Bids are how you use your budget to pay for what different actions on your ads are worth to you on Pinterest. You can select custom bids or automatic bids.
Custom bids
Custom bids are manually set by you. You enter the maximum amount for what that action is worth to you at any one time and update the amount throughout the day manually, when and as often as you want to.
Automatic bids
Note: At this time, automatic bidding is only available for traffic, conversion and catalog sales campaigns, and is the default setting for advertisers running campaigns with these objectives.
Automatic bids are managed by Pinterest instead of you. Bids are updated by Pinterest automatically several times a day. Pinterest aims to get you the most clicks at the lowest possible cost per result while also spending your entire budget.
The automatic bidding strategy can produce cost fluctuation, usually at the beginning of a campaign, as Pinterest’s delivery algorithm searches for possible outcomes. For example, if auction competition decreases, costs may go down. If auction competition increases, costs may go up. Keep in mind that ad group level budgets are still required.
Edit your bid
You can edit your bid type on an existing ad group at any time.