Why your ads spent more than your daily budget (and the most they are allowed to)
A daily budget is an average, not a cap. How far over it Google Ads, Meta, Microsoft, LinkedIn, TikTok and Pinterest can go in a day, what keeps the week or month in line, and what a mid-month change does.
You set a campaign to 100 a day. On Tuesday it spent 170. Nothing is broken, and nobody is overcharging you. On almost every ad platform, the number in the daily budget box is an average the platform aims for over a longer stretch, and it is allowed to spend more on a day when there is more worth buying.
What changes between platforms is how far over, and over what stretch it evens out. Here is each one, from its own help pages, and a free budget pacing calculator that does the sums for your budget.
Why platforms do it at all
Traffic is not flat. Searches spike on some days, auctions get cheaper on others, and a Friday might have twice the good opportunities of a Monday. A hard daily cap would force the platform to stop at the same number on the busy day and scrape for anything on the quiet one. Letting a day run over, and pulling back on another, spends the same money on better slots.
The trade is that you give up day-level control in exchange for a firm ceiling over a longer period. That ceiling is the number to plan around.
Google Ads: up to 2 times a day, 30.4 times a month
Google's rule, from About spending limits: for most campaigns, the daily spending limit is 2 times the average daily budget, and the monthly spending limit is 30.4 times it. 30.4 is the average number of days in a month, 365 divided by 12.
So a 100 daily budget can spend up to 200 on a given day and 3,040 in a month, whether the month has 28 days or 31. If the ads serve more than that, Google says you will not actually pay more than the limits. Pay for Conversions campaigns are the documented exception: no daily spending limit, but the monthly one still applies.
Meta: up to 75% over a day, 7 times a week
Meta paces a daily budget over a calendar week, Sunday to Saturday. From About daily budgets: on days with better opportunities, Meta may spend up to 75% over the daily budget, so no day ending at midnight goes over 175% of it, and no week ending Saturday at midnight goes over 7 times it.
On a 100 daily budget: up to 175 on a day, 700 a week. Turn on ad set budget sharing and Meta may also share up to 20% with other ad sets. Its own example for 100 a day is up to 210 on some days and 840 in a week.
Microsoft Advertising: the real days in the month
Microsoft does not use 30.4. Its budget guide says the monthly budget limit is the daily budget multiplied by the number of days in the month, recalculated at midnight on the first. A 100 daily budget allows 2,800 in February 2026 and 3,100 in October.
On single days, Microsoft is less precise: it calls the budget a target and says it usually keeps overspend to less than 100% above the daily limit. "Usually" is not a promise, so treat 2 times as the normal ceiling, not a guaranteed one.
LinkedIn, TikTok and Pinterest
- LinkedIn says daily spend might be up to 100% higher than the daily budget. On a continuous schedule, spend is paced over a Monday to Sunday week and stays within 7 times the daily budget. With a start and end date, the whole run stays within the daily budget times the days: LinkedIn's example is 100 a day through January, capped at 3,100. From Campaign and ad set budgets.
- TikTok treats a standard daily budget as the maximum per day, per About daily budgets. Turn on Dynamic Daily Budget and it may spend up to 25% more on good days, with the Sunday to Saturday week capped at 7 times the daily budget. TikTok's example: 50 a day can be 62.50 one day, 37.50 another, and at most 350 across the week.
- Pinterest Performance+ daily budgets turn the daily figure from a strict cap into an average. Pinterest tries its best to stay within 125% of it on any day, and average daily spend from Sunday to Saturday is no more than the budget. From Set up a campaign budget.
The same budget, side by side
A daily budget of 100, in a 30-day month:
| Platform | Most on one day | Longer ceiling |
|---|---|---|
| Google Ads | 200 | 3,040 a month |
| Meta | 175 | 700 a week |
| Microsoft Advertising | about 200 (usually) | 3,000 a month |
| 200 | 700 a week | |
| TikTok, standard | 100 | 100 a day |
| TikTok, Dynamic Daily Budget | 125 | 700 a week |
| Pinterest Performance+ | about 125 (tries to) | 700 a week |
What happens when you change the budget mid-month
This is where most "why did it spend that" questions come from. Each platform restarts the arithmetic from the change:
- Google Ads: the rest of the month is capped at the new daily budget times the calendar days left. Google's example: 5 a day in November, 103 spent by the 24th, raised to 10. The month can reach at most 103 plus 10 times 7 days, 173. On the day itself, the daily limit uses the highest budget you had that day, so raising and lowering in one afternoon still allows 2 times the higher number. From How budget changes take effect.
- Microsoft: month-to-date spend plus the new daily budget times the days remaining, including today. Its example: 250 spent, changed to 10 on July 15th, so 250 plus 10 times 17 is 420.
- Meta: the new daily budget times the days left in the week, plus up to 25% of the daily budget. Dropping from 100 to 50 at midnight on Wednesday allows at most 212.50 from Wednesday to Saturday. From About changing your daily budget.
The practical lesson: a big increase late in the month does not get to "catch up" on the days before it, and a cut late in the week does not claw back what already ran.
Setting a daily budget from a monthly one
If the plan is a number per month, the right daily budget depends on the platform:
- Google Ads: divide by 30.4. For 3,040 a month, set 100 a day, and the monthly limit lands exactly on 3,040.
- Microsoft: divide by the days in that month. 3,000 in a 30-day month is 100 a day. Revisit it when the month changes length.
- Meta, LinkedIn, TikTok, Pinterest: divide by the days in the month for a figure that averages out to your number. These platforms cap days and weeks, not calendar months, and a week can straddle two months.
Round down, not up. A daily budget of 32.90 on Google is 1,000.16 a month; 32.89 is 999.86.
Run your numbers
The ad budget pacing calculator applies all of these rules: pick a platform, enter a daily budget and a month, and it shows the most on one day and over the week or month, what a mid-period change allows, and the daily budget for a monthly one on every platform. It runs in your browser and never connects to an account.
If you would rather hand the setup over, Hermoso is an AI marketing agent that runs your marketing on autopilot. It makes the ads and builds campaigns on your own ad accounts from a plain request, and everything is created paused, so nothing spends until you turn it on.
Questions people ask
Why did Google Ads spend more than my daily budget?
Google can spend up to 2 times the average daily budget on a day for most campaigns, to catch busier traffic. The month is held to 30.4 times the daily budget, and Google says you are not billed above its spending limits.
Can Meta spend more than my daily budget?
Yes, up to 75% more on a day, so at most 175% of it, and never more than 7 times the daily budget in a Sunday to Saturday week. With ad set budget sharing, Meta's example allows 210% on a day.
What daily budget gives a monthly budget on Google Ads?
The monthly budget divided by 30.4. For 3,040 a month, set 100 a day.
Does lowering my budget mid-week stop Meta overspending?
It sets a new limit for the rest of the week: the new daily budget times the days left, plus up to 25% of the daily budget. It does not undo anything already spent earlier in the week.