Tool collection

Data Storage Unit Converter

Display Unit System:
1 byte = 8 bits
1 byte = 8 bits = 1 ASCII character
SIDecimal Units (base 1000) — commonly used by hard drive manufacturers
IECBinary Units (base 1024) — commonly used by operating systems
Common Media Capacity Reference
Media Type Nominal Capacity Actual Bytes (Decimal) OS Display (Binary)
CD 700 MB 700,000,000 B 约 667 MiB
DVD 4.7 GB 4,700,000,000 B 约 4.38 GiB
Blu-ray Disc (Single Layer) 25 GB 25,000,000,000 B 约 23.28 GiB
USB Drive / SD Card 32 GB 32,000,000,000 B 约 29.80 GiB
Portable Hard Drive 1 TB 1,000,000,000,000 B 约 931.32 GiB
Solid State Drive 512 GB 512,000,000,000 B 约 476.84 GiB
Enterprise Hard Drive 18 TB 18,000,000,000,000 B 约 16.37 TiB
Tool Description

This tool is an online data storage unit converter supporting real-time mutual conversion between bits, bytes, decimal units such as KB, MB, GB, TB, PB, EB, and binary units such as KiB, MiB, GiB, TiB, PiB, EiB. All calculations are performed locally in your browser, and data is never uploaded to any server.

Why Are There Two Unit Systems?

The existence of two storage unit systems is due to historical and commercial conventions:

  • Decimal (SI):Storage device manufacturers such as hard drives and USB drives use 1000 as the base (1 KB = 1000 B) because it makes nominal capacity appear larger, convenient for marketing.
  • Binary (IEC):Operating systems (such as Windows) use 1024 as the base (1 KiB = 1024 B) because computers process data internally in powers of 2.
  • Result:Buy a hard drive with a nominal capacity of 1 TB, and it shows only about 931 GiB when plugged into a computer. This is the "capacity shrinkage" phenomenon caused by the difference between the two systems.
Common Unit Conversion Quick Reference
  • 1 Byte = 8 bits — Byte and bit are basic units; 1 English character occupies 1 byte
  • 1 KB = 1000 B / 1 KiB = 1024 B
  • 1 MB = 1000 KB / 1 MiB = 1024 KiB
  • 1 GB = 1000 MB / 1 GiB = 1024 MiB
  • 1 TB = 1000 GB / 1 TiB = 1024 GiB
  • 1 PB = 1000 TB / 1 PiB = 1024 TiB
Main Use Cases
  • Compare nominal capacity with actual usable capacity when purchasing hard drives, USB drives, and memory cards.
  • Handle file sizes, limit upload sizes, and calculate bandwidth consumption during development.
  • Estimate cloud storage costs and evaluate data migration time.
  • Study computer organization and understand the difference between binary and decimal units.
Tool Features
  • Dual systems: Decimal (SI) and binary (IEC) unit systems are displayed simultaneously for clarity.
  • Real-time synchronization: Enter in any input box, and all other units automatically synchronize.
  • BigInt support: Implemented with JavaScript native BigInt, supporting precise conversion of extremely large values.
  • Scientific notation: Large values automatically switch to scientific notation display, avoiding long strings of numbers that are difficult to read.
  • Equivalent conversions: Displays equivalent character count, image count, song count, movie count, download time, and other relatable references.
  • Media reference table: Built-in capacity comparison table for common storage media, helping understand the capacity shrinkage phenomenon.
  • One-click copy: Each input box has a copy button; click to copy the content.
  • Safe and reliable: Pure front-end execution, no data uploaded, absolutely protects your data privacy.