Data Storage Converter
Convert between bits, bytes, kilobytes, megabytes, gigabytes and terabytes. Uses the binary convention (1 KB = 1,024 bytes) that operating systems report — and explains why your "1 TB" drive shows only 931 GB.
How to use this calculator
- Enter the size value.
- Choose the from and to units.
- Press Convert — results use the binary convention (×1,024 per step), matching what Windows reports.
Formula used
Drive manufacturers use decimal units (1 GB = 1,000,000,000 bytes) while operating systems use binary (1 GiB = 1,073,741,824 bytes) — the gap is why a marketed 1 TB drive appears as ~931 GB in Windows.
Example calculation
A 4.7 GB DVD: 4.7 × 1,024 = 4,812.8 MB — about 5.05 billion bytes, or 40.4 billion bits.
Bits, bytes and the 1000 vs 1024 problem
A bit is a single 0 or 1; eight bits make a byte, enough for one character. From there, storage scales by 1,024 (2¹⁰) in the binary convention because computer memory is addressed in powers of two.
The confusion: marketers count in clean thousands, operating systems in 1,024s. Internet speeds add a second trap — they're quoted in bits per second, so a "100 Mbps" connection downloads at most 12.5 megabytes per second.
Why use this calculator?
- Work out how many files, photos or videos fit on a drive or plan.
- Decode why drives show less capacity than advertised.
- Convert between bits (network speeds) and bytes (file sizes) correctly.
Frequently asked questions
How many MB are in a GB?
1,024 MB in the binary convention used by operating systems, or 1,000 MB in the decimal convention used by drive manufacturers. This converter uses 1,024.
Why does my 1 TB drive show only 931 GB?
The maker counts 1 TB as 10¹² bytes; your OS divides that by 1,024³ and gets ~931 GiB (displayed as GB). No space is missing — the units differ.
How fast is 100 Mbps in MB per second?
Divide by 8: 100 megabits/s = 12.5 megabytes/s. A 1 GB file therefore takes at least ~82 seconds at full speed.