Data Size

Data Size

Convert between bytes, KB, MB, GB, and TB using decimal (SI) or binary (IEC) units.

Quick Presets

Auto-formatted

Decimal (SI) 1.02 KB
Binary (IEC) 1.00 KiB
📊

Decimal Units (×1000)

SI standard, used by HDD manufacturers

Bits bits
8192
Bytes B
1024
Kilobytes KB
1.024
Megabytes MB
0.001
Gigabytes GB
0
Terabytes TB
0
💾

Binary Units (×1024)

IEC standard, used by RAM and OSes

Bits bits
8192
Bytes B
1024
Kibibytes KiB
1
Mebibytes MiB
0.001
Gibibytes GiB
0
Tebibytes TiB
0

Decimal vs Binary Difference

Decimal
0 GB
Binary
0 GiB

Binary is ~6.8677% smaller than decimal representation

Decimal vs Binary

Decimal (SI): 1 KB = 1,000 bytes. Used by hard drive manufacturers.

Binary (IEC): 1 KiB = 1,024 bytes. Used by RAM, operating systems.

This is why a "1 TB" drive shows less space in your OS!

Features

  • Convert between bytes, KB, MB, GB, TB, PB
  • Decimal (SI) and binary (IEC) unit systems
  • Understand KB vs KiB difference
  • File size calculator
  • Data transfer rate estimation
  • Storage capacity comparison

Common Use Cases

  • Compare file sizes across platforms
  • Understand storage capacity (HDD, SSD)
  • Calculate download times at different speeds
  • Optimize image sizes for web performance
  • Plan database storage requirements

Data Size Units: Decimal vs Binary

Data size uses two systems: Decimal (SI) based on powers of 1000, and Binary (IEC) based on powers of 1024. This causes confusion when "1 GB" means different things.

Decimal Units (SI - International System):

  • Kilobyte (KB): 1,000 bytes (10³)
  • Megabyte (MB): 1,000 KB = 1,000,000 bytes (10⁶)
  • Gigabyte (GB): 1,000 MB = 1,000,000,000 bytes (10⁹)
  • Terabyte (TB): 1,000 GB = 1,000,000,000,000 bytes (10¹²)

Binary Units (IEC - Binary Prefixes):

  • Kibibyte (KiB): 1,024 bytes (2¹⁰)
  • Mebibyte (MiB): 1,024 KiB = 1,048,576 bytes (2²⁰)
  • Gibibyte (GiB): 1,024 MiB = 1,073,741,824 bytes (2³⁰)
  • Tebibyte (TiB): 1,024 GiB = 1,099,511,627,776 bytes (2⁴⁰)

The Confusion:

  • Hard drive manufacturers: Use decimal (1 TB = 1,000 GB)
  • Operating systems (Windows): Use binary but label as GB (1 GB = 1,024 MB)
  • Result: A "1 TB" drive shows as ~931 GB in Windows (it's actually 931 GiB)
  • Solution: Use GiB/MiB for clarity, or specify "1 TB = 1,000 GB (decimal)"

Web Context: Most web tools (file uploads, downloads) use decimal (MB/GB). Network speeds use decimal (100 Mbps Megabits per second). Storage APIs may vary—always check documentation.

Examples

Valid - Hard Drive Capacity
1 TB (decimal) = 931 GiB (binary)
Valid - Image File Size
5 MB (5,000,000 bytes) JPEG
Valid - RAM Specification
16 GB = 16 GiB = 17,179,869,184 bytes

Frequently Asked Questions

Why does my 1 TB hard drive show as 931 GB in Windows?
Hard drive makers use decimal (1 TB = 1,000 GB), but Windows uses binary and displays GiB as "GB". 1 TB = 1,000,000,000,000 bytes ÷ 1,073,741,824 bytes/GiB ≈ 931 GiB. You're not losing space—it's a labeling difference.
What's the difference between MB and MiB?
MB (Megabyte) = 1,000,000 bytes (decimal). MiB (Mebibyte) = 1,048,576 bytes (binary). MiB is ~4.9% larger. Use MiB for clarity when referring to binary (RAM, file systems); MB for network/file sizes.
Which system should I use?
Use decimal (KB, MB, GB) for file sizes, network speeds, and storage (matches industry standard). Use binary (KiB, MiB, GiB) when discussing RAM or being precise about powers of 1024. Specify which you mean to avoid confusion.
How do I calculate file upload time?
File size (megabytes) ÷ upload speed (Mbps) × 8 bits/byte. Example: 100 MB file at 10 Mbps: 100 ÷ 10 × 8 = 80 seconds. Note: Mbps is megabits per second, MB is megabytes (8× difference).
What's the largest data unit?
Petabyte (PB, 1,000 TB), Exabyte (EB, 1,000 PB), Zettabyte (ZB, 1,000 EB), Yottabyte (YB, 1,000 ZB). Google processes ~20 PB daily. Total internet traffic: ~1 ZB/month in 2024. Human brain: ~2.5 PB capacity.

💡 Tips

  • Always specify decimal (GB) vs binary (GiB) to avoid confusion—especially in technical docs
  • For web images: aim for <100 KB per image, <500 KB for hero images, use WebP for better compression
  • Internet speeds are in megabits (Mbps), file sizes in megabytes (MB)—divide speed by 8 for MB/s
  • 1 GiB RAM ≈ 1.074 GB. When buying RAM, "16 GB" usually means 16 GiB (17.2 GB decimal)

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