How Much NAS Storage for 4K Video?

The usable NAS capacity you need depends primarily on video bitrate and total recording hours, not simply the “4K” label.

Use this formula to estimate storage for video files:

Storage (GB) = Bitrate (Mbps) × Hours × 0.45

For example, 100 Mbps of 4K footage uses approximately:

100 × 1 × 0.45 = 45 GB per hour

That is the space for the original video stream only. Your NAS also needs capacity for project files, proxies, exports, duplicate copies, RAID or parity overhead, filesystem overhead, growth, and free-space headroom.

A practical planning target is:

Required usable NAS capacity =
original footage
+ working files and versions
+ expected growth
+ backup requirement
+ free-space headroom

How much storage does 4K video use?

There is no single storage figure for 4K video. Two 4K cameras can use very different amounts of storage because they may record at different bitrates, frame rates, codecs, chroma subsampling, and compression levels.

Approximate original-footage requirements:

Bitrate	Per hour	10 hours	50 hours	100 hours
50 Mbps	22.5 GB	225 GB	1.125 TB	2.25 TB
100 Mbps	45 GB	450 GB	2.25 TB	4.5 TB
150 Mbps	67.5 GB	675 GB	3.375 TB	6.75 TB
200 Mbps	90 GB	900 GB	4.5 TB	9 TB
400 Mbps	180 GB	1.8 TB	9 TB	18 TB

These are decimal storage estimates. Manufacturers generally label drives in decimal terabytes, while some operating systems display capacity using tebibytes. The displayed number may therefore look smaller even before RAID and filesystem overhead are considered.

Check the camera or recorder bitrate

For an accurate estimate, find the camera’s actual recording bitrate or the recorder’s aggregate bitrate. Look for:

• Average or maximum bitrate in Mbps
• Constant-bitrate or variable-bitrate recording
• Number of cameras recording at once
• Frame rate and resolution
• Audio tracks
• Whether the bitrate is per stream or shared across multiple streams

For variable-bitrate video, use a realistic average and add a safety margin for high-motion scenes. For surveillance, calculate from the combined bitrate of all cameras rather than treating each camera as a separate NAS workload.

Convert bitrate into storage

The basic conversion works because bitrate is expressed in megabits per second, while storage is normally measured in gigabytes or terabytes.

Bits per second / 8 = bytes per second

For hourly storage:

Storage (GB) = Bitrate (Mbps) × 3,600 seconds × 1,000,000 / 8 / 1,000,000,000
Storage (GB) = Bitrate (Mbps) × 0.45

For several cameras or streams:

Total bitrate = Camera 1 bitrate + Camera 2 bitrate + ...
Storage per hour = Total bitrate × 0.45

Worked camera example

Suppose six cameras each record at an average of 12 Mbps:

Total bitrate = 6 × 12 = 72 Mbps
Storage per hour = 72 × 0.45 = 32.4 GB

Continuous recording for 30 days would require approximately:

32.4 GB × 24 × 30 = 23,328 GB
23,328 GB = 23.3 TB

That is before RAID, filesystem overhead, retention policies, and free-space headroom. Motion-based recording could use substantially less, but the actual reduction depends on how often each camera records.

Separate raw capacity from usable capacity

A drive’s labeled capacity is not the same as the space available for files on a NAS.

You need to distinguish four numbers:

1. Raw capacity — the sum of all installed drive capacities.
2. RAID or parity-adjusted capacity — the space remaining after redundancy.
3. Filesystem-usable capacity — the space available after filesystem structures and metadata.
4. Planning capacity — the amount you should actually fill while preserving headroom.

Raw capacity

Raw capacity is calculated by adding the drive capacities:

Raw capacity = Drive capacity × Number of drives

For example:

6 drives × 8 TB = 48 TB raw capacity

This does not mean you have 48 TB available for video.

RAID and parity loss

RAID protects against some drive failures and can improve availability, but it reduces usable capacity. The exact result depends on the RAID level, drive sizes, filesystem, and implementation.

