How to change when a campaign's recipients are determined
Owners, Admins, Managers, and Campaign Coordinators can adjust this setting for the account.
You will learn
Learn how to adjust the account-level default for when single-channel campaigns determine recipients. There are 2 options:
- At time of scheduling (the default)
- At send time
Using At send time means that if your lists or segments have grown since you created the campaign, you may use more Mobile Messaging spend or email sends than estimated, be auto-upgraded, or need to upgrade your plan for the campaign to send to everyone.
How do the 2 recipient timing options differ?
These 2 timing options affect who your campaigns send to.
Think of determining recipients as snapping a picture at a point in time.
If you choose At time of scheduling, Klaviyo takes a picture of your lists or segments shortly after the scheduling request completes. Changes after scheduling may not be included. Once recipients are determined, people added later will not be added to that campaign. This helps keep later list or segment growth from increasing your campaign’s send volume.
If you choose At send time, Klaviyo takes the picture once, shortly before the campaign’s first messages go out. This includes list or segment changes made before recipients are finalized. New recipients are not added after that point, including for later sends in recipients’ local timezones. However, this may lead to using more sends than you planned for.
If you choose At send time for SMS, the campaign may use more Mobile Messaging spend than initially estimated. This is particularly true if you have a multi-national account, as subscribers in different countries may be added to the campaign, and rates vary by country.
Change when campaigns determine recipients
This setting provides the default for new single-channel email, SMS, and push notification campaigns. Changing the default does not update campaigns you have already created.
For a single-channel campaign with Fixed send time, select or clear Determine recipients at send time when scheduling to override the default for that campaign. Gradual send does not offer this option.
For omnichannel campaigns, recipients are determined once, shortly before each message first goes out. The account default does not change this behavior.
- Select your account name in the bottom left corner.
- Click Settings.
- Under General, select Messaging.

- Under Campaign sending defaults > Single channel campaigns, select the default option you want to use:
- At time of scheduling.
- At send time.

- Click Save.
Additional resources
- Understanding campaign schedule and send options
Learn what sending options are available for campaigns and how you can use them. When you schedule or send a campaign, you can choose things like your send time, send strategy, timezone, and other details.
- Understanding Smart Sending in Klaviyo
Learn about Smart Sending, which allows you to limit the number of emails, SMS messages, or push notifications someone can receive within a set period of time.
- How to send a campaign to multiple lists or segments
See how to send to multiple lists or segments. This allows you to hone the sending pool of your campaign by including recipients from specific lists while excluding recipients from others. For instance, you could: