Paid Search Bid Calculator
Work out the highest CPC you can afford for any product from its order value, margin, conversion rate and target ROAS.
Product and goal
Bid targets
Recommended max CPC bid
Bid strategy is margin math
Order value divided by your target ROAS tells you how much ad spend each sale can carry. Multiply that by your conversion rate and you get the highest CPC you can pay and still hit the target. Bid above it and you lose margin. Bid far below it and you give up volume to competitors.
The calculator also shows a break-even CPC: profit per sale times conversion rate. That is the absolute ceiling. If your target ROAS allows a higher bid than break-even, the target is too low for your margin and every sale loses money.
Why a 15% buffer?
Conversion rates move from week to week. Bidding about 15% under your maximum leaves room for that noise so one slow week does not push you past your target.
Frequently asked questions
Should I always bid the max?
No. Treat the max as a ceiling. In early campaigns, test bids at 70 to 90% of the max and raise them where conversion data supports it.
How does this relate to Smart Bidding?
If you use a Target ROAS strategy in Google Ads, the same math happens automatically. This calculator helps you choose a realistic target and sanity check the CPCs Google ends up paying.