How much storage do you need for 4K, 6K, or 8K video?
Calculate recording time from bitrate, compare 64GB through 512GB cards, and budget headroom for high-resolution video, proxies, audio, and card rotation.
1. Resolution does not determine storage by itself
A 4K recording can use less space than another camera's 1080p mode or far more than a different 4K mode. Codec, frame rate, bit depth, chroma sampling, compression type, and whether the bitrate is constant or variable all affect storage.
Find the published bitrate for the exact recording menu setting. If the camera lists several numbers, include the video stream plus any separate proxy or simultaneous recording stream you intend to capture.
2. Convert bitrate into recording time
Bitrate is commonly stated in megabits per second, while card capacity is stated in gigabytes. Eight bits make one byte. Using decimal units, one hour at 100 Mbps consumes about 45GB: 100 divided by eight, multiplied by 3,600 seconds, then divided by 1,000.
For a quick recording-time estimate, multiply capacity in GB by 8,000, divide by bitrate in Mbps, and divide by 60. The result is minutes before formatting overhead and working headroom.
3. Compare card capacity by bitrate
These rounded estimates use nominal capacity. Variable-bitrate recording may use less or more space depending on the scene, and cameras reserve some capacity for formatting and management. Do not plan a job to end at the theoretical final minute.
| Video bitrate | 64GB | 128GB | 256GB | 512GB |
|---|---|---|---|---|
| 100 Mbps | 85 min | 171 min | 341 min | 683 min |
| 200 Mbps | 43 min | 85 min | 171 min | 341 min |
| 400 Mbps | 21 min | 43 min | 85 min | 171 min |
| 800 Mbps | 11 min | 21 min | 43 min | 85 min |
4. Add headroom for the complete recording package
Audio is usually small compared with high-bitrate video, but proxies, simultaneous backup, metadata, thumbnails, and multiple cameras add up. Variable-bitrate codecs can also peak above their average. Reserve at least 10–15% and more when a recording cannot be interrupted.
For multicamera work, calculate each camera separately. A low-bitrate wide camera and a high-bitrate primary camera will not consume cards at the same rate even when both record 4K.
- 100 Mbps is about 45GB per hour.
- 200 Mbps is about 90GB per hour.
- 400 Mbps is about 180GB per hour.
- 800 Mbps is about 360GB per hour.
5. Capacity must still meet the camera's speed requirement
A card can be large enough and still be too slow. Check the required Video Speed Class, VPG class, minimum sustained write rate, and approved-media list for the exact recording mode. Divide Mbps by eight for a rough data rate, but follow the camera maker's requirement rather than using that conversion alone.
Plan card changes around natural breaks, label media, and keep enough cards to avoid reformatting before files are copied and verified. Long-form work often benefits from several tested cards plus a deliberate ingest routine more than from one enormous card.
Frequently asked questions
How much space does one hour of 4K video use?
It depends on bitrate. One hour uses about 45GB at 100 Mbps, 90GB at 200 Mbps, 180GB at 400 Mbps, or 360GB at 800 Mbps before overhead.
Is 128GB enough for 4K video?
At 100 Mbps it is roughly 171 theoretical minutes; at 400 Mbps it is about 43 minutes. Check the exact recording mode and leave practical headroom.
Does a larger card record faster?
Capacity alone does not guarantee speed. The card must meet the camera's required interface and sustained write classification.
Primary references
Technical standards can change. We use the relevant standards organizations as primary references and recommend checking the device maker's current manual.