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Enter one storage capacity and keep the source label explicit.
Choose the notation needed for a vendor comparison, operations note, or user explanation.
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Use more decimals when reconciling decimal labels with strict IEC readouts.
UnitEquivalent valueByte basisTypical useCopy
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ContextCurrent readingRecommended wordingCopy
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A storage device labeled 10 TB and a system readout near 9.095 TiB can describe exactly the same bytes. The smaller number is not evidence that capacity vanished. It comes from dividing the byte total by a larger binary unit.

Decimal units use powers of 1000. One gigabyte (GB) is 1,000,000,000 bytes, and one terabyte (TB) is 1,000,000,000,000 bytes. Binary units use powers of 1024. One gibibyte (GiB) is 1,073,741,824 bytes, and one tebibyte (TiB) is 1,099,511,627,776 bytes.

GB and TB
Decimal labels used on drive packaging, vendor quotes, quotas, and many cloud capacity statements.
GiB and TiB
IEC binary labels used in byte-accurate system, memory, and storage reporting.
Legacy shorthand
Some software applies binary math but prints GB or TB, so the documentation must settle what the label means.

Exact bytes provide the common reference when procurement, operations, and finance use different labels. They also expose a same-number mistake: 10 TiB is about 10.995 TB, so a 10 TB purchase does not satisfy a true 10 TiB requirement.

Unit conversion answers only the labeling question. Filesystems, RAID parity, metadata, snapshots, reserved space, recovery partitions, compression, and thin provisioning can change usable capacity after the device or pool is created.

How to Use This Tool:

Keep the source label attached to the number so decimal and binary quantities are not mixed.

  1. Enter the Capacity and choose its source unit from TB, TiB, GB, or GiB.
  2. Choose the Headline unit needed for the comparison. The equivalent-unit table continues to show all four labels for the same bytes.
  3. Increase Display precision when reconciling a vendor label or writing a capacity requirement. Use the exact byte total when rounded labels could affect a purchase or allocation.

Interpreting Results:

Two readings are equivalent when they resolve to the same byte total. A lower TiB or GiB number for a decimal source is expected because each binary unit contains more bytes.

Use decimal wording for a marketed capacity and strict IEC wording for a binary requirement. If a platform prints GB or TB while using binary math, state both the exact bytes and the intended GiB or TiB label to remove the ambiguity.

Technical Details:

All four units convert through bytes. The source value is multiplied by its byte factor, and that exact byte quantity is divided by the target factor. Decimal and binary labels therefore change the displayed number, not the stored quantity.

Formula Core:

B=V×Fs Vt=BFt

V is the entered capacity, Fs is bytes per source unit, B is the byte total, Ft is bytes per target unit, and Vt is the target value.

UnitFamilyBytes per unit
GBDecimal1,000,000,000
GiBBinary1,073,741,824
TBDecimal1,000,000,000,000
TiBBinary1,099,511,627,776

For 10 TB, the byte total is 10,000,000,000,000. Dividing by 1,099,511,627,776 produces 9.0949470177 TiB. The fixed decimal-to-binary number gap is about 6.867743% at the GB/GiB scale and 9.050530% at the TB/TiB scale.

Capacity accepts finite values from 0 through 1,000,000,000. Calculations retain full numeric precision; the selected two, three, four, or six decimal places affect displayed and exported labels only.

References: