Your Amazon campaign runs out of budget. Should you raise it?
When a campaign shows "out of budget", the reflex is to raise the budget. We looked at how often that happens on real accounts and what those campaigns sold. Most campaigns never came near their budget, and many of the ones that did were not campaigns you would want to give more money to.
The measured numbers below come from real accounts: 9 advertiser accounts in Europe, the UK and the US, 10 account and currency pairs, Sponsored Products campaigns, day by day from September 3 to September 30, 2026. We started on September 3 because that is the first day we have the daily budget recorded for each campaign. We stopped at September 30 so that the ad-attributed sales of the last days are close to final. We only counted days on which a campaign spent something: 2,122 campaign days from 179 campaigns. We compared ACOS only inside one account and currency. Below, "account" means one account in one currency.
We counted a day as "hit the budget" if the campaign spent at least 95% of its daily budget. We did not use 100%, because spend often went past the budget: on 193 of the 244 days that reached 95%, the campaign spent more than the budget set that morning, and on 80 days more than 1.25 times as much. We did not check whether a budget rule or a change during the day caused this.
Most campaigns are nowhere near their budget
- On 1,529 of the 2,122 campaign days (72%), the campaign spent less than half its daily budget.
- On 244 days (11.5%) it spent at least 95%.
- 47 of the 179 campaigns hit the budget at least once in the period.
For a campaign that spends a third of its budget, a higher budget changes nothing. What limits it is the bid, the targeting or the search volume, so that is where to look.
It depends on the account
The share of an account's ad spend that fell on days when the campaign hit its budget ranged from 0% to 53.4% across the 10 accounts. In 4 accounts it was 39% or more, in 2 it was zero.
The two accounts with the highest share were not the efficient ones. The account where 53.4% of the spend fell on such days sold at 194.0% ACOS over the period. The one at 42.9% sold at 178.5%. In those accounts the budget was the only thing stopping the campaigns from losing more. Raising it would have bought more of the same.
Hitting the budget is not a reason to raise it
We took the campaigns that were active on at least 10 days and hit their budget on at least 30% of those days. That gave 18 campaigns.
- 6 had at least 5 orders and sold at or below their own account's ACOS. These are the candidates for a higher budget.
- 3 had at least 5 orders and sold above their account's ACOS.
- 9 had fewer than 5 orders in the period. 3 of them had none.
So half of the campaigns that kept running out of budget had too few orders to judge, and only a third looked like a good place for more money. Even among the 6 good ones, 5 had 5 to 9 orders, so their ACOS can still move a lot. One campaign had 57 orders at 34.3% ACOS against 41.3% for its account. That is the only one where we would raise the budget with some confidence on one month of data.
The 5-order cut-off is our choice, not a measurement. With fewer orders, one extra sale changes the ACOS too much to compare it with anything.
What we could not see
We do not have hourly data, so we do not know at what time of day each campaign ran out. A campaign that runs out at 11 pm loses little. One that runs out at 10 am is out of the auction for most of the day. We did not measure how many sales the campaigns missed while they were out of budget. We did not test whether a higher budget keeps the same ACOS: the extra clicks may come from weaker placements or searches. And the report counts the purchases for 7 days after the click, so the last days of September may still have gained a few sales.
Decide in 20 minutes
- Download the Sponsored Products campaign report by day for the last 4 weeks, ending at least a week ago, and next to it each campaign's daily budget.
- For each campaign, count the days on which it spent at least 95% of its budget. Campaigns that spend less than half of it are not budget-limited: leave the budget alone and look at bids and targeting.
- Take the campaigns that hit the budget on a large share of their days. Write next to each its orders and ACOS for the same 4 weeks, and the ACOS of the whole account.
- Raise the budget only where the campaign has enough orders to judge and sells at or below the account's ACOS. Raise it in steps of about a quarter, not double it. This step size is our suggestion, not a measurement.
- If a campaign keeps running out of budget at a worse ACOS than the account, the budget is protecting you. Lower its bids or remove its weakest searches first.
- After 2 weeks, compare the raised campaigns with the same weeks before: did spend grow, and did ACOS stay where it was?
A campaign that runs out of budget is spending fast. Whether it is spending well is a separate question, and you can answer it from the same report.