What that status is actually selling you
Half your Search campaigns show Limited by budget. You open the status and the budget suggestion tool pitches a big weekly spend increase for a ROAS that sits nowhere near your Target ROAS. Your Target ROAS might be in the 3x range while the uplift story lands closer to 1.5x. Actual ROAS over the last month is already close to target. The panel feels insulting.
The projection is usually incremental volume priced at the efficiency Google wants for filling more auctions. It is not a plan for protecting your Target ROAS. People who run their own ads often treat Limited by budget as permission to raise spend immediately. That is how you buy a weaker mix of traffic while the status looks "fixed."
Read Impression Share Lost (Budget), not the uplift story
Add Search impression share lost to budget as a campaign-level column. Some UIs still call it IMPR Lost To Budget. That metric shows how much eligible Search volume you skipped because the daily budget ran out at your current bids. It does not invent a ROAS story on top of the gap.
Auction insights help you check whether you are mostly losing to stronger Ad Rank, which is a different problem. Performance Planner is usually a better place for scenario planning than the tiny panel that opens from Limited by budget. Use the column to decide whether budget is the bottleneck. Use Planner when you want a fuller forecast. Do not let the status write your P&L for you.
One catch... Impression Share Lost (Budget) also moves when you change bids, keywords, or match types, not only when you change budget. Treat it as a directional ceiling. You will not recover every missed impression and keep a high Target ROAS at the same time. Volume and efficiency trade off, and that tradeoff is the point the suggestion panel hides.
Marginal ROAS is not your blended Target ROAS
When the campaign is already near Target ROAS, the next dollars usually buy weaker auctions. You already won a lot of the high-intent searches your bids can afford. Extra budget pushes you into terms and hours that convert worse. The suggestion panel prices that marginal chunk. That is why an account holding a strong Target ROAS can still see a much softer projection on the proposed uplift.
If Actual ROAS and Target ROAS are already within roughly 10% of each other, a recommendation to roughly double spend at 1.5x is not proof that Google forged the math. It is proof that the tool is chasing spend and volume, not guarding your blended target. You still have to decide whether that extra volume is worth the efficiency hit. Sometimes it is. Often it is not, especially soon after an account change that already burned trust.
Raise budget in small weekly steps
If Impression Share Lost (Budget) is high and your Target ROAS is holding, bump budget a little each week and watch where ROAS or CPA starts to crack. That finds the real ceiling faster than one giant jump. Check whether spend dies early on peak hours. That pattern often means you are throttled. Very flat hourly spend can also mean heavy throttling, depending on the account.
Watch Google's forecasted CPA or ROAS at each new budget level, but believe your own last 7 to 14 days more than the chip. Conversion latency makes recent ROAS look worse when people click today and convert later through brand or direct. Give the numbers a little room before you declare the raise a failure.
Fix inventory bloat before you treat the status as opportunity
Limited by budget can appear because Maximize Conversions, aggressive Manual CPC bids, or a pile of weak Broad Match terms create more eligible inventory than the budget can cover. Pausing losers, adding negatives, and setting a Target CPA a bit under your current cost per conversion can clear the status without spending more. Portfolio strategies with bid caps are an option too, with the usual tradeoff that caps can also cut good volume.
Run this order before you open the wallet:
1. Confirm the real gap
Add Search impression share lost to budget. Ignore the uplift ROAS in the suggestion panel until you know the size of the volume gap at current bids.
2. Clean the demand you are already buying
Pause obvious underperformers, tighten negatives, and make sure you are not limited because junk inventory is eating the daily cap.
3. Softscale only if Target ROAS still holds
Raise budget a little each week. Stop when efficiency drops below what the business can live with. That stop point is your ceiling, not Google's recommended spend.
4. Separate budget problems from bid strategy problems
If you are about to flip from Manual CPC to Maximize Conversions, or jump between Target CPA and Target ROAS because the status freaked you out, pause. Budget and bid strategy are different levers. Mixing them in one panic edit is how accounts spend months recovering.
If you are mid-decision on a bid strategy change, use the Bid Strategy Switch Checklist. It is built for the moment before you switch, with a readiness table and a week-by-week recovery chart, so you are not guessing from a Limited by budget status alone.
When leaving the status alone is the right call
If Actual ROAS is already basically matching Target ROAS, and Impression Share Lost (Budget) is modest, you may already be buying the efficient slice. Leaving Limited by budget in place for a few weeks while you watch softscale candidates is more rational than doubling spend because a panel promised 1.5x on the next chunk. The status is a label. It is not a mandate.
Your Target ROAS (or Target CPA) is the scoreboard. Impression Share Lost (Budget) is the volume gap at current bids. The suggestion panel is Google's volume pitch. Read them in that order and Limited by budget stops feeling like a dare.