How much storage does a 4K project need?
More than the footage alone. Here’s how to work out what your camera files take up, what gets added during the edit, and why your backups mean you need the space more than once.
- Per hour of 4K
- From about 45 GB for compressed camera files to over 1,300 GB for 4K RAW.
- The quick sum
- Data rate in Mb/s × 0.45 = GB per hour of footage.
- Add for the edit
- About 20% for renders, cache and proxies, and keep 20% of your storage free.
- Add for backups
- Three copies under 3-2-1, so plan for around four times your footage in total.
SC.01 Data rates
It’s the format, not the 4K
Two cameras can both shoot 4K and fill your storage at very different speeds. What matters is the data rate: how many megabits each second of video takes. A 4K project usually involves three kinds of file.
Camera originals
What the camera records. Compressed formats such as XAVC or H.265 are small. RAW formats such as ARRIRAW, REDCODE or Blackmagic RAW keep far more picture information, and take far more space. These are the files you must never lose.
Edit codecs
Formats such as ProRes and DNxHR are built to play back smoothly while you cut and grade. Some cameras record them directly. Others shoot something lighter and the footage is transcoded, which adds a second full set of files.
Proxies
Small copies you edit from, then swap back to the originals for the finish. HD proxies are tiny. UHD proxies are not: at about 68 GB an hour, they can be as big as some camera originals.
MATHS From Mb/s to GB per hour
Data rates are quoted in megabits per second (Mb/s), and there are 8 bits in a byte. So one hour is Mb/s × 3,600 seconds ÷ 8 ÷ 1,000 gigabytes, which comes down to Mb/s × 0.45. A camera recording at 250 Mb/s fills 112.5 GB an hour. We use decimal units throughout, like drive makers do: 1 TB is 1,000 GB.
SC.02 Quick reference
GB per hour for common formats
Published data rates at 25 fps, the same figures our storage calculator uses. RAW formats are shown at the sizes these cameras commonly record for a 4K finish.
| Format at 25 fps | Kind of file | Mb/s | GB per hour | TB per 10 hours |
|---|---|---|---|---|
| XAVC-L · UHD | Camera | 100 | 45 | 0.45 |
| XAVC S 4:2:2 10-bit · 4K | Camera | 140 | 63 | 0.63 |
| H.264 or H.265 · 4K | Camera | 150 | 68 | 0.68 |
| XAVC-I · UHD | Camera | 250 | 113 | 1.13 |
| XF-AVC Intra · 4K DCI | Camera | 410 | 185 | 1.85 |
| ProRes 422 Proxy · HD | Proxy | 38 | 17 | 0.17 |
| ProRes 422 Proxy · UHD | Proxy | 151 | 68 | 0.68 |
| DNxHR LB · UHD | Proxy | 150 | 68 | 0.68 |
| ProRes 422 LT · UHD | Edit | 342 | 154 | 1.54 |
| ProRes 422 · UHD | Edit | 492 | 221 | 2.21 |
| DNxHR SQ · UHD | Edit | 482 | 217 | 2.17 |
| ProRes 422 HQ · UHD | Edit | 737 | 332 | 3.32 |
| DNxHR HQ · UHD | Edit | 728 | 328 | 3.28 |
| ProRes 4444 · UHD | Edit | 1,106 | 498 | 4.98 |
| Blackmagic RAW 8:1 · 6K | RAW | 807 | 363 | 3.63 |
| Blackmagic RAW 5:1 · 6K | RAW | 1,293 | 582 | 5.82 |
| ARRIRAW · 4K 16:9 | RAW | 3,012 | 1,355 | 13.55 |
For other frame rates, scale the figure: about 4% less at 24p, a fifth more at 30p and double at 50p. Long GOP formats (XAVC-L, XAVC S, H.264 and H.265) are the exception: they stay about the same from 24p to 30p and are roughly 1.5 times as big at 50p. Real files can run a few percent over the published rate. The storage calculator has more cameras and formats, and handles the frame rate for you.
SC.03 Worked example
A documentary, from shoot to terabytes
Let’s size a one-hour documentary shot on two cameras recording XAVC-I in UHD at 25p. We use the same rules of thumb as our storage calculator.
