The Short Answer
We measured the size of every image and video in 949 top-spending Meta ads from 28 brands, then compared ads whose feed version was 4:5 with ads whose feed version was 1:1, inside the same brand.
- 4:5 ads paid more per impression. CPM was 1.39x higher in the median brand, and higher in 12 of 16 brands.
- Click-through rate was about the same. 1.04x, higher in 9 of 16 brands.
- Cost per purchase or lead was even. 1.00x, cheaper for 4:5 in 7 of 14 brands and more expensive in the other 7.
- Brands mostly pick one and stick with it. 16 of 28 brands put 80% or more of their feed-format spend into a single ratio.
- For video, 4:5 is the norm. Among videos with a separate feed version, 4:5 got about 6x the spend of 1:1. For statics, 1:1 still got the most spend.
So 4:5 isn't a free win. It costs more to show, and in this data that extra cost was paid back, not exceeded. Pick the ratio that suits the ad, and spend your testing time on what's in it.
The Data
We pulled ad-level data for every US Meta account we have visibility into as a creative agency that spent at least $100,000 between July 28 and October 27, 2026. For each brand, we took its top ads by spend (up to 40, each with at least $2,000 in spend) and recorded the width and height of every image and video in each ad.
Catalog and dynamic product ads don't report their image sizes, so they're left out. That left 949 ads from 28 brands, with $15.6 million in spend.
Many ads carry more than one file: a feed version plus a 9:16 version for Stories and Reels. So we classified each ad by its feed version:
- 4:5: the ad has a 4:5 file (like 1080x1350) and no 1:1 file
- 1:1: the ad has a 1:1 file (like 1080x1080) and no 4:5 file
- 9:16 only: the ad has only a vertical file, and Meta adapts it for feed
Every comparison is made within a brand first, then we took the median across brands, so one big account can't skew the result. Brand names are anonymized. Part of our Meta Ads Statistics report.
One limit: Meta reports an ad's results across all its placements combined. So this compares ads whose feed version is 4:5 with ads whose feed version is 1:1. It doesn't isolate the feed placement on its own.
Which Aspect Ratios Brands Actually Use
Here's how spend split by the feed version of each ad:
| Feed version | Share of video spend | Share of static spend |
|---|---|---|
| 9:16 only | 56% | 1% |
| 4:5 | 37% | 31% |
| 1:1 | 6% | 58% |
| Both 4:5 and 1:1 | 0% | 8% |
Two patterns stand out:
- Video has moved to vertical. More than half of video spend went to ads with only a 9:16 file. When video ads did have a separate feed version, it was almost always 4:5.
- Statics are split. 1:1 statics still took the biggest share, but 4:5 took almost a third.
Most brands commit to one ratio. Of the 28 brands, 9 put 80% or more of their feed-format spend into 1:1 and 7 into 4:5.
4:5 vs. 1:1: The Head-to-Head
To compare fairly, we only used brands running at least two 4:5 ads and two 1:1 ads. That left 16 brands, with 151 4:5 ads and 166 1:1 ads.
| Metric | 4:5 vs. 1:1 (median brand) | Brands where 4:5 was higher |
|---|---|---|
| CPM | 1.39x | 12 of 16 |
| Link CTR | 1.04x | 9 of 16 |
| Conversion rate after the click | 1.09x | 8 of 14 |
| Cost per purchase or lead | 1.00x | 7 of 14 |
Cost per result only includes the 14 brands that track purchases or leads reliably.
4:5 Costs More to Show
The clearest result is CPM. 4:5 ads paid more per thousand impressions in three out of four brands. This data can't say why. One likely reason: a taller ad takes up more of the screen, and Meta prices that space accordingly.
The Extra Cost Didn't Buy Better Results
Click-through rate was about the same. Conversion rate after the click was slightly higher for 4:5, but not consistently: higher in 8 brands, lower in 6. Put together, cost per purchase or lead landed at exactly 1.00x, with 4:5 ahead in half the brands and behind in the other half.
That matches what we've found for other format choices. In our static vs. video data, video paid a higher CPM and earned a higher CTR, and cost per result ended up close. The higher price and the better engagement tend to cancel out.
Statics Only
Looking at static images alone (9 brands), 4:5 statics again paid about 1.4x the CPM. Their conversion rate was higher in 7 of 8 brands, and their total cost per result was lower in 6 of 8. But the typical 4:5 static ad came out even with the typical 1:1 static. It's a small sample, so treat it as a slight edge for 4:5 statics, not a rule.
Only 4 brands ran enough 4:5 and 1:1 videos to compare, which is too few to draw a conclusion.
Which Aspect Ratio Should You Use?
Based on this data:
- For video, make 9:16 and 4:5. That's what the biggest spenders run. A 1:1 video is now rare among top ads.
- For statics, both work. 4:5 takes more of the screen and costs more to show. 1:1 is cheaper per impression and still carries most static spend. Neither won on cost per result.
- Don't expect a new ratio to rescue an ad. Resizing a 1:1 static to 4:5 changes what you pay per impression more than what you pay per purchase.
- Upload the right file for each placement. A 4:5 or 1:1 file for feed and a 9:16 file for Stories and Reels lets you control what people see instead of letting Meta crop it. Sizes and safe zones are in our Meta ad specs guide.
- Test messages, not just sizes. In our data, most of the difference in cost per purchase between ads came from how well their clicks converted, which depends on what the ad says and who it reaches. See what actually predicts cost per purchase and creative diversity on Meta.
Get Ads Built for Every Placement
Biddyco is a creative agency for Meta ads for brands spending $100K to $5M+ a month. Our US-based senior team makes UGC, motion, hybrid and static ads, delivered in the sizes each placement needs, and judges them on cost per purchase, not CPM or clicks. Book an intro call to talk through your account.
FAQ
Is 4:5 or 1:1 better for Meta ads?
Neither won in our data. Across 16 brands running both, 4:5 ads paid 1.39x the CPM of 1:1 ads, with about the same CTR, and cost per purchase or lead came out even (1.00x). 4:5 was cheaper in 7 brands and more expensive in 7.
What is the best aspect ratio for Facebook and Instagram ads?
For feed, 4:5 or 1:1. For Stories and Reels, 9:16. Among top-spending video ads in our data, 56% of spend went to 9:16-only videos and 37% to videos with a 4:5 feed version. For statics, 1:1 took 58% of spend and 4:5 took 31%.
Do 4:5 ads cost more on Meta?
Per impression, yes. In our data, 4:5 ads paid a higher CPM than 1:1 ads in 12 of 16 brands, 1.39x in the median brand. Per purchase or lead, no: cost per result was even.
Should I change my 1:1 ads to 4:5?
It's unlikely to lower your cost per purchase on its own. In our data, 4:5 ads paid more per impression and converted slightly better, which evened out. Make 4:5 versions for new ads if you like the extra screen space, but put your testing effort into new angles and messages.
What aspect ratio do most top Meta video ads use?
Vertical. Among top-spending video ads, 56% of spend went to ads with only a 9:16 file, 37% to ads with a 4:5 feed version and 6% to ads with a 1:1 feed version.
Where does this data come from?
Ad-level data from US Meta accounts we have visibility into as a creative agency, from July 28 to October 27, 2026: 949 top ads from 28 brands that each spent at least $100,000, with $15.6 million in spend. Aspect ratios were measured from each ad's image and video files. Brand names are anonymized.
