The 3-Phase Prime Day Ad Budget: How to Spend Before, During, and After the Event 

TL:DR; Most Amazon sellers misallocate their Prime Day ad budget by front-loading spend on the event itself. Here’s the 3-phase framework for spending before, during, and after Prime Day.

Key Takeaways: 

• The week immediately before Prime Day is historically one of the lowest-converting windows in the ad calendar. Spiking too early can hurt your performance. 
• Phase 1 (3-4 weeks out): get your campaign structure and conversion history in place, including defensive campaigns on your own ASINs. 
• Phase 2 (during the event): concentrate spend on your 5-15 priority keywords at top-of-search, use day-parting to shift budget toward your highest-converting hours, and cap budgets per campaign so top performers don’t go dark. 
• Phase 3 (7-10 days after): hold keyword budgets steady to lock in organic ranking gains, and activate Sponsored Display retargeting to recapture buyers who viewed but didn’t purchase during the event. 
• The 3-phase approach is primarily a reallocation, not a dramatic increase in total spend. 

Prime Day Is Longer Than You Think 

Prime Day is a two-day event on the calendar, but for Amazon sellers who manage their PPC carefully, it functions more like a six-week campaign, with the real work spread across three distinct phases: the buildup before the event, the event itself, and the follow-through that locks in the gains. 

Here’s how to build a Prime Day ad budget that treats all three phases as part of one connected strategy. 

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Why Most Prime Day Ad Budgets Are Structured Wrong 

The most common mistake is treating Prime Day as a single sprint: increase budgets on the morning of the event, watch the spend climb, cut back the next week. This approach ignores two realities about how Amazon’s ad system works. 

First, the week immediately before Prime Day is historically one of the lowest-converting windows in the Amazon ad calendar. Shoppers are aware something big is coming and they’re holding off on purchases. If you spike your budget during that window without adjusting for it, you’ll pay for a lot of clicks that don’t convert. 

Second, the ranking gains you earn during Prime Day don’t sustain themselves automatically. Your organic rank after the event reflects the sales velocity you maintained during it, but velocity needs to keep up for the rank to hold. Cutting your ad budget the day after Prime Day ends is one of the most reliable ways to give back the rank you just paid to earn. 

A budget structure that accounts for both of these realities looks like three phases, each with its own objective and spend profile. 

Phase 1: Pre-Event (Three to Four Weeks Before Prime Day) 

Objective: Build keyword momentum, establish campaign history, and set up the structure you’ll run during the event. 

The campaigns you launch on the morning of Prime Day will perform worse than campaigns that have been running for three or four weeks with established conversion history. Amazon’s algorithm weights campaign history when determining ad relevance and placement. A campaign that’s been converting on a keyword for a month gets better placement efficiency than a brand-new one competing for the same slot. 

In the three to four weeks before Prime Day, your ad spend doesn’t need to spike dramatically. What matters is that your campaign structure is in place and collecting data. That means: 

Your primary keywords should be running in exact and broad match campaigns, with your bids set at competitive but sustainable levels. If you have Sponsored Display retargeting set up, it should be active now so you’re building a retargeting audience before the event starts. If you have access to AMC Audiences, use this window to build deal-seeker and previous-buyer segments that you’ll activate during the event. 

This is also when to handle the defensive campaign setup: Sponsored Products and Sponsored Display campaigns targeting your own ASINs, so that when Prime Day traffic arrives, competitors can’t buy placements on your own detail pages. 

For a deeper look at campaign structure choices that hold up at scale, this guide to advanced Amazon PPC strategies covers the structural decisions worth making before the event. 

Budget guidance for Phase 1: Spend at roughly your normal rate, or modestly above it on your top-performing keywords. The goal is history and structure, not maximum impressions. 

Phase 2: During the Event 

Objective: Maximize visibility on high-converting keywords, defend your listings, and convert the traffic surge into ranking gains. 

