How to use the impression share budget calculator
Impression share is the slice of eligible impressions your ads actually received. Enter current monthly spend, current share, and the share you want, and the calculator returns the monthly budget the target implies, the extra spend on top of today's, and the percentage increase. The figure is rounded up, so it never lands just short of the target.
One assumption matters more than the rest: this is a linear proportional estimate. Search auctions do not behave that way. The easy impressions are already won, so lifting share means buying the remaining impressions at higher bids, and each additional point costs more than the last. Read the result as a floor to plan from rather than a promise.
Low impression share is not always a budget problem. Search platforms report impressions lost to budget separately from impressions lost to ad rank, and if rank is the bigger share, extra spend will not move the number much. Check keyword coverage, ad relevance, and landing page quality before committing the increase.
Frequently asked questions
Not guaranteed. The calculation assumes spend and impression share move in strict proportion. Real search auctions are non-linear: the cheap impressions are already bought, so each further point of share costs more. Treat the figure as a starting point, not a ceiling.
No. Impression share is the impressions you received divided by the impressions you were eligible for; click share is your clicks divided by all clicks on the query. This calculator works on impression share, so feeding it click share figures returns the wrong answer.