Data Storage Converter
Data storage sizes are confusing. Hard drive manufacturers use decimal gigabytes (1 GB = 1,000,000,000 bytes) while operating systems use binary gibibytes (1 GiB = 1,073,741,824 bytes). This free calculator eliminates the confusion by showing both decimal (SI) and binary (IEC) values simultaneously. Convert instantly, see why your hard drive shows less space than advertised, and estimate file transfer times accurately.
Hard drive manufacturers use decimal (1 GB = 1,000,000,000 bytes).
Your OS uses binary (1 GiB = 1,073,741,824 bytes).
This is why a "1 TB" hard drive shows as ~931 GB in Windows or macOS.
DECIMAL (SI)
BINARY (IEC)
File Transfer Time
Estimated transfer time:
Note: Internet speeds are measured in megabits (Mbps), while file sizes are in megabytes (MB). This tool converts them automatically so assumptions are accurate.
Why Does My Drive Show Less Space?
Calculate actual OS capacity vs advertised.
This difference grows with larger drives. A 4 TB drive shows as ~3.64 TB in your OS. Nothing is wrong - this is a difference in standards, not missing storage.
How Much Fits on My Drive?
| File Type | Typical Size | Notes | Action |
|---|---|---|---|
| Plain text file (.txt) | 1-10 KB | ||
| Web page (HTML) | 50-200 KB | ||
| JPEG photo (smartphone) | 2-6 MB | ||
| JPEG photo (DSLR RAW) | 20-40 MB | ||
| MP3 song (3 min, 128kbps) | ~3 MB | ||
| MP3 song (3 min, 320kbps) | ~7 MB | ||
| HD video (1 min, 1080p) | ~150 MB | ||
| 4K video (1 min) | ~375 MB | ||
| Feature film (HD) | 4-8 GB | ||
| Feature film (4K Blu-ray) | 50-100 GB | ||
| Video game (modern AAA) | 50-150 GB | ||
| OS install (Windows 11) | ~20 GB | ||
| OS install (macOS) | ~15 GB |
Quick Storage Conversions
How to Convert Data Storage Units
- Enter your value in the input field and select your unit from the dropdown
- Both decimal and binary equivalents are shown simultaneously in two columns
- Click any unit in the output to make it the new reference for bidirectional conversion
- Use the "Why Does My Drive Show Less Space?" calculator to understand storage discrepancies
- Use the Storage Capacity Estimator to calculate how much content fits on a drive
- Use the Transfer Time calculator to estimate download or copy times
Decimal vs Binary - The Critical Difference
The decimal (SI) standard defines 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, 1 GB = 1,000,000,000 bytes. Storage manufacturers use this standard because it makes their drives appear larger. The binary (IEC) standard defines 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes, 1 GiB = 1,073,741,824 bytes. Operating systems use this standard for historical reasons tied to how computer memory is addressed. The IEC introduced the kibibyte/mebibyte/gibibyte notation in 1998 specifically to resolve the ambiguity, but the industry has been slow to adopt it uniformly. The result is that a drive advertised as "1 TB" by its manufacturer contains 1,000,000,000,000 bytes which your OS reports as approximately 931 GB - the "missing" ~69 GB is a measurement artifact, not actual missing storage.
Bits vs Bytes - A Constant Source of Confusion
A bit is the fundamental unit of digital information - a single 0 or 1. A byte is 8 bits and is the standard unit for file sizes. Internet speeds are always rated in bits per second (Mbps, Gbps) while file sizes are always in bytes (KB, MB, GB). To convert a download speed in Mbps to a file transfer rate in MB/s divide by 8 - a 100 Mbps connection transfers approximately 12.5 MB per second.
Common Data Size Reference
A plain text email is typically a few KB. A high-resolution smartphone photo is 3–6 MB. A three-minute MP3 song is about 3–7 MB. A 1080p HD video runs about 150 MB per minute. A modern AAA video game install is 50–150 GB. A full 4K Blu-ray movie can reach 100 GB uncompressed. Understanding these reference points helps make sense of storage capacity and data usage.
Key Features
- Decimal (SI) and binary (IEC) standards shown simultaneously
- All units from bits to yottabytes and yobibytes
- "Why does my drive show less space?" calculator with visual comparison
- Storage Capacity Estimator (photos, songs, videos, documents)
- File Transfer Time calculator with speed unit conversion (Mbps, MBps, Gbps)
- Real-world file size reference table
- Quick conversion panel for 8 most searched pairs
- BigInt-based precision for large storage values
- Works on all devices including mobile
- 100% free - no signup, no account, no data uploaded
100% Free & 100% Private
All processing happens entirely in your browser. We never upload your data to any server. No signup, no account, no hidden fees. Just free, secure tools.
Frequently Asked Questions
How many MB are in a GB?
In the decimal (SI) standard used by storage manufacturers, 1 GB = 1,000 MB. In the binary (IEC) standard used by operating systems, 1 GiB = 1,024 MiB. The difference is why a drive advertised as 1 GB shows slightly less in your OS.
Why does my hard drive show less space than advertised?
Hard drive manufacturers measure in decimal (1 GB = 1,000,000,000 bytes) while operating systems like Windows and macOS measure in binary (1 GiB = 1,073,741,824 bytes). A 1 TB drive contains 1,000,000,000,000 bytes which your OS displays as approximately 931 GB. No storage is missing — it is a difference in measurement standards.
What is the difference between MB and MiB?
MB (megabyte) is the decimal unit where 1 MB = 1,000,000 bytes. MiB (mebibyte) is the binary unit where 1 MiB = 1,048,576 bytes. The IEC introduced the MiB, GiB, TiB notation in 1998 to remove ambiguity, but MB/GB/TB are still commonly used for both standards in practice.
What is the difference between bits and bytes?
A bit is the smallest unit of digital information — either 0 or 1. A byte is 8 bits. File sizes are measured in bytes (KB, MB, GB). Network and internet speeds are measured in bits per second (Mbps, Gbps). This is why a 100 Mbps internet connection downloads at about 12.5 MB/s — you divide by 8 to convert bits to bytes.
How do I convert MB to GB?
Divide megabytes by 1,000 to get gigabytes (decimal standard). Example: 2,500 MB ÷ 1,000 = 2.5 GB. In the binary standard divide by 1,024: 2,500 MiB ÷ 1,024 = 2.44 GiB.
How long does it take to download 1 GB?
At 100 Mbps internet speed, downloading 1 GB (8,000 megabits) takes about 80 seconds. At 1 Gbps it takes about 8 seconds. Remember that internet speeds are in megabits (Mb) while file sizes are in megabytes (MB) — divide the speed by 8 to get the byte transfer rate.
How many photos fit in 1 GB?
Approximately 250 smartphone JPEG photos (at ~4 MB each) fit in 1 GB. DSLR RAW photos (~25 MB each) give about 40 per GB. Use the Storage Capacity Estimator in this tool to calculate for your specific file sizes.
Is this data storage converter free?
Yes, completely free with no account required. All conversions happen in your browser instantly. No data is sent to any server.
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