Convertisseur de taille de données

What the data size converter does

This converter translates a quantity of digital data from one unit to another — bytes, KB, MB, GB, TB and PB — and, crucially, lets you choose whether the units are decimal (powers of 1000) or binary (powers of 1024). Enter a value, pick its unit, choose the standard, and it shows the equivalent across every scale. You reach for it whenever a number doesn’t line up: your operating system reports a “1 TB” drive as 931 GB, a hosting quota is stated in one convention and your usage graph in another, a database row estimate needs turning into gigabytes, or you are sizing a download, a backup, or a monthly traffic allowance and want the arithmetic done correctly rather than in your head.

Decimal vs binary: the root of all confusion

There are two coexisting standards for what a “kilobyte” means, and mixing them is the source of nearly every data-size discrepancy. The decimal (SI) convention says 1 KB = 1000 bytes, 1 MB = 1000 KB, and so on — each step multiplies by 1000. The binary (IEC) convention, properly written KiB/MiB/GiB, says 1 KiB = 1024 bytes, 1 MiB = 1024 KiB — each step multiplies by 1024, matching how memory is addressed. The gap is small at first (1024 vs 1000 is 2.4%) but compounds at every level: it is about 5% at the megabyte, ~7% at the gigabyte, and roughly 10% by the terabyte. That is precisely why a drive marketed as 1 TB (1,000,000,000,000 decimal bytes) shows up as ~931 GiB in an operating system that counts in binary but still writes the label “GB.” Storage vendors and networking use decimal; RAM and many operating systems use binary. This tool makes the choice explicit so you always know which one you are getting.

Worked examples

• 1536 bytes = 1.536 KB decimal, or exactly 1.5 KiB binary — a clean illustration of the two conventions side by side.
• A 4 GB (decimal) file is about 3.73 GiB, which is why it may not fit where you expected on a binary-counted volume.
• A 500 GB monthly allowance converts to 0.5 TB decimal, handy when a cap is quoted in one unit and metered in another.

Tips and gotchas

The biggest trap of all lives one level below this tool: bits versus bytes. Network and connection speeds are quoted in bits per second (Mbps, Gbps), while file sizes are in bytes — and one byte is eight bits. So a “100 Mbps” link delivers at most about 12.5 MB per second, not 100; forgetting the factor of eight is the classic reason a download “feels” slower than the advertised speed. Two more habits worth keeping: when you see a plain “GB” label, check which standard the source actually uses before trusting a comparison, and prefer the explicit KiB/MiB/GiB spelling in your own documentation so nobody has to guess. Converting your VPN or proxy usage into consistent units also makes it far easier to sanity-check a traffic figure — you can cross-reference the connection details on our IP check and read plan terms on the VPN page.

All local, nothing uploaded

This converter is pure client-side JavaScript: the value you type is calculated on your own device and never sent to, stored on, or logged by any server. There is nothing to upload and no account to create — open the page, convert, done. It is a small tool, but the same privacy principle applies to every utility on s4m: your input stays with you.