DocumentationAdvertisingAdvertising Search, Social, & Commerce Guide

Manage constraints for search bid units

Last update: June 2, 2026

CREATED FOR:

  • User

Applicable for bid units in CPC campaigns in legacy keyword-level portfolios only

Bid unit constraints are rules that restrict optimized bids for all bid units with cost and revenue models that are associated with the constraint.

About constraints

Each constraint applies to a specific currency and optionally includes triggering conditions that must be met during a specified data evaluation period in order for the rule to apply. The data to be evaluated can include channel type, match type, click data, conversion data, or derived metrics. For example, you can restrict bids to a specific monetary range, continuously increase or decrease bids by a specified amount, or bid according to the average bid for the portfolio. Each constraint has an applicable start date and either expires on a specific date or is applied indefinitely.

After you set up a constraint, you can assign it to specific bid units or to all bid units within specific ad groups or campaigns. Each bid unit can have one constraint. Constraints are inherited by child entities but can be overridden. A constraint assigned at the lowest level always overrides a constraint assigned at a parent level. When you assign a constraint to a bid unit, bidding operates within the specified constraints for that bid unit, regardless of how much revenue the bid unit generates, when the bid unit has cost and revenue models.

CAUTION
When you assign constraints to a bid unit, you override the bid optimization system’s decision and assume responsibility for the ROI on that bid unit yourself.
NOTE
  • Active constraints restrict bidding only for assigned bid units in optimized legacy keyword-level portfolios. They’re ignored for bid units that are in hybrid portfolios, are in active portfolios, or aren’t in portfolios. Tip: In the portfolio settings, turn on the portfolio option to “'Auto adjust campaign budget limits.” The recommended “Multiple” value is “1.”
  • Bid constraints are ignored for bid units without enough data to generate cost and revenue models.
  • (Campaigns with a CPC or eCPC bid strategy) When a bid constraint conflicts with a portfolio-level bid limit, the constraint overrides the portfolio-level limit. For example, if a portfolio’s minimum bid is 5 USD but you constrain a bid unit in the portfolio to a minimum bid of 3 USD, then the bid unit is bid to 3 USD or higher. Overall spending for constrained bid units, however, is determined by the portfolio’s “Spend Around Constraints” parameter.
  • Constraints operate on the base bid. Any type of bid adjustment to the base bid (such as raising the bid for end users on mobile devices) may move the bid outside of the allowable range for the constraint. For example, if the constraint requires a maximum CPC of 6 USD, the base bid is already 6 USD, and the portfolio auto-optimizes bid adjustments for mobile devices at 50%-60%, then the maximum CPC is 9.00-9.60 USD — not 6 USD.

Constraint types constraint-types

  • Bid: Restricts bids to a monetary range.

  • Bid Shift: Continuously changes the optimized bids for all associated bid units by a specified amount, within bidding bounds. A bid shift causes the relevant portfolios to over- or under-spend by the total amount caused by the bid shift, regardless of the portfolio’s setting for “Spend Around Constraints.” Note: If the current CPC bid is already equal to or greater than the Max Bid, or equal to or lower than the Min Bid, then the constraint is ignored and the bid isn’t changed. Also, bid shift constraints aren’t applied to bid units without enough data to generate cost and revenue models.

  • Incremental Bidding: (Applicable only to keywords with no impressions) Increases or decreases the bid incrementally at a specified rate until the bid reaches a designated target.

  • Search Engine Min Bid: (Google Ads accounts only) Uses the minimum CPC bids determined by the search engine as your minimum bids. As the search engine changes its minimum bids, your bid changes accordingly. You can optionally specify additional bid limits for all associated bid units.

  • Impression Share: (Google Ads and Microsoft Advertising CPC campaigns with exact match only) Restricts bids to a monetary range when the ads are between a minimum and maximum impression share. Note: When the constraint isn’t cost-efficient, the optimization capability may override it.

When to apply constraints

Some reasons to constrain bid units include the following:

  • To quickly expose untested keywords and ads.

  • To mitigate risks for new portfolios, accounts, campaigns, and ad groups. For example, before you launch a portfolio, you can set maximum bids on high-traffic bid units and then gradually raise the values each day. This allows the bidding model to adjust each day without the risk of big bid increases.

  • To make sure that tail keywords with high conversion rates aren’t bid down.

  • To bid up specific terms that are central to your brand or during promotions.

Where to view information about constraints within the UI

Besides opening the Constraints view, you can also see information related to your constraints in the following ways:

  • All of your constraints are label values for a single label classification called “Constraints.”

    • “Constraints” is included in the “Classifications” list in your default and custom view settings and in scheduled reports. You can add the column wherever you want to see the constraints assigned to the relevant entities.