This is the phase most sellers over-index on, and the mistake usually isn’t spending too much. It’s spending indiscriminately. Prime Day traffic is real, but it’s also expensive: CPCs spike as every seller in your category increases their budgets simultaneously. 

The brands that get the best return during the event are the ones that concentrated their budget on a short list of high-priority keywords rather than trying to be everywhere at once. That means top-of-search placements on the 5 to 15 keywords you identified during Phase 1, and letting lower-priority terms run at their normal rates or reduced rates if their conversion history suggests they won’t perform. 

There are two specific plays worth activating during Phase 2 that many sellers skip: 

Day-parting adjustments. Prime Day runs for roughly 48 hours, but not all hours convert equally. Hourly ad analytics in Helium 10 Ads shows you which hours of the day have historically shown the strongest ACoS for your products, and rules-based bidding lets you automatically increase bids during your best windows and pull back during off-peak hours. Spreading your budget evenly across 48 hours means you’re often overpaying during low-conversion windows and underfunding during high-conversion ones. 

Budget caps per campaign, not overall. If you set a single overall daily budget, you risk your best-performing campaigns going dark mid-day because a lower-priority campaign burned through budget in the morning. Structure your budgets at the campaign level so your top-performing placements never run out. 

For sellers who want a systematic framework for allocating PPC budget across campaigns, this guide walks through the prioritization logic. 

Budget guidance for Phase 2: Increase budgets on your target keyword campaigns by 50 to 150 percent above your Phase 1 baseline, focused on top-of-search placements for your shortlist of priority keywords. 

Phase 3: Post-Event (Seven to Ten Days After Prime Day) 

Objective: Lock in organic ranking gains from the event and capture buyers who viewed but didn’t purchase during Prime Day. 

This phase is where most of the post-Prime Day value gets left on the table. The organic ranking lift you earned from Prime Day’s sales velocity starts to decay as soon as your sales rate slows. If you cut ad spend the day after the event ends, you’re allowing that decay to happen faster than it needs to. 

For the week following Prime Day, keep your budget and bids on your target keywords at or close to your during-event levels. You don’t need to maintain peak spend indefinitely, but a seven-to-ten day holdout period gives your rankings time to stabilize at their new positions before you start scaling back. 

Retargeting is the other Phase 3 play worth executing. Prime Day drives an enormous number of product page views from shoppers who didn’t buy: they looked, compared, and left. Sponsored Display retargeting campaigns serve ads to exactly those shoppers in the days after the event, catching buyers who were interested but hesitated. The cost per click for retargeting is typically lower than during the event itself, making this some of the most efficient ad spend in your Prime Day cycle. 

This analysis of how to continue Prime Day momentum covers the specific post-event moves that translate short-term sales spikes into lasting rank improvements. 

Budget guidance for Phase 3: Hold your target keyword budgets steady for seven to ten days, then taper back to your normal baseline over the following week. Activate retargeting campaigns with a dedicated budget separate from your keyword campaigns. 

Putting the Three Phases Together 

The three-phase structure works because each phase feeds the next. The campaign history and structure you build in Phase 1 makes your Phase 2 spend more efficient. The rankings you earn in Phase 2 give you something worth defending in Phase 3. And the retargeting work in Phase 3 captures value you already paid for in Phase 2 but didn’t fully convert. 

The total budget across all three phases doesn’t have to be dramatically higher than what you’d spend in a normal six-week window. It’s primarily a reallocation: less spend in the pre-event week when conversion rates drop, more concentrated spend during the event on your highest-priority placements, and a deliberate hold on budget in the week after rather than an immediate pullback. 

If you want to build and manage this campaign structure without manually tracking bid changes across every keyword, Helium 10 Ads handles rules-based bid adjustments automatically, including day-parting rules and ACoS-triggered bid changes, so your campaigns adapt to real-time performance without requiring you to be in Seller Central every hour.