Plan a transfer from bytes and a scoped upload speed
Upload Time calculates a payload-transfer scenario from file size, byte unit and upload Mbps. A local file picker reads only its size. The optional receiver test uses a generated body rather than the selected file, its name or the planning inputs.
Start with the units
One byte contains eight bits. MB and GB use powers of 1,000; MiB and GiB use powers of 1,024. Ideal seconds equal file bytes times eight divided by upload Mbps times 1,000,000. At an entered 20 Mbps, 1 decimal GB gives 400 seconds, while 1 GiB gives about 429.5 seconds.
Treat the working fraction as your scenario
- Use upload speed rather than download speed or MB/s. Check the file-size unit before calculating.
- Choose a working fraction between 50% and 100%. A lower percentage adds scenario time; it is not automatically measured overhead.
- Read the planning markers as portions of the estimate. Setup, retries, fluctuating throughput and processing can add time outside the calculation.
Use a confirmed probe only within its scope
With explicit consent and an enabled receiver, the browser can send one synthetic 1 MiB POST to this site's own HTTPS address. It times request start through the complete receiver response and accepts a speed only after the receiver confirms the exact byte count, discarded body, approved origin and measurement scope. A failed or unavailable test supplies no accepted speed; manual planning remains available. A pass has finite byte, time and fragment bounds, with two concurrent tests and 20 starts per hour per runtime isolate.
Keep the limit in view
A short browser-to-Cloudflare burst includes setup, round-trip latency, slow start and the response. It does not establish sustained ISP capacity or speed to another upload destination. The calculator cannot inspect live upload progress, a server queue or video-processing time. The receiver starts disabled until the operator approves its real runtime check.