The video completion rate calculator above converts quartile view counts into retention rates, identifies the segment where you lose the most viewers, and prices the result — cost per completed view and effective CPM from the same spend figure. Completion rate on its own tells you how many people made it to the end. The quartile curve tells you why the rest did not, which is the part you can act on.
Arb Digital reviews this curve on every video campaign before touching targeting or bidding, because the most common cause of poor video performance is an opening that does not earn the next five seconds. Retargeting settings and audience definitions get blamed for a problem that lives entirely in the first frames of the creative.
What This Video Completion Rate Calculator Does
Enter your denominator — impressions or video plays — and the number of views reaching each quartile, and the tool returns the percentage of that base still watching at 25%, 50%, 75% and 100%. The bars show the shape of the curve, so a steady decline is immediately distinguishable from a cliff at one specific point.
It calculates the proportion lost before the first quartile, which is almost always the largest single loss, and names the segment with the steepest drop so you know which part of the edit to look at. Adding spend gives you cost per completed view and effective CPM, the two figures needed to compare a video buy against any other media buy on a like-for-like basis.
How to Use It
- Choose your denominator carefully. Use impressions for a true view-through rate, or video plays if you want to measure the edit's holding power among people who actually started watching.
- Enter the four quartile counts exactly as the platform reports them. These are cumulative counts of viewers reaching each point, not viewers who stopped there.
- Enter the spend for the same campaign and the same date range.
- Click Calculate and read the bar shape before the headline number.
- Compare across creatives by running each one separately and noting where their curves diverge — that point identifies the edit decision worth changing.
The Formula / How It's Calculated
Every retention figure is a share of the same base: Quartile Rate = Views at Quartile ÷ Denominator. Video completion rate is the final one, Views to 100% ÷ Denominator. With 500,000 impressions and 62,000 full views, completion rate is 12.4%, with retention of 42%, 24% and 17% at the earlier quartiles.
Segment drop-off is the loss between consecutive points expressed as a share of the viewers who reached the earlier one: (Earlier − Later) ÷ Earlier. From start to the first quartile that is (500,000 − 210,000) ÷ 500,000 = 58%. From 25% to 50% it is 42.9%, from 50% to 75% it is 29.2%, and from 75% to completion 27.1%. The largest single loss is at the start, which is the normal pattern.
Cost figures use the same two inputs as any media calculation: cost per completed view is Spend ÷ Views to 100%, here $9,000 ÷ 62,000 = $0.145, and effective CPM is Spend ÷ Impressions × 1,000, or $18.00. Platforms differ in what they count as a view and when they charge for one — the definitions used on YouTube and Google video campaigns are documented in Google Ads Help, and Meta's in the Meta Business Help Center.
Choosing the Denominator Changes the Answer Completely
This is the detail that makes most published video benchmarks useless. A completion rate calculated against impressions includes everyone who scrolled past without engaging. A completion rate calculated against video plays only includes people who started watching. On a feed placement with autoplay, those two denominators can differ by an order of magnitude, and both are legitimately called "completion rate" in different reports.
Pick one and use it consistently. Impressions as the denominator answers "what proportion of the audience we paid to reach watched this to the end", which is the right question for a reach-based awareness buy. Plays as the denominator answers "among people who started, how many finished", which is the right question when you are judging the edit itself. Comparing a rate built on one against a rate built on the other will lead you to the wrong conclusion every time.
The First Quartile Is a Different Test From the Rest
The drop between the start and the first quartile is not really a measure of your video. It is a measure of your opening — the first frames, whether the sound is on, whether the subject is legible on a small screen, and whether anything in the frame gives a scrolling viewer a reason to stop. Every quartile after that measures a different thing: whether the content justified the attention it already had.
