File Size Converter
Convert between bytes, KB, MB, GB and other file size units.
Convert File Size
About file size units: Digital storage can be measured in decimal units (KB, MB, GB) based on powers of 1000, or binary units (KiB, MiB, GiB) based on powers of 1024. Both are commonly used, which can lead to confusion. For example, 1 KB = 1000 bytes, while 1 KiB = 1024 bytes. Many operating systems label binary units with decimal names (showing "MB" when they mean "MiB"), adding to the confusion.
Understanding File Size Units
File Size Units Explained
Digital storage and file sizes are measured using two different standards: the decimal (SI) system and the binary system. This dual standard can lead to confusion when interpreting storage capacities.
Decimal (SI) Units
Based on powers of 1000, these are the units used by most storage manufacturers and in networking:
- 1 Kilobyte (KB) = 1,000 bytes
- 1 Megabyte (MB) = 1,000 KB = 1,000,000 bytes
- 1 Gigabyte (GB) = 1,000 MB = 1,000,000,000 bytes
- 1 Terabyte (TB) = 1,000 GB = 1,000,000,000,000 bytes
- 1 Petabyte (PB) = 1,000 TB = 1,000,000,000,000,000 bytes
Binary Units
Based on powers of 1024 (2¹⁰), these are commonly used in computing contexts because computers operate on binary:
- 1 Kibibyte (KiB) = 1,024 bytes
- 1 Mebibyte (MiB) = 1,024 KiB = 1,048,576 bytes
- 1 Gibibyte (GiB) = 1,024 MiB = 1,073,741,824 bytes
- 1 Tebibyte (TiB) = 1,024 GiB = 1,099,511,627,776 bytes
- 1 Pebibyte (PiB) = 1,024 TiB = 1,125,899,906,842,624 bytes
The Storage Size Discrepancy
When you purchase a 1 TB hard drive, you might notice that your operating system shows less storage capacity than expected, perhaps around 931 GB. This isn't a defect—it's the result of the different unit systems.
Storage manufacturers use the decimal system (1 TB = 1,000,000,000,000 bytes), while operating systems often use binary measurements but display them with decimal unit names. So what your OS calls "1 GB" is actually 1 GiB (1,073,741,824 bytes), making a "1 TB" drive appear as approximately 931 "GB" in your OS.
Example: Capacity of a "1 TB" Hard Drive
- Marketing capacity: 1 TB = 1,000,000,000,000 bytes
- Windows displays this as: 1,000,000,000,000 ÷ 1,073,741,824 ≈ 931 GB
- Actual capacity is unchanged, just measured differently
When Different Units Are Used
Decimal (SI) Units Commonly Used For:
- Hard drive and SSD marketing and labeling
- Network speeds and data transfer rates
- Internet service provider data caps
- Telecommunications and data transmission
- Scientific and technical publications
- Consumer marketing of storage devices
Binary Units Commonly Used For:
- Operating system file and memory reporting
- Programming and software development
- RAM capacity specifications
- File sizes in many applications
- Computer architecture and system design
- Low-level disk operations
Practical Impact of the Difference
The difference between decimal and binary units grows larger as the sizes increase:
- 1 KB vs 1 KiB: ~2.4% difference
- 1 MB vs 1 MiB: ~4.9% difference
- 1 GB vs 1 GiB: ~7.4% difference
- 1 TB vs 1 TiB: ~10% difference
Frequently Asked Questions (FAQs)
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