Choose the unknown
Calculate either ideal duration from size and rate or minimum sustained rate from size and target duration.
Download planning without unit guesses
Turn a file size and sustained rate into arithmetic you can inspect.
Enter the file size and sustained transfer rate to calculate an ideal duration, or enter a target duration to find the minimum sustained rate. DownloadTime keeps bits separate from bytes and GB separate from GiB. It does not test your connection, read a file, predict network conditions, or promise a wall-clock finish time.
Free · No signup · No network test · Runs in your browser
Three checkable steps
Choose units, supply two values, inspect the result
Read every symbol exactly
Select GB or GiB and Mbit/s or MB/s as printed; the capitalization and the letter i change the quantity.
Review the normalized arithmetic
Use the exact fraction and conservative rounding, then remember that real transfer conditions remain outside the estimate.
Three finite planning views
Answer one download question at a time
- Find the ideal duration for one known file size at one entered sustained rate.
- Find the minimum sustained line rate needed to transfer a known size within a target duration.
- Compare a reviewed set of common decimal sizes and rates in one static reference table.
Bring the size and sustained rate
Calculate a duration you can explain
Enter the units exactly as reported and keep the theoretical line-rate result separate from real network behavior.