Amazon dayparting calculator

How the bid adjustments are worked out

Good dayparting is not “where did I spend?” — it is “which hours pay off, and which quietly bleed?” The tool answers that from each hour’s ACoS, nudging every hour’s bid toward your account-wide average: raise where an hour runs more efficiently than your average, ease off where it runs above. Because ACoS already folds in both what a click costs (CPC) and what it returns (revenue per click), it catches the most common leak — paying peak prices midday when competition spikes, even though those hours convert no better than cheaper overnight ones.

Two things keep it honest. Every adjustment is weighted by click volume, so a lucky overnight hour with a handful of clicks can’t trigger a reckless swing — only hours with real traffic move much. And the headline “reclaimable spend” is the actual money sitting in hours above your average ACoS, not a guess. Switch the metric on the chart to see the full picture: revenue per click, conversion rate, CPC and demand all shift through the day.

Sanity-check the hours you trim against your break-even ACoS so you keep the ones that are still profitable, just less so.