Free tool
Storage Unit Converter
Convert between bytes, KB, MB, GB and TB — decimal and binary, side by side.
Decimal (1000-based)
- B
- 1,000,000,000
- KB
- 1,000,000
- MB
- 1,000
- GB
- 1
- TB
- 0.001
Binary (1024-based)
- B
- 1,000,000,000
- KiB
- 976,562.5
- MiB
- 953.67
- GiB
- 0.931323
- TiB
- 0.000909
Storage sizes get confusing fast because two different math systems share the same names. Hard drive and cloud storage vendors advertise capacity in decimal units (1 GB = 1,000 MB), while operating systems usually report file and disk sizes in binary units (1 GiB = 1,024 MiB) — even when they label them “GB”.
That mismatch is why a drive sold as “1 TB” shows up as roughly 931 GB in your file explorer. Neither number is wrong — they're just different units wearing the same name. This converter shows both at once so you always know which one you're looking at.
How to use it
- 01Enter an amount and pick its unit — you can start from bytes, KB, MB, GB, TB, or their binary counterparts KiB, MiB, GiB and TiB.
- 02Read the decimal column for the number a cloud provider or drive manufacturer would advertise.
- 03Read the binary column for the number your operating system is likely to display.
Frequently asked questions
Why does my hard drive show less space than advertised?
Manufacturers advertise capacity in decimal units (1 TB = 1,000,000,000,000 bytes), but your OS reports it in binary units (1 TiB = 1,099,511,627,776 bytes) while still labeling it “GB” or “TB”. The bytes are all there — it's the same number measured with a different ruler.
What's the difference between GB and GiB?
GB (gigabyte) is decimal: 1 GB = 1,000 MB = 1,000,000,000 bytes. GiB (gibibyte) is binary: 1 GiB = 1,024 MiB = 1,073,741,824 bytes. Most operating systems display GiB but label it “GB” — that's the source of most storage-math confusion.
Which one should I use — decimal or binary?
Use decimal (GB, TB) when comparing against what a provider or manufacturer advertises. Use binary (GiB, TiB) when comparing against what your file explorer or OS actually reports for used or free space.
Related tools
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