Download Time Calculator

A 90 GB game on a 100 Mbps connection. Go make dinner. Then go make breakfast.

Use this free download time calculator to estimate how long a download will take. Enter the file size in GB and your connection speed in Mbps, and get the time in minutes — for game installs, OS updates, video files, and backups.

The confusion here is deliberate and industry-wide: files are measured in bytes, internet speeds in bits, and there are 8 bits in a byte. That factor of eight is why a "100 Mbps" connection downloads at about 12 MB/s and why everyone feels slightly cheated.

What This Download Time Calculator Does

Calculates download time in minutes from file size and connection speed
Handles the bits-to-bytes conversion so you do not have to
Useful for planning large game downloads, updates, and cloud backups
Works in reverse to sanity-check the speed your plan is actually delivering

How to Use the Download Time Calculator

Inputs:

Size — file size in GB
Speed — connection speed in Mbps (megabits per second), the number your ISP advertises

Steps:

Enter the file size in gigabytes
Enter your real download speed from a speed test, not the plan you pay for
Click Calculate for time in minutes
Divide by 60 for hours. Then add 10–20%, because no download sustains peak speed the whole way

How the Calculation Works

Megabits = Size (GB) × 1,024 × 8 Seconds = Megabits ÷ Speed (Mbps) Minutes = Seconds ÷ 60

8 bits = 1 byte, so divide Mbps by 8 for MB/s: a 100 Mbps line peaks near 12.5 MB/s
This calculator uses 1 GB = 1,024 MB (binary), matching how Windows and most game launchers report sizes
Quick estimate: GB ÷ (Mbps ÷ 8,000) seconds, or more simply, a 1 GB file takes about 80 seconds at 100 Mbps
Wi-Fi, ISP throttling, server limits, and other devices on the network all reduce real throughput below the line speed

Worked Example: 90 GB game on a 100 Mbps connection

Megabits = 90 × 1,024 × 8 = 737,280 Mb
Seconds = 737,280 ÷ 100 = 7,373 s
Minutes = 7,373 ÷ 60 = 123 minutes, about 2 hours
On a 500 Mbps line: 25 minutes. On 25 Mbps DSL: 8.2 hours. Same game, entirely different evening.

Tips (From People Who Have Made These Mistakes)

Run a speed test first. Real throughput is commonly 60–90% of the advertised plan, and worse over Wi-Fi at distance
Use Ethernet for anything over 20 GB. Wi-Fi typically loses 30–50% of available speed and drops packets under load
Game launchers and cloud backups often throttle by default — check their bandwidth settings before blaming the ISP
Data cap? Divide the cap by typical file sizes before a download spree. Three 90 GB games is 270 GB of a 1 TB monthly allowance

Frequently Asked Questions

How long does it take to download 100 GB?

At 100 Mbps, about 2.3 hours. At 500 Mbps, 27 minutes. At 1 Gbps, roughly 14 minutes — assuming the server can keep up, which is often the real limit.

Why is my download speed slower than my internet plan?

Because plans are advertised in megabits and downloads display megabytes — divide by 8. A 400 Mbps plan shows about 50 MB/s at best, minus Wi-Fi and overhead losses.

How do I convert Mbps to MB/s?

Divide by 8. 100 Mbps = 12.5 MB/s, 300 Mbps = 37.5 MB/s, 1 Gbps = 125 MB/s. This single division explains most internet complaints.

What internet speed do I need?

Streaming 4K needs about 25 Mbps per stream, video calls 3–5 Mbps, gaming very little bandwidth but low latency. Large downloads are the only common task that genuinely benefits from 500+ Mbps.

Does the calculator account for overhead?

No — it gives the theoretical best case at the speed you enter. Protocol overhead, Wi-Fi, and server limits typically add 10–20%, so treat the result as a floor.

Mini Roast Disclaimer

We roast the number, not you. Two hours is the download. The 40 minutes of "preparing to install" afterward is between you and the launcher.

Reality Check

Real downloads rarely sustain peak speed. Server capacity, network congestion, Wi-Fi interference, and other devices in the house all cut throughput, and some ISPs shape large transfers. Use the estimate for planning and expect 10–25% longer in practice.

Download Time Calculator

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