How-to · Updated October 11, 2026
Warn Smart Bidding about a short sale or promotion
Updated October 11, 2026
15 minutes
For a short sale or promotion of 1 to 7 days that will change conversion rates sharply, add a seasonality adjustment: open Adjustments from the Tools icon, pick Seasonal, and enter the dates and expected change. Skip regular busy seasons, which Smart Bidding already manages; Google says it may not work as well over 14 days.
Before you start
- Standard or Admin access. Google's access levels page lists editing campaigns for those two levels only.
- A campaign that supports it. Google lists Search, Shopping and Display campaigns on Target CPA or Target ROAS, and Performance Max on any bid strategy, but not Travel campaigns.
- Numbers from a past event. Have the conversion rate from a similar past event and from the days just before it.
Decide whether the event needs one
Use a seasonality adjustment only for a short event you expect to change conversion rates a lot; Google says Smart Bidding already manages seasonal events.
- Good fits are short, planned events such as a sale, a promotion or a product launch: a weekend flash sale at a store, say.
- Leave out busy seasons that come every year. Google says in most cases Smart Bidding automatically handles seasonal increases in traffic without any input. The adjustment changes the conversion rate bidding expects, so more traffic alone is not a reason to add one.
- Keep it short. Google calls 1 to 7 days ideal and says adjustments may not work as well over more than 14 days at a time.
- Confirm the bid strategy. For Search, Shopping and Display, Google names Target CPA and Target ROAS; it treats Maximize conversions with a Target CPA as the same strategy as Target CPA. A Search campaign on Maximize conversions with no target is not on Google's list. For a campaign with a target, Google's other option is to adjust the target for the sale.
Estimate the change from a past event
Base the percentage on a comparable past event, because Google's instructions are to add up to the change you expect, not more.
- Click Campaigns and set the date range to the last comparable event. Note Conv. rate, then do the same for the same number of days just before it.
- A worked example: a business that converts 4% of clicks on normal days and 6% during last year's three-day sale saw a 50% rise, so it would add up to +50%, the same figure as Google's example.
- Without a past event to measure, stay conservative. This is a judgment: the adjustment tells bidding to expect more conversions per click, so an overestimate can push bids higher than the event earns. Google warns that adjustments may change how bid strategies perform.
- An adjustment can also be a decrease, for a short future period you expect to convert worse than usual.
Create the adjustment before the event
Add it ahead of the event, scoped to only the campaigns the event affects.
- Click the Tools icon, open the Budgets and bidding drop-down in the section menu, and click Adjustments.
- Select Seasonal at the top, then click the blue plus button.
- Under Adjustment type, select Conversion rate. Give it a name and an optional description, and fill in the event's start and end dates.
- Under Scope, choose Campaign type (all campaign types or specific ones) or Specific campaigns. Pick specific campaigns when the sale covers only some of what you advertise.
- Under Conversion rate adjustment, enter your estimate, such as +50%. Click Save, then Create seasonality adjustment.
Do not add an opposite adjustment for the days after. Google says campaigns return to their pre-adjustment performance when the event ends, with no negative adjustment needed.
Check it worked
Go back to Adjustments and select Seasonal. The new adjustment should be listed with the dates, scope and percentage you entered.
After the event, wait until its conversions have had time to arrive, then compare Conv. rate for the event days with your estimate. Google notes that recent days can look weaker because some people who clicked have not converted yet.
Seasonality adjustment or data exclusion?
A seasonality adjustment is for a future change in how customers behave. A data exclusion is for conversion tracking problems, such as a tag removed from the site. If the conversions are wrong rather than the customers different, use a data exclusion.
Can the target be changed instead?
Yes. Google names adjusting targets on the day of a sale as the alternative to a seasonality adjustment, and says changing a target won't trigger a Learning status or reset what Smart Bidding has learned. Remember to set the target back when the event ends; unlike the adjustment, it does not expire.