Treat them as separate problems with separate fixes. A large first-quartile loss with a healthy curve afterwards means the video is good and the opening is not doing its job — recut the first two seconds and the rest of the asset can stay. A modest first-quartile loss followed by a collapse at the halfway point means the hook worked and the payoff did not, which is a script problem no thumbnail change will solve.
A High Completion Rate Is Not Automatically Good News
Completion rate is heavily influenced by things that have nothing to do with creative quality. Shorter videos complete more often simply because there is less to sit through. Non-skippable and sound-off placements produce inflated figures relative to skippable formats. A narrow retargeting audience of existing customers will complete at rates a cold prospecting audience never approaches.
This makes cross-campaign comparison dangerous unless length, format, placement and audience are all held constant. It also creates a real risk of optimising towards the wrong thing: cutting a video from 30 seconds to 10 will reliably raise completion rate and may well reduce the number of people who understood the offer. Judge video against the outcome it exists to produce, using the CPA calculator or the ROAS calculator, and use completion rate to explain the result rather than to define it.
Cost Per Completed View Is Only Half the Comparison
Cost per completed view is a clean way to compare video buys with each other, and a misleading way to compare video with anything else. A completed view is not a business outcome — it is an input to one — and its value depends entirely on what the video was supposed to achieve. A cheap completed view of a video nobody acts on is not a good deal.
Where video sits alongside other channels, convert it onto a common footing: the effective CPM tells you what you paid for attention, and downstream conversion tracking or a lift test tells you what that attention was worth. If completed views are cheap but the campaign contributes nothing measurable, the problem is the video's message rather than the media buying. Compare the impression side with the CPM calculator and the engagement side with the engagement rate calculator.
Arb Digital plans video around the drop-off curve — openings built for a scrolling feed, messages that land before the halfway point, and measurement tied to conversions rather than to views.
Social Media Marketing Paid Advertising ServicesCommon Mistakes to Avoid
- Mixing denominators — a rate based on impressions and one based on plays are not comparable, even with identical labels.
- Comparing videos of different lengths — shorter assets complete more often regardless of how good they are.
- Comparing skippable and non-skippable formats — the format determines much of the result before the creative is seen.
- Optimising for completion rate itself — cutting length raises the metric and can cut comprehension along with it.
- Ignoring sound-off viewing — a video whose message depends on audio will lose most of a feed audience in the first quartile.
Related Free Tools From Arb Digital
Price the impression side with the CPM calculator, check click behaviour with the CTR calculator, and measure interaction with the engagement rate calculator or the social media engagement calculator. Tie it back to outcomes with the CPA calculator, and browse the full free online tools hub.
Frequently Asked Questions
Divide the number of views that reached 100% of the video by your chosen denominator, then multiply by 100. The denominator is usually either impressions or video plays, and the two produce very different figures for the same campaign.
There is no single benchmark, because length, format, placement and audience all shift the number substantially. A fifteen-second non-skippable pre-roll and a sixty-second feed video are not comparable, so the useful comparison is against your own previous creative in the same placement.
Use impressions when you want to know what proportion of the audience you paid to reach watched to the end, and plays when you want to judge how well the edit holds people who chose to start watching. Use one consistently rather than switching between reports.
The first quartile drop measures the opening rather than the video. In feed placements viewers decide within a second or two whether to keep watching, so a large loss here usually points to a weak hook, an unreadable frame on a small screen, or a message that depends on sound.
Shorter videos complete more often, which is not the same as performing better. If the shorter cut removes the information a viewer needed in order to act, completion rate rises while conversions fall, so the trade-off should be judged on outcomes.
It is media spend divided by the number of views that reached the end of the video. It is a useful way to compare video buys against each other, but a completed view is an input to an outcome rather than an outcome in itself.
Each platform defines a view, a play and a completion differently, and charges on different events. Those definitional differences mean completion rates are only reliably comparable within a single platform and placement type.
Figures produced by this tool are planning estimates only — platform view definitions differ, and completion rate is affected by format, length and placement as much as by creative quality.
