Apple's published figure for ProRes file size is a relative one: "ProRes files are up to 30 times larger than HEVC files." That sentence comes from Apple's ProRes support article, and the two words doing the most work in it are up to.
Almost every article on this topic drops those two words and tells you ProRes is "30 times bigger than normal video." That is not what Apple wrote. Up to 30 times is a ceiling — the worst case across the whole range of ProRes recording modes — not a multiplier you apply to your own clip. If you plan storage as though every ProRes recording is exactly 30x, you will over-provision badly; if you assume the ceiling never applies, you will run out of space mid-take.
The figures Apple publishes, at a glance
| What you want to know | What Apple's pages state | Source |
|---|---|---|
| ProRes size vs HEVC | "ProRes files are up to 30 times larger than HEVC files." | About Apple ProRes on iPhone |
| Free space needed to record ProRes | "you need at least 10 percent of your device's storage to be free" | Same page |
| Per-minute size, regular 1080p 30 fps video | "one minute of regular 1080p 30 fps video is approximately 65 MB" | iPhone User Guide, iOS 18 |
| Per-minute size, spatial video 1080p 30 fps SDR | "One minute of spatial video is approximately 130 MB" | Same page |
| Per-minute size of ProRes at any resolution | Not given on these pages — check the official documentation | — |
| Recording bitrate in Mbps | Not given on these pages — check the official documentation | — |
Two things to take from that table. First, the only per-minute numbers Apple states anywhere in these pages are scoped to 1080p at 30 fps, and Apple itself hedges them with "approximately." Second, that per-minute note lives in the iOS 18 version of the User Guide page; the current iOS 27 version of the same page no longer carries the sentence, so the archived URL above is the one to cite.
Why you cannot just multiply 65 MB by 30
This is the arithmetic everyone reaches for, and it is worth understanding exactly what it does and does not give you.
The 65 MB figure is scoped to regular 1080p 30 fps video. The "up to 30 times" figure is a maximum across ProRes generally. Multiply them and you get an upper bound for one specific recording mode — not an estimate, and not a number that transfers to 4K, to 60 fps, or to Log. Apple's ProRes page states the ratio and nothing more granular; for a real per-minute figure at your own settings, check the official documentation or, more practically, record ten seconds and look at the file on disk.
What Apple does confirm is the direction of travel. The User Guide's video-recording page puts it plainly: "Faster frame rates and higher resolutions result in larger video files." So the modes at the top of the ProRes table are the ones that will push you toward the ceiling.
The rule that actually stops the recording: 10 percent free
The size ratio is the headline, but the constraint that bites first is a hard gate on free space. Apple: "To record in ProRes, you need at least 10 percent of your device's storage to be free."
Read that as a percentage, not a fixed amount, because it scales with the phone. On a 1 TB iPhone that is roughly 100 GB you must keep clear before the Camera app will let you record in ProRes at all — considerably more headroom than most people leave lying around.
There is a second behaviour on the same page: "If ProRes is turned on and less than five minutes of recording time is available, the Camera app might free storage automatically." Note the "might" — Apple does not promise it, so do not treat automatic cleanup as your storage plan.
What to do when ProRes files fill the phone
The realistic workflow is to keep ProRes for the recordings that need it and move everything else into a delivery codec. Apple documents the fallback explicitly: "If you turn ProRes off in the Camera app, the video format defaults to either High Efficiency Video Coding (HEVC) or Most Compatible (H.264)." To choose between them: "open Settings, tap Camera, tap Formats, and then choose a format."
For clips already on disk that only need to be watched, shared, or posted, re-encoding is the fastest way to get the space back:
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
That runs entirely inside this browser tab — the file is read from disk, re-encoded locally, and handed straight back, so nothing is uploaded to a server. If the file is a QuickTime movie and you need a broadly playable container instead, MOV to MP4 does the container swap on the same terms.
