Data Storage Converter | Bytes, KB, MB, GB & TB
Convert between bits, bytes, KB, MB, GB, TB, PB and binary KiB, MiB, GiB, TiB units. Explains the 1 TB = 931 GB discrepancy between SI and IEC standards.
Base value
1,000,000,000 bytes
= 8,000,000,000 bits
Base units
Decimal (SI), 1 KB = 1,000 B
Binary (IEC), 1 KiB = 1,024 B
Networking, bits (SI)
Transfer time estimate
At sustained theoretical max speed, real speeds are typically 50–70% of these values
4G Mobile (50 Mbps)
2m 40s
WiFi (802.11ac) (150 Mbps)
53 sec
Ethernet (1 Gbps) (1 Gbps)
8 sec
USB 3.0 (5 Gbps)
2 sec
USB 3.2 Gen 2 (10 Gbps)
< 1 second
Real-world equivalents
Click any row to copy the value. Press Esc to reset. Last-used unit and value are saved in your browser.
What Is the Data Storage Converter | Bytes, KB, MB, GB & TB?
Two competing measurement systems define data storage units. The decimal (SI) system uses powers of 1,000: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes. Storage manufacturers use this system because it makes drive capacities look larger. The binary (IEC) system uses powers of 1,024: 1 KiB = 1,024 bytes. Operating systems (Windows, macOS, Linux) traditionally report storage in binary units.
The IEC standardized binary prefixes in 1998: kibi- (Ki), mebi- (Mi), gibi- (Gi), tebi- (Ti). These eliminate ambiguity, 1 KiB is always exactly 1,024 bytes. In practice, the term “KB” is used ambiguously for both 1,000 and 1,024 bytes depending on context, which is why the discrepancy persists.
Networking units (Kbps, Mbps, Gbps) always use decimal (SI), 1 Mbps = 1,000,000 bits/second. This converter includes networking units separately so you can accurately estimate file transfer times.
Formula
Decimal SI Units (storage manufacturers)
1 KB = 1,000 bytes (10³)
1 MB = 1,000,000 bytes (10⁶)
1 GB = 1,000,000,000 bytes (10⁹)
1 TB = 10¹² bytes → 1,000 GB
1 PB = 10¹⁵ bytes → 1,000 TB
Binary IEC Units (operating systems)
1 KiB = 1,024 bytes (2¹⁰)
1 MiB = 1,048,576 bytes (2²⁰)
1 GiB = 1,073,741,824 bytes (2³⁰)
1 TiB = 2⁴⁰ bytes → 1,024 GiB
Why 1 TB drive = 931 GiB:
1,000,000,000,000 ÷ 1,073,741,824 ≈ 931.32 GiB
Manufacturer uses 10⁹; OS counts in 2³⁰, both are correct.
| Symbol | Name | Standard | Exact bytes |
|---|---|---|---|
| B | Byte | Both | 1 |
| KB | Kilobyte | SI/Dec. | 1,000 |
| KiB | Kibibyte | IEC/Bin. | 1,024 |
| MB | Megabyte | SI/Dec. | 1,000,000 |
| MiB | Mebibyte | IEC/Bin. | 1,048,576 |
| GB | Gigabyte | SI/Dec. | 1,000,000,000 |
| GiB | Gibibyte | IEC/Bin. | 1,073,741,824 |
| TB | Terabyte | SI/Dec. | 1,000,000,000,000 |
| TiB | Tebibyte | IEC/Bin. | 1,099,511,627,776 |
How to Use
- 1Enter a value: Type any number into the input field at the top of the converter.
- 2Select the unit: Choose the source unit from the dropdown (organized by group: Common, Decimal SI, Binary IEC, Networking).
- 3Read all conversions: All equivalent values across every unit appear instantly in the table below.
- 4Click to copy: Click any row in the result table to copy that value to your clipboard.
- 5Check transfer times: Scroll to the Transfer Time section to see how long your file size takes at various speeds.
- 6See real-world scale: The Real-World Comparisons section puts your value in context with everyday file sizes.
Example Calculation
Example 1, The 1 TB Hard Drive Mystery
- ›Manufacturer labels the drive as "1 TB" using decimal: 1 × 10¹² = 1,000,000,000,000 bytes.
