Marketer, analyst, ex-CMO focused on the Google ecosystem (Ads, Merchant Center, GA4, GTM). Google Partner. 150+ projects, 100+ positive reviews on Freelancehunt, 12+ countries.
- I work directly, with no account managers or subcontractors
- I measure results in sales, not in-platform conversions
- Maximum expertise in the Google ecosystem
A familiar situation: the daily budget is UAH 500 ($11), but yesterday the campaign spent 900 ($20). That’s how Google works, and it’s written into its rules. You should count by the month, not the day, and below I’ll break down how much can actually be charged per month.
Contents
How Campaign Budgets Are Spent: Why Google Ads Spends More on Some Days and Less on Others
How Google counts the daily budget
The daily budget in Google Ads is an average for the month. Search is different every day: on high-demand days the system picks up more clicks, on quiet days fewer. There are two limits. In a day a campaign can spend up to twice the daily budget, and in a month no more than the daily budget × 30.4 (the average number of days in a month).
For UAH 500 a day that’s up to UAH 1,000 per day and up to UAH 15,200 ($338) per month. If you plan from a monthly amount, divide it by 30.4: UAH 30,000 a month is about UAH 987 a day.
You won’t be charged more than the monthly limit. Google counts the cost of impressions and the billed cost separately: impressions sometimes go over the limit, the bill doesn’t. You can see the difference in the Report Editor, in the “Billed cost” report in the billing section.
And don’t judge your ads by a single day. In the dental equipment store analysis, daily ROAS over seven months swung from 0.16 to 83. With that kind of spread, a day “with overspend” means nothing on its own.
Scheduled campaigns: what changed on June 1, 2026
This is where overspend can come as a surprise. If a campaign is paused on certain days of the week, Google used to calculate the budget for the active days only. Since June 1, 2026 the system aims to spend the same 30.4 daily budgets per month, no matter how many days the campaign runs.
Take a campaign that runs only on weekdays, about 22 days a month, with a budget of UAH 1,000 a day. Before June it spent about UAH 22,000 a month. Now it can spend up to UAH 30,400, more than a third more, even though nobody touched the settings.
The exact limits are these. If there are 16 or more active days in the month, the maximum is the daily budget × 30.4. If 15 or fewer, it’s twice the daily budget × the number of active days. Hourly ad schedules weren’t affected by this change.
What to do about it: calculate the daily budget from the monthly amount divided by 30.4, even if the campaign doesn’t run every day. Google gives an example itself: to spend $2,000 over 20 days, set about $66 a day.
And if you need a hard cap for a promotion or a season, since January 15, 2026 Search, Performance Max and Shopping have a campaign total budget, still in beta. You set the amount for a period of 3 to 90 days and Google won’t exceed it. It only works for new campaigns.
Budget changed mid-month
The monthly limit is recalculated from the day of the change: the old budget for the days already passed, the new one for the rest. The daily maximum changes immediately. So if you tweak the budget every few days, monthly spend becomes hard to predict. And for smart bid strategies Google recommends waiting one or two conversion cycles after increasing the budget before drawing conclusions.
When a campaign underspends
The opposite happens just as often. In the footwear store audit, a Target CPA campaign spent less in a month than the daily budget × 30: the target simply kept it out of auctions where it couldn’t hit the set cost per conversion. Too narrow a location or low search volume do the same.
To spot such campaigns right away, I add a separate “cost / daily budget” column in the account:
A Useful Column for Anyone Running tROAS and tCPA in Google Ads
What to check today
Open your campaign list and divide your monthly ad budget by 30.4. Compare it with the daily budgets in the account. Separately check campaigns scheduled by day of the week: if their budget was calculated for active days, since June they may be spending more than you planned.
How much to set aside for ads at all, so that they can be evaluated, I calculated separately.
Google AdsIs $10, $50 or $100 a Day Enough for Google Ads?Is $10, $50 or $100 a day enough for Google Ads? How to budget from your goal and why a small budget slows down both tests and Google's algorithms.
07 — ConsultationGoogle Ads consultationYour specific question worked through on Zoom or Google Meet: performance drops, conversions, launch strategy.
How much to budget for ads and when they pay off — the free Google Ads ROI calculator.
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