A bid modifier is a percentage that raises or lowers an advertiser's base bid when an auction matches a specific condition, such as a searcher's device, location, time of day or membership of an audience list. Google Ads and Microsoft Advertising call the feature a bid adjustment in their interfaces; "bid modifier" is the name used in Google's application programming interface (API) and across much of the industry. The idea exists because a click is not worth the same in every context. A smartphone search a mile from a shop may be worth more than the same query typed on a desktop at 3am, and one keyword bid cannot express that. Modifiers let one bid carry many prices.

How a modifier changes the bid

A base bid, usually the maximum cost per click (CPC) set on a keyword or ad group, is multiplied by one plus the adjustment. In Google's own example, a 1 pound bid with a +20% mobile adjustment becomes 1.20 pounds; a -20% adjustment turns it into 0.80 pounds, according to the Google Ads help page "About bid adjustments".

When several modifiers apply to one auction, Google multiplies them. The rule dates from the original launch: "Bid adjustments combine using multiplication," Surojit Chatterjee, then a group product manager at Google, wrote on February 20, 2013. His example applied +50% for proximity to a store, -20% for a Wednesday and +25% for a smartphone to a 1 dollar bid, giving 1.50 dollars (1 x 1.5 x 0.8 x 1.25).

Three exceptions shape the outcome:

  • Location does not stack. If an advertiser sets +50% for France and +100% for Paris, a searcher in Paris receives only +100%. The most specific location wins.
  • Ad group beats campaign for device. An ad group device adjustment overrides the campaign-level one for the same device, unless the campaign has set that device to -100%.
  • There is a ceiling and a floor. Combined adjustments cannot exceed a 900% increase, so a 1 pound bid with +900% for device and +900% for location still tops out at 10 pounds. The lowest combined adjustment is -90%.

The dimensions and their ranges

As of October 2026, Google Ads offers adjustments on these dimensions, according to its help page:

  • Device (computers, mobile phones, tablets): -100% to +900%, at campaign and ad group level. It is the only dimension that can reach -100%, which removes the device entirely.
  • Location: -90% to +900%, campaign level only.
  • Ad schedule: -90% to +900%, campaign level, and only where a custom schedule exists.
  • Audience segments, including remarketing lists for search ads (RLSA): -90% to +900%.
  • Demographics (age, gender, household income): -90% to +900%.
  • Interactions, meaning call adjustments: -90% to +900%.

Top content adjustments on the Display Network are "no longer available", Google says. Performance Max, App and Smart campaigns accept no manual adjustments at all.

Microsoft Advertising uses the same scale. Its API reference for the BidMultiplier object, published on Microsoft Learn, sets a valid range of -90 to 900 for most criteria and -100 to 900 for devices, where -100 excludes the device. Microsoft also supports adjustments on dimensions Google does not have. Advertisers can bid on LinkedIn profile attributes such as company, industry and job function, and job seniority was added on June 15, 2026, with each of its 10 levels adjustable separately.

In the API, Google Ads exposes a CampaignBidModifier resource; Microsoft's equivalent is BidMultiplier.

Origin and evolution

Modern bid modifiers arrived with enhanced campaigns, which Google announced on February 6, 2013. Before that, advertisers wanting different mobile prices typically built duplicate smartphone-only campaigns. Enhanced campaigns merged devices into one campaign with three adjustments: mobile, location and time of day. Desktop and tablet shared one price, a point of criticism for three years.

Refinements followed quickly. On April 9, 2013, Google said mobile adjustments would be available at ad group level from mid-May. On June 12, 2013, Sridhar Ramaswamy, then senior vice president of engineering, set July 22, 2013 as the date on which remaining legacy campaigns would be upgraded automatically, each with a default mobile bid adjustment. The original mobile range was -100% to +300%.

The second milestone came on May 24, 2016 at the Google Performance Summit in San Francisco. Google split tablets from desktops, let the base bid sit on any device and raised the ceiling to +900%. Ramaswamy, by then senior vice president of Ads and Commerce, said advertisers could "anchor your base keyword bid to the device most valuable to your business", according to Search Engine Land.

The third shift was automation. As Smart Bidding grew from 2016, most manual modifiers stopped working under automated strategies, a change examined further below. The retirement of Enhanced CPC by March 2025 removed the last semi-manual strategy combining adjustments with automated bid changes.

Why it matters for marketers

For a decade, modifiers were the main way an advertiser told a search engine what different traffic was worth. Device bidding decided how much budget went to mobile, location adjustments let chains bid harder near branches, and RLSA modifiers raised bids for past visitors without separate campaigns. Much of PPC work from 2013 to the early 2020s consisted of setting and pruning these percentages.

The feature now matters partly because of where it is disappearing. Its removal tracks the wider transfer of bidding control from advertisers to platform models, a trend PPC Land documented in the week Google and Microsoft both narrowed bid controls in August 2026. A removed modifier is also a lost way of stating, in a number the platform must respect, that one segment is worth less.

Limitations and disputes

Smart Bidding ignores most of them. Google's help page is direct: "If you make a manual bid adjustment to your automated Smart Bidding strategy, it won't be supported." Under Target ROAS (return on ad spend), Maximize conversions and Maximize conversion value, the only device modifier honoured is -100%. Target CPA (cost per acquisition) treats a device adjustment differently, changing the CPA target for that device rather than the bid. Among automated strategies, only Maximize clicks honours location, schedule, audience, call and demographic modifiers. Smart Bidding still respects an ad schedule's hours but ignores a +20% for Saturdays. Microsoft documents a softer position: its BidMultiplier reference says that under Max Clicks, Max Conversions, Target CPA or Target ROAS the multiplier "informs the automated bid rather than directly modifying or overriding it".

