To convert Mbps to MB/s, divide by 8. So 400 Mbps — a typical 4K60 10-bit bitrate — is 50 MB/s. To go the other way, multiply by 8: a card rated V60 (60 MB/s sustained) can absorb 480 Mbps.
If you shoot video, you’ve almost certainly run into this math problem: your camera records at 400 Mbps, the memory card in your hand boasts 150 MB/s, and you’re left wondering whether the card is fast enough.
Camera makers quote megabits per second for video streams; card makers quote megabytes per second for transfer speeds. It’s exactly the same data, just described with different units.
That’s where this calculator comes in. It converts in either direction, and the tables underneath cover the bitrates cameras commonly use.
Mbps to MB/s conversion calculator
Edit any field and the others update. 1 byte = 8 bits; an X-rating is a multiple of 150 KB/s (the original CD-ROM transfer speed), so 1066× ≈ 160 MB/s.
Common camera bitrates, converted
These are the bitrates you’ll see in camera menus and spec sheets, converted to the write speed the card has to sustain, with the minimum card rating I’d pair with each. The right-hand column builds in some headroom, for reasons explained further down.
| Camera bitrate | Card write speed needed | Card rating I’d pair it with |
|---|---|---|
| 50 Mbps | 6.25 MB/s | Any current card (V10/V30) |
| 100 Mbps | 12.5 MB/s | V30 |
| 150 Mbps | 18.75 MB/s | V30 |
| 200 Mbps | 25 MB/s | V30 (V60 for comfort) |
| 240 Mbps | 30 MB/s | V60 — V30 is exactly at its limit |
| 400 Mbps | 50 MB/s | V60 minimum; V90 if you shoot long takes |
| 600 Mbps | 75 MB/s | V90 |
| 800 Mbps | 100 MB/s | V90 only if the camera explicitly lists it; otherwise CFexpress |
| 1,000 Mbps (1 Gbps) | 125 MB/s | CFexpress (VPG200/VPG400) |
| 1,600 Mbps | 200 MB/s | CFexpress (VPG400) |
The row that gets asked about most is 400 Mbps: that’s 50 MB/s, so a V60 card meets it and a V90 gives you margin (al V60 and V90 cards are UHS-II, so your camera will need a UHS-II slot to make use of it).
Whether your camera can even use a faster card is a separate question — the slot is often the real ceiling — which I cover in what memory card speed your camera actually needs.
Card ratings converted to Mbps
Going the other direction — useful when a card says “60 MB/s” and your camera’s speed need are quote in Mbps:
| Card rating | MB/s | In Mbps |
|---|---|---|
| V30 (minimum sustained write) | 30 MB/s | 240 Mbps |
| V60 | 60 MB/s | 480 Mbps |
| V90 | 90 MB/s | 720 Mbps |
| UHS-I bus ceiling | ~104 MB/s | ~832 Mbps |
| UHS-II bus ceiling | ~312 MB/s | ~2,496 Mbps |
| CFexpress VPG400 | 400 MB/s sustained | 3,200 Mbps |
The V ratings are guaranteed minimum sustained write speeds, which is the number that matters for video; the bus ceilings are theoretical maximums you won’t see in practice. More on how those ratings work in my guide to SD card speed classes.
The capitalization trap: Bits vs bytes
The difference between a working recording and a locked-up camera often comes down to a single capitalized letter.
Megabits per second can be written as either Mbps or Mb/s. They both use a lowercase “b.” Video bitrate is conventionally measured in Mb/s. It is also the standard measurement used by internet service providers to measure network connection speeds.
Megabytes per second can be written as either MBps or MB/s. They use a capitalized “B.”
Because there are 8 bits in a single byte, there are 8 megabits in a megabyte. This means you must divide your camera’s stated Mbps video bitrate by 8 to find the actual physical size of the data being written to your card.
With this simple, bidirectional calculator, you can instantly convert megabits per second to megabytes per second — and vice versa — to ensure your media has the bandwidth to handle your camera’s data output without dropping frames.
Heads up! What else to factor in
If you use the calculator above and discover your camera’s 400 Mbps codec translates to a 50 MB/s write speed, it’s tempting to assume a card that writes at 60 MB/s will handle it just fine.
In practice, it usually doesn’t work out that way. Making it even more complicated is that most storage devices can’t actually transfer data at their maximum theoretical speed. Just because a label claims a transfer speed of 300 MB/s doesn’t mean you’re actually going to get those speeds in real-world conditions.
To guarantee a recording won’t fail, you have to account for two hidden bottlenecks: compression spikes and hardware overhead.
Variable bitrate spikes
With the exception of a few high-end cinema formats that shoot uncompressed video, almost all modern hybrid mirrorless and DSLR cameras compress video on the fly to save storage space. To do this efficiently, they use a Variable Bitrate (VBR).
When camera manufacturers list a “400 Mbps” codec in their manuals, they’re usually quoting the target average data rate — not the absolute maximum peak.
With VBR, the camera’s processor constantly analyzes the scene and adjusts the data rate based on what is actually happening in the frame. If you are filming a static interview on a tripod, the camera recognizes that the background isn’t moving. It aggressively compresses the footage, dropping the data rate way down.
But if you suddenly pan the camera quickly across a highly detailed forest or another scene with lots of fine details, the processor has to write entirely new, complex pixel data for every single frame. When that happens, the amount of data the processor has to handle spikes dramatically.
Hardware overhead
Beyond those compression spikes, the system also has to handle invisible hardware overhead. The camera and the media aren’t just transferring pure video pixels; they are constantly communicating via an interface protocol.
As the data flows, the card’s internal flash controller is simultaneously running error correction, managing background wear-leveling, and updating the file system directory in real-time. All of this necessary housekeeping eats into your available bandwidth.
If your card doesn’t have the physical headroom to absorb both the VBR compression spike and the background hardware overhead, the camera’s internal buffer will fill up instantly and the recording will abruptly stop.
Real-world workflow applications
Because of this overhead, it’s risky to rely on a direct mathematical comparison. This is precisely why I run my own independent benchmarks on storage media, testing for sustained real-world results rather than the theoretical burst speeds printed on the box.
In my own workflow, once I use the calculator to find the exact MB/s requirement for a video codec, I look for media with a guaranteed sustained write speed — like an SD card with a V90 logo or a CFexpress card with a VPG400 rating — that sits comfortably above that calculated average.
But it’s also equally important not to overbuy, which is all too easy to do. If you’re shooting with a camera that only records standard 100 Mbps 4K video (which translates to just 12.5 MB/s), an older UHS-I camera body simply cannot utilize the fastest memory cards on the market. Overpaying for peak speed in that scenario is a waste of money. You also save yourself headaches by steering clear of formats that have known compatibility issues with modern camera tech.
Finally, building in speed overhead only works if the file system is clean. Which is why it’s always good practice to prep your memory cards directly in-camera before every shoot rather than just deleting clips on the computer. This rebuilding process prevents fragmentation errors when the data rate spikes. Just ensure everything is backed up first — though if you do make a mistake during prep, it is sometimes possible to rescue accidentally erased footage.
