Data size converter
Convert between bytes and larger data units — and know whether you mean decimal (1 KB = 1000 bytes, used by drive manufacturers) or binary (1 KiB = 1024 bytes, often shown by operating systems). Explains why a "1 TB" SSD reports ~931 GB in Windows.
Value
From
B
KB
MB
GB
TB
To
B
KB
MB
GB
TB
Result
0 GB
How to convert data sizes
1. Enter the size value (e.g. 500).
2. Select source unit: decimal KB/MB/GB or binary KiB/MiB/GiB.
3. Select target unit and read the equivalent.
4. Match the convention your tool uses — macOS mixes labels; Linux often uses IEC binary names.
Data size examples
1 TB drive in Windows
1 TB (decimal 10¹² bytes) ≈ 931 GiB binary — not "missing" space, different counting base.
File download
850 MiB = 891.29 MB decimal ≈ 0.85 GB marketing size.
Network speed context
100 Mbps link ≠ 100 MB/s file speed. Bits vs bytes: divide by 8; 100 Mbps ≈ 12.5 MB/s theoretical max.
When to use the data size converter
• When you reconcile hard drive capacity with OS-reported free space.
• When you compare cloud storage plans quoted in GB vs GiB.
• When you convert log file sizes or database backup totals.
When to choose something else
• When you measure network throughput over time — use bandwidth calculators.
• When you need bits per second — remember 8 bits = 1 byte.
• When you compress data — compressed size is format-dependent, not unit conversion.
The binary vs decimal marketing gap
Storage vendors use decimal prefixes (1 TB = 10¹² bytes) because numbers look bigger. Operating systems historically used binary counting (1024-based) while still labeling "GB". The ~7% gap at each step compounds: after TB scale, users see noticeably less than the box label.
Naming standards (IEC vs SI)
SI decimal: k, M, G (1000-based). IEC binary: Ki, Mi, Gi (1024-based). A file "500 MB" on a download site is often decimal 500×10⁶ bytes. Linux `ls -h` may show MiB correctly; Windows Explorer labels can still say "GB" for GiB values.
Frequently asked questions
KB vs KiB — what is the difference?
KB (decimal) = 1000 bytes. KiB (binary) = 1024 bytes. IEC recommends KiB/MiB/GiB for binary to avoid confusion.
Why does my 32 GB USB show less?
Marketing uses decimal GB; systems often display GiB. Formatting overhead also consumes space.
How many bytes in a megabyte?
1 MB decimal = 1,000,000 bytes. 1 MiB binary = 1,048,576 bytes.
Are RAM sizes binary?
Yes — 8 GB RAM modules are typically 8 GiB (8×1024³ bytes) in practice.
Bits or bytes for internet speed?
ISPs advertise megabits per second (Mb/s). File sizes use bytes. Divide Mb/s by 8 for MB/s.
Is data uploaded?
No. Conversions run locally.