How to convert MB to KB
- 1 Type a value in the megabytes box; the kilobytes appear as you type.
- 2 Or type in the kilobytes box to convert the other way.
- 3 Choose decimal (1,000) or binary (1,024).
- 4 Use the conversion table for common values.
Meeting upload limits
Forms state limits in KB or MB and usually mean decimal units. If your file is just over the limit, compress it rather than renaming or zipping it. For bigger sizes, use GB to MB; for every unit at once, the Data Storage Converter.
- Scanned documents saved as images are often larger than needed; reduce the resolution.
- A limit of 2 MB is 2,000 KB in decimal units.
- Keep a copy of the original before compressing.
Features
Decimal or binary
Switch between 1,000 and 1,024; the chart updates too.
Two-way
Type KB to get MB.
Upload sizes
Chart includes common limits such as 2 MB and 5 MB.
When to use it
Upload forms
A form that accepts up to 500 KB will reject a 0.6 MB file. To make an image smaller, use the Image Compressor.
Email attachments
Many email services limit attachments to 20 or 25 MB, which is 25,000 KB.
Photos
A 2.4 MB photo is 2,400 KB in decimal units, or about 2,458 KiB in binary.
Reading file properties
Windows shows sizes in binary units labelled KB, so a 1 MB file may show as 977 KB.
Related Unit tasks
Frequently asked questions
How many KB is 1 MB?
1,000 KB in decimal units, or 1,024 KiB in binary units.
Which one should I use?
Use decimal for storage devices, cloud plans and most websites. Use binary to match sizes shown in Windows File Explorer.
How many KB is 5 MB?
5,000 KB in decimal units, or 5,120 KiB in binary.
How many MB is 500 KB?
0.5 MB in decimal units, or about 0.49 MiB in binary.
Why does Windows show a different size?
Windows divides by 1,024 but labels the result KB and MB, so its numbers look smaller than the decimal sizes used by makers and websites.
What is a KiB?
A kibibyte, 1,024 bytes. It is the correct name for the binary kilobyte.
Is kb the same as KB?
No. A lower-case b means bits. 1 KB is 8 kb, so internet speeds in kbps are eight times smaller in bytes.
How do I make a file under 100 KB?
Compress the image or PDF, reduce its dimensions or save at a lower quality. Our image and PDF tools can target sizes such as 100 KB.
Does the converter upload my file?
No. It only converts numbers you type; no file is needed or sent.
Why do websites set upload limits?
Small files load faster, cost less to store and are safer for the server to process. Forms for passports, exams and jobs often set strict limits so that thousands of uploads stay manageable.
How can I check the size of a file?
On Windows, right-click the file and choose Properties. On a Mac, select it and press Command and I. On a phone, the file manager or gallery details show the size.
Why do photos from my phone exceed upload limits?
Modern phone cameras capture very detailed images, often several megabytes each. Most forms only need a small, clear picture, so compressing or resizing before upload is normal and does not affect how it looks on screen.
Do PDF files count the same way?
Yes. A document's size is measured in the same units whatever its format, so a PDF limit of five hundred kilobytes means the same as for an image.
Built and reviewed by Hamza Farooq, founder and lead developer
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