Convert Gigabytes to Megabytes
Gigabyte (GB) to Megabyte (MB) unit conversion — enter any value below to get an instant result, or use the table for common values.
Results from this calculator are estimates provided for general informational purposes only, based on formulas, rates, and standards commonly accepted as of 2026. Figures may differ slightly from other calculators or professional sources due to rounding methods, differing assumptions, or regional regulations, and rules may change over time. Always consult a qualified professional — such as a financial advisor, healthcare provider, or other relevant specialist — before making decisions based on these results.
Result
1 GB = 1000 MB
1 Gigabyte = 1000 Megabytes
1 Megabyte = 0.001 Gigabytes
1 GB in every supported unit
Conversion chart: Gigabyte to Megabytes
Conversion table
| Gigabyte (GB) | Megabyte (MB) |
|---|---|
| 0.01 GB | 10 MB |
| 0.1 GB | 100 MB |
| 1 GB | 1000 MB |
| 2 GB | 2000 MB |
| 3 GB | 3000 MB |
| 5 GB | 5000 MB |
| 10 GB | 10000 MB |
| 20 GB | 20000 MB |
| 50 GB | 50000 MB |
| 100 GB | 100000 MB |
| 1000 GB | 1000000 MB |
Gigabyte (GB)
Definition: Equal to 1,000,000,000 bytes (10^9) under the decimal standard, or roughly 1.074 billion bytes when historically interpreted using binary math.
History: Entered mainstream consumer use in the 1990s as hard drives crossed the gigabyte threshold for the first time; the same decimal-versus-binary interpretation split that affected the kilobyte and megabyte carried over to the gigabyte.
Current use: The standard unit for advertised hard drive, SSD, and USB flash drive capacity, and the unit most smartphone and computer storage tiers are marketed in — 64 GB, 128 GB, 256 GB, and so on.
Megabyte (MB)
Definition: Equal to 1,000,000 bytes (10^6) under the decimal SI standard; historically also used to mean 1,048,576 bytes (2^20) in binary computing contexts.
History: Came into common use during the 1970s and 80s as storage capacities grew past the kilobyte scale, inheriting the same decimal-versus-binary ambiguity that already existed for the kilobyte.
Current use: This is the classic source of the "missing space" confusion: storage manufacturers advertise capacity using decimal megabytes and gigabytes (1 MB = 1,000,000 bytes), while Windows' File Explorer has historically displayed file and drive sizes using binary math — labeling 1,048,576 bytes as "1 MB" — which makes a purchased drive appear to have less space than advertised even though no storage is actually missing.
Supported Units
| Unit | Symbol | In Bytes |
|---|---|---|
| Bit | bit | 0.125 B |
| Byte | B | 1 B |
| Kilobyte | KB | 1000 B |
| Megabyte | MB | 1000000 B |
| Gigabyte | GB | 1E+09 B |
| Terabyte | TB | 1E+12 B |
| Kibibyte | KiB | 1024 B |
| Mebibyte | MiB | 1048576 B |
| Gibibyte | GiB | 1.07374E+09 B |
| Tebibyte | TiB | 1.09951E+12 B |
About These Parameters
- Value
- The number you want to convert, expressed in the "From" unit. Accepts decimals.
- From Unit
- The unit your input value is currently measured in.
- To Unit
- The unit you want the result converted into. Use the swap button to flip From and To instantly.
How Data Storage Conversion Works
The Formula
Every unit here is defined by a fixed multiplier relative to the byte. To convert a value from one unit to another:
result = value × (factor of "From" unit ÷ factor of "To" unit)
For Gigabyte → Megabyte: multiply by 1000. For example, 1 GB × 1000 = 1000 MB.
Decimal (1000) vs. Binary (1024)
Data storage is the one measurement family where the same prefix means two different things. Storage manufacturers, and the SI and IEC standards bodies, define a kilobyte as exactly 1,000 bytes, a megabyte as 1,000,000 bytes, and so on — clean powers of ten, matching every other metric prefix. But because computer memory is physically organized in powers of two, operating systems have long used the same labels — "KB," "MB," "GB" — to mean powers of 1,024 instead: 1,024 bytes, 1,048,576 bytes, and so on. This converter treats the decimal units (kilobyte, megabyte, gigabyte, terabyte) and the binary units (kibibyte, mebibyte, gibibyte, tebibyte) as distinct, precisely defined units so there is no ambiguity — 1 kilobyte is always 1,000 bytes, and 1 kibibyte is always 1,024 bytes.
This is exactly why a drive advertised as "500 GB" (500,000,000,000 bytes under the manufacturer's decimal definition) shows up as roughly "465 GB" in Windows' File Explorer — Windows is dividing that same byte count using binary gibibyte math (2^30 bytes per unit) while still displaying the label "GB" instead of the technically correct "GiB." No storage is missing; two different definitions of the same word are being compared.
Bits vs. Bytes: Why Network Speeds Look Slower Than They Are
Internet and Wi-Fi speeds are almost always advertised in bits per second (Mbps or Gbps), while file sizes and download progress bars are shown in bytes (MB or GB) — and there are 8 bits in a byte. A connection advertised as "100 Mbps" therefore has a real-world maximum download speed of about 100 ÷ 8 = 12.5 megabytes per second, not 100 megabytes per second. This single unit mismatch is one of the most common sources of confusion in consumer networking, and it is worth double-checking whenever comparing an advertised connection speed to an actual download time.
Example
1 GB equals 1000 MB. For scale, that's about 200× a typical high-resolution smartphone photo (5 MB, or 0.005 GB).
Frequently Asked Questions
How many Megabytes are in 1 Gigabyte?
1 Gigabyte (GB) equals exactly 1000 Megabytes (MB).
Why does my new hard drive show less space than advertised?
Manufacturers advertise capacity using decimal gigabytes (1 GB = 1,000,000,000 bytes), while your operating system typically calculates and displays free space using binary gibibytes (1 GiB = 1,073,741,824 bytes) but still labels it "GB." The byte count is identical — only the unit definition used to display it differs, so a 500 GB drive reads as about 465 "GB" in Windows.
What is the difference between a bit and a byte?
A bit is a single binary digit (0 or 1); a byte is a group of 8 bits and is the smallest unit typically used to represent a character of data. Network and internet speeds are conventionally measured in bits per second, while file and storage sizes are measured in bytes, so an "8 Mbps" connection transfers roughly 1 megabyte per second at best.
Should I use KB/MB/GB or KiB/MiB/GiB?
Use the decimal units (KB, MB, GB, TB) when matching a manufacturer's advertised storage capacity or a network speed. Use the binary units (KiB, MiB, GiB, TiB) when you need the exact power-of-two value a computer uses internally, such as memory addressing or precise free-space reporting — this converter supports both so you can convert accurately between either system.