Google Ads Shared Budgets: One Budget Across Campaigns

This guide uses Google Ads Help: About shared budgets, Manage a shared budget across campaigns and Link shared budgets to portfolio bid strategies, plus the pages linked in each section. Checked on 8 November 2026.

What a shared budget is

Google defines a shared budget as "a single average daily budget that's shared by multiple campaigns in an account." Instead of giving each campaign its own amount, you set one amount and attach several campaigns to it. Every campaign still needs a budget; with a shared budget, that budget is the pool.

How average daily budgets, daily and monthly limits and bid strategies work in general is covered in our Google Ads budgets and bidding guide. This page covers only what changes when campaigns share one budget.

How spend moves between campaigns

Google says shared budgets work "by allowing underutilized budgets to automatically reallocate to budget-capped campaigns." In other words, money that one campaign does not use that day can go to another campaign on the same budget that would otherwise have stopped at its limit.

Google's example uses $100 a day split evenly between two campaigns. One campaign gets less traffic than usual and spends only $40 of its $50. With a shared budget, "if your second campaign can reach enough traffic," Google Ads can move the leftover $10 to the second campaign.

The flip side follows from the same rule: no campaign on a shared budget has a fixed share. If one campaign can use more of the pool, the others may get less. Google lists the benefits as less time spent moving budget by hand, better use of the overall budget, and better performance "when used with Portfolio Bid Strategies" on campaigns with similar goals.

Google adds that "customers that adopt Shared Budgets and Portfolio Bid Strategies on Search campaigns typically experience +13% more conversions," with the footnote "Google Internal Data, Global, 1/2024 - 3/2025." That is Google's own average, not a result you can expect in a given account.

Which campaigns can use one

Google says "Shared budgets are only available on Search, Shopping, Display, and Video campaigns." Its About page also says shared budgets "aren't compatible with campaigns that are part of an experiment such as App campaigns, Hotel campaigns with a Commission bid strategy, Performance Max campaigns, and Smart Shopping campaigns." Read together, Performance Max, App and Demand Gen campaigns keep their own budgets.

Two more limits matter in practice:

• Campaign total budgets: Google says campaigns using a total budget "aren't compatible with shared budgets."
• Experiments: Google's custom experiment setup page lists "Your original campaign already has a shared budget" as a reason an experiment cannot be created, and the fix is to remove the shared budget from that campaign. Our Google Ads experiments guide covers the other requirements.

Google recommends pairing a shared budget with a portfolio bid strategy, and says "It's best practice to implement shared budgets with portfolio bidding," because portfolio bidding works across campaigns "that share the same goals." Google's pages do not say a shared budget requires one.

Creating a shared budget

Google's steps for creating one in the Shared library:

1. Click the Tools icon, open Budgets and bidding in the section menu and click Shared budgets.
2. Click the plus button.
3. Name the shared budget and set the amount.
4. Add campaigns (optional at this point), then click Save.

To add campaigns later, select the shared budget, press the plus button, tick the campaigns and save. Watch the amount when you do. Google notes: "When you add a campaign to a shared budget, the campaign's budget is also added to the shared budget's amount." If you meant to keep the total the same, lower the shared amount after adding campaigns.

Removing a campaign or a shared budget

"Because every Google Ads campaign has to have a budget," Google says, you can only remove a shared budget that no campaign uses. So there are two steps:

1. For each campaign on the shared budget, open its Settings, click Budget, choose Individual campaign budget and save.
2. When no campaign is left, go to Shared budgets, tick the budget, click Edit in the blue bar and choose Remove.

Moving a campaign back to its own budget is also the way to give one campaign a guaranteed amount again.

Switching budgets in the middle of the day

Changing budget type during the day resets the count for that day. Google says that if you switch between an individual and a shared budget mid-day, "we will start serving from the time you switch, as though the campaigns have spent $0 up until that point."

Its example: four campaigns each have a $6 budget and have each spent it by 3:00 pm. At 4:00 pm you put them on a new $24 shared budget. The $24 starts from $0, "as if the $6 campaigns had not already served." So in Google's example the four campaigns spend $24 before the switch and can spend up to $24 more after it. If that matters, make the switch late in the evening or early in the morning.

