OBS's Lossless recording preset produces files of "around 7 GB of data per minute of video." That figure is OBS's own, straight out of its Recording Encoder Presets guide, and it arrives with a second sentence almost nobody quotes: "This also uses the CPU encoder."
Both halves matter. Lossless is not just the expensive option for your disk — it is the one preset OBS explicitly ties to CPU encoding.
The recording quality presets, at a glance
OBS ships four presets in Simple output mode. Its own guide frames them as a convenience: "OBS Studio comes with encoder presets to make recording videos in high-quality simple." Here is what the documentation actually says about each one, word for word, alongside the only file-size figure it publishes.
| Preset | What OBS's guide says | Published size figure |
|---|---|---|
| Same as stream | "This preset uses the same settings as the streaming video encoder. This lets you record exactly the same quality as your stream." | None published — see official docs |
| High Quality | "This preset produces a high quality video with a medium file size." | None published ("medium file size" only) |
| Indistinguishable | "This preset provides a higher quality video at the cost of larger file sizes and a potential performance impact on older or weaker hardware, depending on the choice of encoder." | None published ("larger file sizes" only) |
| Lossless | "This preset produces tremendously large file sizes, around 7 GB of data per minute of video, in lossless quality. This also uses the CPU encoder." | around 7 GB per minute |
Read the right-hand column carefully. OBS puts a number on exactly one of these four presets; for the other three it gives comparative words — medium, larger — and nothing more. Any article handing you gigabytes-per-minute figures for High Quality or Indistinguishable is not getting them from OBS.
Note the qualifiers baked into the Lossless line itself: 7 GB/min describes the Lossless preset, not OBS recording in general, and "also uses the CPU encoder" is part of the same sentence. Strip either one and the number stops being true.
What "around 7 GB per minute" adds up to
OBS gives a per-minute rate and stops there. The only thing we can add is arithmetic on OBS's own figure:
| Recording length | At around 7 GB per minute |
|---|---|
| 5 minutes | ~35 GB |
| 15 minutes | ~105 GB |
| 30 minutes | ~210 GB |
| 60 minutes | ~420 GB |
These rows are multiplication, not separate official numbers — OBS publishes the per-minute rate only, and the word it uses is "around." Treat them as an order-of-magnitude sanity check, not a promise.
The consequence is blunt: a one-hour Lossless capture is in the same size class as a small SSD. For a full stream session or a long gameplay run, Lossless is a storage decision as much as a quality one.
One thing OBS's knowledge base does not state: a maximum size or maximum duration for a single recording file. There is no published cap to plan around, so if you need a hard ceiling for compliance or workflow reasons, check the official documentation rather than assuming one exists.
The clause that costs more than the disk space
"This also uses the CPU encoder" is doing a lot of work in that sentence.
OBS's Hardware Encoding page explains why that matters: "Hardware encoders, as opposed to the included x264 software encoder, are generally recommended for best performance as they take the workload off the CPU and to a specialised component in the GPU that can perform video encoding more efficiently. Modern hardware encoders provide very good quality video with minimal performance impact."
So the path OBS calls generally recommended for best performance is the hardware one — and Lossless, by OBS's own description, is not on it. If you are recording a game or anything else that already wants your CPU, that is the trade you accept when you pick this preset.
The dial that actually controls file size
If Lossless is too much and Same as stream is too little, the real control is quality-based rate control in Advanced output mode. OBS's Advanced Recording Settings guide gives baseline values per encoder — x264 uses CRF 16-23, NVENC uses Constant QP 16-23, AMD uses CQ Level 16-23, and Quicksync uses ICQ Quality 16-23 — with keyframe interval 2 across all four. The direction is stated outright: "Constant QP: 16-23 (Lower CQ level will result in higher quality and larger file sizes)."
That is the whole trade in one line: lower number, bigger file. The values above come from the newer Advanced Recording Settings guide — an older OBS guide gives a slightly different range, so check the current page before committing.
