Calculator
Formula used
- Total bitrate = video + audio + extra (in bps)
- Total bits = total bitrate × duration (seconds)
- Total bytes = total bits ÷ 8
- Final bytes = total bytes × (1 + overhead% ÷ 100)
size ≈ (6,192,000 × 600 ÷ 8) × 1.02How to use this calculator
- Enter your known bitrates (video, audio, and optional extra streams).
- Set the duration using hours, minutes, and seconds.
- Add container overhead if you want a closer real-world estimate.
- Select decimal or binary units, then choose rounding precision.
- Press Calculate to show results above the form.
- Use Download CSV or Download PDF for sharing.
Example data table
| Scenario | Video bitrate | Audio bitrate | Duration | Overhead | Estimated size (approx.) |
|---|---|---|---|---|---|
| HD clip | 5.0 Mbps | 192 Kbps | 00:05:00 | 2% | ~ 193 MB |
| Podcast episode | — | 128 Kbps | 00:45:00 | 1% | ~ 44 MB |
| Conference recording | 8.0 Mbps | 256 Kbps | 01:30:00 | 3% | ~ 5.2 GB |
Why bitrate drives predictable file sizing
Bitrate is the rate of data produced each second. When you multiply a stream’s total bitrate by duration, you get total bits, then convert to bytes for storage. This calculator supports separate video and audio inputs, plus an optional extra stream for subtitles or metadata. It is useful when planning backups, estimating cloud transfer, or checking whether a target device has enough free space for a recording. For live capture, verify peak bitrate before recording.
Understanding bps, Kbps, and Mbps
Most encoders report bitrates in decimal units where 1 Kbps equals 1,000 bps and 1 Mbps equals 1,000,000 bps. Some tools show binary-style labels, so this page lets you enter both decimal and binary bitrate units. Treat kb/s listings as standard Kbps values. Enter the rate you actually see in your encoder or media spec sheet, then choose the preferred display system to reduce confusion across platforms.
Overhead and real container behavior
File formats include headers, indexing, and packetization, so the final size is usually slightly larger than pure payload math. The overhead field models this as a percentage increase, which is practical for MP4, MKV, TS, and similar containers. Set overhead to zero for raw streams. Use 1–5% for many cases, and increase it when you have frequent keyframes, multiple tracks, or segmenting for adaptive streaming.
Decimal versus binary reporting
Storage vendors commonly advertise decimal GB, while operating systems often display GiB. The difference grows with size, so a “5 GB” estimate may appear smaller in a file manager. Binary units match many operating system displays. This calculator prints both families of units and lets you set rounding precision. For technical reports, keep two to three decimals; for quick planning, one decimal is usually enough.
Operational planning with the results
Once you know the estimated size, you can budget upload time by dividing bytes by your network throughput, and you can forecast monthly storage by multiplying by expected volumes. For encoding experiments, adjust bitrate and duration to compare scenarios quickly. Exporting CSV supports spreadsheet tracking, while PDF provides a shareable snapshot for approvals and documentation. Re-check assumptions after codec or container setting changes.
FAQs
1) What bitrates should I enter for variable bitrate encodes?
Use the average bitrate reported by your encoder or the media file’s metadata. For tighter bounds, run two estimates using average and peak values. Storage planning usually works best with an average plus a small overhead buffer.
2) Why does the calculated size differ from the exported file size?
Real files contain headers, timestamps, indexing, padding, and sometimes codec delay. Streaming segmenting and multiple tracks also add bytes. Increase the overhead percentage until the estimate matches your typical format and workflow.
3) Should I choose decimal or binary units?
Choose decimal when comparing against vendor storage labels and network plans. Choose binary when matching operating system displays or server quotas. The calculator shows both so you can communicate clearly with different teams.
4) How do I include multiple audio tracks or subtitles?
Add the main audio bitrate in the Audio field, then put additional tracks, subtitles, or data streams in the Extra field. If you know each track bitrate, sum them first, or run separate scenarios and compare.
5) How can I estimate upload time using the result?
Convert the final size to bits, then divide by your measured upload throughput in bits per second. Add extra time for protocol overhead and network variability. For example, a 1 GB upload on 20 Mbps typically takes several minutes.
6) What overhead percentage is reasonable for common containers?
Many MP4 and MKV files land around 1–3% overhead, while transport streams or segmented outputs may be higher. If you use chapters, multiple tracks, or frequent seeking indexes, start at 3–5% and adjust based on samples.