Data source & methodology
AuthoritativeDataSource: International System of Units (SI) — BIPM “SI Brochure” (9th ed.), and ITU-T definitions of bit rate (Recommendation I.113). Direct links:
- BIPM — SI Brochure (latest edition)
- ITU-T Recommendation I.113
All calculations strictly follow the formulas and unit definitions provided by these sources.
The formula explained
\[ t = \frac{S_{\text{bits}}}{R_{\text{eff}}} \quad\text{with}\quad S_{\text{bits}} = S_{\text{bytes}} \times 8,\; R_{\text{eff}} = R_{\text{raw}} \times \left(1 - \frac{\text{overhead\%}}{100}\right) \]
\[ S_{\text{bytes}} = \begin{cases} \text{value}\times 10^6 & \text{MB} \\ \text{value}\times 10^9 & \text{GB} \\ \text{value}\times 10^{12} & \text{TB} \\ \text{value}\times 2^{20} & \text{MiB} \\ \text{value}\times 2^{30} & \text{GiB} \\ \text{value}\times 2^{40} & \text{TiB} \end{cases} \quad;\quad R_{\text{raw}} = \begin{cases} \text{Mbps}\times 10^6 & (\text{bits/s})\\ \text{MB/s}\times 8\times 10^6 & (\text{bits/s}) \end{cases} \]
Glossary of variables
| Symbol / Field | Meaning |
|---|---|
| S (File size) | The total payload to upload, selectable in MB/GB/TB or MiB/GiB/TiB. |
| Rraw (Raw link rate) | Advertised upload speed from ISP or speed test (Mbps or MB/s). |
| Overhead% | Percentage of bandwidth used by headers, encryption, framing. |
| Reff (Effective throughput) | Actual payload rate after overhead. |
| t (Time) | Estimated upload duration (seconds; also shown as hh:mm:ss). |
How it works: a step-by-step example
Example: Uploading a 12 GB video at 100 Mbps (HTTP/TLS ~7% overhead)
- Convert 12 GB to bytes: \(12\times 10^9 = 12{,}000{,}000{,}000\ \text{bytes}\).
- Convert to bits: \(12{,}000{,}000{,}000\times 8 = 96{,}000{,}000{,}000\ \text{bits}\).
- Raw rate: \(100\ \text{Mbps} = 100\times 10^6\ \text{bits/s}\).
- Effective rate: \(R_{\text{eff}} = 100\times 10^6 \times (1 - 0.07) = 93\times 10^6\ \text{bits/s}\).
- Time: \(t = 96\times 10^9 / 93\times 10^6 \approx 1032.26\ \text{s} \approx 17\ \text{min} 12\ \text{s}\).
FAQ
Why are some calculators wrong by 8×?
They confuse bits with bytes. Remember: 1 byte = 8 bits. We explicitly convert and show both units to avoid this pitfall.
Should I pick MB/GB or MiB/GiB?
Use MB/GB if your tool shows decimal units. If you see MiB/GiB in your app, choose the binary option to match exactly.
What overhead applies to S3/Drive/Dropbox?
5–10% is a practical range. Start at 7%. For well-optimized multipart uploads, 5% is often reasonable.
Wi-Fi vs Ethernet — does it matter?
Yes. Wi-Fi retransmissions and interference reduce throughput. Ethernet is typically more consistent.
Server throttling?
Some services cap per-connection rates. Your line may be fast, but the server may limit speed, increasing upload time.
Formula (LaTeX) + variables + units
t = \frac{S_{\text{bits}}}{R_{\text{eff}}} \quad\text{with}\quad S_{\text{bits}} = S_{\text{bytes}} \times 8,\; R_{\text{eff}} = R_{\text{raw}} \times \left(1 - \frac{\text{overhead\%}}{100}\right)
S_{\text{bytes}} = \begin{cases} \text{value}\times 10^6 & \text{MB} \\ \text{value}\times 10^9 & \text{GB} \\ \text{value}\times 10^{12} & \text{TB} \\ \text{value}\times 2^{20} & \text{MiB} \\ \text{value}\times 2^{30} & \text{GiB} \\ \text{value}\times 2^{40} & \text{TiB} \end{cases} \quad;\quad R_{\text{raw}} = \begin{cases} \text{Mbps}\times 10^6 & (\text{bits/s})\\ \text{MB/s}\times 8\times 10^6 & (\text{bits/s}) \end{cases}
\[ t = \frac{S_{\text{bits}}}{R_{\text{eff}}} \quad\text{with}\quad S_{\text{bits}} = S_{\text{bytes}} \times 8,\; R_{\text{eff}} = R_{\text{raw}} \times \left(1 - \frac{\text{overhead\%}}{100}\right) \] \[ S_{\text{bytes}} = \begin{cases} \text{value}\times 10^6 & \text{MB} \\ \text{value}\times 10^9 & \text{GB} \\ \text{value}\times 10^{12} & \text{TB} \\ \text{value}\times 2^{20} & \text{MiB} \\ \text{value}\times 2^{30} & \text{GiB} \\ \text{value}\times 2^{40} & \text{TiB} \end{cases} \quad;\quad R_{\text{raw}} = \begin{cases} \text{Mbps}\times 10^6 & (\text{bits/s})\\ \text{MB/s}\times 8\times 10^6 & (\text{bits/s}) \end{cases} \]
- No variables provided in audit spec.
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https://calcdomain.com/subcategories/miscellaneous - BIPM — SI Brochure — bipm.org · Accessed 2026-01-19
https://www.bipm.org/en/publications/si-brochure - ITU-T Recommendation I.113 — itu.int · Accessed 2026-01-19
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Last code update: 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.