Quick answer
If Google Ads spends less than your budget, there usually isn't enough search volume for your keywords, or your bids or target CPA are too low to win auctions. "Limited by budget" means the opposite: demand is there and the budget runs out. Daily spend can reach twice your average daily budget, but the month is capped.
This guide is for owners who look at the Campaigns screen and see spend that doesn't match the number they typed in. It is part of our Google Ads help centre.
How Google Ads daily budgets and the monthly cap work
The figure you enter is an average daily budget, not a hard daily limit. Google's own help page says a campaign can spend up to two times its average daily budget on a given day, to catch busier days.
Across a month you are protected by a monthly charging limit. For most campaigns that is your average daily budget multiplied by 30.4, the average number of days in a month. A $50 average daily budget gives a monthly limit of $1,520. Google says you won't be charged more than that for the month, even if some days ran high.
So a $90 day on a $50 budget is normal. A month well under $1,520 is the thing worth looking into.
Check these first
- Read the campaign status. In Google Ads, go to Campaigns and look at the Status column. "Eligible" with low spend points to demand or bids. "Limited by budget" means the budget is the ceiling.
- Check keyword statuses. Open Keywords for the campaign. Keywords marked "Low search volume" are not showing much, and a campaign full of them will underspend.
- Look at the bid strategy and target. Open the campaign settings, then Bidding. If you use Target CPA or Target ROAS, compare the target with what the campaign actually achieved over the last 30 days.
- Check location and schedule. In settings, look at Locations and Ad schedule. One suburb, or ads that run only during office hours, can cap reach.
- Check match types. If every keyword is exact match and very specific, there may simply not be many searches to show on.
Underspending vs "Limited by budget"
These two problems look similar on a bill but need opposite fixes.
| Underspending | Limited by budget |
|---|---|
| Spend sits well below the daily budget most days. | Spend sits at or near the daily budget most days. |
| Not enough eligible searches, or bids too low to win them. | More searches are available than the budget can pay for. |
| Status usually "Eligible", sometimes with "Low search volume" keywords. | Status column shows "Limited by budget". |
| Raising the budget changes nothing. | Raising the budget usually brings more clicks, if the extra clicks are worth having. |
| Fix: broaden keywords, raise bids or loosen the target CPA, widen location or schedule. | Fix: raise budget, or narrow keywords and lower bids so the same money buys better clicks. |
Cause and fix table
| What you see | What it means | How to fix it | How long it takes |
|---|---|---|---|
| Spend far below budget, few impressions | Keywords too narrow, or only exact match | Add phrase match versions and closely related terms; remove "Low search volume" keywords that will never show | Changes apply within hours; judge over 1 to 2 weeks |
| Spend dropped after switching to Target CPA | Target set below what the campaign can achieve | Set the target near your recent average CPA, or switch to Maximise conversions for a while | Allow a learning period of about 1 to 2 weeks |
| Manual CPC campaign, low impression share | Bids too low to win auctions | Raise bids on the keywords that convert; check Search impression share lost to rank | Same day |
| Ads show only a few hours a day | Tight ad schedule or small radius | Widen the schedule or location, keeping areas you actually service | Same day |
| "Limited by budget" status | Budget runs out before demand does | Raise the budget, or cut weak keywords and locations so the budget lasts | Same day |
| Some days spend nearly double | Normal daily flexibility | Nothing, as long as the month stays under the 30.4 cap | None |
Why a low target CPA stops spend
Target CPA tells Google the average cost per conversion you want. Google's Target CPA help says a target set too low may cause the campaign to skip clicks that could have converted, which means fewer conversions overall. In practice you see spend fall away within days of setting an ambitious target.
Google's troubleshooting advice is to compare your target with the campaign's historical average CPA. If you paid around $80 a lead last quarter and set a $40 target, expect spend to drop sharply. Bring the target closer to reality, then lower it in small steps once results hold.
"Limited by budget": when to raise it and when to ignore it
Google shows "Limited by budget" when the campaign could get more traffic with more money. It also offers a recommended budget based on recent performance, keywords and targeting. Google says it won't show a recommendation if you rarely reach your current budget or the campaign has limited data.
Raise the budget only if the campaign already brings leads or sales at a cost you are happy with. If it doesn't, more budget just buys more of the same. In that case, tighten first: pause keywords that spend without converting, add negative keywords, and cut locations you don't service. The status may stay on, and that is fine.
The August 2026 bidding change
From 17 August 2026, Google changed how Target CPA and Target ROAS behave in campaigns that are limited by budget. Google says these campaigns now aim to perform consistently toward the target you set, rather than beating it and then swinging when budgets change. It also says it won't change your targets or budgets for you. If an older campaign was comfortably beating its target, spend and CPA may have moved closer to the target since August. Check that the target still reflects what you are willing to pay.
Overspending on some days
A day at up to double your average budget is expected behaviour. Google spreads spend toward days with more searches. Check the month as a whole in Billing, not the single day. If a whole month looks too high, lower the daily budget; the monthly limit moves with it.
Smart campaigns and Performance Max
Smart campaigns (Smart mode) don't show bid or match-type settings. Underspend there usually means too few keyword themes or a small area. Add relevant themes and check the service area.
Performance Max spends across Search, YouTube, Display and other Google inventory, so underspend is less common. When it does happen, it is often a Target CPA or Target ROAS set too tightly, or very little conversion data. See our guide to Performance Max for small businesses.
Australian detail
Budgets are in the currency your account was set up in, normally AUD for Australian businesses. Google adds 10% GST for accounts with an Australian business address, so your bank statement will be higher than the spend shown in campaigns. A $1,520 monthly limit becomes $1,672 once GST is added. Your account's day runs in the time zone set when it was created, usually AEST or AEDT, and that is when the daily budget resets. Billing details are in our Google Ads billing guide.
If your ads are not showing at all rather than just underspending, start with why Google Ads are not showing. For realistic budget ranges, see how much Google Ads cost in Australia.
When to get help
If spend still won't settle, a specialist looks next at impression share lost to rank versus budget, search term quality and whether conversion tracking is feeding the bid strategy good data. We do that as part of month-to-month Google Ads management, and you keep ownership of the account.
About this guide
Written by Amann Jhamb, Director of AR Digital Solutions, 17 years in web design, SEO and paid ads. Last checked: 3 November 2026 against Google Ads Help: About average daily budgets. Change note: first published 3 November 2026. Part of our Google Ads help centre.