Linking it to a portfolio bid strategy

Google says "Some Google Ads accounts can now link portfolio bid strategies and shared budgets together." Once a portfolio strategy is linked to a shared budget, "the shared budget will always be associated with the campaigns that are part of your portfolio bid strategy." Adding a campaign to the strategy or taking one out updates the shared budget too, and Google may ask whether you want to change the amount.

When you create a portfolio strategy under Tools, then Bidding strategies, the box "Create a shared budget to use with this portfolio bid strategy" is ticked by default. A few details from Google's page:

• The budget amount must be filled in, "even if you have not yet selected the campaigns."
• If you picked campaigns first, the amount starts as the sum of their budgets. Google's example: five campaigns at $50 each give $250.
• If you edit that amount, the pre-filled sum "will not return after you've edited it, even if you delete the amount."
• To unlink, untick "Use a shared budget with this portfolio bid strategy" in the strategy's settings. You can then add or remove campaigns on the shared budget directly.

In the strategy table's Budget column, "Varied" means the campaigns have different budgets and you can create one shared budget for them. If the edit icon is greyed out, Google says "the number of campaigns might be greater than 500" and you should reduce the number of campaigns in the strategy. How portfolio and standard strategies differ is covered in our budgets and bidding guide.

Spending limits and the budget report

Google calls a shared budget an average daily budget. Its spending limits page says average daily budgets have a daily limit of 2 times the budget and a monthly limit of 30.4 times the budget "for most campaigns," and that you are not billed above those limits even when served costs go higher. Google's shared budget pages do not restate these limits for a shared pool, so we do not add rules of our own here.

The budget report is available for shared budgets too. Under Tools, Budgets and bidding, Shared budgets, hover over the amount in the budget column or click the pencil icon. The window that opens lets you change the amount and links to the report.

Channel priorities on a shared budget

Google's newer channel prioritization settings, which control spend on Google Search, search partners and the Display Network, can be set "at the account, shared budget, or campaign level." For shared budgets Google adds three points:

• Campaigns on the shared budget "must use identical campaign types (all Search or all Shopping)" for the settings to apply.
• A budget allocation percentage "applies to the shared budget as a whole, across all campaigns that use it."
• If you change the setting in one campaign's settings and that campaign uses a shared budget, "these settings apply to all campaigns that share that budget."

Whether search partners are worth it at all is covered in our Google search partners guide.

Campaign total budgets instead

For a fixed amount over a set period, Google offers campaign total budgets. These work per campaign, not across campaigns. Google says they are "only available for new campaigns," that "you can't change the budget type after a campaign is created," and that the period runs from 3 to 90 days (up to a year for Demand Gen and YouTube). As noted above, a campaign on a total budget cannot use a shared budget.

When a shared budget fits a small account

The facts above are Google's; this view is ours:

• Good fit: two to five Search or Shopping campaigns with the same goal and the same value per lead or sale, where you care about the total, not which campaign spends it. Pairing them with one portfolio strategy follows Google's advice.
• Poor fit: a campaign that must always get a set amount (brand terms, a new service you are testing), campaigns with very different goals, or any campaign you plan to test in an experiment. Give those their own budgets.
• Before switching: check whether the shared amount went up when you added campaigns, make the switch outside busy hours because of the mid-day reset, and look at each campaign's spend in the first week so one campaign is not taking the whole pool.

Frequently asked questions

Can Performance Max use a shared budget?

No. Google says shared budgets are only available on Search, Shopping, Display and Video campaigns, and names Performance Max among the campaigns they are not compatible with.

Does a shared budget split money evenly between campaigns?

No. Google describes it as one budget where unused money moves automatically to campaigns that would otherwise be capped. No campaign has a fixed share.

What happens to the amount when I add a campaign?

Google says the campaign's own budget is added to the shared budget's amount. Lower the shared amount afterwards if you want the total to stay the same.

Why can't I remove a shared budget?

Every campaign must have a budget, so a shared budget can only be removed when no campaign uses it. Move each campaign to an individual budget first.

Do I need a portfolio bid strategy?

Google calls it best practice; its pages do not make it a requirement. Some accounts can link a portfolio strategy and a shared budget, so campaigns added to or removed from the strategy also join or leave the budget.

A shared budget only helps if every campaign on it sends people to pages that convert. See our Google Ads basics guide, our website development service and all our services, or email [email protected].