MB to GB Converter

megabytes to gigabytes — quick reference

The formula, worked line by line

A gigabyte is exactly one thousand megabytes in decimal SI, so the conversion is one division and the constant carries no rounding of its own. The same factor of a thousand joins every rung of the decimal ladder, which is why the whole system never gets harder than moving a decimal point three places at a time.

If the number you are holding came from a tool that reports binary units, the pivot goes through bytes instead of through a second rounded factor. Multiply megabytes by 1,000,000 to get bytes, then divide by 1,073,741,824 for gibibytes or by 1,048,576 for mebibytes. Going through bytes once, rather than chaining rounded intermediate values, is what keeps the answer exact at the terabyte end.

GB = MB ÷ 1,000
bytes = MB × 1,000,000
GiB = MB × 1,000,000 ÷ 1,073,741,824
GiB = GB ÷ 1.073741824

How to use the MB to GB converter

Megabytes are the unit you meet on an email attachment limit, an app download, a camera card, a podcast episode or the data-usage screen on a phone. They are a comfortable size for one file and a useless one for a collection: past a few thousand the number stops meaning anything, and 47,300 MB tells you nothing you can act on.

This converter divides by 1,000 and gives you the gigabyte figure to three decimal places, updating as you type, so 47,300 MB resolves to 47.300 GB and lands somewhere you can picture against a 64 GB phone or a 500 GB drive.

The arithmetic here is decimal, and that is a deliberate choice rather than a convenience. Under the SI prefixes, kilo means a thousand, mega means a million and giga means a billion, so 1 GB = 1,000 MB = 1,000,000 KB = 1,000,000,000 bytes. Every consumer-facing number you are likely to type into this box was written that way.

Hard drive and SSD manufacturers define capacity in decimal, and most print the exact byte count in the small type on the packaging to prove it. Mobile carriers sell decimal gigabytes, so a 5 GB allowance is 5,000 MB and not a byte more. Internet providers quote decimal megabits. Phone and laptop spec sheets follow the same convention. If the figure came off a box, a bill or a store listing, dividing by 1,000 is the right move.

There is a second system using the same three letters, and it is the reason this conversion gets searched at all. Computers address memory in powers of two, so early practice rounded 1,024 bytes up to a kilobyte and the habit stuck all the way up the ladder.

The IEC gave those binary quantities their own names to end the collision: kibibyte, mebibyte, gibibyte and tebibyte, written KiB, MiB, GiB and TiB, where 1 GiB = 1,024 MiB = 1,073,741,824 bytes. The binary prefixes were adopted in December 1998 as an amendment to IEC 60027-2 and now live in IEC 80000-13, which reserves the plain SI prefixes for powers of a thousand.

So there is no genuine ambiguity in the standard itself. The ambiguity is entirely in what software chooses to print on screen. That last point is where the missing-storage myth comes from, and it is a labelling problem rather than a capacity problem.

Windows calculates sizes in binary but still writes GB and TB on screen, so a decimal drive always looks smaller in File Explorer than it did on the box: a 1 TB drive holding 1,000,000,000,000 bytes divides by 1,073,741,824 and displays as roughly 931 GB, when what it actually means is 931 GiB. Nothing was lost.

Apple went the other way, and its own support documentation notes that iOS 10 and earlier and OS X Leopard and earlier reported capacity using the binary system — meaning the switch to decimal came with OS X 10.6 Snow Leopard and with iOS 11, and current Apple devices agree with the advertised figure. On Linux it depends on the flag: `df -h` prints 1024-based units and `df -H` prints 1000-based ones.

How wide does the decimal-binary gap grow?

The gap between the two systems widens at every rung because it compounds. A kibibyte is 2.4 percent larger than a kilobyte, a mebibyte 4.86 percent larger than a megabyte, a gibibyte 7.374 percent larger than a gigabyte and a tebibyte 9.95 percent larger than a terabyte.

Read from the other direction — which is the direction that annoys people — a binary readout of a decimal drive shows 6.87 percent less at the gigabyte and 9.05 percent less at the terabyte than the number printed on the box.

Every megabytes value, worked out

49 common megabytes figures each get their own page, with the answer at full precision, the arithmetic, what rounding costs, and the nearest real-world reference point on the scale.

Questions people ask