Convert Megabytes (MB) to Kilobytes (KB)

The formula for MB to KB

In binary units, 1 MB equals 1024 KB, so you multiply the MB value by 1024 to get KB. For example, 5 MB is 5 × 1024 = 5120 KB, and 10 MB is 10 × 1024 = 10240 KB. Decimals work the same, so 0.5 MB becomes 0.5 × 1024 = 512 KB. The 1024 constant comes from computers counting in powers of two (2^10), not a round 1000. That's why 2 MB is exactly 2048 KB rather than 2000 KB.

When you actually need this

You use it when an upload limit is set in KB and you need to know your file's size. If a government site says 'attachments up to 2048 KB,' you check whether your 2 MB file fits exactly. When an image compressor reports results in KB, converting your original MB shows how much you saved. Setting a KB budget for resources like web fonts or icons means translating MB-sized assets down. Game mods and config files that demand precise KB values also rely on this conversion.

Reference points and a common gotcha

Memorizing 1 MB = 1024 KB, 2 MB = 2048 KB, and 5 MB = 5120 KB covers most cases. The gotcha is that some programs display in decimal, treating 1 MB as 1000 KB. So the same 2 MB file can appear as 2000 KB or 2048 KB depending on the tool. Your operating system's file explorer usually uses 1024, matching this calculator. When a single KB decides whether an upload succeeds, computing precisely in binary is the safe choice.

Frequently asked questions

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