Convert data sizes between decimal KB, MB, GB and binary KiB, MiB, GiB in your browser. See the exact 1000 vs 1024 difference. Private, offline, and no uploads.
Runs entirely in your browser — your data never leaves your device.
How to use Data Size Converter
What it does & when you need it
Is your log file 4 MB or 4 MiB? Does a 500 GB drive really hold 500 gigabytes?
Data sizes are quietly ambiguous because two different unit families share
similar-looking abbreviations. This converter moves a value between decimal units
(KB, MB, GB, TB, PB — powers of 1000) and binary units (KiB, MiB, GiB, TiB, PiB —
powers of 1024) and shows the exact result, all in your browser.
How to use
Enter a number in the Value field.
Choose the From and To units, or press Swap to reverse them.
Read the converted amount in the result panel; the footer shows the same size
expressed in raw bytes.
Press Copy result or Ctrl/Cmd + Enter to copy the number.
Things worth knowing
Decimal and binary are not the same. One megabyte (MB) is 1,000,000 bytes,
while one mebibyte (MiB) is 1,048,576 bytes. So 1 MB is only about 0.9537 MiB — a
roughly 4.9% gap that compounds at every larger step, reaching about 10% by the
tebibyte range.
This is why your disk looks smaller. Drive manufacturers advertise capacity
in decimal GB, but many operating systems report the same bytes in binary units
while still writing "GB". A 500 GB drive is about 465.7 GiB, and that relabeling
is exactly the space that seems to vanish. Convert 500 GB to GiB here to see it
for yourself.
Where each unit belongs. Network speeds, drive marketing, and SI-based tools
use the decimal family; RAM, file sizes in many operating systems, and most
programming contexts use the binary family. Values are trimmed to about twelve
significant figures to avoid floating-point noise, and negative or non-finite
input is rejected. Working with raw byte counts in another base? Try the
Number Base Converter.
Examples
Decimal vs binary: MB to MiB
1 (MB → MiB)
One megabyte is 1,000,000 bytes, which is about 0.9537 mebibytes.
Binary back to decimal: GiB to GB
1 (GiB → GB)
One gibibyte is 1,073,741,824 bytes, which is about 1.0737 gigabytes.
The disk-marketing gap
500 (GB → GiB)
A 500 GB drive is about 465.66 GiB — the space that appears to go missing.
Frequently asked questions
What is the difference between MB and MiB?+
They use different bases. A megabyte (MB) is a decimal unit equal to 1,000,000 bytes (1000²), while a mebibyte (MiB) is a binary unit equal to 1,048,576 bytes (1024²). That is why 1 MB is about 0.9537 MiB — roughly a 4.9% gap that grows with each larger step (GB vs GiB, TB vs TiB).
Which units does the converter support?+
The decimal family B, KB, MB, GB, TB, and PB (powers of 1000) and the binary family KiB, MiB, GiB, TiB, and PiB (powers of 1024). You can convert freely within a family or across the two, for example GB to GiB or MiB to MB.
Why does my 500 GB drive show only about 465 GB free?+
Drive makers advertise capacity in decimal GB (500 × 1,000,000,000 bytes), but many operating systems report it in binary units while still labelling them "GB". 500 decimal GB is about 465.7 GiB, and that relabelling is exactly the missing space. Convert 500 GB to GiB here to see it.
How large or small a value can I convert?+
Any non-negative, finite number. Results are trimmed to about twelve significant figures to avoid floating-point noise, so very large or very small conversions still come out clean. Negative or non-finite input is rejected.
Is my input sent anywhere?+
No. The math runs entirely in your browser, so nothing you type is transmitted, and the converter keeps working offline once the page has loaded.