What memory card do I need to record video?
It depends on your camera's bitrate, not just the resolution. With H.265 in 4K 30p at 100 Mbps, one hour takes up about 45 GB and a V30 card is enough. With All-Intra 4K 60p at 600 Mbps, one hour takes up about 270 GB and you need a V90 in a UHS-II SD slot, or CFexpress if your camera requires it.
Camaralia's free calculator solves this in three steps: you choose how you record, how long you record, and what slot your camera has, and it tells you the GB per hour, the minimum speed, and which card from the catalog to buy.
What does the tool calculate and how do you use it?
Camaralia's memory card calculator for video is free and used in three steps. With your data, it returns how many GB each hour of video takes up, what minimum speed the card needs (V30, V60, V90, or CFexpress), and what card to buy from the catalog, with a direct link to the product page.
Step 1: how you record
- Recording format: H.264 / H.265 (MP4, MOV, XAVC S, XAVC HS), All-Intra (XAVC S-I, XAVC-I, ALL-I), Apple ProRes, Blackmagic RAW (constant ratio), or other, by entering the Mbps yourself.
- Resolution.
- Frames per second.
Step 2: how long you record
- Recording hours per day: the total material you want to be able to record before offloading the cards.
Step 3: your camera
- Slot type: SD UHS-II (two rows of contacts), SD UHS-I, microSD UHS-II, microSD UHS-I, CFexpress Type A, CFexpress Type B, or CompactFlash.
- If you don't know which one it is, it appears in your camera's manual or inside the slot cover.
What it returns to you
- The GB per hour of your configuration and the total of your day.
- The minimum speed the card must sustain.
- The recommended card from the Camaralia catalog and a recommended reader.
How much does one hour of video take up?
One hour of video takes up between 45 GB (H.265 in 4K 30p) and about 396 GB (ProRes 422 HQ in 4K 30p), depending on the codec and bitrate. This is the calculator's reference table:
|
Format |
Bitrate |
MB/s |
GB per hour |
|---|---|---|---|
|
H.265 · 4K 30p |
100 Mbps |
12.5 |
45 |
|
H.265 · 4K 60p |
200 Mbps |
25 |
90 |
|
All-Intra · 4K 30p |
300 Mbps |
37.5 |
135 |
|
All-Intra · 4K 60p |
600 Mbps |
75 |
270 |
|
ProRes 422 HQ · 4K 30p |
≈ 880 Mbps |
≈ 110 |
≈ 396 |
|
Blackmagic RAW 3:1 · 4K DCI 24p |
≈ 850 Mbps |
≈ 106 |
≈ 382 |
These are reference values. The actual bitrate depends on the camera and the mode; consult your equipment's manual.
What do V30, V60, and V90 mean?
V30, V60, and V90 are the video speed classes of the SD Association. They indicate the minimum sustained write speed: V30 guarantees 30 MB/s, V60 guarantees 60 MB/s, and V90 guarantees 90 MB/s.
To find out which one you need, compare the MB/s of your format with the card class. Minimum speed required according to the reference table:
- H.265 4K 30p (12.5 MB/s): V30.
- H.265 4K 60p (25 MB/s): V30.
- All-Intra 4K 30p (37.5 MB/s): V60.
- All-Intra 4K 60p (75 MB/s): V90.
Camaralia recommends one step above the minimum. The actual bitrate has peaks and cards lose some performance with use; that margin prevents recording stops and lost frames.
What factors change the size of your recording?
The size depends mainly on the bitrate, which is the amount of data per second that the camera writes. It is determined by these factors:
- Resolution: 4K generates much more data than Full HD.
- Frames per second: 60p needs more data than 30p.
- Codec: H.265 compresses more than H.264; All-Intra formats save each complete frame and weigh much more.
- Color depth and sampling: 10 bits and 4:2:2 increase the size compared to 8 bits and 4:2:0.
The bitrate appears in the manual or in your camera's menu, in Mbps. With that data the formula is direct: GB per hour = Mbps × 3,600 ÷ 8 ÷ 1,000, and MB/s = Mbps ÷ 8.
What type of card do I need: SD, CFexpress, or other?
It depends on what your camera records. As a general rule:
- Up to 60 MB/s sustained: an SD card with class V30 or V60 is usually enough.
- Up to 90 MB/s: a V90 UHS-II SD card.
- More than 90 MB/s sustained: CFexpress is needed, common in high-rate RAW or All-Intra formats.
V60 and V90 classes require a UHS-II SD, the one with double rows of contacts. Before buying, check in the manual what type of slot your camera has, because some bodies use SD, others CFexpress, and others combine two different slots.
What other tools does Camaralia offer?
In addition to the memory card calculator, you can use:
- What camera do you need?: 7-question advisor that recommends a camera and completes the kit.
- Filter diameter search by lens: it tells you the thread of your lens to buy the correct filter.
They are all on the tools page. More will be coming soon.
Calculate your card now
Enter your resolution, your frames per second, and your format, and get the GB per hour and the card class you need: Memory card calculator for video.
With the result, check the memory cards available in the store.