Approximate capacity formulas for equal-sized drives are:

Layout	Approximate usable capacity before filesystem overhead	Main trade-off
RAID 0	Number of drives × drive size	No drive-failure protection
RAID 1	One drive’s capacity in a two-drive mirror	Strong redundancy, inefficient capacity
RAID 5	(Number of drives - 1) × smallest drive	One-drive fault tolerance; rebuild considerations
RAID 6	(Number of drives - 2) × smallest drive	Two-drive fault tolerance; more parity overhead
RAID 10	Approximately half of raw capacity	Good performance and redundancy, lower capacity
RAIDZ	Depends on vdev layout and parity level	ZFS-specific planning is required

These formulas are estimates, not guarantees. Mixed drive sizes, reserved space, hot spares, pool design, snapshots, and NAS-specific implementation can change the result.

Do not choose RAID 0 for irreplaceable camera originals or editing projects unless another independent copy exists and the risk is acceptable. RAID is not a backup.

Filesystem overhead and reserved space

Filesystems require space for metadata and internal structures. ZFS also needs careful pool planning because performance and resilience can suffer if a pool is filled too close to its limit. Snapshots and copy-on-write behavior can consume additional space as files change.

The exact overhead is filesystem- and configuration-dependent, so do not subtract a fixed percentage unless your NAS documentation or storage calculator provides one.

Leave free-space headroom

A NAS should not be sized so that the footage fills every last available terabyte. Free space is needed for:

• New recordings and imports
• Temporary editing files
• File transfers and exports
• Snapshots
• Metadata and filesystem operations
• Rebuilds or replacement-drive workflows
• Unexpected growth

As a planning rule, reserve around 15% to 20% of usable capacity for headroom, then adjust for your filesystem and workload. This is not a universal technical limit; it is a practical budgeting margin.

If your calculated data requirement is 8 TB and you want 20% free space:

Required usable capacity = 8 TB / (1 - 0.20)
Required usable capacity = 10 TB

Do not simply add 20% if you mean that 20% must remain free. Dividing by 0.80 gives the correct target.

Account for editing files, proxies, and exports

Original 4K footage is only one part of an editing workflow. Capacity can multiply when you keep:

• Camera originals
• Audio recordings
• Proxy or optimized media
• Project databases
• Render caches
• Intermediate files
• Master exports
• Client review versions
• Archived project versions

A simple editing estimate might look like this:

Working-set capacity =
originals
+ proxy files
+ project and audio files
+ active renders
+ planned exports

Proxy storage varies widely by codec and workflow, so measure a representative project rather than assuming it equals the size of the camera originals. Render caches may be temporary, but they still require fast local or NAS storage while a project is active.

For frequently edited footage, consider separate storage tiers:

• NAS HDD pool: large, economical storage for originals and completed projects
• SSD or local workspace: active editing, cache, and high-throughput scratch work
• Backup target: a separate copy that is not dependent on the primary NAS

SSD cache is not a substitute for sufficient capacity or a backup. It may help with metadata or repeated access in some workloads, but it does not turn a small NAS into unlimited video-editing storage. Check whether your editing application, network, NAS, and cache design can use it effectively before paying for additional SSDs.

Worked 4K NAS sizing example

Assume the following workflow:

• 40 hours of 4K originals
• Average bitrate of 150 Mbps
• 20% additional capacity for project files, proxies, and exports
• 20% free-space headroom
• A RAID6 or comparable two-drive-parity layout
• One independent backup copy of the working data

Step 1: Calculate original footage

150 Mbps × 40 hours × 0.45
= 2,700 GB
= 2.7 TB

Step 2: Add project and working files

2.7 TB × 1.20 = 3.24 TB

This 20% allowance is only an example. A project with large intermediate files or several retained exports may need much more.

Step 3: Add free-space headroom

To keep 20% of the usable NAS capacity free:

3.24 TB / 0.80 = 4.05 TB usable capacity

So the primary NAS should provide at least approximately 4.05 TB of usable space after RAID and filesystem effects, not merely 4.05 TB of raw drive capacity.

Step 4: Plan the backup

A full independent backup of this working set also needs approximately:

3.24 TB minimum backup data capacity

If the backup target must also preserve 20% free space:

3.24 TB / 0.80 = 4.05 TB usable backup capacity

The backup may use a different drive arrangement, but it must be large enough for the data and retention policy you choose. If you retain multiple versions, deleted files, or snapshots, increase the backup requirement.

