By Tim King · Updated 7 October 2026

GB to MB Converter

Decimal and Binary Storage Units, 1,000 or 1,024 Per Step, Live as You Type

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gigabytes to megabytes formula

MB = GB × 1,000

1 gigabyte = 1,000 megabytes, so multiply gigabytes by 1,000. Going the other way, 1 megabyte = 0.001 gigabytes.

gigabytes to megabytes table

gigabytes (GB)	megabytes (MB)
0.1	100
0.25	250
0.5	500
0.75	750
1	1,000
1.5	1,500
2	2,000
3	3,000
4	4,000
5	5,000
8	8,000
10	10,000
15	15,000
16	16,000
20	20,000
25	25,000
32	32,000
50	50,000
64	64,000
100	100,000
128	128,000
200	200,000
256	256,000
500	500,000
512	512,000
1,000	1,000,000
2,000	2,000,000

How many megabytes in gigabytes?

1 GB = 1,000 MB. There are 1,000 megabytes in 1 gigabytes.

2 GB = 2,000 MB. There are 2,000 megabytes in 2 gigabytes.

5 GB = 5,000 MB. There are 5,000 megabytes in 5 gigabytes.

10 GB = 10,000 MB. There are 10,000 megabytes in 10 gigabytes.

100 GB = 100,000 MB. There are 100,000 megabytes in 100 gigabytes.

megabytes to gigabytes formula

GB = MB ÷ 1,000

1 megabyte = 0.001 gigabytes, so multiply megabytes by 0.001, or divide by 1,000.

megabytes to gigabytes table

megabytes (MB)	gigabytes (GB)
1	0.001
5	0.005
10	0.01
25	0.025
50	0.05
100	0.1
200	0.2
250	0.25
500	0.5
512	0.512
700	0.7
750	0.75
1,000	1
1,024	1.024
1,500	1.5
2,000	2
2,048	2.048
3,000	3
4,000	4
4,700	4.7
5,000	5
8,000	8
10,000	10
16,000	16
25,000	25
50,000	50
100,000	100

How many gigabytes in megabytes?

100 MB = 0.1 GB. There are 0.1 gigabytes in 100 megabytes.

500 MB = 0.5 GB. There are 0.5 gigabytes in 500 megabytes.

1,000 MB = 1 GB. There are 1 gigabytes in 1,000 megabytes.

1,024 MB = 1.024 GB. There are 1.024 gigabytes in 1,024 megabytes.

5,000 MB = 5 GB. There are 5 gigabytes in 5,000 megabytes.

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How the GB To MB works

This GB to MB converter multiplies by 1,000 as you type: 1 GB is 1,000 MB in the decimal units that drive makers, phone plans and the SI system use. If your operating system reports 1,024, it is using binary units, and the explainer below covers the difference and when it matters. Press the swap button to convert MB to GB.

GB to MB: why there are two answers

Converting gigabytes to megabytes should be the simplest sum in computing. Yet it causes more support tickets and "missing space" complaints than any other unit. The reason is that "GB" carries two meanings. The SI prefixes are powers of ten, so 1 GB is 1,000 MB. Memory chips are addressed in powers of two, so for decades programmers used "megabyte" for 2²⁰ = 1,048,576 bytes and "gigabyte" for 2³⁰ = 1,073,741,824. In 1998 the IEC gave the binary sizes their own names: kibibyte, mebibyte and gibibyte (KiB, MiB, GiB). Much software still labels them KB, MB and GB anyway.

The formula

MB = GB × 1,000, and GB = MB ÷ 1,000. This page uses the decimal definition, which is exact.

For the binary figure that Windows shows, the conversion is GB × 1,000,000,000 ÷ 1,048,576. That is about GB × 953.67 MiB. The gap between the two systems grows with each prefix. It is 2.4% at kilo-to-mega, 7.4% at giga and almost 10% at tera. That is why a 1 TB drive appears as 931 GB.

Who uses which

Decimal (1 GB = 1,000 MB): drive and SSD makers, USB sticks and SD cards, phone data plans, broadband speeds, cloud storage quotas, and macOS since 10.6 Snow Leopard in 2009.
Binary (1 GB = 1,024 MB): Windows File Explorer, most Linux tools (usually labelled correctly as MiB and GiB), and RAM. An 8 GB memory module is 8 GiB, or 8,589,934,592 bytes.

Worked examples

The first example is a single-layer DVD, sold as 4.7 GB. 4.7 × 1,000 = 4,700 MB, which is 4,700,000,000 bytes. In binary that is 4,482 MiB, and burning software shows that figure. A folder that Windows reports as 4,600 MB will not fit.

