File Size Converter

Free File Size Converter calculator with clear step-by-step results.

About File Size Converter

File size conversion has two answers because there are two conventions. Operating systems and tooling generally report binary multiples of 1024, while drive manufacturers and network speeds use decimal multiples of 1000. The gap compounds with each step: it is 2.4% at the kilobyte and about 9.95% at the terabyte, which is exactly why a 1 TB drive shows as roughly 931 GB. Both results are shown so you can see which convention a figure came from.

Formulas

To bytes

Bytes = value × base^(exponent of source unit)

To target unit

Result = bytes ÷ base^(exponent of target unit)

Worked example

With the default values below, File Size Converter returns Converted Value of 1.464844. Change any input above and every figure here is recalculated in your browser.

Inputs used

Value to convertminimum 0: 1,500
Fromone of Bytes (B), Kilobytes (KB), Megabytes (MB), Gigabytes (GB), Terabytes (TB): Megabytes (MB)
Toone of Bytes (B), Kilobytes (KB), Megabytes (MB), Gigabytes (GB), Terabytes (TB): Gigabytes (GB)
Unit baseone of Binary — 1024 (KiB, MiB, GiB), Decimal — 1000 (SI, as drive vendors use): Binary — 1024 (KiB, MiB, GiB)

Results

Converted Value: 1.464844
Exact Size in Bytes: 1 GiB
Same Value in the Other Base: 1.572864
Conversion: 1500 MB = 1.464844 GB (base 1024)

Step by step

1Values used
2To bytes
3To target unit
4Converted Value= 1.464844
5Exact Size in Bytes= 1,572,864,000
6Same Value in the Other Base= 1.572864
7Conversion= 1500 MB = 1.464844 GB (base 1024)

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 6 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Reported sizes also depend on filesystem block size and metadata, so on-disk usage can exceed the logical file size shown here.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Reported sizes also depend on filesystem block size and metadata, so on-disk usage can exceed the logical file size shown here.

Frequently Asked Questions

Why does my 1 TB drive show 931 GB?

The manufacturer counts 1 TB as 1,000,000,000,000 bytes; the operating system divides by 1024 three times and calls the result GB. The same bytes, two conventions — nothing is missing.

What are KiB, MiB and GiB?

They are the unambiguous binary units defined by IEC: 1 KiB = 1024 bytes. KB strictly means 1000 bytes under SI, but is very widely used to mean 1024, which is why selecting the base explicitly matters.

Which base should I use?

Binary for RAM, file sizes reported by your OS and most software tooling. Decimal for storage device capacity, bandwidth and anything quoted by a vendor or ISP.