Codec choice pulls in the same direction. OBS's formats guide recommends that "for high quality local recording one should use the best quality hardware encoder available (AV1 > HEVC > H.264) together with high-bitrate AAC or lossless audio (e.g. ALAC)," describing HEVC as offering "better quality at the same bitrate/file size" than H.264 and AV1 as offering "improved quality/file size over HEVC." Two caveats OBS attaches: HEVC "is supported only via hardware encoders in OBS Studio (NVIDIA NVENC, AMD AMF, Intel QSV, Apple VT)," and AV1 software encoding "requires high end CPUs for real-time compression."
What to do when the recording is too big
In rough order of how much they help:
- Step down a preset. High Quality is described by OBS as "a high quality video with a medium file size" — for most screen recordings and tutorials, that is the sane default rather than Lossless.
- Move to Advanced output mode and set the quality dial yourself. Start at the documented 16-23 range and go up in number if the file is too large.
- Rescale the output. OBS notes in Advanced view that you can "rescale the output to have a different resolution, but maintained aspect ratio, relative to your canvas size in OBS." Recording a 1440p canvas out at a smaller resolution is one of the cheapest size wins available.
- Compress the finished file when the recording already exists and re-recording is not an option.
That last one is the case most people are actually in: the capture is done, the session is over, and the file will not fit anywhere.
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
This runs inside your browser tab — the file is read from disk, re-encoded locally, and handed back, with nothing uploaded. That matters when the source is a 40 GB capture: no upload to sit through, no server copy of your recording. For the reasoning behind the settings, see how to compress a video without losing quality, or go straight to the video compressor.
Gotchas worth knowing before you record
- Presets other than "Same as stream" cost extra resources. OBS says it directly: "Recording Quality when in Simple view will let you select what quality you'd like your recording to be at, anything that is not Same as stream will take extra resources from your computer."
- "Same as stream" disables pausing. From the same presets guide: "recordings cannot be paused if the recording quality is set to 'Same as stream'." If your pause button is greyed out, that is why.
- Container choice is your insurance on a long capture. OBS recommends MKV in its Standard Recording Output guide "in case of unforeseen issues arising, since MKV will not corrupt the whole file if there is no graceful stoppage of recording." On a multi-hour Lossless session, that is not a small detail. If MP4 is what your editor needs, see MKV or MP4 for OBS recordings.
- Remux is a conversion, not a documented size change. OBS can convert non-MP4 recordings via File → Remux Recordings, but its knowledge base does not state whether that step re-encodes the video. Do not assume remuxing shrinks anything.
FAQ
How big is an OBS lossless recording? OBS states "around 7 GB of data per minute of video" for the Lossless preset. That is roughly 105 GB for 15 minutes and roughly 420 GB for an hour, by simple multiplication of OBS's figure.
Does OBS Lossless use the GPU or the CPU? OBS's own description of the preset ends with "This also uses the CPU encoder." Its hardware encoding page separately says hardware (GPU) encoders are "generally recommended for best performance" because they move work off the CPU.
What is the maximum file size for an OBS recording? OBS's knowledge base does not publish a maximum recording file size or duration. Check the official documentation if you need a definitive answer for your setup.
Which preset should I use instead of Lossless? High Quality, which OBS describes as producing "a high quality video with a medium file size," is the reasonable default. Indistinguishable sits between them, with OBS warning of "a potential performance impact on older or weaker hardware, depending on the choice of encoder."
Can I shrink a Lossless recording I already made? Yes — re-encode it once with the compressor above, or with ffmpeg if you prefer the command line. Nothing about a lossless source prevents compression; you just cannot get the original quality back afterwards.
Why is my OBS recording silent even though the file is huge? Size and audio are unrelated problems. The usual cause is audio landing on a track your player does not read — see OBS recording has no audio.
More on platform and software ceilings in the limits archive, and the full set of browser-side converters and compressors at all Clapr tools.
All OBS quotes are from OBS Studio's own knowledge base (Recording Encoder Presets Guide, Hardware Encoding, Advanced Recording Settings Guide, Audio/Video Formats Guide, Standard Recording Output Guide), checked 16 September 2026. Start at obsproject.com/help for the current text.
