Download Time Calculator
A download time calculator estimates transfer time from a file size and connection speed, correctly handling the common mismatch where file sizes are quoted in megabytes (MB) but connection speeds are quoted in megabits per second (Mbps) — an 8x difference if not converted. ISPs advertise connection speed in megabits per second specifically because the larger unit makes the number look bigger, while file sizes are conventionally shown in megabytes — remembering the 8x relationship between the two units is the single most common point of confusion this tool exists to remove.
How it works
- Enter the file size in megabytes (MB).
- Enter your connection speed in megabits per second (Mbps) — as most ISPs advertise it.
- Read the estimated download time.
Formula time (seconds) = (file size in MB × 8) ÷ speed in Mbps
Frequently asked questions
Why multiply the file size by 8?
File sizes are conventionally shown in bytes (MB); connection speeds are conventionally shown in bits per second (Mbps). Since 1 byte = 8 bits, the file size in bits is 8× the number in MB.
Why does my actual download take longer than this estimate?
This assumes you get the full advertised speed with no overhead — real-world downloads are affected by server speed, network congestion, Wi-Fi signal, and protocol overhead.
What speed should I enter — the number my ISP advertises?
Yes, if it's in Mbps (the usual unit ISPs advertise). If you measured your actual speed with a speed test that shows MB/s instead, multiply by 8 first to get Mbps.
Does this account for multiple simultaneous downloads?
No — it assumes the full connection speed is available to this one transfer.
What connection speed should I assume if I don’t know mine?
A reasonable modern broadband estimate is 50-100 Mbps, but actual speeds vary widely by provider and plan — run a speed test for an accurate number rather than guessing.