Why Don't My Numbers Match? How SimpleEvents Syncs With HubSpot

"My registered list shows 48 but SimpleEvents shows 52." This article explains how the sync works, when a difference is normal, and when it's a real problem with a fix.

How the sync works (one direction!)

SimpleEvents is the source of truth for registrations, and data flows from SimpleEvents into HubSpot:

1. An attendee registers (via your HubSpot form, the embed, a batch import, or a manual add).
2. SimpleEvents records the registration and links the attendee to a HubSpot contact.
3. SimpleEvents updates HubSpot: the marketing event, the event's lists (Registered / Attended / No-Shows / Waitlist), and enrolls contacts into your event workflows.

The reverse is not true: creating a Marketing Event in HubSpot does not create an event in SimpleEvents, and manually adding a contact to the Registered list in HubSpot does not register them for the event. Always make registration changes in SimpleEvents (or through your registration form).

Differences that are normal

• Timing: form submissions are picked up on a regular check cycle, not instantaneously. A brand-new registration can take a little while to appear everywhere. If a submission from days ago is still missing, that's not timing — see below.
• Guests: a registration with 2 guests counts as 3 attendees in SimpleEvents, but guests without their own email address may not exist as separate HubSpot contacts — so the HubSpot list can legitimately be smaller.
• List type: the event lists are managed by SimpleEvents. If someone manually edited list membership in HubSpot, the list will drift from the true registration count (and SimpleEvents will keep managing it based on actual registrations).
• Cancelled attendees: cancellations are removed from the registered count but a manually-copied list in HubSpot won't shrink on its own.

Differences that are real problems — and their fixes

1. Contacts aren't being added to the lists at all

Usually a missing HubSpot permission (scope) or an expired connection. Fix: reconnect HubSpot from Settings → HubSpot Connection. See How to reconnect your HubSpot account. Also see Why contacts are not showing up for your event registration.

2. Some attendees never got a HubSpot contact

Registrations imported without an email address, or with a malformed one, can't be matched to a HubSpot contact. Check your attendee list for entries missing an email.

3. Deleted attendees reappear

If the original registration source still exists (for example, the contact re-submits the form, or a batch import is re-run), the attendee is re-created. Cancel the attendee in SimpleEvents instead of deleting, so the cancellation is remembered.

4. Nothing has synced for days

Use the re-sync option on your event to force a fresh pass, and if that doesn't resolve it, contact support with your Event ID.

Quick reference: where each number lives

• SimpleEvents attendee list — the source of truth for who is registered, waitlisted, attended, cancelled.
• HubSpot Registered/Attended/No-Show lists — synced snapshots for segmentation and workflows, maintained by SimpleEvents.
• HubSpot Marketing Event — registration/attendance rollups used in HubSpot reporting.