Cropping & sizing
Why your video does not fill the screen on mobile
Short answer
A video that does not fill a phone screen is almost always one of two documented choices. Meta states that on devices with screens taller than 9:16 it may either zoom the creative to fill the whole screen, which crops areas outside the safe zone, or show it in its original 9:16 and use a black background to fill the extra space. LinkedIn describes the same pair in different words. You cannot choose, so export 1080 × 1920 and keep the subject inside the safe area; then both outcomes look intentional.
Key takeaways
- Screens are taller than 9:16, so the platform must zoom or letterbox.
- Meta documents both choices for 9:16 creative on taller devices.
- LinkedIn documents cropping for a larger aspect ratio and fitting for a wider one.
- Export 1080 × 1920 so there is nothing to zoom into.
- Design for the zoom option: keep the subject inside the safe area, not just the frame.
Why the same file fills one phone and not another
Screens are not 9:16. Most current phones are taller, so the platform has to choose: zoom the video until it fills the height and cut the sides, or show the whole 9:16 frame and fill the extra height with black. Meta documents exactly this choice for 9:16 creative, including that it may either zoom the creative or show it in its original 9:16 with a black background.
LinkedIn documents the same pair of outcomes: uploaded videos with a larger aspect ratio may be cropped on the sides as well as at the top and bottom, while videos with a wider aspect ratio may be fitted to the screen.
| What you see | What the platform did | What you can change |
|---|---|---|
| Full screen, edges of the picture gone | Zoomed to fill the screen height | Nothing, but design for it |
| Black area above and below | Fitted to the screen | Export 9:16 so there is nothing to fit |
| Thin bars on one device only | Device aspect differs from the file | Nothing: it is the device |
The practical answer is the same in all three rows: export 1080 × 1920 and keep everything important inside the safe area, so whichever option the player picks, your subject survives.
Find your case
| What you see | What it usually means | Do this |
|---|---|---|
| Black area on one device, full screen on another | The device aspect differs; the platform chose differently | Accept it, design for the safe area (step 4) |
| Black area on every device | The file is not 9:16 and is being fitted | Export 1080 × 1920 (step 1) |
| Fills the screen but the sides are gone | The platform zoomed to fill the height | Keep content inside the safe area (step 3) |
| Fills the screen and is soft | A small file was scaled up | Export at 1080 × 1920 (step 1) |
| Feed fills, full-screen player does not | Different surfaces apply different rules | Check the surface that matters (step 5) |
| Bars on desktop only | The desktop player pads vertical video | Upload without baked-in bars (step 2) |
Fix it step by step
Export the shape players expect
For short-form vertical video that is 1080 × 1920 at 9:16. Instagram documents that a Reel can be uploaded at an aspect ratio between 1.91:1 and 9:16, and Pinterest recommends 9:16 or 1080 × 1920 for full-bleed video Pins. Inside those values there is nothing for the player to fit or zoom.
Do not bake bars into the file
YouTube documents that for some video and device aspect ratios, such as 9:16 vertical video on computer browsers, it may add more padding for optimal viewing, and advises against adding padding or black bars directly to your video because that interferes with the player resizing dynamically. Upload the clean frame.
Keep the subject inside the safe area
Meta's guidance for 9:16 creative says to keep the edges, top, bottom and sides free of key creative elements, text and logos, and adds that on taller screens it may zoom the creative, which crops areas outside the safe zone. On a 1080 × 1920 frame, keep content below the top 14% and above the bottom 35%.
Accept the device difference
The crop amount follows the screen shape. Computed: if the app scales a 9:16 video to fill the screen height, a 1179 × 2556 screen cuts (1 − (1179 ÷ 2556) ÷ (9 ÷ 16)) ÷ 2 = 9.0% of the width from each side, which is about 97 px of a 1080 px frame. A 1080 × 2400 screen cuts 10.0%, about 108 px. The table below lists common phones.
Preview on the surface you care about
LinkedIn's vertical video help states that uploaded videos with a larger aspect ratio may be cropped on the sides as well as at the top and bottom, while videos with a wider aspect ratio may be fitted to the screen. The same file can therefore look full-screen in one place and letterboxed in another.
Fix a stretched file rather than a small one
If the picture looks stretched rather than letterboxed, the display aspect ratio is wrong. FFmpeg documents DAR = width ÷ height × SAR, so a file whose sample aspect ratio is not 1 displays incorrectly. Correct it with
ffmpeg -i in.mp4 -vf setsar=1 -c:a copy fixed.mp4before worrying about fill.
