Digital Data Storage & Bandwidth Calculators.
Understand the real math behind your storage drives and network connections. Accurately translate between Decimal (SI / 1000) and Binary (IEC / 1024) memory standards, or calculate exact file download times.
Universal Data Sizing Engine
Interactive CalculatorGB to MB Calculator
Decimal (SI / Base 1,000): 1 KB = 1,000 Bytes, 1 MB = 1,000 KB, 1 GB = 1,000 MB. Used by macOS, hard drive & SSD makers (WD, Samsung, Seagate), and networking standards.
1,024,000,000
1,000,000,000 KiB1,024,000
976,562.5 MiB1,024
953.674 GiB1.024
0.931 TiBCalculated according to IEEE 1541 and IEC 80000-13 standards.
Data Storage Converters Directory.
Dedicated converters, file size calculators, and network transfer estimators.
Bytes Converter (B, KB, MB, GB, TB)
Convert raw computer bytes to bits, KB, MB, GB, TB, and PB across binary and decimal computer standards.
Download Time Calculator & Bandwidth Speed Estimator
Calculate how long files take to download based on file size and internet connection speed in Mbps and Gbps.
File Size Converter & Multi-Unit Calculator
Calculate and convert file sizes across bytes, kilobytes, megabytes, gigabytes, and terabytes with storage approximations.
GB to MB Converter
Convert Gigabytes (GB) to Megabytes (MB) across decimal and binary standards with exact byte calculations.
GB to TB Converter
Convert Gigabytes (GB) to Terabytes (TB) for SSDs, HDDs, and cloud backup systems with decimal and binary options.
KB to MB Converter
Convert Kilobytes (KB) to Megabytes (MB) with decimal (1000) and binary (1024 KiB) conversion formulas.
MB to GB Converter
Convert Megabytes (MB) to Gigabytes (GB) with both Decimal (SI 1000) and Binary (IEC 1024) calculations.
TB to GB Converter
Convert Terabytes (TB) to Gigabytes (GB) for hard drives, SSDs, and cloud storage with Windows usable space analysis.
The Binary (IEC) vs Decimal (SI) Difference.
Why hard drives never appear to have the full advertised space when plugged into a PC.
Manufacturer Math (SI)
Storage manufacturers (WD, Seagate, SanDisk, Samsung) sell products in powers of 10. A 1 TB drive has 1,000,000,000,000 bytes.
Operating System Math (IEC)
Windows addresses storage in powers of 2 (1,024³ bytes per GiB). Dividing 1 trillion bytes by 1,073,741,824 yields 931.32 GiB.
macOS vs Windows
Apple switched macOS (Mac OS X Snow Leopard+) to decimal base 1,000, so a 1 TB drive displays as a full 1.0 TB on a Mac.
Decimal (SI) vs Binary (IEC) Storage Reference.
Why data storage calculations differ between disk manufacturers and operating systems.
Prefix Multipliers: Decimal (1000) vs Binary (1024)
| Scale | Decimal (SI / Base 10) | Decimal Bytes | Binary (IEC / Base 2) | Binary Bytes | Capacity Difference |
|---|---|---|---|---|---|
| Kilo / Kibi | 1 KB = 1,000 B | 1,000 | 1 KiB = 1,024 B | 1,024 | +2.4% |
| Mega / Mebi | 1 MB = 1,000,000 B | 1,000,000 | 1 MiB = 1,048,576 B | 1,048,576 | +4.86% |
| Giga / Gibi | 1 GB = 1,000,000,000 B | 1,000,000,000 | 1 GiB = 1,073,741,824 B | 1,073,741,824 | +7.37% |
| Tera / Tebi | 1 TB = 10¹² B | 1,000,000,000,000 | 1 TiB = 2⁴⁰ B | 1,099,511,627,776 | +9.95% |
| Peta / Pebi | 1 PB = 10¹⁵ B | 1,000,000,000,000,000 | 1 PiB = 2⁵⁰ B | 1,125,899,906,842,624 | +12.59% |
Real-World Drive Usable Capacity in Windows
| Advertised Drive Size | Manufacturer Bytes | Reported in Windows (GiB) | Discrepancy Cause |
|---|---|---|---|
| 256 GB SSD | 256,000,000,000 | 238.4 GiB | 17.6 GB apparent loss |
| 512 GB SSD | 512,000,000,000 | 476.8 GiB | 35.2 GB apparent loss |
| 1 TB Drive | 1,000,000,000,000 | 931.3 GiB | 68.7 GB apparent loss |
| 2 TB Drive | 2,000,000,000,000 | 1,862.6 GiB | 137.4 GB apparent loss |
| 4 TB Drive | 4,000,000,000,000 | 3,725.3 GiB | 274.7 GB apparent loss |
| 8 TB NAS | 8,000,000,000,000 | 7,450.6 GiB | 549.4 GB apparent loss |
Download Time Reference Matrix
| File Size | 50 Mbps (DSL) | 100 Mbps (Cable) | 300 Mbps (Fiber) | 1,000 Mbps (Gigabit) |
|---|---|---|---|---|
| 1 GB (Movie clip) | 2m 44s | 1m 22s | 27s | 8s |
| 5 GB (HD Movie) | 13m 40s | 6m 50s | 2m 17s | 41s |
| 25 GB (4K Video) | 1h 08m | 34m 08s | 11m 23s | 3m 25s |
| 50 GB (Modern Game) | 2h 16m | 1h 08m | 22m 45s | 6m 50s |
| 100 GB (AAA Title) | 4h 33m | 2h 16m | 45m 31s | 13m 39s |
Frequently Asked Questions About Digital Storage.
Everything you need to know about hard drive space, file sizes, and download speeds.
Why does my 1TB hard drive show as only 931 GB in Windows?↓
Hard drive manufacturers calculate capacity using the decimal SI standard (1 TB = 1,000,000,000,000 bytes). Microsoft Windows measures storage using the binary IEC standard (1 TiB = 1,024³ bytes), but mislabels it as 'GB'. Dividing 1 trillion bytes by 1,073,741,824 yields approximately 931.32 GiB.
What is the difference between KB and KiB?↓
KB (Kilobyte) is a decimal unit equal to 1,000 bytes (10³). KiB (Kibibyte) is a binary unit established by the International Electrotechnical Commission (IEC) equal to 1,024 bytes (2¹⁰).
What is the difference between Mbps and MB/s?↓
Mbps (Megabits per second) measures network speed and bandwidth. MB/s (Megabytes per second) measures file download and write rate. Because 8 bits equal 1 byte, a 100 Mbps internet connection downloads at a maximum theoretical speed of 12.5 MB/s.
How many gigabytes are in a terabyte?↓
In the decimal system used by hard drive makers, 1 Terabyte (TB) equals exactly 1,000 Gigabytes (GB). In the binary system used by computer operating systems, 1 Tebibyte (TiB) equals 1,024 Gibibytes (GiB).