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Data Size Converter

A high-precision data storage unit converter supporting bits (b), bytes (B), metric prefixes (KB, MB, GB, TB, PB), and IEC binary prefixes (KiB, MiB, GiB, TiB, PiB) using both Base 1024 (binary) and Base 1000 (decimal) standards. Includes a storage capacity loss analysis explaining why a 1TB drive registers as 931GB on Windows, computed entirely in your local browser.

Enter Data Size

STANDARD BASEChoose which numbering base to display

Real-Time Unit Conversion Results

Total 1,000,000,000 Bytes
bit (b)(Binary Digit)
8,000,000,000
1 / 8 Byte
Byte (B)(Byte (8 bits))
1,000,000,000
8 bits
KiB(Kibibyte (IEC))
976,562.5
2¹⁰ = 1,024 B
MiB(Mebibyte (IEC))
953.674316
2²⁰ = 1,048,576 B
GiB(Gibibyte (IEC))
0.931323
2³⁰ = 1,073,741,824 B
TiB(Tebibyte (IEC))
0.000909
2⁴⁰ = 1,099,511,627,776 B
PiB(Pebibyte (IEC))
8.8818e-7
2⁵⁰ B
EiB(Exbibyte (IEC))
8.6736e-10
2⁶⁰ B
KB(Kilobyte (SI))
1,000,000
10³ = 1,000 B
MB(Megabyte (SI))
1,000
10⁶ = 1,000,000 B
GB(Gigabyte (SI))
1
10⁹ = 1,000,000,000 B
TB(Terabyte (SI))
0.001
10¹² = 1,000,000,000,000 B
PB(Petabyte (SI))
0.000001
10¹⁵ B
EB(Exabyte (SI))
1.0000e-9
10¹⁸ B
STORAGE DISCREPANCY EXPLAINED

Why does a 1TB SSD show as 931GB on Windows?

Storage manufacturers sell drives in decimal (1 TB=1012 B1\text{ TB} = 10^{12}\text{ B}), but Microsoft Windows calculates capacity in binary (1 TiB=10243 B1\text{ TiB} = 1024^3\text{ B}) while labeling it with legacy GB units.

Manufacturer Labeled (Base 1000)1,000 GB
Windows Actual Display (Base 1024)931.32 GiB
A gap of about 68.68 GB (6.87%) is not a hard drive defect — it's a normal display difference caused by the numbering base.

Standards Guide (SI vs. IEC)

Historically, 1024 bytes was colloquially called 1KB. Under IEC international standards, base-1000 is designated as KB, MB, GB, while base-1024 is designated as KiB, MiB, GiB.

Decimal (SI, 1000): 1 KB = 1,000 Bytes
Binary (IEC, 1024): 1 KiB = 1,024 Bytes

All conversions and arithmetic run locally within your browser memory, without transmitting a single byte to an external server.

Computer Architecture & Storage Standards Guide

Mathematical Mechanics of Data Storage Units: IEC (1024) vs. SI (1000)

In computing, the fundamental unit of storage is the binary bit (Bit, b), representing a 0 or 1. Eight bits form 1 Byte (Byte, B = 8 bits), capable of storing an ASCII character or an integer from 0 to 255.

Early computer scientists colloquially referred to 1024 bytes as 1 Kilobyte because 210=10242^{10} = 1024 was close to 103=100010^3 = 1000. In 1998, the International Electrotechnical Commission (IEC) standardized binary prefixes (Kibi, Mebi, Gibi, Tebi) to eliminate ambiguity between base-2 and base-10 metrics.

This guide clarifies unit standards across storage hardware manufacturers, networking bandwidth specifications, and operating systems (Windows vs. macOS/Linux).

1Full Support for 14 Standard Units from Bit to Exabyte (EB)

Seamlessly convert between bits (b), bytes (B), KB, KiB, MB, MiB, GB, GiB, TB, TiB, PB, PiB, EB, and EiB in real-time.

2Real-Time IEC (1024) and SI (1000) Base Switching

Freely toggle between OS-level base-1024 binary units and hardware manufacturer base-1000 decimal units with a single click.

3Smart Scientific Exponential Formatting

Handles astronomical quantities cleanly across 10−1510^{-15} to 101810^{18} with automated thousand-separators and copy controls.

4Drive Capacity Discrepancy (931GB) Visualizer

Visual progress indicators and exact mathematical formulas explain why newly purchased SSDs register less capacity on Windows.

