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File Size Converter

Utilities Free Updated 1 Sep 2026
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ⓘ About this tool 🔄 Last updated 1 Sep 2026 ✓ Reviewed by TopToolAI Team

Convert file sizes between bytes, KB, MB, GB and TB instantly — handy for checking storage space, upload limits, or download sizes. A 4.5MB photo converts to roughly 4,608 KB or 0.0044 GB — useful when an upload form quotes its limit in a different unit than the one your file manager shows.

How to use File Size Converter

Step-by-step guide to the boxes below. Open it only if you need help.
  1. 1
    Value Number

    Type the size as a number, for example 250.

  2. 2
    Unit Choose one

    Choose the unit that number is in right now. The other units are worked out from it.

    Choose one: BKBMBGBTB

  3. 3
    Check the result

    There is no button to press here, the result updates by itself while you type or choose.

  4. 4
    Read your result

    The same size is shown in every unit, so you can compare bytes, KB, MB, GB and TB. Change any box and try again to compare different numbers.

Go to the calculator

File Size Converter FAQs

Does this use 1000 or 1024 as the base?
It uses the standard binary base (1024), which is what operating systems typically use for file sizes.
Can I convert in either direction?
Yes, enter a value in any unit and see it converted across all the others at once.
Why does my OS show a different size than the download page?
Some platforms advertise file size using base-1000 (decimal) while operating systems display it in base-1024 (binary), causing small discrepancies.
What's the difference between MB and MiB?
MB technically means 1000 KB (decimal) while MiB means 1024 KiB (binary) — in casual use "MB" is often used to mean either.

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