Worth knowing before you hand a ProRes file to some other app: Apple states that "Apps might transcode a ProRes video to a smaller H.264 format if ProRes isn't supported." So a ProRes file can arrive somewhere as a much smaller H.264 without you asking. AirDrop has a documented chain of its own — Apple says AirDrop "transfers the original ProRes video to supported devices," and "For all other devices, you'll share an HEVC video if the devices supports it, or H.264 video if the device doesn't." That chain is written about ProRes specifically; it says nothing about how AirDrop treats an ordinary HEVC clip.
Model and storage gotchas that change the size question
Which ProRes modes you can even reach depends on the phone and the card you pay for. From Apple's ProRes table: a 128 GB model is limited to 1080p HD at 30 or 25 fps; 256 GB, 512 GB, 1 TB and 2 TB models add 1080p at 60 fps plus 4K at 30, 25 and 24 fps. 4K at 60 fps is listed for "iPhone 17 Pro models, iPhone 16 Pro models, and iPhone 15 Pro models only," and 4K at 120 fps for "iPhone 17 Pro models and iPhone 16 Pro models only."
The User Guide is blunter about the small card: "On iPhone 15 Pro models and iPhone 16 Pro models with 128 GB, recording to internal storage is only available at 1080p at 30 fps."
The high-frame-rate modes are not internal recordings at all. Apple's footnotes require an external storage device that supports "at least 220 MB per second" for 4K60 ProRes and "at least 440 MB per second" for 4K120, each with "maximum power draw of 4.5 W," a drive "formatted with exFAT" (password-encrypted drives aren't supported), and "a USB 3 cable with speed of at least 10 Gbits per second." Apple adds that you "must reformat your external storage device before beginning each 4K120 ProRes recording session." A slower drive earns you a "Slow Recording Speed" message.
One more scoping note that saves disappointment: ProRes is a Pro-model feature. The iPhone 17 Pro tech specs list "Video formats recorded: HEVC, H.264, ProRes, and ProRes RAW," while the iPhone 17 specs list "Video formats recorded: HEVC and H.264." And Apple's mode exclusions apply regardless of storage: "You can't use ProRes with Cinematic mode, slo-mo mode, or time-lapse video."
FAQ
How many GB is one minute of ProRes on iPhone? Apple's ProRes page states the size only in relative terms — up to 30 times larger than HEVC — and gives no per-minute figure for ProRes at any resolution. The only per-minute numbers in these pages are for 1080p 30 fps regular video (approximately 65 MB) and spatial video (approximately 130 MB). For your own settings, check the official documentation or measure a short test clip.
Is ProRes always 30 times bigger than HEVC? No. Apple's wording is "up to 30 times larger," which is an upper bound across ProRes modes, not a fixed ratio. Treat it as the worst case when budgeting storage.
Why won't my iPhone let me record in ProRes? The most commonly missed requirement is free space: Apple requires at least 10 percent of the device's storage to be free. Beyond that, ProRes needs a supported Pro model, and it cannot be used in Cinematic, slo-mo or time-lapse mode.
Can I record 4K ProRes to the phone itself? Only within the limits of your storage tier. Apple lists 4K at 30, 25 and 24 fps from 256 GB upward, and notes that 15 Pro and 16 Pro models with 128 GB are limited to 1080p at 30 fps internally. 4K60 and 4K120 ProRes are documented with external storage requirements of 220 MB/s and 440 MB/s respectively.
What is the smallest way to keep a ProRes recording? Turn ProRes off for takes that do not need it — the camera falls back to HEVC or H.264 — and re-encode finished ProRes clips you only need to watch or share. See all Clapr tools for the browser-side options, and how to compress video without losing quality for what the bitrate and resolution knobs actually do.
Figures cited from Apple's About Apple ProRes on iPhone and the iPhone User Guide, checked 24 September 2026. More storage and upload ceilings are collected in the limits section; codec headaches on the receiving end are covered in HEVC video not playing in Google Drive.