Growth changes the NAS size

A NAS that fits today’s footage may be too small next year. Include:

• Hours of footage added per month or year
• Increasing camera count
• Higher recording bitrates
• More 4K or 8K projects
• Longer surveillance retention
• Client or family archives
• Versioned backups
• New services such as Plex libraries or photo storage

A basic growth formula is:

Future footage = Current footage + (New footage per month × Months)

Then apply your working-file and headroom allowances:

Future usable requirement =
Future footage × workflow multiplier / (1 - headroom percentage)

If you expect capacity to double within the life of the NAS, buying only today’s minimum can force an expensive migration. Balance this against expansion options: free drive bays, larger replacement drives, an expansion chassis, a second NAS, or an external backup system.

RAID is not backup

RAID can keep a NAS online after certain drive failures, but it does not protect against:

• Accidental deletion
• Ransomware
• File corruption
• Fire, theft, or water damage
• A failed NAS enclosure or controller
• Syncing an unwanted change to every copy
• Poorly planned replacement or rebuild operations

Use a 3-2-1-style approach where practical:

• Keep at least three copies of important data
• Use at least two different storage types or devices
• Keep at least one copy off-site or otherwise isolated

For irreplaceable 4K footage, the backup NAS, external drive set, or cloud destination should be independent from the primary storage pool. Test restores; a backup that cannot be recovered is not a reliable backup.

Network and performance considerations

Capacity answers “how much can I store?” It does not answer “can I edit or stream it smoothly?”

A rough throughput conversion is:

Bandwidth (Gbps) / 8 = theoretical GB/s

For megabits per second:

Bandwidth (Mbps) / 8 = theoretical MB/s

Actual file-transfer speed is lower because of protocol overhead, NAS processing, drives, filesystem behavior, network equipment, and simultaneous users.

Consider:

• The bitrate of the source footage
• Number of editors or playback clients
• Whether files are copied locally before editing
• Network link speed
• Switch and adapter capabilities
• NAS CPU and memory
• HDD or SSD pool design
• Whether Plex is direct-playing or transcoding
• Surveillance writes occurring at the same time as editing

Plex libraries usually affect capacity more than sustained write performance, although transcoding can create CPU demands and temporary files. Surveillance can create continuous writes, while editing often needs high burst throughput and responsive random access. A capacity-focused HDD pool may be appropriate for archives, while active projects may benefit from local SSD storage or a properly designed SSD tier.

Should you use ZFS for 4K video?

ZFS can be a strong choice when data integrity, snapshots, checksums, and pooled storage management are priorities. It also requires more deliberate planning than simply combining disks:

• Choose the vdev layout before building the pool
• Match redundancy to drive count and failure tolerance
• Account for usable capacity rather than raw capacity
• Leave appropriate free space
• Plan expansion carefully
• Use ECC memory if it fits your reliability goals and platform
• Keep a separate backup even when using ZFS

ZFS does not remove the need for backups, and adding drives to an existing pool may not work the same way as replacing drives with larger models. Confirm the expansion path before buying a NAS that you expect to keep for many years.

NAS sizing checklist for 4K video

Before choosing the enclosure or drives, calculate:

• [ ] Average or maximum bitrate in Mbps
• [ ] Total hours of footage currently stored
• [ ] Expected new footage per month or year
• [ ] Number of cameras or simultaneous recording streams
• [ ] Space for proxies, audio, caches, projects, and exports
• [ ] Retention period for surveillance recordings
• [ ] RAID or ZFS redundancy level
• [ ] Usable capacity after parity and filesystem effects
• [ ] Free-space headroom, preferably at least 15% to 20% for planning
• [ ] Capacity for an independent backup
• [ ] Network speed and editing workflow
• [ ] Plex, surveillance, photo, or other services sharing the NAS
• [ ] SSD requirements for active projects or cache
• [ ] Future drive-bay or expansion options
• [ ] Restore testing and off-site protection

When comparing enclosures, start with the usable-capacity target and the backup plan, then evaluate bays, drive compatibility, networking, expansion, and software. You can Browse NAS or narrow the search to NAS and storage servers.