What Bandwidth Calculator helps you do

Estimate how long a file transfer will take after accounting for data size, link speed and protocol overhead. It gives a realistic estimate rather than a best-case divide, because the overhead percentage reduces the effective rate. Size units include both decimal MB/GB/TB and binary MiB/GiB/TiB, and speed can be entered in bits or bytes per second.

Transfer math runs in your browser. No data or speeds are uploaded to Haivix.

How it works

Most tools here are offline calculators: the address math, RAID capacity, permission bits, TCP window sizing and transfer-time estimate all run in your browser with no request. The RDAP lookup is the exception, because registration data lives in public registries and the domain must be sent to a lookup service. Unit conventions matter throughout: a megabyte may mean 1,000,000 or 1,048,576 bytes, and a megabit is always one eighth of a megabyte. These are reference models, not live checks, so a port can be listed without a service running, a permission mode can be valid without being appropriate, and a RAID estimate can differ from formatted capacity.

How to use Bandwidth Calculator

Enter the file size and choose its unit.
Enter the link speed and choose the speed unit.
Set a realistic overhead percentage.
Read the estimated duration and effective Mbps.

When to use it

Estimate how long a large upload or backup will run.
Estimate a transfer window for a maintenance task.
Sanity-check a quoted transfer time from a provider.
Compare a wired and a Wi-Fi estimate for the same file.
Plan a migration window with a safety margin.
Explain the difference between line rate and file rate.

When not to use it

Do not treat the estimate as a guarantee; congestion and server limits change it.
Do not ignore storage speed on a local copy.
Do not use it for a multi-stream transfer without adjusting the effective rate.

Example

A 10 GB file over a 100 Mbps link with 5% overhead has an effective rate of 95 Mbps. The transfer takes 80,000,000,000 bits divided by 95,000,000 bits per second, about 842 seconds, or roughly 14 minutes. At 1 Gbps the same file takes about 84 seconds.

What you can do with Bandwidth Calculator

Estimate transfer time from size and speed.
Mix decimal and binary size units.
Accept Mbps, Gbps, MBps or GBps.
Apply a protocol overhead percentage.
Format the duration in days, hours, minutes and seconds.
Run the estimate locally in the browser.

Example: check the model against the live system

Note the unit convention before comparing figures. Mbps and MB/s differ by a factor of eight, and MB and MiB differ by about 5 percent.

Treat a lookup as a starting point. A port reference, a permission mode and a RAID calculation all describe expectations, not the state of a running host.

Confirm on the system itself where it matters: ss or netstat for listeners, ls -l for permissions, the controller utility for array status.

Keep RAID in perspective. It protects against a disk failure, not against deletion, corruption, ransomware or a lost site.

Record the inputs alongside the result so a later comparison uses the same assumptions.

Check the time unit on latency. A round-trip time is usually milliseconds, and entering seconds changes the bandwidth-delay product by a factor of a thousand.

Treat registry data as a snapshot. RDAP records can be redacted, cached or updated after a transfer, so confirm ownership and expiry with the registrar.

What to know before you start

It is an estimate and cannot account for real-world congestion or server limits.
It assumes a sustained rate; many links slow down under load.
The overhead is a single percentage rather than a protocol model.
It does not include connection setup, retransmissions or encryption cost.

Common mistakes

Confusing MB/s with Mbps and losing the factor of eight.
Using a binary unit for a decimal size.
Forgetting the overhead and underestimating the time.
Assuming the link runs at its nominal rate all the way to the server.

Troubleshooting

If the result is eight times off, check whether the speed is in bits or bytes.

If the overhead is rejected, it must be below 100%.

If the duration is implausibly short, the size unit may be decimal when binary was intended.

If the real transfer is slower, the bottleneck may be storage, latency or the remote end.

Bandwidth Calculator