- ›Windows reports storage in GiB (binary): 1,000,000,000,000 ÷ 2³⁰ = 931.32 GiB.
- ›Windows rounds and shows "931 GB", but it means 931 GiB, not gigabytes.
- ›No storage is missing: the full 1,000,000,000,000 bytes are present on the disk.
- ›The confusion arises entirely from the difference in measurement definitions.
Example 2, Estimating File Storage Needs
- ›You have 500 RAW photos at 25 MB each: 500 × 25 MB = 12,500 MB = 12.5 GB (decimal).
- ›In binary: 12,500,000,000 ÷ 2³⁰ ≈ 11.64 GiB.
- ›A 16 GB (decimal) SD card holds 16,000,000,000 bytes.
- ›That SD card can store 16,000 ÷ 25 = 640 RAW photos.
- ›Check: 640 × 25 MB = 16,000 MB = 16 GB (decimal), exactly fits.
Example 3, Network Bandwidth vs. File Size
- ›Your internet connection is 100 Mbps (megabits per second, always decimal).
- ›100 Mbps = 100,000,000 bits/sec ÷ 8 = 12,500,000 bytes/sec = 12.5 MB/s.
- ›Downloading a 4 GB (decimal) file: 4,000,000,000 ÷ 12,500,000 = 320 seconds ≈ 5.3 minutes.
- ›At 1 Gbps: 4,000,000,000 ÷ 125,000,000 = 32 seconds.
- ›Note: ISPs advertise in megabits (Mb), not megabytes (MB), always divide by 8 for bytes.
Understanding Data Storage Converter | Bytes, KB, MB, GB & TB
The History of Binary vs. Decimal Prefixes
The confusion between binary and decimal storage units has a 60-year history. When early computer engineers needed to describe memory sizes, they borrowed SI prefixes (kilo-, mega-, giga-) but redefined them as powers of 2 because that matched physical hardware architecture. 1 KB became 1,024 bytes, close enough to 1,000 that nobody objected at the kilobyte scale.
The problem became significant at the terabyte scale: 1 TiB is 9.95% larger than 1 TB. In 1998, the International Electrotechnical Commission (IEC) formalized binary prefixes, kibibyte (KiB), mebibyte (MiB), gibibyte (GiB), tebibyte (TiB), pebibyte (PiB), exbibyte (EiB), giving engineers unambiguous terminology. Despite this, informal usage of KB/MB/GB remains inconsistent.
Where Each Standard Is Used
| Context | System used | Examples |
|---|---|---|
| Hard drives, SSDs | Decimal (SI) | Seagate 2TB = 2 × 10¹² bytes |
| RAM, CPU cache | Binary (IEC) | 16 GiB RAM = 2³⁴ bytes |
| Operating systems | Binary (IEC) | Windows, Linux (macOS switched to decimal in 2009) |
| Networking / ISPs | Decimal (SI) | 1 Gbps = 10⁹ bits/sec |
| Cloud storage billing | Decimal (SI) | AWS, Google Cloud, Azure |
| File systems (Linux) | Binary (IEC) | df -h shows GiB units |
Practical Tips for Data Planning
- ›Buying storage: A drive labeled 1 TB holds 931 GiB. Add ~10% headroom to your storage budget to account for the unit difference.
- ›Estimating backups: Calculate in decimal GB (matches the OS file size display in most modern systems) for cloud backups.
- ›Network speed vs. download size: ISP gives speed in Mbps (bits); divide by 8 to get MB/s (bytes) for download time estimates.
- ›RAM vs. disk: RAM is always in binary GiB; disk is in decimal GB. Comparing them directly will give you a ~7–10% error per GiB.
- ›Streaming and video: A 4K movie at 25 Mbps uses 25 × 60 × 120 ÷ 8 ÷ 1000 ≈ 22.5 GB for a 2-hour film (decimal).
Frequently Asked Questions
Why does Windows show less storage than the drive label?
- ›Hard drive manufacturers measure capacity in decimal (SI) units: 1 TB = 10¹² bytes.
- ›Windows historically displays binary gigabytes (GiB): 1 GiB = 2³⁰ ≈ 1.074 × 10⁹ bytes.
