HBO Max on an ultrawide monitor, filled edge to edge
Series and movies on HBO Max usually play inside a 16:9 frame. On a 21:9 or 32:9 monitor that leaves black space at the sides, and often above and below the picture too. Here is why it happens and how to fill the screen in Chrome.
Why HBO Max leaves black space on an ultrawide
Many prestige series are made in a frame of about 2.00:1, a little wider than a TV, and many cinema releases use the wider scope format of 2.39:1. Streaming services typically deliver all of them inside a 16:9 video, with black bars added above and below the picture so the same file plays on every TV and laptop.
On a 21:9 monitor such as 3440×1440, the player fits that 16:9 video to the height of the screen. It is 2560 pixels wide, so 440 black pixels remain on each side. Inside the 16:9 area a 2.00 series takes 2560×1280 pixels, and the rest is the baked-in letterbox. In total about a third of your screen stays black. For a 2.39 movie it is almost half.
The numbers for 21:9 and 32:9
| What you watch | 21:9 (3440×1440) | 32:9 (5120×1440) |
|---|---|---|
| 2.00 series inside a 16:9 stream | 34% black | 56% black |
| 2.39 movie inside a 16:9 stream | 45% black | 63% black |
| 16:9 show or documentary | 26% black | 50% black |
Your exact numbers depend on the monitor. The black bar calculator on the home page shows them for any resolution and movie format.
How to fill the screen with UltraFill
- Add UltraFill to Google Chrome on Windows or macOS and pin its icon to the toolbar.
- Open a series or movie on HBO Max and switch to full screen.
- Move the mouse to the top of the video and click the UltraFill button, or press Alt + U (Option + U on a Mac).
- In the Screen tab, pick the movie format. There is no 2.00 preset, so for many series choose 2.20: it removes all of the baked-in bars, and on a 21:9 screen the result is the same as an exact 2.00 crop. For cinema releases choose 2.39. If thin bars remain, step to the next wider format.
- Click Fill the screen or press Alt + Z.
- Hold Alt + C to compare with the original view whenever you like.
A 2.00 picture is narrower than a 21:9 monitor, so filling it with crop cuts a strip from the top and bottom: you keep 83.7% of the height, about 8% gone at each edge. Most framing survives that well. In close-ups, drag the frame in the panel preview or press Alt + Shift + arrows to show more of the top or bottom.
Choosing a fill mode
- Crop (free): no distortion, a little is cut. The usual choice for 2.39 movies and for 2.00 series on 21:9.
- Stretch (free): the whole picture, stretched evenly. With a 2.00 series on 21:9 the stretch is about 19%, which some people do not notice in wide shots.
- Elastic stretch (PRO): the center stays natural and mostly the edges stretch. On a protected player like HBO Max it uses a gentler, simpler stretch, because the browser does not let extensions read the frames.
On a 32:9 monitor the gap is bigger, so you will usually combine a crop with some zoom or stretching. The Disney+ on 32:9 guide walks through super ultrawide settings that apply here too.
Let the title profile remember it
Because HBO Max is a protected service, UltraFill cannot see the picture to measure the bars, so the format is chosen by hand. With PRO, the title profile remembers the format and fill mode for each series or movie. Open the next episode and it fills the screen the same way. Turn on auto-fill in full screen as well, and you no longer open the panel at all. PRO starts with a 7-day trial the first time you use a PRO feature, with no card needed.
Limits on protected video (DRM)
- Automatic bar detection does not work, because the frames are hidden from extensions. You pick the format once per title.
- Effects that read the frames, such as denoise, ambient glow, the split before and after view and frame snapshots, only work on unprotected video.
- Sound tools (clear dialog, night mode, volume leveling, the 5-band equalizer) need one extra click: the UltraFill icon in the toolbar, or Alt + Shift + U (Option + Shift + U on a Mac). Chrome then shows a small sharing badge on the tab, which is expected.
- Zoom, framing, rotate, flip and the color and light sliders work normally.
Night mode and clear dialog are worth a try with series that mix quiet conversations and loud action, especially late in the evening.
Questions
Why are there black bars on HBO Max on my ultrawide monitor?
Series and movies are usually delivered inside a 16:9 video with bars baked in for wider formats. A 21:9 or 32:9 screen is wider than 16:9, so the player adds black space at the sides as well.
Which format should I choose for HBO Max series?
Many series are made in about 2.00:1. There is no 2.00 preset, so choose 2.20, which removes the bars and fills a 21:9 screen the same way. For cinema releases use 2.39. Hold Alt + C to compare with the original.
Will filling the screen cut off part of the picture?
With crop, a 2.00 series on a 3440×1440 monitor keeps 83.7% of its height. If you would rather keep everything, use stretch, or elastic stretch with PRO.
Do I have to set the format again for every episode?
Without PRO you set it when you start watching. With PRO, the title profile remembers the format for each series, and auto-fill can apply it as soon as you go full screen.
Do the sound tools work on HBO Max?
Yes. Click the UltraFill icon in the toolbar or press Alt + Shift + U (Option + Shift + U on a Mac) once on the tab, and the sound goes through UltraFill.
UltraFill is an independent extension and is not affiliated with HBO Max, Disney+ or any other streaming service mentioned on this page. Service names are used only to describe compatibility.