When you change your average daily budget, you'll view these adjustments immediately in your account. Changing your average daily budget or campaign total budget can impact how frequently your ads are shown, as well as how much you can be charged.
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1. Average daily budgets
Budget changes can impact how frequently your ads are shown
Google optimizes your campaign spend for days of the month when you’re more likely to get clicks and conversions. When you change your average daily budget, Google will start serving your ads taking into account your recently changed budget. An increase in budget may be followed by an increase in spend, while a decrease may have the opposite effect.
Budget changes can impact how much you can be charged
Changing your average daily budget impacts both your daily spending limit and your monthly spending limit. Learn more About spending limits.
Impact on daily spending limit
On the day you make a change (or more than one change) to your average daily budget, your daily spending limit will be based on the highest average daily budget that you chose for that day. This means that for most campaigns you will never be charged more than 2 times your highest average daily budget on that day.
Example:
Let’s say you have a campaign with an average daily budget of $10 USD. On the same day, you first increase your budget to $50 USD, and then lower it to $5 USD. The daily spending limit for the day is going to be the highest of your average daily budgets multiplied by 2, therefore $50 USD * 2 = $100 USD.
Impact on monthly spending limit
When you change your budget, your spend for the rest of the month won’t exceed your new average daily budget multiplied by the remaining days in the month.
Example:
Let’s look at a monthly spending limit for November, which spans from November 1 to November 30. On November 1, you set an average daily budget of $5 USD, for a monthly spending limit of $152 USD ($5 USD * 30.4). Then assume that, on November 24, you’ve only spent $103 USD and you decide to increase your average daily budget for the remaining days of the month. You then change your average daily budget to $10 USD. The maximum you’ll be charged for the month of November will be:
$103 USD spent so far + ($10 USD/day * 7 days remaining in November) = $173 USD monthly spending limit
Putting everything together
When you change an average daily budget, 2 things are going to happen:
- Google will start serving your ads taking into account the newly changed budget.
- Your daily spending limit and your monthly spending limit are going to be updated accordingly.
Some additional examples below:
Single budget increase
Assume you have a campaign that has been running since the beginning of September. At the beginning of September:
- Average daily budget: $10 USD
- Daily spending limit = $10 USD * 2 = $20 USD
- Monthly spending limit = $10 USD * 30.4 = $304 USD
With 5 days left in the month (including the day the budget is edited) and $270 USD total spent, the average daily budget is increased to $50 USD. This will result in:
- Average daily budget: $50 USD
- Daily spending limit: $50 USD * 2 = $100 USD
- Monthly spending limit = $270 USD + ($50 USD/day * 5 remaining days in September) = $520 USD
Single budget decrease
Assume you have a campaign that has been running since the beginning of September. At the beginning of September:
- Average daily budget: $10 USD
- Daily spending limit = $10 USD * 2 = $20 USD
- Monthly spending limit = $10 USD * 30.4 = $304 USD
With 5 days left in the month (including the day the budget is edited) and $270 USD total spent, the average daily budget is decreased to $5 USD. This will result in:
- Average daily budget: $5 USD
- Daily spending limit for the day with the edit: $10 USD * 2 = $20 USD
This is because we pick the highest daily budget for the day.
- Daily spending limit for remaining days of the month: $5 USD * 2 = $10 USD
- Monthly spending limit = $270 USD + ($5 USD/day * 5 remaining days in September) = $295 USD
Multiple edits on the same day
Assume you have a campaign that has been running since the beginning of September. At the beginning of September:
- Average daily budget: $10 USD
- Daily spending limit = $10 USD * 2 = $20 USD
- Monthly spending limit = $10 USD * 30.4 = $304 USD
With 5 days left in the month (including the day the budget is edited) and $270 USD total spent, the average daily budget is increased to $50 USD. This will result in:
- Average daily budget: $50 USD
- Daily spending limit: $50 USD * 2 = $100 USD
- Monthly spending limit = $270 USD + ($50 USD/day * 5 remaining days in September) = $520 USD
On the same day, a few hours after the first edit and now $280 USD total spent, the average daily budget is decreased to $30 USD. This will result in:
- Average daily budget: $30 USD
- Daily spending limit for the day with the edit: $50 USD * 2 = $100 USD
This is because we pick the highest daily budget for the day.
- Daily spending limit for remaining days of the month: $30 USD * 2 = $60 USD
- Monthly spending limit = $280 USD + ($30 USD/day * 5 remaining days in September) = $420 USD
Note: Even if you don't deliberately change the average daily budget in your campaign, changing your campaign end date is considered a budget change (for computing the maximum amount you'll pay within a calendar month).
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2. Campaign total budgets
Campaign total budgets (flighted budgets) allow you to set a fixed budget for a specific duration, ranging from 3 to 90 days. This feature is designed for Search, Shopping, and Performance Max campaigns during specific events like flash sales or seasonal promotions.
Unlike average daily budgets, a campaign total budget acts as a hard cap for the total duration of the campaign.
How do budget changes impact serving
Campaign total budgets aim to maximize budget utilization by the end date, changing the budget amount affects how the system paces your spend:
- Re-distribution of spend: If you increase or decrease the total budget (or change the end date) while the campaign is live, the system recalculates the daily spend required to exhaust the remaining budget over the remaining days.
- No daily spending limit: Unlike average daily budgets, campaign total budgets don’t have a daily cap (such as the 2x daily limit). The system may spend more or less on specific days based on traffic opportunities to attempt to spend the total budget by the end date.
- Impact of frequent changes: It is recommended to minimize budget or duration changes once a flighted campaign has started. Sudden changes may lead to uneven spend or performance shifts as the system attempts to re-optimize towards the new total goal.
Example:
Let's say you are running a 10-day "Flash Sale" from December 1 to December 10 with a Campaign total budget of $1,000 USD.
- Initial pacing: Google aims to spend roughly $100 USD per day ($1,000 USD / 10 days).
- Day 3 adjustment: By the end of Day 3, you have only spent $200 USD (perhaps due to low search volume). You have $800 USD remaining and 7 days left.
- System re-calculation: Google will automatically re-pace your campaign to spend roughly $114 USD per day ($800 USD / 7 days) for the remainder of the flight.
- Budget increase: On Day 5, you decide to increase the total budget to $1,500 USD.
- New math: Total budget ($1,500 USD) - spent so far (~$430) = $1,070 remaining.
- New pacing: The system will now aim to spend $178 USD per day over the last 6 days to spend the full $1,500 by December 10.
Key differences from daily budgets
- Hard cap: The total budget set will not be exceeded.
- Switching: You can’t switch an existing campaign from an average daily budget to a campaign total budget. You must create a new campaign to use this feature.
Learn more About campaign total budgets.
