Data Storage Converter

Two families of units, one honest conversion

Storage confusion almost always comes from two vocabularies sharing words. The decimal family — kB, MB, GB, TB — steps by 1,000 and is what drive manufacturers print on the box. The binary family — KiB, MiB, GiB, TiB — steps by 1,024 and is what your operating system displays when a "500 GB" drive shows 465.661287 GiB. This page converts in both directions across the two families, keeps the unit label attached to every figure, and states which family each belongs to, so a quote in one system never contaminates a budget written in the other.

The stable identities are worth knowing once: 1 GB is 1,000,000,000 bytes, and 1 GiB is 1,073,741,824 bytes — a gap of about 7.37% at every single step. The gap compounds by the step count, which is why small units look harmless and a terabyte looks like a scandal on a spec sheet: 1,000 decimal gigabytes is 931.32 GiB, and the difference is precisely the ladder you climbed, not missing storage.

A worked example, step by step

Problem: a laptop box says "500 GB SSD". How much does the operating system display, and where does a 620 MiB folder of design work fit?

1. Decimal claim: 500 GB = 500 × 10⁹ = 500,000,000,000 bytes.
2. Binary display: 500,000,000,000 ÷ 1,073,741,824 = 465.661287 GiB — the panel's exact figure.
3. Folder check: 620 MiB = 620 × 1,048,576 = 650,117,120 bytes, which is about 650.117 MB in the decimal family.
4. Fit test: 650.117 MB is about 0.13% of the five-hundred-GB drive. The folder fits trivially; the interesting part is that no conversion was needed to know that.
5. Sibling values: 250 GB displays as 232.830644 GiB and 1,000 GB as 931.322575 GiB — the same shrink per family step, every time.

Nobody is being cheated by either figure: both describe the same 500,000,000,000 bytes in the two families' honest vocabularies. What the tool removes is the arithmetic between them, which is otherwise where marketing claims and system panels meet in a blaze of confusing screenshots. The widest value of the page, though, is organisational: backups quoted in one family and disks quoted in the other are the everyday source of "the drive should have fitted" incidents, and a converter that labels its outputs is the quiet fix.

The two families, side by side

The binary column is not a rounding of the decimal column; it is a genuinely different ladder. Cross-ladder comparisons are exactly what this page performs, and the unit label in the result is the promise that no step happened silently.

Everyday reading of a capacity figure

Four habits make the two families painless. Read the suffix first — the i is the whole message. Convert once, at the boundary where the quote meets the system, rather than converting mid-conversation. When a figure looks 7% too small, check the label before the maths: 465.661287 against a 500 GB claim is not shrinkage, it is translation. And keep tool-agnostic anchors in your head: a two-hour film at moderate quality runs 2–4 GB, a smartphone photo 3–5 MB, a Windows or macOS update 2–6 GB — anchors that let you sanity-check any capacity discussion before doing the precise arithmetic on this page.

Mistakes that quietly distort a storage plan

• Quoting a decimal figure into a binary conversation. "931 GB free!" is 1,000 decimal GB in binary clothes; both are true, but only one fits the budget.
• Compounding errors across steps. A 7.37% miss at each of three steps is a 20% total miss; convert once, from source to destination, in one hop.
• Using MB and MiB labels loosely. The letters do real work; a 4.7 MB email attachment and a 4.7 MiB one differ by half a megabyte.
• Forgetting overhead. File systems consume space for their own bookkeeping; the tool's exact answer is a ceiling, not a promise.
• Assuming network bandwidth shares the ladder. Transfer speeds quote decimal megabits; storage pages quote decimal megabytes — eight times apart by definition.

Keep exploring

• Area Converter — the sibling converter for squares: m², hectares, acres and ft².
• Volume Converter — the sibling converter for litres, gallons and cups.
• Speed Converter — another cross-system pair, for km/h against mph and m/s.
• Guide: Unit Conversion Mistakes to Avoid.