What’s the difference between Mbps and MB/s?

Mbps is megabits per second; MB/s is megabytes per second. 1 byte = 8 bits. Network speeds are usually advertised in Mbps.

What concurrency should I use?

Concurrency is the share of users active at once. Homes often see 30–50%; busy offices peak higher. Use a conservative value to avoid congestion.

What is protocol efficiency?

It’s the fraction of link capacity available to payload after overhead (TCP/IP headers, Wi-Fi/ethernet framing). Typical 70–95%, depending on medium and conditions.

Why add a safety margin?

Bandwidth demand is spiky. A margin helps absorb peaks, background updates, and QoS variability so apps stay smooth.

Does upload speed matter for video calls?

Yes. Video conferencing needs both downlink and uplink. Ensure the upload requirement meets or exceeds your codec’s bitrate.

Will Wi-Fi reduce my real throughput?

Often yes. Shared medium, signal quality, and interference lower efficiency versus wired links. Prefer ethernet for critical tasks.

How accurate is file transfer time?

It’s an estimate. Real times vary with server limits, congestion, disk speed, and protocol behavior (e.g., TCP slow start).

Bandwidth Calculator — Estimate Internet Speed Needs & File Transfer Time

Professional bandwidth calculator: estimate household or office internet speed needs by activities and users, plus compute file transfer time with protocol overhead and efficiency.

Activity-based bandwidth

Define the active activities and how many concurrent users participate. The calculator sums traffic and applies concurrency, margin, and efficiency assumptions.

Activity	Download (Mbps)	Upload (Mbps)	Users	Action

Concurrency (%)

Safety margin (%)

Protocol efficiency (%)

File transfer target

File transfer time

File size

Unit

Link speed (Mbps)

Transfer efficiency (%)

Required bandwidth (after safety margin)

—

Download required —

Upload required —

Plan suggestion —

File transfer estimate

Transfer time —

Effective throughput —

Calculation steps

—

Assumptions

Concurrency: 40%
Safety margin: 25%
Efficiency: 85%

How to use

Add the activities you expect on the network, specifying how many people use each simultaneously and what each activity consumes in Mbps. The calculator combines concurrency, margin, and efficiency assumptions to produce a recommended downlink/upload target and a friendly plan suggestion.

For a file transfer estimate, enter the file size, desired direction, and link speed plus protocol efficiency to see how long the transfer will take and the effective throughput.

Methodology

Activity-based demand multiplies each activity’s bitrate by the number of concurrent users, then scales the sum by the assumed concurrency rate, safety margin, and protocol efficiency. The result rounds up to common plan tiers for ease of purchasing.

File transfer times convert the file size to bits, adjust for the efficiency of the protocol, and divide by the ambient link throughput to produce a deterministic hh:mm:ss estimate.

Formulas

Activity-based bandwidth:

\[B_{\text{req}} = \frac{\alpha}{\eta}\; \Big( c \cdot \sum_{i=1}^{N} n_i \; r_i \Big)\]

\(n_i\): concurrent users on activity \(i\)
\(r_i\): bitrate required for activity \(i\)
\(c\): concurrency fraction (percent / 100)
\(\alpha = 1 + \text{safety margin}\)
\(\eta\): protocol efficiency fraction

File transfer time:

\[ t = \frac{S_{\text{bits}}}{R_{\text{link}} \cdot \eta} \quad,\quad S_{\text{bits}} = S \times \kappa \]

\(S\): file size in selected unit
\(\kappa\): bytes per unit (e.g., GB = \(10^9\) B)
\(R_{\text{link}}\): link speed in bits/s
\(\eta\): transfer efficiency

Citations

IEC — https://www.iec.ch/ (accessed 2026-01-19)
RFC-editor — https://www.rfc-editor.org/rfc/rfc6349 (accessed 2026-01-19)
ITU — https://www.itu.int/ (accessed 2026-01-19)

Changelog

0.1.0-draft — 2026-01-19: Initial audit-spec draft and code consolidation.

✓ Verified by Ugo Candido

Last Updated: 2026-01-19

Version 1.5.0