File Size Converter
Convert between file size units instantly. Supports both binary (KiB, MiB, GiB) and decimal (KB, MB, GB) standards with a complete reference table for all units.
Unit System
Convert
Conversion Details
Quick Reference — 1 Gibibyte (GiB) in All Binary Units
How to Use This Tool
- Choose a unit system: Binary (1024-based, KiB/MiB/GiB) or Decimal (1000-based, KB/MB/GB).
- Enter the value you want to convert.
- Select the unit you are converting from in the "From" dropdown.
- Select the unit you want to convert to in the "To" dropdown.
- Read the converted result along with the equivalent value in bytes and bits.
- Scan the Quick Reference table to see the value expressed in every unit within the chosen system.
Formula & How It Works
File Size Conversion Formula
result = (value × fromByteFactor) ÷ toByteFactorThe value is first converted to bytes using the source unit's byte factor, then divided by the target unit's byte factor.
Binary (IEC) Byte Factors
1 KiB = 1024¹ bytes, 1 MiB = 1024² bytes, 1 GiB = 1024³ bytesBinary units use powers of 1024, matching how computer memory is actually addressed.
Decimal (SI) Byte Factors
1 KB = 1000¹ bytes, 1 MB = 1000² bytes, 1 GB = 1000³ bytesDecimal units use powers of 1000, matching how storage manufacturers advertise drive capacity.
Practical Examples & Common Use Cases
Converting gigabytes to mebibytes (binary)
1 GiB = 1024³ bytes = 1,073,741,824 bytes. Converting to MiB: 1,073,741,824 ÷ 1024² = 1024 MiB.
Explaining the "missing" drive space
A drive advertised as 500 GB (decimal) has 500,000,000,000 bytes. Displayed in binary GiB: 500,000,000,000 ÷ 1024³ ≈ 465.66 GiB — which is why Windows shows "465 GB" for a 500 GB drive.
Converting megabytes to bits
1 MB (decimal) = 1,000,000 bytes. In bits: 1,000,000 × 8 = 8,000,000 bits.
Frequently Asked Questions
KB (kilobyte) uses the decimal standard where 1 KB = 1000 bytes. KiB (kibibyte) uses the binary standard where 1 KiB = 1024 bytes. The difference grows larger with bigger units: 1 GB = 1,000,000,000 bytes while 1 GiB = 1,073,741,824 bytes, a difference of about 7.4%. The IEC introduced the binary prefixes (KiB, MiB, GiB) in 1998 to eliminate ambiguity.
Drive manufacturers use decimal units (1 GB = 1,000,000,000 bytes) to measure capacity, but Windows reports sizes in binary units while labeling them as GB. So a 500 GB drive (500,000,000,000 bytes) shows as approximately 465 "GB" in Windows because it is actually dividing by 1,073,741,824 (the binary gigabyte). The data is all there — the discrepancy is purely a labeling issue.
One byte always contains exactly 8 bits. This is a fixed relationship that applies regardless of whether you use binary or decimal unit systems. A bit (binary digit) is the smallest unit of data, representing a 0 or 1. A byte is the standard grouping of 8 bits and is the fundamental addressable unit in most computer architectures.
Binary units (KiB, MiB, GiB) are appropriate when discussing RAM, cache sizes, and operating system file sizes, as these systems allocate memory in powers of two. Decimal units (KB, MB, GB) are standard for storage manufacturer specifications, network bandwidth, and data transfer rates. In general, use binary when talking about computer memory and decimal when talking about storage capacity or network speeds.
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