    • When you download a bulksheet, “Constraints” is listed under the “Classifications” column for the applicable entities in the Download Bulksheet dialog. When you include the column, the downloaded bulksheet includes any constraints assigned to the relevant entities.

    The Constraints classification isn’t included in the Label Classifications view — the Constraints view is separate. The Constraints classification also isn’t included in the 30-label classification limit.

  • The Constraint Report includes cost, click, and (optionally) conversion data for constraints that use the label classification architecture.

The Constraints view constraints-view

The Goals > Constraints view lists all of your constraints. Available columns include the constraint status; constraint type, start and end dates; the number of campaigns, ad groups, keywords, ads, placements, auto targets, and product groups with which the constraint is associated; impressions, clicks, and cost data; and revenue data for all visible conversion metrics.

IMPORTANT
The performance data for a row in the Constraints view may not match the performance data for the top-level entity to which the constraint is assigned. Bbecause a constraint assigned at the lowest level always overrides a constraint assigned at a parent level, a constraint assigned to a campaign or ad group may not remain assigned to the child ad groups and keywords. For example, if Campaign A is assigned Constraint A, then all of the ad groups and keywords in Campaign A automatically inherit Constraint A. However, those ad groups and keywords could later be assigned to other constraints, such as Constraint B, and they would then lose their association with Constraint A.
NOTE
Assign constraints to bid units, and unassign them, from the relevant entity management view (such as from the Campaigns view for campaign-level constraints).

Available actions

Create a constraint constraint-create

  1. In the main menu, click Goals > Constraints.

  2. In the upper right toolbar above the data table, click Create Constraint.

  3. Enter the constraint settings.

    To move between the Constraint Type tab and the Conditions tab, either click the tab that you want to open or click the Next and Back buttons.

  4. Click Review and Save to review the settings.

  5. Click Save.

Once you create a constraint, you can assign it to campaigns, ad groups, keywords, placements, and unit-level product groups.

Edit constraint settings constraint-edit

You can edit the settings for one constraint at a time.

  1. In the main menu, click Goals > Constraints.

  2. (Optional) Filter the list from the toolbar or from a column heading.

  3. Select the check box next to the constraint you want to edit.

  4. In the bulk actions toolbar, click Edit .

  5. Edit the constraint settings.

    To move between the Constraint Type tab and the Conditions tab, either click the tab that you want to open or click the Next and Back buttons.

  6. Click Review and Save to review the settings.

  7. Click Save.

Change the status of constraints constraint-change-status

You can pause any active constraint to disable it. You can later enable it by changing the status back to active.

You also can delete a constraint, which removes all associations with account components and makes the constraint unavailable for future use. Report data for the constraint is longer available. Note: To simply disassociate a constraint from an account component, see “Unassign constraints from search bid units.”

  1. In the main menu, click Goals > Constraints.

  2. (Optional) Filter the list from the toolbar or from a column heading.

  3. Select the check box next to each constraint whose status to want to change.

    For tips on selecting multiple rows, see “Select multiple rows.”

  4. In the bulk actions toolbar, click the status button:

    • To activate all selected rows, click Activate .

    • To pause all selected rows, click Pause .

    • To delete all selected rows, click Delete .

  5. In the confirmation message, click Confirm.

Constraint settings constraint-settings

Tab
Parameter
Description
[Basic information]
Constraint Name
A unique name for the constraint.
Currency
The currency in which any applicable bid units are bid. Bid units for which a different currency is used are ignored.
Status

The status of the constraint:

  • Active: (The default) The constraint is applied during the specified conditions and date range.
  • Paused: The constraint isn’t applied.
Constraint Type
Constraint Type
The type of constraint. For descriptions of the constraint types and the eligible ad networks for each, see “Constraint types.”
Start Date
The first day on which the constraint takes effect. The default is the current day. To change the date, enter a date or click Calendar to open the calendar and select a date.
[End Date]
Whether the constraint will become ineffective on a specific date. To apply the constraint indefinitely, such as when the bid unit is central to the company’s brand, leave the field empty. To end the constraint on a specific date, enter a date or click Calendar to open the calendar and select a date. Note: The constraint can’t expire before tomorrow.
Set constraint options for Bid

(Bid constraints only) Settings include:

  • Min Bid: The minimum base bid for associated bid units.
  • Max Bid: The maximum base bid for associated bid units.
Set constraint options for Bid Shift

(Bid Shift constraints only) The type and amount of bid shift to continuously apply to the base bid:

  • Increases: Increases bids by a specified percentage or currency value. Enter the amount to change, and then select either $ or %. Also enter a Max Limit, which is the highest possible bid (ceiling) when the constraint is applied. Note: If the current CPC bid is already equal to or greater than the Max Limit, then the constraint is ignored and the bid isn’t changed.
  • Decreases: Decreases bids by a specified percentage or currency value. Enter the amount to change, and then select either $ or %. Also enter a Min Limit, which is the lowest possible bid (floor) when the constraint is applied. Note: If the current CPC bid is already equal to or less than the Min Limit, then the constraint is ignored and the bid isn’t changed.

