Why does my 1 TB drive show only 931 GB?

Manufacturers use decimal (1 TB = 10¹² bytes). Windows reports binary GiB but labels them "GB". 10¹² / 2³⁰ ≈ 931 GiB.

1 GB = 1,000 MB in decimal (manufacturer), or 1 GiB = 1,024 MiB in binary (OS).

🔄 Conversion

Data Storage Converter

Convert digital storage units — bits, bytes, KB/MB/GB/TB (decimal, base 10) and KiB/MiB/GiB/TiB (binary, base 2). Critical for storage purchasing because manufacturers use base-10 while OS'es use base-2.

Last reviewed: January 2026 Formula shown No signup required

Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.

Data Storage Converter

Bytes, KB/MB/GB/TB (Decimal & Binary)

Value to Convert

Enter any number (decimals allowed).

From

📐 Formula & Method

Linear conversion

result = value × (factor_from / factor_to)

All units are stored as a multiplier against an internal base unit. To convert, the input is first scaled to the base, then divided by the target factor.

📋 How to Use

1
Enter the numeric value you want to convert.
2
Pick the source unit in the From dropdown.
3
Pick the target unit in the To dropdown.
4
Click Calculate. You will see the result, a full conversion table to every supported unit, and a list of common conversions.

💡 Key Insights

Marketing uses decimal (GB = 10⁹ bytes). Operating systems often use binary (GiB = 2³⁰ bytes). 1 TB drive shows ≈ 931 GiB in Windows.
1 byte = 8 bits. Network speeds are usually in bits/sec; storage in bytes.
Common file sizes: a high-quality JPEG ≈ 5 MB; a 1080p HD movie ≈ 5 GB; a Blu-ray-quality 4K movie ≈ 50–100 GB.

🔬 Methodology & Accuracy

Formula: Linear unit conversion with high-precision constants. All math runs client-side in your browser using IEEE-754 doubles.

Data sources: BIPM SI brochure (9th ed.); NIST SP 811 (2008 ed.); ISO 80000-1 quantities and units.

Last reviewed: January 2026 · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.

For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.

Accuracy & Feedback

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❓ Frequently Asked Questions

🧭 Next Steps

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