Size from bitrate.
Bitrate from a budget.
Exact arithmetic in both directions, so you can plan storage before you export anything.
This is the one calculation on the site with no assumptions in it at all — a video file is its bitrate multiplied by its duration, and that is the whole story.
1 Mbps = 1000 kbps.
128 is normal stereo; 192 for music.
Same bitrate, other lengths
| Duration | Size | In MB |
|---|---|---|
| 10 minutes | 0.36 GB | 367 MB |
| 30 minutes | 1.07 GB | 1,100 MB |
| 60 minutes | 2.15 GB | 2,201 MB |
| 120 minutes | 4.30 GB | 4,401 MB |
| 240 minutes | 8.60 GB | 8,803 MB |
File size
2.15 GB
2,201 MB
Total bitrate
5,128 kbps
Per hour
2.15 GB
Per day of runtime
51.58 GB
if it were one long file
A 60-minute file at 5,000 kbps video plus 128 kbps audio comes to 2.15 GB — about 2.15 GB for every hour of runtime.
Storage context: one unexpired monthly slot carries 10 GB and one daily slot 5 GB, and slots add together. A 2.15 GB file uses about 21% of a single monthly slot.
GB here is 1024-based, matching what your operating system shows rather than what a drive box claims.
How this is calculated
Size from bitrate
Size in bits = (video kbps + audio kbps) × 1000 × seconds. Divide by 8 for bytes. Bitrate literally means bits per second, so this is a definition rather than an estimate.
Bitrate from a budget
The same equation rearranged: available bits ÷ seconds gives the total bitrate that fits, and subtracting your audio bitrate leaves what the video can have. If the answer is zero, the audio alone does not fit.
GB here means 1024-based
We use 1 GB = 1,073,741,824 bytes, which is what your operating system reports. Drive manufacturers use 1,000,000,000, which is why a "1 TB" disk shows up smaller — the difference is about 7%.
Why it matters for a 24/7 loop
Your loop file lives in storage for as long as the stream runs. Each unexpired monthly slot carries 10 GB and each daily slot 5 GB, and slots add up — so knowing the file size before you export saves a re-export later.
Questions about this tool
Why is my exported file bigger than this says?
Almost always because the export used a higher bitrate than you entered, or variable bitrate pushed the average up on demanding footage. Check the actual bitrate your encoder reports for the finished file, not the target you asked for.
Does resolution change file size?
Not directly — bitrate does. Resolution matters because a higher resolution needs a higher bitrate to look acceptable. 1080p at 3 Mbps and 720p at 3 Mbps produce the same file size; only one of them looks right.
What bitrate should I use for a 24/7 loop?
It depends on resolution, frame rate and how much your picture moves. Our bitrate calculator works it out from those three inputs and shows the maths, so you can see why the number is what it is.
How much storage does a stream slot include?
Each unexpired monthly slot contributes 10 GB and each daily slot 5 GB, and multiple slots add together. The storage widget in our pricing section works out what your library needs.
What this tool cannot tell you
Every calculator on the internet hides its assumptions. Here are ours, in the open.
This calculates constant-bitrate size. Variable bitrate encoding aims at an average, so a real export lands near this figure rather than exactly on it.
Container overhead — MP4 headers, index tables, chapter data — adds a small amount on top. It is under a percent for a long file, but it is not zero.
A bitrate that fits is not automatically a bitrate that looks good. Use the bitrate calculator to check whether your target is realistic for the resolution and content you have.
Two-pass encoding hits a target size more accurately than one pass. If you are squeezing into a tight budget, that setting matters more than the number here.
Audio bitrate is per stream. A second language track or a higher-quality music mix adds its own bitrate for the whole duration.
Next steps
Free tool
Streaming Bitrate Calculator
Choose export settings for a file that has to look right for weeks, not minutes.
Free tool
Upload Time Calculator
Plan the wait before your file is in the cloud, with parallel chunked uploads accounted for.
Guide
How to Compress Video for Streaming Without Visible Quality Loss
A longer read on the same problem, with the steps this tool skips.
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