Convert Megabytes to Kilobytes
Megabytes to kilobytes is handy when something is quoted in MB but the tool or limit in front of you counts in KB. Using the decimal convention that storage is sold in, one megabyte is exactly 1000 kilobytes, so the number grows by a thousand when you go from MB to KB.
Megabytes to Kilobytes conversion table
| Megabytes (MB) | Kilobytes (KB) |
|---|---|
| 1 | 1,000 |
| 2 | 2,000 |
| 3 | 3,000 |
| 5 | 5,000 |
| 10 | 10,000 |
| 20 | 20,000 |
| 50 | 50,000 |
| 100 | 100,000 |
| 500 | 500,000 |
| 1,000 | 1,000,000 |
The formula
To convert megabytes to kilobytes, multiply the size in megabytes by 1000:
kilobytes = megabytes × 1000
A worked example
Say an app's icon pack is 4.2 MB and an old upload tool wants the size in KB:
4.2 × 1000 = 4200 KB
Same digits, decimal point shifted three places right.
Decimal vs binary — the two rulers
Here we use the decimal (SI) rule: 1 MB = 1000 KB, the way drives and data plans are labelled. Operating systems often measure in binary, where what they call a "megabyte" is a mebibyte of 1024 kibibytes. That's why a 4.2 MB file (decimal) can read as about 4300 KiB inside your computer. Same file, different counting — worth knowing before you argue with an upload limit.
When you'll use it
Setting or reading upload caps that are written in KB, sizing images for a web page where budgets are given in kilobytes, or double-checking a hosting quota that lists everything in the smaller unit.
Frequently asked questions
How many kilobytes are in a megabyte?
Exactly 1000 in the decimal convention. To go from MB to KB you multiply by 1000.
Why does an upload form sometimes reject a file that 'should' fit?
Some tools measure in binary (1 MB = 1024 KB) while others use decimal (1 MB = 1000 KB). If a form's limit is set one way and your file size is read the other, a file right at the edge can be counted as too big.
Is the multiplication exact?
In the decimal convention, yes — you just move the decimal point three places to the right.