What Is a Post-Roll Ad?
A post-roll ad is a video advertisement that plays after the main content has finished. Unlike pre-roll ads, which interrupt before viewing begins, post-roll ads run once the viewer has already consumed the content they came for. They appear on platforms including YouTube, streaming services, and publisher video players.
How Post-Roll Ads Work
Post-roll ads trigger automatically when a video reaches its end point. The ad unit plays in the same video player, typically lasting 15 to 30 seconds. Most implementations allow the viewer to skip after five seconds, though unskippable formats exist on certain platforms and inventory types.
Because the primary content is already complete, advertisers face a specific behavioral challenge: viewers who have finished watching often close the player, switch tabs, or leave the page before the ad loads. This dynamic shapes everything from targeting strategy to creative execution.
Post-Roll vs. Pre-Roll: Placement Trade-Offs
| Factor | Pre-Roll | Post-Roll |
|---|---|---|
| Average completion rate | 45–65% | 10–25% |
| Audience intent | High (committed to content) | Variable (content already consumed) |
| CPM relative cost | Higher | Lower |
| Brand recall lift | Moderate | Can be strong for completers |
| Skip rate | High | Very high |
The lower completion rate translates directly into lower CPMs, making post-roll one of the more cost-efficient video ad formats when optimized correctly. Advertisers can reach audiences at a fraction of the cost of pre-roll inventory on the same publisher.
Why Advertisers Still Use Post-Roll
Post-roll performs well in specific scenarios despite low average completion rates.
Retargeting and Warm Audiences
Viewers who have already watched a full video have demonstrated category interest. A post-roll ad served to someone who just finished a product review or tutorial carries stronger contextual relevance than most display formats. Retargeting campaigns frequently use post-roll as a low-cost touchpoint for audiences already in the consideration phase of the marketing funnel.
Sequential Messaging
When advertisers control both the content and the ad, post-roll enables narrative sequencing. A brand sponsoring a YouTube creator’s cooking video, for example, can run a post-roll ad that picks up thematically where the content left off. This approach is common in branded content partnerships where the advertiser has negotiated placement continuity.
Budget Efficiency
For smaller advertisers, post-roll inventory offers access to premium publisher environments at reduced rates. A campaign running on mid-tier news or entertainment sites can secure post-roll placements at CPMs of $3 to $8, compared to $15 to $25 for pre-roll on the same properties.
Key Metrics for Post-Roll Campaigns
Video Completion Rate (VCR)
VCR measures the percentage of ad impressions watched to 100%. Most buyers consider a VCR above 20% strong for post-roll, given the high drop-off environment.
Formula:
VCR = (Complete Views / Total Impressions) × 100
Example: 50,000 complete views out of 300,000 impressions yields a VCR of 16.7%.
Cost Per Completed View (CPCV)
Because raw impressions can be misleading when completion rates are low, CPCV provides a more accurate efficiency measure.
Formula:
CPCV = Total Ad Spend / Complete Views
Example: $2,000 spent generating 50,000 complete views equals a CPCV of $0.04. Compare this against pre-roll CPCV benchmarks (often $0.10 to $0.18) to assess relative efficiency.
View-Through Rate (VTR)
VTR tracks conversions attributed to viewers who watched the ad without clicking. Post-roll ads tend to generate higher view-through attribution than mid-roll placements. One reason is that once the content is finished, any conversion the viewer completes is more cleanly tied to the ad itself rather than the surrounding content experience.
Creative Best Practices
Post-roll creative demands a different approach than pre-roll. The viewer is not waiting to access something they want and has no implied obligation to watch. Effective post-roll creative accounts for this context.
- Front-load the brand and offer. Place the brand name and primary message within the first three seconds. Viewers who skip at five seconds should still receive the core impression.
- Use shorter formats. Fifteen-second post-roll ads consistently outperform 30-second units on completion rate. For brand awareness goals, a 6-second bumper variant can achieve strong recall at minimal cost.
- Match the content tone. Post-roll served after relaxed entertainment content performs better with conversational creative. Post-roll after instructional or how-to content pairs well with direct-response messaging.
- Include a clear call to action. Because completion rates are lower, the viewers who do finish are higher-intent. A specific, time-limited CTA captures that segment effectively.
Platform-Specific Behavior
YouTube
YouTube, operated by Google, offers post-roll as a standard placement option within Google Ads video campaigns. Advertisers select it through the “After video” placement setting. Google’s own performance benchmarks suggest post-roll generates roughly 35% lower brand lift than pre-roll at equivalent spend, though the CPM discount often offsets this gap on a cost-per-lift basis.
Programmatic Platforms
Programmatic platforms including The Trade Desk and DV360 allow buyers to target post-roll inventory across open web publishers. Filtering by placement position in the bid request lets media buyers isolate post-roll supply and apply separate frequency caps and creative rotations from pre-roll campaigns.
Connected TV (CTV)
CTV platforms generally favor mid-roll and pre-roll placements. Post-roll appears less frequently there because auto-play pushes viewers directly into the next episode or recommended content. Post-roll on CTV is more common on ad-supported video on demand (AVOD) services with single-episode viewing patterns.
When Post-Roll Fits the Strategy
Post-roll works well as part of a broader video advertising mix rather than as a standalone tactic. Campaigns using pre-roll for awareness and post-roll for retargeted conversion messaging can achieve lower blended CPAs than single-placement strategies. The format also suits advertisers with strong brand recognition, since completion-dependent recall matters less when brand identification happens in the first seconds of the ad.
Advertisers who want guaranteed attention should look to mid-roll or interactive formats instead. Post-roll’s value is in volume and efficiency, not in guaranteed engagement.
Frequently Asked Questions
What is a post-roll ad?
A post-roll ad is a video advertisement that plays automatically after the main video content ends, within the same player. It is one of three standard video ad placements alongside pre-roll (before content) and mid-roll (during content).
Do viewers actually watch post-roll ads?
Completion rates for post-roll ads typically range from 10% to 25%, significantly lower than pre-roll. However, the viewers who do complete a post-roll ad have already engaged with the surrounding content, making them a more qualified audience than a raw impression count suggests.
What is a good video completion rate for post-roll ads?
A VCR above 20% is considered strong for post-roll advertising, given the high drop-off rate that occurs after content ends. Pre-roll benchmarks run 45% to 65% by comparison, but post-roll CPMs are also significantly lower, which changes the cost-efficiency calculation.
How much do post-roll ads cost?
Post-roll CPMs typically range from $3 to $8 on mid-tier news and entertainment publishers, compared to $15 to $25 for pre-roll on the same properties. Programmatic buyers can often secure lower rates by targeting post-roll supply specifically through platforms like The Trade Desk or DV360.
When should I use post-roll instead of pre-roll?
Post-roll works best for retargeting campaigns, sequential messaging tied to specific content, and budget-constrained campaigns that need video reach at lower CPMs. Pre-roll is the better choice when guaranteed attention and higher completion rates are the priority.