Data Size Converter
Convert MB, GB and TB across SI (1000) and binary IEC (1024) units — exact to the last digit, entirely on this device.
| Bytesbyte | 1,000,000,000 | |
|---|---|---|
| Decimal — SI (÷1000) | ||
| KBkilobyte | 1,000,000 | |
| MBmegabyte | 1,000 | |
| GBgigabyte | 1 | |
| TBterabyte | 0.001 | |
| PBpetabyte | 0.000001 | |
| EBexabyte | 0.000000001 | |
| Binary — IEC (÷1024) | ||
| KiBkibibyte | ≈ 976,563 | |
| MiBmebibyte | ≈ 953.674 | |
| GiBgibibyte | ≈ 0.931323 | |
| TiBtebibyte | ≈ 0.000909495 | |
| PiBpebibyte | ≈ 0.000000888178 | |
| EiBexbibyte | ≈ 0.000000000867362 | |
- Rounded for display — copy or download takes the exact value
Press ? for shortcuts
Do it offline:$ echo 'scale=21; 1000000000 / 2^30' | bc
How to use it
- Enter a data size and pick its unit — bytes through exabytes, decimal or binary.
- Read every unit at once in two ladders: SI by 1000 (KB, MB, GB), IEC by 1024 (KiB, MiB, GiB).
- Copy a row or the whole panel; the copy and download keep the exact value even when the display rounds.
- Or paste the size with its unit, like 1.5 GiB — the tool detects it and names it in a badge you can pin.
Type a size, pick a unit — 500 MB, 1.5 GB, 1024 MiB — and read it in every byte unit at once, in decimal SI (1 kB = 1000 B) and binary IEC (1 KiB = 1024 B). Big integers do the math, so 0.931322574615478515625 GiB is exact, not rounded. Nothing you enter leaves this device.
How it works
No floating point is used. Your value is a big integer with a power-of-ten scale, and each unit is an exact integer factor — 1000 to a power for SI, 1024 for IEC. A decimal unit shifts the scale; a binary unit multiplies by a power of five, since one half is five tenths. Every result terminates.
So a gigabyte, 1000000000 bytes, and a gibibyte, 1073741824 bytes, differ. One gigabyte in gibibytes is exactly 0.931322574615478515625 — twenty-one digits, none dropped. The display keeps six significant figures behind a ≈; copy and download give the full value.
Examples
1000 MBGB 1
GiB 0.931322574615478515625
B 1000000000The literal MB-to-GB answer: 1000 MB is exactly 1 GB, and 0.931322574615478515625 GiB in binary — shown as ≈0.931323.
1 GiBGB 1.073741824
MiB 1024
B 1073741824A gibibyte is a gigabyte's binary neighbour: exactly 1024 MiB, and 1.073741824 GB in decimal.
1024 MiBGiB 1
GB 1.073741824
B 1073741824The other way, 1024 MiB is exactly 1 GiB — the same 1073741824 bytes, or 1.073741824 GB.
1.5 GBB 1500000000
MB 1500
GiB 1.3969838619232177734375A fractional decimal stays exact: 1.5 GB is 1500000000 bytes and 1500 MB. Binary rows like 1.3969838619232177734375 GiB run long.
Every example on this page is executed against the same engine that powers the tool, on every build.
Gotchas worth knowing
SI and IEC are two systems
A kilobyte is 1000 bytes in SI, a kibibyte 1024 in IEC. Higher up, a GiB is 1073741824 bytes to a GB's 1000000000.
Why a new drive looks smaller
Makers count decimal bytes; systems often count binary but print GB. A 1 TB drive holds 1000000000000 bytes, shown as about 931 GB — 1000 read as 1024.
kB, KB and KiB
SI's strict symbol is lowercase kB, but people write KB, so KB here means 1000 and KiB means 1024. Input takes either case.
The long decimals are exact
Because 1024 is a power of two, binary conversions terminate. A mebibyte is 1048576 bytes and 1.048576 MB; a gigabyte is 0.931322574615478515625 GiB. The ≈ is display rounding only.
Zero is the shared value
Enter 0 in any unit and every row reads 0, no rounding chip — the one size identical in SI and IEC.
Separators are removed and counted
Commas, spaces and underscores inside the number are stripped and tallied: 1 separator stripped, 2 separators stripped. A comma is a thousands mark, never a decimal point.
Common errors
`12.3.4` is not a valid data-size value — enter a number like 500, 1.5, or 2 GiB- Two dots or a stray letter stops the parse. The message quotes your text and highlights the span, leaving the input untouched.
Data size cannot be negative — enter 0 or more- Sizes start at zero. A leading minus is refused rather than reinterpreted, with the sign highlighted.
`XB` is not a known unit — use B, KB, MB, GB, TB, PB, EB or KiB, MiB, GiB, TiB, PiB, EiB- Only unit symbols are known — B, KB, MB up to EB, and binary KiB through EiB. An unknown token is named back, not guessed.
Value has more than 1,000 significant digits — the limit for this tool.- The tool caps a value at 1000 significant digits so the math stays instant, refusing rather than stalling past that.
Input is larger than the 1 MB limit for this tool. For arbitrary-precision math use the CLI: echo 'scale=21; 1000000000 / 2^30' | bc- Above one megabyte the page declines the whole paste. The banner prints the bc command that does the same at any size.
FAQ
How many MB are in a GB?
In decimal SI a gigabyte is 1000 megabytes, so 1000 MB is exactly 1 GB. In binary IEC it takes 1024 mebibytes to make a gibibyte — powers of ten versus powers of two.
Why does my hard drive show less than advertised?
The box counts decimal gigabytes; your system counts binary ones yet writes GB. A 1 TB drive holds 1000000000000 bytes, shown as roughly 931 of those GB; nothing is lost.
What is the difference between GB and GiB?
A GB is 1000000000 bytes; a GiB is 1073741824. KiB, MiB and GiB are IEC binary prefixes for naming powers of two. One GiB is 1.073741824 GB.
Is 1 GB 1000 or 1024 MB?
It is 1000 MB. The 1024 figure belongs to the binary units — 1024 MiB make 1 GiB, not 1 GB. Confusing the two is the usual mistake.
Does this converter round anything?
The headline keeps six significant digits and adds a ≈ when the exact value is longer. Copy and download keep every digit — one GB is 0.931322574615478515625 GiB in full.
Keyboard shortcuts
- ⌘/Ctrl + Enter
- Re-run the conversion.
- ⌘/Ctrl + S
- Download all rows as an exact .txt.
- ⌘/Ctrl + C
- Copy the panel when nothing is selected.
- ⌘/Ctrl + Shift + C
- Copy the panel even over a selection.
- t
- Switch theme (ignored while typing).
- ? or ⌘/Ctrl + /
- Open the keyboard reference.
- Esc
- Dismiss the top overlay.