Data & Storage · Bandwidth
Download Time & Bandwidth Calculator
Work out how long it takes to download or upload a file at a given speed — with realistic protocol overhead — or the speed you need to transfer something in a set time, or how much data a connection can move. Handles megabits vs megabytes and decimal vs binary file sizes, the two classic sources of confusion.
Also listed inNetworkingDeveloper / IT
Your inputs
Quick start — try a typical case
Internet plans are sold in megabits per second (Mbps); download managers show megabytes per second (MB/s) — 8 times smaller.
Your result Live
Download Time
1 h 14 min 4 s
50 GB at 100 Mbps with 10% overhead
- Without Overhead (theoretical)
- 1 h 6 min 40 s
- Effective Speed
- 90 Mbps = 11.25 MB/s
50 GB at common speeds
5 rowsHow this is calculated
Time = file size (bits) ÷ (speed × (1 − overhead)) · 1 byte = 8 bits · 1 MB = 1,000,000 bytes, 1 MiB = 1,048,576 bytes
- Mbps vs MB/s
- Megabits vs megabytes per second — divide Mbps by 8 for MB/s
Connection speeds are quoted in bits per second, file sizes in bytes — and a byte is 8 bits, so a 100 Mbps line moves at most 12.5 MB a second. Real transfers are a bit slower than the line speed because network protocols use some of the bandwidth. Windows shows sizes in binary units (1 GiB = 1.074 GB), which makes files look smaller than the decimal size on the box.
Assumptions & sources
- Constant speed for the whole transfer; real speeds vary with Wi-Fi, server load and congestion.
- 1Definitions of the SI prefixes and binary prefixes (IEC 80000-13) — NIST — Prefixes for binary multiples
Calculator ID DATA-DOWNLOAD-001 · version 1.0.0
Common questions
How long does a 50 GB game take on 100 Mbps?
About 1 hour 14 minutes with 10 % overhead (66.7 minutes in theory).
Why is my download speed 8 times slower than my plan?
It isn't — plans are in megabits, downloads in megabytes. 100 Mbps ≈ 12.5 MB/s.
What speed do I need for a 4 GB movie in 10 minutes?
About 59 Mbps with 10 % overhead (53 Mbps in theory).