Utility

File Size Converter

Enter a file size value and unit to see it instantly converted across bytes, KB, MB, GB, and TB. Choose between 1024-based (binary) or 1000-based (decimal/SI) calculations to match how you need to report the size.

  • Files never leave your device
  • Runs entirely in your browser
  • Free, no account needed
Use File Size Converter - free

How to use File Size Converter

  1. 1

    Open the File Size Converter

    Go to tools.slaytic.com and open the File Size Converter. No sign-up or account required.

  2. 2

    Enter a value and unit

    Type the size and choose whether it is in bytes, KB, MB, GB or TB.

  3. 3

    Pick binary or decimal

    Choose 1024-based to match operating systems, or 1000-based to match manufacturer specifications.

  4. 4

    Read all five units

    The value is converted across every unit at once for comparison.

How this works in your browser

The input is normalised into a plain byte count using the multiplier you selected, then divided back out into each unit for display. Routing everything through a single byte value is what keeps the conversions internally consistent and makes the choice of base a single decision rather than something applied inconsistently at each step. The two bases exist because the prefixes were borrowed from the metric system, where they mean powers of a thousand, and then applied to computing, where powers of two are what hardware naturally works in. Neither convention is wrong, and the discrepancy compounds with each step up, which is why it is invisible at kilobytes and impossible to ignore at terabytes.

File Size Converter vs. traditional online converters

FeatureFile Size Converter (in-browser)Traditional online converters
File upload requiredNo - never leaves your deviceYes - file is sent to a server
Processing queueNone - starts instantlyOften, especially at peak times
Watermark on outputNeverCommon on free plans
Usage limitsNone - free, unlimited useOften capped per day or file size
Works offline once loadedYes, for most toolsNo - requires a live connection
Account requiredNoOften, for anything beyond a trial

Who uses File Size Converter

Understanding drive capacity

Reconcile the number on the box with what your computer reports.

Checking upload limits

Convert a stated limit into the unit your file size is displayed in.

Planning storage and backups

Work out how much space a set of files will actually need.

Server and hosting specifications

Translate quoted allowances into comparable units.

Frequently asked questions

What is the difference between 1024-based and 1000-based?

Operating systems traditionally use 1024 (binary), while storage manufacturers and some modern conventions use 1000 (decimal, SI) - this explains why a 1TB drive shows less space in your OS.

Which should I use?

Use 1024-based to match how most operating systems report file and disk sizes; use 1000-based to match manufacturer specifications.

Can I convert very large or very small values?

Yes, any positive numeric value is supported across all five units.

Why does my 1TB drive show as 931GB?

Because the manufacturer counted in thousands and your operating system counts in 1024s. The drive genuinely holds a trillion bytes, but dividing that by 1024 three times gives 931, not 1000. Nothing is missing and nothing is misleading; the two are simply using different definitions of the same prefix.

What are GiB and MiB?

The unambiguous binary units, gibibyte and mebibyte, introduced precisely to end this confusion. A GiB is 1024 cubed bytes and a GB should strictly be 1000 cubed. Linux tools and technical documentation use them; consumer software largely does not, which is why the ambiguity persists.

Which convention should I use?

Match whoever will read the number. Use 1024-based to line up with what Windows and macOS report to a user, and 1000-based to match a drive specification, a hosting plan or a bandwidth allowance. Stating which one you used avoids the argument entirely.

Why does the gap grow with larger units?

Because the discrepancy compounds at each step. It is around 2.4 percent at kilobytes and roughly 10 percent by terabytes, which is why nobody argues about a kilobyte and everybody notices on a hard drive.

Convert file sizes instantly - free.

Open File Size Converter
  • Files never leave your device
  • No upload required
  • No account needed
  • Unlimited use, always free