Safe area for a 1080×1920 video
| Edge | Keep text out of | Pixels |
|---|---|---|
| Top | 14% | 269 px |
| Bottom | 35% | 672 px |
| Left | 6% | 65 px |
| Right | 6% | 65 px |
Official guidance (approximate). Source: Sales Video Ad Specs on Instagram Reels (Meta Ads Guide), checked 2026-10-05. Meta publishes this for Reels ads; organic Reels can differ.
How much a full-screen 9:16 video loses on tall phones
Computed, not published by the platform: if the app scales a 9:16 video to fill the whole screen height, this much of the width is cut from each side.
| Phone | Screen | Cut per side | Of a 1080 px frame |
|---|---|---|---|
| iPhone 15 / 16 | 1179×2556 | 9.0% | 97 px |
| iPhone 15 Pro Max | 1290×2796 | 9.0% | 97 px |
| iPhone 16 Pro Max | 1320×2868 | 9.1% | 98 px |
| iPhone SE (3rd gen) | 750×1334 | none | 0 px |
| Samsung Galaxy S24 | 1080×2340 | 9.0% | 97 px |
| Google Pixel 8 | 1080×2400 | 10.0% | 108 px |
What to export so fill is not a gamble
| Frame | 1080 × 1920 (9:16) |
|---|---|
| Instagram Reels | Aspect ratio between 1.91:1 and 9:16 · published minimum 30 fps and 720 px |
| Pinterest video Pin | 9:16 or 1080 × 1920 recommended for full bleed |
| Safe area | Top 14%, bottom 35% of 1080 × 1920 |
| Baked-in bars | Do not add them · YouTube advises against padding in the file |
| Stretch fix | setsar=1 when SAR is not 1 |
Where the bars come from, in pixels
A player that shows a 16:9 file in a 9:16 frame can either letterbox it (bars) or zoom it (crop). Both are the same arithmetic. A 1920 × 1080 file scaled to 1080 px wide is 1080 ÷ 16 × 9 = 608 px tall, so a 1080 × 1920 frame leaves 1920 − 608 = 1312 px of empty space, which is 656 px above and below when centered.
The same numbers decide whether padding or cropping is the right answer for you.
| Source | Placed in 1080 × 1920 | Padding needed | Pixels lost if you crop |
|---|---|---|---|
| 1920 × 1080 (16:9) | 1080 × 608 picture | 656 px top and bottom | 608 of 1920 px of width |
| 1080 × 1080 (1:1) | 1080 × 1080 picture | 420 px top and bottom | 420 px of each side |
| 1080 × 1350 (4:5) | 1080 × 1350 picture | 285 px top and bottom | 228 px of each side |
| 1080 × 1920 (9:16) | 1080 × 1920 picture | None | None |
Computed: each figure is the source scaled to 1080 px wide, then the difference from 1920 px of height split evenly. A 4:5 file is the mildest case: it matches the frame width but not its height, so it gets 285 px bars, and if it is scaled to fill the height it loses 228 px per side.
Frequently asked questions
Why does my video not fill the screen on my phone?
Screens are taller than 9:16, so the platform chooses: Meta documents that on taller devices it may either zoom the creative, cropping outside the safe zone, or show it in 9:16 with a black background.
How do I make my video fill the whole screen?
Export 1080 × 1920 and keep the subject inside the safe area. If the platform zooms, nothing important is lost; if it letterboxes, the bars are the platform's own.
Why is it full screen on one device and letterboxed on another?
Device aspect ratios differ, and platforms document both behaviors. Check the surface that matters most to you rather than one device.
Is my video being cropped by the app?
Possibly. Meta states it may zoom 9:16 creative on screens taller than 9:16, and LinkedIn says videos with a larger aspect ratio may be cropped on the sides as well as at the top and bottom.
Sources
- Meta Business Help: About text overlays and the safe zone for ads (official, checked 2026-10-07)
- Instagram Help: Reel size & aspect ratios (official, checked 2026-10-07)
- Pinterest Help: Review Pin specs (Video Pin specs and safe zones) (official, checked 2026-10-07)
- YouTube Help: Video resolution & aspect ratios (official, checked 2026-10-07)
- LinkedIn Help: Full-screen vertical video on LinkedIn (official, checked 2026-10-07)
- FFmpeg Documentation: Video filters (crop, pad, scale, setsar, subtitles) (official, checked 2026-10-07)
Reviewed 2026-10-07. Steps not attributed to a source are general video practice or computed above.