Bid, budget and target simulators in Google Ads

This guide is built from Google Ads Help, mainly Estimate your results with bid, budget, and target simulators, plus the pages linked in each section. Menu names change from time to time, so treat the click paths as a guide rather than a fixed route. How to pick a target in the first place is covered in our guides to Target CPA, Target ROAS and Maximize conversions; this page is only about the simulator.

The simulator types and where they are

Google splits simulators into two groups: Manual CPC bid simulators and Smart Bidding simulators. You open both by selecting the small simulator (graph) icon next to a bid, budget or target. Google's help page lists these:

Simulator	Where the icon is	What it changes
Bid Simulator (keyword or ad group)	Keywords page, "Max. CPC" column; Ad groups page, "Default max. CPC" column	Max. CPC bid
Campaign Bid Simulator	Campaigns page, "Budget" column	All bids in the campaign, by a percentage or to one fixed bid
Shopping Campaigns Bid Simulator	Product groups in the ad group, "Max. CPC" column	Product group bids
Hotel Campaigns Bid Simulator	Hotel groups page, or Campaigns page for Commission %	Max. CPC, max. CPC% or Commission %
App, Demand Gen and Performance Max simulators	Campaigns page, "Budget" column	The campaign's target or budget

Simulators work on the Search and Display Networks. In a Search campaign with Display Select, only the search part of the traffic is simulated. Google notes that bid simulators aren't supported in Travel campaigns. If a campaign has a "Limited by budget" status, the Campaigns page shows budget ideas in a pop-up instead of the Campaign Bid Simulator; our Limited by budget guide covers that case.

How the estimates are made

Google says the simulators "collect and analyze data from ad auctions while considering information such as Quality Score, keyword traffic, and competition in the ad auction", and use it to estimate cost, impressions, clicks and conversions. The base is the last 7 days: the tool shows what your results could have been over the previous 7 days with a different setting. Any active bid adjustments for the campaign or ad groups are taken into account.

So the default reading is "what would have happened last week", not a promise about next week. Google's statistics table columns page says it plainly about the simulator columns: they "aren't meant to serve as predictions or guarantees of future ad performance".

There is one exception for Search. In a November 2020 announcement, Google said Target CPA, Target ROAS and budget simulators for Search campaigns can forecast forward: "By choosing a date range up to 90 days in the future, simulators will incorporate seasonality to better predict how your performance might change after budget or target changes." For a planned sale or a quiet season, a forward date range is more useful than last week's data. Seasonal spikes you know about and Google doesn't are a separate tool, covered in our seasonality adjustments guide.

Google also points to the Google Ads API for running simulator estimates at scale, which is useful only if you manage many accounts.

Target and budget simulators for Smart Bidding

With Smart Bidding there is no max. CPC to change, so the simulator moves the target or the budget instead. Google's About Smart Bidding page describes simulators that estimate cost, conversions, conversion value, impressions and clicks "if you had set different CPA, ROAS targets, or budgets".

Which one you get depends on the bid strategy. Google's Search Ads 360 help page on Google Ads simulators sets out availability by campaign type:

• Target CPA simulators: Search, Performance Max, Display, Shopping and App campaigns. Key metric: conversions.
• Target ROAS simulators: Search and Performance Max campaigns. Key metric: conversion value.
• Target impression share, Maximize conversions, Maximize conversion value and Maximize clicks simulators: Search campaigns only. The three Maximize strategies get a campaign budget simulator, because the budget is the setting they work with.

Target simulators exist at portfolio, campaign and ad group level. The same page notes that setting a portfolio-wide or campaign target there "will clear any ad group targets you have set", so check for ad group targets before you apply one.

For App campaigns, Google's App campaign bidding tools page says the Bid Simulator is available for App campaigns for installs on target cost per install, target CPA and target ROAS, and appears "after 1 week of data has accumulated". Its panel lists targets, the estimated weekly installs, in-app actions or conversion value, the total cost and "any additional daily budget that may be required". Your current target shows as a gray circle on the trend line and the selected one as a blue circle.

Conversion estimates

If you use conversion tracking, simulators also estimate conversions, and on the Search Network conversion value if you've set values. Google lists a few things that make these estimates weaker than click estimates:

• Tag changes. Removing or moving the conversion tag can invalidate the estimates. Google advises no major changes to the conversion tracking code for at least 2 weeks before you rely on conversion estimates.
• Conversion delay. Search, Performance Max and App campaign simulators count conversions recorded so far plus those expected to arrive. Simulators for all other campaign types only count conversions recorded during the simulation period, so a recent click that converts later is left out. Google's conversion delay estimates page explains why lag makes CPA look higher and ROAS lower than they end up.
• Sparse data. There are fewer conversions than clicks, so they are harder to estimate. An account with few conversions may get no conversion estimate at all. Google says the longer the history and the more conversions, the more accurate the estimates.

