zone abbreviations
Some files, such as webinar exports, include times like "04:01:07 PM IST". Abbreviations with only one meaning are resolved automatically.
When an abbreviation has several meanings, choose the correct region in Timezone for {abbreviation}. For example, IST can mean India, Ireland or Israel Standard Time. The general time zone does not answer this question for you.
Save regular answers in Settings > Date and Time > Timezone labels, so future imports apply them automatically.
Fill missing dates
Each date field can use a fallback date and time for blank values. Fallbacks only fill missing dates. They never replace populated dates that are invalid; those must be corrected.
In Review, you can also override the note date for a specific row, or choose whether a blank event timestamp uses its fallback.
How dates are exported
Prepared timestamps are converted to UTC in an ISO format, for example 2026-05-04T13:00:00+00:00. HubSpot then displays them in each user's time zone.
When dates block a file
A missing, invalid or ambiguous date only blocks the file that needs it:
- Note date problems block the notes file.
- Event timestamp and custom event date problems block the contact file.
Other files remain available. Review lists every affected row.
Save defaults
Settings > Date and Time stores the default time zone, date interpretation, time for date-only values and time zone labels for new imports. Fallback dates are chosen for each import and are not saved as defaults.
Why it matters
Accurate dates keep timelines, attendance history, activity reporting and follow-up workflows trustworthy. A single wrong assumption about date order or time zone can shift thousands of activities. Explicit choices make each import auditable.
What to do next
- Set your team's usual date settings in Settings.
- Read Create Notes from Source Data and Import Marketing Event Registration and Attendance for field-specific guidance.