The second example is a 2 GB mobile data plan. 2 × 1,000 = 2,000 MB, because carriers meter in decimal. A minute of standard-definition video uses about 5 MB and high definition about 25 MB. So 2 GB covers roughly 400 minutes of SD or 80 minutes of HD.

The third example goes the other way, from 750 MB to 0.75 GB. On a 5 GB plan that is 15%.

How many MB in a GB for everyday files and devices

Read the decimal column for anything printed on a box or a bill. Read the binary column to match the number Windows shows for the same file or drive.

Common sizes in GB, MB and binary MiB

Example	GB	MB (decimal)	MiB (Windows shows as MB)
Phone photo, 12 MP HEIC	0.003	3	3
MP3 album, 45 min at 320 kbps	0.108	108	103
HD film stream, 1 hour	3	3,000	2,861
Single-layer DVD	4.7	4,700	4,482
Dual-layer DVD	8.5	8,500	8,106
Blu-ray single layer	25	25,000	23,842
Blu-ray dual layer	50	50,000	47,684
USB stick	16	16,000	15,259
USB stick	32	32,000	30,518
SD card	64	64,000	61,035
Phone storage	128	128,000	122,070
Phone storage	256	256,000	244,141
SSD	500	500,000	476,837
SSD	512	512,000	488,281
Monthly mobile plan	5	5,000	4,768
Monthly mobile plan	20	20,000	19,073
Game update	1.5	1,500	1,431
Windows 11 ISO	5.8	5,800	5,531
4K film download	20	20,000	19,073
Google Drive free tier	15	15,000	14,305
1 TB hard drive	1000	1,000,000	953,674

How to read the result

GB equals gives the converted figure in decimal megabytes, updating as you type.
Conversion shows the factor used, 1 GB = 1,000 MB. Swap direction and it becomes 1 MB = 0.001 GB.
Inverse gives the factor for the other direction, handy for a quick sum in a spreadsheet.

The engine does not apply the binary factor. When you need the Windows figure, multiply the decimal megabytes by 0.9537. The GB to GiB converter does the full binary conversion.

Tips and pitfalls

Bits are not bytes. Network speeds are quoted in megabits per second (Mbit/s). There are 8 bits in a byte, so a 50 Mbit/s line moves 6.25 MB/s, and a 1.5 GB update takes about four minutes.
Nothing is missing from your drive. A 500 GB SSD holds 500,000,000,000 bytes. Windows divides by 2³⁰ and shows 465 GB. The formatted filesystem then takes a little more, and the recovery partition more still.
RAM is always binary. When a spec sheet says 16 GB of memory, it means 16 GiB. Nobody sells decimal RAM.
Check the label before you compare. A cloud plan's 15 GB and a Windows folder's 15 GB are different quantities. The folder is about 7% bigger in bytes.
Round sensibly. For planning storage or data use, 1,000 is close enough at the megabyte level. The binary gap only matters near a hard limit, such as a disc, an email attachment cap or a data plan's last few hundred megabytes.

For bigger numbers use the GB to TB converter. To estimate how large a recording will be, try the video bitrate calculator.

Sources: NIST prefixes for binary multiples.

Checked against: 1 GB = 1,000 MB (SI decimal prefixes)

FAQ

How many MB are in a GB?

1,000 MB in decimal units, which is what storage manufacturers, phone plans and macOS use. 1,024 in binary units, which is what Windows and RAM use. The binary unit is properly called a gibibyte, GiB, and equals 1,024 MiB.

Is 1 GB 1,000 or 1,024 MB?

Both are in use. The SI definition is 1,000 and it is the one on the box; the binary definition is 1,024 and it is the one in Windows Explorer. This page uses 1,000. Multiply by 1.024 to get the other.

How many MB is 1.5 GB?

1,500 MB, or 1,536 MiB in binary. It is about 300 minutes of SD video streaming, or a 16-minute 4K video from a phone, or 400 typical photos.

Why does my drive show less than the label says?

Because the label is decimal and Windows is binary. A 500 GB drive is 500,000,000,000 bytes, which is 465.7 GiB, and Windows labels that "465 GB". Nothing is missing; the units differ.

How many GB is 1,000 MB?

Exactly 1 GB in decimal units, which is what storage manufacturers and data plans mean. In binary it is 0.977 GiB, since a gibibyte is 1,024 MiB. Windows shows the binary figure.