Bid simulator columns

Instead of opening the simulator one keyword at a time, you can add bid simulator columns to the statistics table on the Keywords page. Google's columns page says these estimate how bid changes might affect weekly Search Network traffic, are "generally refreshed once a day", and reflect the last 7 days. They exist at keyword level, and at campaign level for device bid adjustments (under Devices).

• Read the estimates against the "Base max. CPC" column (or "Base bid adj." for devices), not your current bid, because the bid may have changed since Google made the estimate.
• A "--" means there wasn't enough data in the last 7 days.
• The columns won't produce estimates for campaigns on automatic CPC bidding or Target CPA, or for campaigns that spend their entire daily budget on a regular basis.
• Device columns assume all ad group-level bid adjustments have been removed.

Applying a change

The simulator is also where you make the change. In the keyword or ad group Bid Simulator you change the bid by selecting a new bid option; for a Shopping product group you then select Save. In App, Demand Gen and Performance Max simulators you select Save and continue, or Cancel to leave without changes. The Campaign Bid Simulator has two modes:

• Bid scaling: raise or lower all bids by a percentage, such as 10%.
• One fixed bid: if you apply a campaign-wide fixed bid, Google says "your ad group default bids will be changed to this fixed value, and your keyword-level bids will be erased". Use this only if you no longer need the keyword bids you set by hand; our Manual CPC guide covers when keyword bids matter.

Because campaign-wide changes can raise traffic a lot, Google says the Campaign Bid Simulator tells you whether you need a bigger budget and what to change it to. In Shopping campaigns, bid changes across many product groups can do the same, and Google shows the projected cost. For a subdivided product group you can choose Bid scaling (%) or a product group-wide bid.

A simulator only gives an estimate. If you want to measure a change against a control, run it as a Google Ads experiment.

Why a simulator is missing

When no estimate is possible, the icon is grayed out with a slash through it. Google lists these common reasons:

• Not enough data. The campaign, ad group, keyword or product group is new or got few clicks in the last 7 days. Google's advice is to check back later.
• Shared budget. The Campaign Bid Simulator isn't available for campaigns on a shared budget.
• Budget reached. If the campaign reached or nearly reached its average daily budget at least once in the last 7 days, the simulators may not give estimates.
• Experiments. Simulators don't work with campaigns that have running experiments, or experiments that ended in the last 8 days.
• Shopping product groups. Not available for product groups that use the Item ID attribute, or for excluded product groups.

Sometimes the simulator opens but columns are missing. Clicks and cost only show after a minimum number of clicks in the last week. Top of page impressions only show on the Search Network, if at least one is estimated. Conversions and conversion value need Google Ads conversion tracking and a minimum number of conversions in the last week. "Additional budget/day required" may only appear at campaign level.

Simulators and Keyword Planner

Google draws the line this way: simulators estimate performance from information specific to your campaign, including your Quality Score and keywords, while Keyword Planner and Display Planner estimate from traffic patterns across all Google advertisers. Use Keyword Planner before a campaign has data, and the simulator once it has run for a while. Google's Evaluate and optimize your bids page puts it as tools that give "more personalized recommendations" after campaigns run "for a few weeks".

How we use simulators

This part is our own practice, not Google guidance:

• We look at the step just above and just below the current setting, not the far ends of the curve, where the estimate rests on the least data.
• We read cost per conversion along the curve, not total conversions alone. A curve that flattens means each extra conversion costs more.
• We don't use simulators in a week with a sale, an outage or a tag change, because the 7-day base is not typical then.
• After applying a change we note the date and the estimate, then compare it with actual results a few weeks later in change history and the reports.

If you want help planning or running Google Ads, see our services.

Frequently asked questions

Where is the bid simulator in Google Ads?

Select the simulator icon next to a bid or budget: in the "Budget" column on the Campaigns page, the "Default max. CPC" column on the Ad groups page, or the "Max. CPC" column on the Keywords page.

How many days of data does the bid simulator use?

The last 7 days. Search campaigns can also forecast a date range up to 90 days ahead in the Target CPA, Target ROAS and budget simulators, which take seasonality into account.

Why is the bid simulator icon grayed out?

Usually because there isn't enough data from the last 7 days, the campaign uses a shared budget, it reached or nearly reached its daily budget in the last 7 days, or it has a running or recently ended experiment.

Is there a Target ROAS simulator for Shopping campaigns?

Google lists Target ROAS simulators for Search and Performance Max campaigns. Target CPA simulators cover Search, Performance Max, Display, Shopping and App campaigns.

Are bid simulator estimates guaranteed?

No. Google says they show how other bids might have affected past performance and aren't predictions or guarantees of future results.

For more on bidding in Google Ads, see our guides to budgets and bidding, value-based bidding, Target impression share and Quality Score.