1. Data Storage Unit Mathematical Conversion Formulas

① Bit and Byte Fundamental Relationship:
- 1 Byte (B)=8 Bits (b)1\text{ Byte (B)} = 8\text{ Bits (b)}
- Bytes=Bits8\displaystyle \text{Bytes} = \frac{\text{Bits}}{8}
② Binary System (IEC 60027-2, 210n2^{10n} Base):
- 1 KiB=210 B=1,024 Bytes1\text{ KiB} = 2^{10}\text{ B} = 1,024\text{ Bytes}
- 1 MiB=220 B=1,048,576 Bytes1\text{ MiB} = 2^{20}\text{ B} = 1,048,576\text{ Bytes}
- 1 GiB=230 B=1,073,741,824 Bytes1\text{ GiB} = 2^{30}\text{ B} = 1,073,741,824\text{ Bytes}
- 1 TiB=240 B=1,099,511,627,776 Bytes1\text{ TiB} = 2^{40}\text{ B} = 1,099,511,627,776\text{ Bytes}
③ Decimal System (SI International System of Units, 103n10^{3n} Base):
- 1 KB=103 B=1,000 Bytes1\text{ KB} = 10^3\text{ B} = 1,000\text{ Bytes}
- 1 MB=106 B=1,000,000 Bytes1\text{ MB} = 10^6\text{ B} = 1,000,000\text{ Bytes}
- 1 GB=109 B=1,000,000,000 Bytes1\text{ GB} = 10^9\text{ B} = 1,000,000,000\text{ Bytes}
- 1 TB=1012 B=1,000,000,000,000 Bytes1\text{ TB} = 10^{12}\text{ B} = 1,000,000,000,000\text{ Bytes}

2. SI Decimal vs. IEC Binary Storage Standards Comparison Table

Byte counts, exponents, and percentage differences between decimal and binary naming standards.

Unit (SI / IEC)SymbolByte CountMathematical FormulaBinary vs. Decimal Difference
Kilobyte / KibibyteKB / KiB1,000 B / 1,024 B10³ B / 2¹⁰ B+2.40% (24 Bytes difference)
Megabyte / MebibyteMB / MiB1,000,000 B / 1,048,576 B10⁶ B / 2²⁰ B+4.86% (48.6 KB difference)
Gigabyte / GibibyteGB / GiB1,000,000,000 B / 1,073,741,824 B10⁹ B / 2³⁰ B+7.37% (73.7 MB difference)
Terabyte / TebibyteTB / TiB10¹² B / 1,099,511,627,776 B10¹² B / 2⁴⁰ B+9.95% (99.5 GB difference)
Petabyte / PebibytePB / PiB10¹⁵ B / 1,125,899,906,842,624 B10¹⁵ B / 2⁵⁰ B+12.59% (125.9 TB difference)

3. Operating System Storage Reporting Policies (Windows vs. macOS)

① Microsoft Windows:
- Windows calculates capacity using binary 10241024 math (210,220,2302^{10}, 2^{20}, 2^{30}) but applies legacy KB, MB, GB labels. A 1TB drive (1012 bytes10^{12}\text{ bytes}) is divided by 102431024^3, registering as 931.32 GB931.32\text{ GB}.
② Apple macOS (Since Snow Leopard 10.6):
- macOS strictly follows decimal SI standards (103,106,10910^3, 10^6, 10^9). A 1TB SSD displays cleanly as 1 TB or 1,000 GB.
③ Linux:
- Linux command-line utilities (ls -lh, df -h) default to base-1024 binary with explicit KiB, MiB, GiB units, or support base-1000 via --si.

Frequently Asked Questions (FAQ)

Q.Is 1 KB equal to 1,000 Bytes or 1,024 Bytes?

Under standard SI definitions, 1 KB is exactly 1,000 Bytes1,000\text{ Bytes}. When referring to 1,024 Bytes1,024\text{ Bytes}, the official IEC standard symbol is 1 KiB (Kibibyte), though Windows still uses KB for 1024 bytes.

Q.Why does my 1TB hard drive display as 931GB on Windows? Is it defective?

No, it's working as expected. Manufacturers build 1TB drives with 1,000,000,000,000 Bytes1,000,000,000,000\text{ Bytes}. Windows divides this by 102431024^3 (1,073,741,8241,073,741,824), resulting in 931.32 GiB931.32\text{ GiB} and displaying it as 931GB.

Q.What is the difference between lowercase "b" and uppercase "B"?

Lowercase b represents bits, while uppercase B represents bytes (1 Byte=8 bits1\text{ Byte} = 8\text{ bits}). For example, 100 Mbps is 100 Megabits/second (approx. 12.5 MB/s), an 8-fold difference.

Q.How large is a Petabyte (PB) or an Exabyte (EB)?

1 PB is 1,000 TB (~250,000 Full HD movies). 1 EB is 1,000 PB (1 billion GB), typically used to measure global annual internet traffic.

Q.Is my input data transmitted to any external server?

No. All storage calculations run locally in your browser memory via client-side JavaScript.