The calculation
For a constant or average bitrate, decimal storage in gigabytes is approximately:
GB = bitrate in megabits per second × recording seconds ÷ 8,000.
For one hour, multiply the bitrate by 0.45. A 100 Mb/s recording therefore produces about 45 GB per hour. At 250 Mb/s it is 112.5 GB; at 500 Mb/s it is 225 GB. Allow additional space for audio, metadata, variable bitrate behaviour and other production files. These are planning calculations, not a promise about a particular camera mode.
| Average video bitrate | 30 minutes | One hour | Four camera-hours |
|---|---|---|---|
| 50 Mb/s | 11.25 GB | 22.5 GB | 90 GB |
| 100 Mb/s | 22.5 GB | 45 GB | 180 GB |
| 250 Mb/s | 56.25 GB | 112.5 GB | 450 GB |
| 500 Mb/s | 112.5 GB | 225 GB | 900 GB |
Be careful with units. Mb/s means megabits per second; MB/s means megabytes per second. Confusing them introduces an eightfold error. A computer may also report binary units, so the displayed free space can differ from a drive’s decimal capacity label.
Three examples with explicit assumptions
A short corporate interview
Two cameras record a 45-minute interview at an assumed average of 100 Mb/s each. That is 1.5 camera-hours and about 67.5 GB. Add 30 minutes of separately recorded B-roll from one camera at the same rate and the source video becomes about 90 GB. The interview has not become 90 minutes long: the two angles overlap in time.
A three-camera conference session
Three cameras run for two hours at 100 Mb/s. Six camera-hours produce about 270 GB before slides, separate sound and other assets. Recording every session all day scales quickly even if the highlight film will be only three minutes.
A detail-heavy product shoot
One camera records two hours at an assumed 500 Mb/s, producing about 450 GB. That can exceed the interview example despite fewer recorded hours. Repeated lighting setups, movement variations and high-frame-rate takes affect the quantity and usefulness of the material separately.
Why “4K” is not a storage specification
Resolution tells you frame dimensions, not how heavily the frames are compressed. Codec, frame rate, bit depth, recording mode and compression settings also matter. Sony’s FX6 specifications, for example, list different bitrates for different XAVC modes. Two cameras both set to 4K can generate very different file sizes.
Ask the production company for the exact recording mode or a measured sample-file rate. If the camera uses variable bitrate or a quality-based RAW setting, treat the estimate as a range and leave headroom. Do not choose recording settings solely to make files smaller when the edit needs grading latitude, reframing or slow motion.
What is in all those files?
The source material normally includes repeated answers, pauses, slates, focus checks, alternative compositions and the seconds before and after a usable action. An interview may explore ten topics to find the three relevant to the final story. B-roll needs enough duration for clean starts and ends, not only the instant that appears in the edit.
A high shooting ratio is therefore not automatically wasteful, and a low one is not automatically efficient. A scripted demonstration can be planned tightly. An unpredictable live event needs continuous coverage because the important moment cannot be repeated. Our B-roll guide explains why apparently secondary material is essential to a coherent edit.
The project takes more space than the camera originals
The working project may also contain proxies, synchronised audio, graphics, cached renders and review exports. A proxy is a smaller editing copy; it does not replace the original. A colour-graded master can be much larger than the compressed web version.
Then account for backups. If the originals total 500 GB, maintaining three copies requires roughly 1.5 TB for those files alone. Working assets and free-space allowance are additional. This is why a folder that eventually produces a small download can require substantial production storage.
If you want the original files
Agree this before filming. Ask whether the delivery contains untouched card structures, selected clips or transcoded viewing files; whether audio is separate; and whether the editing project and licensed assets are included. A drive of originals is not the same product as a ready-to-watch film.
For delivery, establish total size, drive format, transfer method, verification and the receiving computer’s ability to decode the footage. At a theoretical sustained upload of 100 Mb/s, 500 GB takes just over eleven hours before overhead or interruptions. A physical drive can be sensible when connectivity is limited.
Tell us how you intend to use the footage when briefing the shoot. We can estimate recording volume and specify a useful handover rather than surprising you with an unfamiliar folder after delivery.
