Estimate downloads, uploads and backups
- Choose transfer time, required speed or transferable size.
- Enter the two known quantities and select their explicit units. Valid unit changes preserve the quantity.
- Optionally adjust effective speed. This is your assumption, not a speed test.
- Read and copy the estimate with its units and assumptions.
Formats, output and limits
Local decimal inputs only. No file selection or transfer. Size up to 1 PiB, speed up to 1 Pbit/s and time up to 1 trillion seconds. At most 128 characters per input. Decimal/binary byte units and bit/s or byte/s speeds are distinct.
A worked example
1 GB contains 8,000,000,000 bits. At 100 Mbps, ideal time is 80 seconds. At 80% effective speed, the estimate is 100 seconds. 1 GiB at the same nominal speed instead takes 85.89934592 seconds at 100%.
Common questions
Is Mbps the same as MB/s?
No. A byte is eight bits: 100 Mbps equals 12.5 MB/s. Decimal GB is 1,000,000,000 bytes; binary GiB is 1,073,741,824 bytes.
Does this measure my connection?
No. It calculates from your entered speed. Real transfers also depend on servers, contention, devices and protocols. Effective speed is an explicit assumption.
Why is a unit conversion unavailable?
Size and rate conversions retain exact quantities. Some time conversions need a repeating decimal, such as one second in minutes. Keep the original unit for an exact value.