- The shoot
- 10 shoot days × 2 cameras × about 4 hours recorded per camera a day = 80 hours of rushes. That’s a shooting ratio of 80:1 for a one-hour film
- Footage
- 80 hours × 112.5 GB an hour (250 Mb/s) = 9,000 GB, or 9.0 TB
- Working space
- 9.0 TB + 20% for renders, cache and proxies = 10.8 TB
- Studio storage
- 10.8 TB is 80% of 13.5 TB, so 20% stays free and the storage stays fast. In practice, that’s 15 TB of usable space
- Offsite backup
- 10.8 TB + 10% for earlier versions = 11.9 TB
- Local backup
- Another 11.9 TB if you keep a second copy in the studio, as the 3-2-1 rule suggests
- In total
- About 37 TB of storage across three copies, for 9 TB of footage: just over four times as much
SC.04 Same shoot, other formats
80 hours can be 5 TB or 108 TB
Change the camera format and the same 80 hours of rushes needs a very different amount of space. Choosing your recording format is the single biggest storage decision on a 4K project.
Transcoding adds up too. If our documentary’s XAVC-I footage were transcoded to ProRes 422 HQ for the edit, that’s another 26.5 TB on top of the 9 TB of camera originals, because you keep both. Our 20% allowance covers renders, cache and small proxies, not a second full set of media.
Proxies are only small when they’re HD. HD ProRes Proxy is about 17 GB an hour, or 1.4 TB for the whole shoot. UHD proxies would be 5.4 TB.
SC.05 The hidden extras
Footage is only the start
Most storage plans that run out early counted the rushes and nothing else. These are the things that fill the rest.
Renders and cache
Effects, grades and playback caches all write new media while you work. Together with proxies, allow about 20% on top of your footage.
Transcodes
If you convert camera files to an edit codec, add the full size of that format for every hour you convert. Use the table above.
Versions and deliverables
Review cuts, masters, textless versions and social edits. Each is small next to the rushes, but a long project collects a lot of them.
Free space
Shared storage slows down as it fills. Keep about 20% free, so a project that needs 10.8 TB wants 13.5 TB of space.
Backup versions
A good backup keeps earlier versions as well as the latest copy, so you can roll back a mistake. Allow about 10% on top of what you back up.
Three copies
The 3-2-1 rule means three copies of your data, one of them offsite. You need the capacity for each of them. Our backup guide explains why.
SC.06 Planning for growth
Size for the year, not the project
One project is easy to size. The harder question is how much you shoot each month, and how long it stays on your live storage. Plan for that and you won’t be buying more space in a hurry halfway through an edit.
Our storage calculator works this way: tell it your hours a month and how many months you keep, and it sizes the studio storage, the offsite backup and the network to match.
Count hours a month
Add up a typical month of shooting across all your projects, not just the biggest one.
Decide how long work stays live
Months of footage on your shared storage, multiplied by your monthly figure, is your working space.
Archive finished projects
Move them off your live storage to an offline archive. Ours uses 20 TB drives, from £10 per drive a month + VAT, kept in fire-rated data safes.
Allow for your next camera
A move to RAW, 6K or 50p can double or triple your data rate overnight. Check the table before you upgrade.
Act at 80% full
When your storage passes 80%, it’s time to archive or expand, before it starts to slow down.
Choose storage that can grow
Shared storage that takes more drives later costs less than replacing it when you outgrow it.
SC.07 How we help
Storage sized for how you shoot
We size your storage around your formats, your team and your growth plans, then install it and look after it.
In the studio
Shared NAS storage for fast editing, easily expandable from 4 terabytes to over a petabyte. Local storage
In our data centre
Live storage in our own UK-based data centre that your team reads, writes and shares remotely. From £6.50 per TB a month + VAT. Cloud storage
The offsite copy
Automated, encrypted cloud backup, or an offline archive for finished projects. Offsite backup
END Next step
Planning a 4K project?
Tell us what you shoot and we’ll size the storage, backup and network around it. We manage the storage, so you can focus on what you do best.