Notes:

  • A bid shift will cause the relevant portfolios to over- or under-spend by the total amount caused by the bid shift, regardless of the portfolio’s setting for “Spend Around Constraints.”
  • If you specify an end date for the constraint and the optimization capability is automatically adjusting spending limits for the campaigns in the portfolio, then the bids don’t simply revert to the original amounts after the end date but are adjusted as optimal.
  • Bid shifts aren’t applied to bid units without enough data to generate cost and revenue models.
Set constraint options for Incremental Bidding

(Incremental Bidding constraints only) A bid target, and how much and how often to increase or decrease the bid incrementally until it reaches the target:

  • Bid target: The target bid amount.
  • Incrementally change bids by and [Type]: How much to incrementally increase or decrease bids, and whether to change bids by a currency value ($) or percentage (%).
  • Every __ days: How often to increment bids.

For example, say that the current bid for one of the keywords is 100 cents and that you want to change the bid by 10% every day until you reach a bid target of 500 cents. On Day 1 after the constraint is set, the bid for that keyword is 110 cents (current bid + 10%). On Day 2, the bid is 120 cents (current bid for Day 1 + 20%), and so on. However, if the bid target is 50 cents and the other parameters are the same, then the bids incrementally decrease until the bid reaches 50 cents.

Set constraint options for Search Engine Min Bid
(Search Engine Min Bid constraints) Uses the minimum bid required to show a bid unit on the first page of search results on Google (Google First Page CPC). Optionally enter a Min Bid value and/or a Max Bid value to define the range of eligible bids for the constraint. For example, if you specify a Min Bid of 2.50 USD and a Max Bid of 4 USD, then you won’t bid on the bid unit if the Google Ads first page bid is below 2.50 USD or above 4 USD.
Set constraint options for Impression Share

(Impression Share constraints only) Settings include:

  • Min Bid (Optional) The minimum base bid for associated bid units.
  • Max Bid: (Optional) The maximum base bid for associated bid units.
  • Min Impression Share: The lowest impression share, as a percent, that will trigger the constraint for the applicable bid units. It must be between 10 and 90. Note: When the constraint isn’t cost-efficient, the optimization capability may override it.
  • Max Impression Share: The highest impression share, as a percent, that will trigger the constraint for the applicable bid units. It must be between 10 and 90.Note: When the constraint isn’t cost-efficient, the optimization capability may override it.

>

Conditions
Condition Type

Whether to apply conditions to the constraint:

  • No Condition: (the default) The constraint is applied unconditionally during the specified date range.
  • Satisfy: The constraint is applied only when specified conditions are met during a specified data evaluation period.
Data Evaluation Period
(When conditions are set) The time period for which to valuate data for the specified criteria. If you select Custom date range,* specify the Start Date and the End Date by entering each date in the format MM-DD-YYYY (such as 03-29-2026 for March 29, 2026) or by clicking Calendar button to open the calendar and selecting each date.
When to Apply Constraints

(When conditions are set) How many filter conditions must be met to apply the constraint:

  • Match All Filters: Applies the constraint when every specified filter condition is met.
  • Match Any Filters: Applies the constraint when at least one of the specified filter conditions is met.
Filters
(When conditions are set) One or more criteria that must be met. To create a filter, select a property or metric from the list. For properties (such as Channel Type), select the applicable values in the list. For metrics (such as Clicks), select an operator, and then enter the applicable value. For example, to return only bid units with more than 100 clicks, select Clicks, select greater than, and then enter 100 in the input field.

Assign constraints to search bid units constraint-assign

You can apply bid unit constraints to any campaign, ad group, keyword, placement, or dynamic search target (auto target).

Each entity can have only one constraint. You can assign a single constraint to one or more entities at the same time.

NOTE

  1. From the main menu, open the relevant management view.

    For example, to assign constraints at the campaign level, go to Manage > Campaigns.

  2. (Optional) Filter the list from the toolbar or from a column heading.

  3. Select the check box next to each entity to which you’ll assign a single constraint.

  4. In the bulk actions toolbar, click + Assign > Constraint.

  5. Select the constraint.

  6. Click Assign Now.

Unassign constraints from search bid units constraints-unassign

NOTE

  1. In the main menu, open the relevant management view.

    For example, to unassign campaign-level constraints, go to Manage > Campaigns.

  2. Select the check box next to each entity from which you’ll unassign constraints.

  3. In the bulk actions toolbar, click - Unassign > Constraint.

  4. Click Confirm.

Related Articles
recommendation-more-help
advertising-help-search-social-commerce