- ›A 1 TB drive contains 1,000,000,000,000 bytes. Divide by 2³⁰ and you get ≈ 931 GiB.
- ›Windows labels this as "931 GB" even though it technically means GiB, hence the confusion.
- ›macOS switched in 2009 to reporting decimal GB, so a 1 TB drive shows as ~1 TB there.
What is the difference between GB and GiB?
- ›GB (gigabyte) = 1,000,000,000 bytes in the SI/decimal system used by manufacturers.
- ›GiB (gibibyte) = 1,073,741,824 bytes in the IEC/binary system used by OS kernels.
- ›The difference is about 7.4%: 1 GiB is 7.4% larger than 1 GB.
- ›At the terabyte scale the gap grows: 1 TiB is about 9.95% larger than 1 TB.
- ›The IEC introduced GiB in 1998 specifically to eliminate this ambiguity in technical standards.
How many bytes are in a gigabyte?
- ›Decimal (SI): 1 GB = 1,000,000,000 bytes (10⁹), used by storage manufacturers.
- ›Binary (IEC): 1 GiB = 1,073,741,824 bytes (2³⁰), used by operating systems.
- ›The ambiguity in the abbreviation "GB" is the source of much confusion.
- ›In networking contexts, 1 Gbps always means 10⁹ bits per second (decimal).
What does Mbps mean, and how does it relate to MB/s?
- ›Mbps = megabits per second (decimal: 1 Mbps = 1,000,000 bits/sec).
- ›MB/s = megabytes per second (decimal: 1 MB/s = 8,000,000 bits/sec).
- ›To convert Mbps to MB/s, divide by 8: 100 Mbps ÷ 8 = 12.5 MB/s.
- ›ISPs advertise in Mbps; download managers typically show MB/s, always divide by 8.
- ›Networking always uses decimal (SI) units, never binary IEC units.
Why do operating systems use binary units?
- ›Computer memory (RAM) and address spaces are organized in powers of 2 for hardware efficiency.
- ›Memory chips come in sizes like 2¹⁰, 2²⁰, 2³⁰ bytes, it's natural to measure in those blocks.
- ›Early OS designers used KB = 1,024 bytes because it was the closest power of 2 to 1,000.
- ›Storage manufacturers later chose the decimal definition because it made drives look bigger.
- ›macOS switched to decimal reporting in 10.6 (Snow Leopard, 2009); Linux/Windows still use binary.
What is a petabyte, and how big is it?
- ›Decimal: 1 PB = 10¹⁵ bytes = 1,000 terabytes = 1,000,000 gigabytes.
- ›Binary: 1 PiB = 2⁵⁰ bytes ≈ 1.126 × 10¹⁵ bytes ≈ 1,024 TiB.
- ›Real-world scale: the entire text of the English Wikipedia is about 21 GB, a petabyte holds ~47,000 copies.
- ›Facebook stores roughly 100 petabytes of photos. Google processes exabytes (10¹⁸ bytes) daily.
- ›Typical large enterprise data centers operate at 50–500 PB scale.
How does cloud storage measure gigabytes?
- ›Most cloud providers (Google Drive, Dropbox, iCloud, AWS S3) bill in decimal gigabytes (GB = 10⁹ bytes).
- ›AWS S3 charges per GB where 1 GB = 1,000,000,000 bytes, the SI definition.
- ›If you upload a 1 TiB file, AWS charges for approximately 1.099 GB (since 1 TiB ≈ 1.0995 TB).
- ›Always check the provider's definition in their pricing pages to avoid billing surprises.
What is the largest standard unit of digital storage?
- ›Official IEC/SI prefixes go up to yotta-: 1 YB = 10²⁴ bytes (decimal), 1 YiB = 2⁸⁰ bytes (binary).
- ›Above yotta-, the informal terms zetta- (10²¹) and yotta- (10²⁴) are the current standards.
- ›Beyond yotta-, unofficial terms like ronnabyte (10²⁷) and quettabyte (10³⁰) were added by BIPM in 2022.
- ›The total estimated data ever created globally is around 120–150 zettabytes (as of 2024).
- ›This converter handles up to exabytes (10¹⁸), sufficient for any real-world storage calculation.