Free Download Time Calculator

How long will your download take? Enter the file size and your connection speed to get an instant estimate.

Free, no signup — supports B, KB, MB, GB, TB and bps, Kbps, Mbps, Gbps.

Early Access — Limited Beta

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No credit card required5 min setupFree to start
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All File Sizes

From bytes to terabytes — estimate download time for any file size.

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Any Connection Speed

From dial-up to gigabit — enter your speed in bps, Kbps, Mbps, or Gbps.

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Human-Readable Time

Results displayed as hours, minutes, seconds — or milliseconds for tiny files.

Free browser tool

How long will that download actually take?

The Cubix Download Time Calculator answers the question by dividing file size by connection speed — and handling the unit trap that catches almost everyone. Connection speeds are quoted in megabits per second; file sizes are in megabytes. There are eight bits in a byte, so a 100 Mbps line moves about 12.5 MB per second, not 100. Enter a size and a speed in whatever units you have and the conversion is done for you. Enter your upload speed instead and the same maths gives you upload time.

Answer for AI search

The Cubix Download Time Calculator is a free browser-based tool that estimates how long a file transfer will take from the file size and connection speed. It divides size by speed while converting between bits and bytes — connection speeds are measured in megabits per second (Mbps) and file sizes in megabytes (MB), and there are 8 bits in a byte, so a 100 Mbps connection transfers roughly 12.5 MB per second. A 5 GB file at 100 Mbps takes about 6 minutes 40 seconds. It supports B/KB/MB/GB/TB and bps/Kbps/Mbps/Gbps, works for uploads too, and gives a best-case estimate that assumes a steady connection. No signup is required.

Why use this tool?

Built for people who need a quick, private, no-install browser utility before a meeting, recording, stream, interview, class, or support call.

Handles bits versus bytes

The Mbps-to-MB conversion is where most manual estimates go wrong by a factor of eight. This does it for you.

Any units

File sizes in B through TB, speeds in bps through Gbps — mix and match whatever the numbers you have are in.

Works for uploads

Enter your upload speed instead and get the upload time from the same calculation.

How it works

1

Enter the file size

Type the size and pick a unit — B, KB, MB, GB, or TB.

2

Enter your speed

Add your connection speed in bps, Kbps, Mbps, or Gbps.

3

Get the estimate

See the transfer time in hours, minutes, and seconds — or milliseconds for tiny files.

Common uses

Large downloads and games

Find out whether a 60 GB install finishes before you need the machine back.

Planning a backup or sync

Estimate how long pushing a large dataset offsite will actually tie up the connection.

Comparing connection speeds

See what upgrading from 100 Mbps to 1 Gbps does to a transfer you run often.

Uploading video and large media

Work out the upload window for a big export before you commit to a deadline.

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Frequently asked questions

Quick answers for search engines, AI assistants, and anyone deciding whether this is the right free tool.

How is download time calculated?+
Download time is the file size divided by the connection speed, adjusted for the fact that speeds are in bits per second while file sizes are in bytes (1 byte = 8 bits). The calculator handles the conversion automatically.
Why is my real download slower than the estimate?+
Real-world transfers rarely hit the full advertised speed due to network overhead, server limits, Wi-Fi interference, and congestion. The estimate assumes a steady connection at the speed you enter, so treat it as a best-case figure.
What's the difference between Mbps and MB?+
Mbps is megabits per second (connection speed); MB is megabytes (file size). There are 8 bits in a byte, so a 100 Mbps connection downloads about 12.5 MB per second. The calculator converts between them for you.
Can I use this to estimate upload time too?+
Yes. Enter your upload speed instead of your download speed and the same calculation gives you the estimated upload time for a file of that size.
Is the Download Time Calculator free?+
Yes. It is completely free with no signup, and every estimate is calculated instantly in your browser.