How to Change Video Resolution on a Mac (4K to 1080p and Lower)

1. Open the video in QuickTime Player.
2. Choose File > Export As.
3. Pick 4K, 1080p, 720p or 480p. Only sizes at or below the original appear.
4. Name the file, choose a folder and click Save.

That is the whole feature. You cannot type a custom width, you cannot choose the codec in the dialog, and the output is a QuickTime movie rather than a plain MP4. If the recipient needs MP4, see how to convert MOV to MP4 on a Mac.

macOS ships a command-line tool called avconvert that uses the same Apple export presets. Pick a preset by size:

avconvert -s clip-4k.mp4 -p Preset1920x1080 -o clip-1080p.mov
avconvert -s clip-4k.mp4 -p Preset1280x720 -o clip-720p.mov
avconvert --help   # lists every preset name

If you have ffmpeg installed, you get any size you like and a plain MP4. -2 keeps the aspect ratio and rounds the width to an even number, which video codecs require:

ffmpeg -i clip-4k.mp4 -vf scale=-2:1080 -crf 23 -c:a copy clip-1080p.mp4

The -c:a copy part leaves the audio untouched, so only the picture is re-encoded.

We generated one 8-second 3840 × 2160 H.264 clip with a sine tone (30.7 MB) and downscaled it four ways on 8 November 2026. The clip is synthetic test footage, so it compresses far better than camera video. Treat the ratios as a direction, not a promise.

Two details are worth knowing. The 640x480 preset kept the 16:9 shape and produced 640 × 360, so presets never stretch or crop. And Apple’s presets spent more bytes than a CRF 23 encode: the preset targets a fixed bitrate, while CRF targets constant quality. For picture quality on real footage, check the result by eye.

The names are shorthand for the picture size in a 16:9 video. Knowing the numbers helps when an upload form asks for a maximum width or height, or when you need to type a size into a command.

Pixels are not the only thing that sets file size. A 1080p clip of a still talking head can be smaller than a 720p clip full of fast motion, because the encoder has less change to describe from frame to frame. That is why a resolution change gives a direction, not a fixed percentage.

Frame rate matters too. A 60 fps clip carries twice as many frames as a 30 fps one. Dropping to 30 fps shrinks the file further. In ffmpeg that is the -r 30 option; we did not test frame-rate changes here.

Vertical phone video swaps the two numbers, so a 1080p vertical clip is 1080 × 1920. When you resize with ffmpeg, set the side that matters and let the other follow with -2. For a vertical clip, use scale=1080:-2 to fix the width instead of the height.

Match the screen the video will be watched on. 1080p is the safe default for sharing, email, Discord and most uploads. 720p is fine for phones, screen recordings and anything where file size matters more than detail. Keep 4K only when the viewer has a 4K display and you need to crop or zoom later.

Resolution is only half of the size story. Codec and quality setting matter as much, and we compare them in H.265 vs H.264. For the full set of options, read how to reduce video file size on a Mac. If your source is 4K, the 4K-specific guide goes deeper.

Yes, a little, because every export re-encodes the picture. Going from 4K to 1080p throws away three quarters of the pixels, and the encoder then compresses what is left. That is the point of the exercise, but it means you should always keep the original file and export a copy. All four methods above write a new file and leave the source alone.

To keep quality as high as possible, export once from the original instead of resizing an already-resized copy. Each generation adds a small loss. If you need both a 1080p and a 720p version, make each one from the 4K source.

Lower resolution does not fix a blurry or noisy source. It only hides some of the softness, because the same blur is spread over fewer pixels. If a clip is soft at 4K, it will look acceptable at 1080p, but it will not look sharper.

Screen recordings are large because a Retina display records at a very high pixel count, often well above 1080p. The methods are the same: QuickTime Player’s File > Export As, an avconvert preset, or ffmpeg with scale. Text stays readable down to 1080p on most recordings, so that is a good first target before you try 720p.

We cover the size side of recordings, including what to expect from compression, in how to compress a screen recording on a Mac.

Not in QuickTime, which only offers sizes at or below the source. You can force a larger size with ffmpeg’s scale filter, but that only stretches the pixels. A 720p clip scaled to 1080p has the same detail and a bigger file. Video upscaling models exist, but none of the free built-in tools do it.

For one video and one size, QuickTime Player is enough. It is free, already installed, and takes three clicks. If you are comfortable with a terminal, ffmpeg gives you exact control.

Smol earns its $29 (once, one Mac) when you have a folder of clips, or a mix of videos, photos and PDFs. In Smol you drag the files in, keep or reduce the resolution, choose H.265 or H.264 and a quality, and get a copy beside each original. Nothing is uploaded. There is also a Finder right-click action. Smol also has an option to drop the audio. See the best video compressor for Mac roundup, or buy Smol.