LineaChiara

Convert Mbps, MB/s and MiB/s.

Your speed test shows Mbps, while a file download may show MB/s or MiB/s. They express speed in different units. Compare them here and turn a speed into an estimated time for a file.

By PHABDEV ·

Convert a speed and choose your file size

Mbps
100
MB/s
12.5
MiB/s
11.9209

Theoretical transfer time: 5 min 20 s

Calculated at the entered constant speed. This is not a measured download or upload.

1 GB = 1,000,000,000 bytes. You can leave inputs empty: unavailable results are shown as —. Nothing is downloaded or uploaded by this calculator.

What is the difference between Mbps, MB/s and MiB/s?

A lowercase b means bits; an uppercase B means bytes. One byte contains 8 bits. Mbps means millions of bits per second; MB/s means millions of bytes per second. MiB/s uses mebibytes: one MiB contains 1,048,576 bytes.

For example, 100 Mbps equals 12.5 MB/s, or about 11.92 MiB/s. The smaller number does not mean your connection became slower: the unit changed. MBs and MiBs are informal spellings; we use MB/s and MiB/s to make “per second” clear.

The conversion formulas

  • Mbps to MB/s: divide by 8.
  • Mbps to MiB/s: divide by 8.388608.
  • MB/s to Mbps: multiply by 8.
  • MiB/s to Mbps: multiply by 8.388608.
  • Transfer time in seconds: GB × 8,000 ÷ Mbps.

We use decimal GB: 4 GB is 4 billion bytes. A 4 GiB file is larger; check the unit shown by your software. Calculations use the full value and round only the displayed result.

How long does a 4 GB download take?

Constant-speed examples for a 4 GB decimal file
MbpsMB/sMiB/sTheoretical time
101.251.192153 min 20 s
10012.511.92095 min 20 s
30037.535.76281 min 47 s
1000125119.209332 s

At a constant 100 Mbps, the calculation is 4 × 8,000 ÷ 100 = 320 seconds, or 5 minutes and 20 seconds. To estimate sending a file, use your upload speed: download speed does not tell you how quickly you can upload.

Why an actual transfer may take longer

This is constant-speed arithmetic, not a guaranteed countdown. The file server, Wi-Fi, other transfers, connection startup and changes in speed can increase the actual time. An advertised plan speed is not a measurement of the speed available right now.

For a measured reference, run a LineaChiara test. Its summary shows a 4 GB estimate only from the latest completed test with usable data; it never substitutes an older result when the latest test is incomplete. Measurements describe the path to the test server, not every Internet service.

A unit conversion does not assess stability. Fast downloads can coexist with irregular response times. Read speed, latency and jitter together.

Put the checks into practice

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Method and references

LineaChiara measurement method and limitations

These checks help narrow down a problem; they are not a guarantee of its cause. Suggest a correction.

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