The -90% floor is not an exclusion. Except for devices, no modifier can switch a segment off. That gap became a live dispute at Meta, where value rules, its bid adjustment tool, range from +1,000% to -90%. When advertisers reported in August 2026 that some accounts had lost manual placement controls, the 90% cap meant a placement could be made expensive but not removed. Meta has not confirmed a general removal.

Stacking makes final prices opaque. The Federal Trade Commission's August 31, 2026 complaint against Amazon, as summarised in PPC Land's report on Amazon's Ad Lab video published today, cites an internal observation that placement adjustments of up to 900% may leave advertisers unsure what bid they actually entered. On Amazon Sponsored Products, a 1 dollar bid with a 900% placement adjustment and "up and down" dynamic bidding can theoretically resolve to 20 dollars a click.

Platforms disagree on the arithmetic. Google multiplies. Google's own Search Ads 360 help page describing Microsoft Advertising campaigns gives an example in which a 1 dollar bid with +10% for device and +10% for location yields 1.20 dollars, which is what addition produces; multiplication would give 1.21 dollars. Microsoft's own help pages were unreadable for this article, so its combination rule is unconfirmed here.

Simplicity versus control. When Google announced the removal of bid multipliers from Display & Video 360 (DV360) in May 2025, one Reddit user called it "insane"; others noted the feature required fixed bidding and saw little use.

Not the same as

Bid strategy. A strategy, such as Target CPA or a portfolio bid strategy, decides the bid. A modifier adjusts a bid that already exists, and under most automated strategies it no longer applies.

Bid shading. Bid shading is a buy-side algorithm that lowers bids in first-price programmatic auctions to avoid overpaying.

Seasonality adjustment. Google's seasonality adjustments tell Smart Bidding to expect a conversion-rate change, such as a +50% lift during a short sale. They change a model input, not the bid; PPC Land covered their extension to App campaigns in September 2025.

Programmatic bid multipliers. In demand-side platforms (DSPs), the same concept applies to a fixed CPM (cost per thousand impressions) bid. DV360's multipliers ran from 0.1 to 10.0, so a 5 dollar CPM with a 2.0 multiplier became 10 dollars, with stacked multipliers capped at 10.0.

Recent developments

The trend in 2025 and 2026 has run one way. DV360 dropped bid multipliers in May 2025. On October 1, 2026, Microsoft Advertising stopped accepting a maximum CPC on new campaigns using Max Conversions, Max Conversion Value or Max Clicks, which removes the fixed base bid that modifiers multiply. Navah Hopkins, Microsoft's Ads Liaison, argued that a maximum bid "can lead to spend pacing irregularities".

New ad platforms are launching without the feature. When OpenAI added iOS, Android and web targeting to ChatGPT Ads Manager in August 2026, it shipped an inclusion list rather than a multiplier: as PPC Land reported, "there is no bid modifier". Meta moved the other way, expanding value rules to all ad accounts and objectives from August 2025, though critics argued value rules can raise cost per result. In Google Ads, modifiers now fully work only under Manual CPC or Maximize clicks.

Timeline

  • February 6, 2013 - Google announces enhanced campaigns, merging devices into one campaign with mobile, location and time adjustments.
  • February 20, 2013 - Google publishes the bid adjustment rules, including multiplication and most-specific-location precedence.
  • April 9, 2013 - Ad group-level mobile bid adjustments announced, available from mid-May 2013.
  • July 22, 2013 - Remaining legacy AdWords campaigns upgraded automatically, each with a mobile bid adjustment.
  • May 24, 2016 - Google Performance Summit: separate desktop, tablet and mobile adjustments, base bid on any device, ceiling raised from +300% to +900%.
  • July 25, 2016 - Google adopts the Smart Bidding name for its automated conversion strategies, which largely ignore manual adjustments.
  • April 1, 2022 - Microsoft launches LinkedIn profile targeting with bid adjustments in search and audience campaigns.
  • March 2025 - Enhanced CPC retired for Google search and display campaigns.
  • May 2025 - Bid multipliers removed from Display & Video 360.
  • June 4, 2025 - Meta announces value rules; universal availability follows on August 20, 2025.
  • June 15, 2026 - Microsoft adds job seniority, with per-level bid adjustments, to LinkedIn profile targeting.
  • August 25, 2026 - Reports surface of Meta placement controls disappearing, leaving value rules capped at -90%.
  • August 31, 2026 - FTC and 22 states sue Amazon; the complaint cites confusion over 900% placement adjustments.
  • October 1, 2026 - Microsoft stops accepting maximum CPC bids on new Max Conversions, Max Conversion Value and Max Clicks campaigns.

Summary

Who: Google Ads and Microsoft Advertising operate bid modifiers, called bid adjustments in their interfaces; Amazon, Meta and Yandex run comparable tools. Advertisers and agencies set the percentages.

What: A percentage, usually from -90% to +900% and down to -100% for devices, that raises or lowers a base bid when an auction matches a device, location, schedule, audience, demographic or other condition. Multiple modifiers multiply on Google, within a 900% ceiling.

When: Introduced with Google's enhanced campaigns in February 2013, expanded to separate device bids and a +900% ceiling on May 24, 2016, and progressively sidelined by Smart Bidding, the DV360 removal in May 2025 and Microsoft's October 1, 2026 Max CPC change.

Where: Search, shopping and display campaigns on manual or click-based bidding, retail media placements on Amazon, and Meta ad sets through value rules. Performance Max, App and Smart campaigns do not accept them.

Why: A click's value varies with context, and modifiers let one bid express that variation without duplicate campaigns. Their decline reflects platforms' argument that models price context better, and advertisers' counter-argument that they lose a control the platform must respect.