Download and Upload Time Calculator
Works out a transfer time from a file size and a line speed.
Transfer time
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Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
In other units —
With no overhead —
Effective speed — MB/s
The formula
time = size × 8 ÷ (speed × (1 − overhead))
Multiplying by 8 turns bytes into bits. Time depends on the slowest part of the path, which is often the far server or Wi-Fi rather than your line.
What to watch out for
The overhead allows for protocol headers, retries and the line running below its sold speed. Measure your real speed for a closer figure.
Frequently Asked Questions
How long does 50 GB take on 100 Mbit/s?
About 1 h 14 min 4 s with 10% overhead, and 1 h 6 min 40 s with none.
Why is my upload so much slower?
Many home lines have far less upload speed than download speed. Enter the upload figure from a speed test.