File Size Converter
Convert file size units between bytes, KB, MB and GB for uploads, downloads, storage and image optimization.
Last updated: July 3, 2026
How to use File Size Converter
- Enter a file size number.
- Select the starting unit: bytes, KB, MB or GB.
- Run the converter to see the equivalent value in all common file-size units.
What file size units mean
File sizes are commonly shown in bytes, kilobytes, megabytes and gigabytes. This converter uses a 1024-based calculation, which is the common practical standard used by many operating systems and file tools.
When this converter is useful
- Checking whether an image fits an upload limit.
- Comparing PDF, image or document file weights.
- Estimating storage space before downloading files.
- Converting KB, MB and GB values for simple reporting.
Related workflow
If a file is too large, use the Image Size Checker to inspect dimensions, Image Compressor to reduce photo weight or Compress Image to Target Size when a form requires a specific KB target.
Best for
Upload limits, image optimization, PDF checks, storage estimates and everyday file conversions.
Privacy note
This converter works from the number you enter. It does not upload a file.
FAQs
Is File Size Converter free?
Yes. The tool is free to use in your browser.
Does it upload my file?
No. This tool converts a number only and does not require a file upload.
Can I convert MB to KB?
Yes. Enter the MB value, choose MB, and the result shows the equivalent KB, bytes and GB values.
Why does this use 1024 instead of 1000?
Many file systems and everyday file tools use 1024-based units, so this converter follows that practical convention.