Video too large for Discord?
How video file size is calculated, how to work out your bitrate budget, and how to get a clip under 20 MB with a browser-only tool.
Video is a different problem from images. A 4K photo squeezed to 20 MB is barely distinguishable from the original, but a three-minute recording at the same size will visibly suffer. The reason is that video size is bitrate multiplied by duration, and duration is the one variable compression cannot touch.
The size equation
The formula is simple enough to do in your head:
size in MB ≈ total bitrate in kbps × duration in seconds ÷ 8000
Rearranged, your available bitrate is:
bitrate in kbps ≈ target MB × 8000 ÷ duration in seconds
So a 90-second clip aimed at 20 MB has about 1777 kbps to work with in total. Subtract audio and roughly 1650 kbps is left for picture, workable at 720p, and starting to fall apart at 1080p.
Bitrate budget by duration
Targeting 20 MB, after reserving a 5% safety margin:
| Duration | Total bitrate | Suggested resolution | What to expect |
|---|---|---|---|
| 15 seconds | ~10100 kbps | 1080p | Indistinguishable from source |
| 30 seconds | ~5060 kbps | 1080p | Clean |
| 60 seconds | ~2530 kbps | 720p | Fine for normal viewing |
| 2 minutes | ~1265 kbps | 720p | Blocking during fast motion |
| 5 minutes | ~505 kbps | 480p | Clearly soft, content still readable |
| 10 minutes | ~250 kbps | 360p | Use an external link instead |
When to drop resolution or frame rate
Once the bitrate gets low, holding a high resolution backfires: the same bits are spread across more pixels and every one of them looks bad. Cutting resolution gives the remaining pixels room to breathe.
- Above 3000 kbps: stay at 1080p.
- 1200 to 3000 kbps: drop to 720p.
- 600 to 1200 kbps: drop to 480p.
- Below 600 kbps: trim the clip instead of degrading it further.
Frame rate depends on content. Gameplay and sports survive 30fps but stutter noticeably at 24fps, while a screen recording or slide deck loses nothing at 24fps and hands the saved bits to picture quality.
How much audio costs
Stereo AAC at 128 kbps costs about 0.96 MB per minute. That sounds trivial until you have a five-minute video, where audio alone eats 4.8 MB, a quarter of a 20 MB budget. Many tools assume a flat 64 kbps for audio and then blow past the limit whenever the source has a richer track.
FitSize measures the real byte size of the audio track, subtracts it from the budget, and gives the rest to video. The AAC data is copied through without re-encoding, so there is no second generation of audio loss.
Step by step
- Open the FitSize Discord page and pick your plan, or switch to a custom size if the destination server is boosted.
- Drag the video in, or click to browse. Phones can pick straight from the camera roll.
- Wait for the progress bar. The first run loads the video engine, which takes a few seconds.
- Check the compressed size on the result card and download.
Browsers with WebCodecs support (Chrome, Edge) encode on the GPU and finish far faster. Firefox and Safari fall back to a compatibility path automatically, same result, more patience required.
When it still will not fit
If three passes still overshoot, that duration simply cannot reach the target at watchable quality. Your options:
- Trim: keep only the part that matters. By far the biggest lever.
- Split it: one message takes up to 10 attachments, so two or three parts is fine.
- Post in a boosted server: level 2 gives 50 MB, level 3 gives 100 MB.
- Link it: for anything past ten minutes, cloud storage or an unlisted upload is the honest answer.
The tool still hands you the final attempt when it misses the target, marked as over-limit, so check the real size before you upload.
Frequently asked questions
How long a video actually fits in 20 MB?
It depends on the quality you will accept. At 720p and 2500 kbps you get about 65 seconds. Stretching to three minutes drops you near 900 kbps, where blocking becomes visible. In practice, trim anything over two minutes.
The audio disappeared after compression. Why?
Usually the source used an audio codec other than AAC, or the tool failed while re-encoding it. FitSize copies AAC tracks through untouched and flags unsupported audio formats on the result card instead of silently dropping them.
My portrait phone video came out sideways.
That is the classic symptom of ignored rotation metadata. Phones record landscape frames plus a rotation flag that players apply. FitSize detects the flag and bakes the rotation into the pixels, so the output is upright.
Is it normal for compression to be slow?
It depends on your device. The encoding runs on your own computer rather than a server, so your hardware sets the pace. With a GPU hardware encoder a one-minute clip usually finishes in well under a minute; CPU-only software encoding is several times slower; and the compatibility fallback is slowest of all because it has to play the video through in order to record it. The result row shows which path is in use and how long it has been running. Trimming the clip is by far the most effective way to speed things up.
Why is the result bigger than the estimate?
Bitrate is an average, and busy scenes overshoot it. That is why the target is set to 95% of the limit. If a pass still exceeds it, the next bitrate is derived from the measured result rather than guessed, up to three attempts.
Want to just do it? The compressor lives on the home page and nothing gets uploaded.
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