Data Storage Converter (MB, GB, TB)
Type in either box to convert GB to MB, TB to GB, MB to GB or any data size, with decimal (1000) and binary (1024) units side by side.
Type in either box. Tap a unit under a box to change it.
Uses the size in the box you typed in. Real downloads often reach 80–90% of the advertised speed.
GB to MB table
Common values both ways. Change the units above and the table follows.
| GB | MB |
|---|---|
| 1 | 1,000 |
| 2 | 2,000 |
| 4 | 4,000 |
| 8 | 8,000 |
| 16 | 16,000 |
| 32 | 32,000 |
| 64 | 64,000 |
| 128 | 128,000 |
| 256 | 256,000 |
| 500 | 500,000 |
| 512 | 512,000 |
| 1,000 | 1,000,000 |
| 1,024 | 1,024,000 |
| 2,000 | 2,000,000 |
| 4,000 | 4,000,000 |
| MB | GB |
|---|---|
| 1 | 0.001 |
| 2 | 0.002 |
| 4 | 0.004 |
| 8 | 0.008 |
| 16 | 0.016 |
| 32 | 0.032 |
| 64 | 0.064 |
| 128 | 0.128 |
| 256 | 0.256 |
| 500 | 0.5 |
| 512 | 0.512 |
| 1,000 | 1 |
| 1,024 | 1.024 |
| 2,000 | 2 |
| 4,000 | 4 |
Common examples
- Megabytes in a gigabyte1 GB = 1,000 MB · 1 GiB = 1,024 MiB
- Gigabytes in a terabyte1 TB = 1,000 GB · 1 TiB = 1,024 GiB
- A “1 TB” drive in Windows1 TB = 931.32 GiB (shown as “931 GB”)
- A “256 GB” phone256 GB = 238.42 GiB
- Bits in a byte1 B = 8 bit · 1 MB = 8 Mbit
- A 100 Mbps connection100 Mbit = 12.5 MB each second
- A 5 GB film at 100 Mbps5 GB × 8 ÷ 100 Mbps = 400 s = 6 min 40 s
- Mebibyte vs megabyte1 MiB = 1.048576 MB · 1 MB = 0.953674 MiB
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How your data size is converted
Every unit goes into bytes first, then out to the unit you want.
- 1
Your size
1 GB →
MB - 2
Into bytes
1 × 1,000,000,000 =
1,000,000,000 B - 3
Out to MB
1,000,000,000 ÷ 1,000,000 =
1,000 MB - 4
The shortcut
1 GB =
1,000 MB
Read more: the formula, a worked example, 1000 vs 1024, bits vs bytes and why 1 TB shows 931 GB
The formula
bytes = your number × bytes in one of your unit
answer = bytes ÷ bytes in one of the unit you want
decimal: 1 kB = 1,000 B, 1 MB = 1,000 kB, 1 GB = 1,000 MB, 1 TB = 1,000 GB
binary: 1 KiB = 1,024 B, 1 MiB = 1,024 KiB, 1 GiB = 1,024 MiB, 1 TiB = 1,024 GiB
1 byte = 8 bits
download time = size in bits ÷ speed in bits per second
Worked example
1 GB in MB. First into bytes: 1 × 1,000,000,000 = 1,000,000,000 B. Then out to MB, where 1 MB is 1,000,000 B: 1,000,000,000 ÷ 1,000,000 = 1,000 MB.
The other way, MB to GB: 2,500 MB ÷ 1,000 = 2.5 GB. In binary units, 1 GiB = 1,073,741,824 ÷ 1,048,576 = 1,024 MiB.
Why a 1 TB drive shows 931 GB
Drive makers sell in decimal units: 1 TB is 1,000,000,000,000 bytes. Windows divides by 1,024 at each step instead of 1,000, so it shows 1,000,000,000,000 ÷ 1,024³ = 931.32 and labels it “GB” (it is really GiB). macOS, iOS and Android count in 1000s, so they show the full size. Formatting also uses a little space for the file system, so you’ll see slightly less again.
| Size on the box | Windows shows (GiB) | Mac / phone shows |
|---|---|---|
| 128 GB | 119.21 GiB | 128 GB |
| 256 GB | 238.42 GiB | 256 GB |
| 500 GB | 465.66 GiB | 500 GB |
| 512 GB | 476.84 GiB | 512 GB |
| 1 TB | 931.32 GiB | 1 TB |
| 2 TB | 1,862.65 GiB | 2 TB |
| 4 TB | 3,725.29 GiB | 4 TB |
Bits and bytes
A bit is a single 0 or 1. A byte is 8 bits, enough for one letter of text. Storage is sold in bytes (big B) and internet speeds in bits per second (small b), so divide Mbps by 8 for MB per second: 100 Mbps is 12.5 MB/s at most.
Download time
Turn the size into bits and divide by the speed. A 5 GB film is 5 × 8,000 = 40,000 megabits; at 100 Mbps that is 40,000 ÷ 100 = 400 s, or 6 min 40 s. At 90% efficiency it takes 400 ÷ 0.9 = 444 s.
Prefixes follow the international standard IEC 80000-13: kilo, mega, giga and tera are powers of 1000; kibi, mebi, gibi and tebi are powers of 1024. Checked 11 October 2026.
Common questions
How many MB are in a GB?
1,000 MB in the decimal system that drive makers, phone makers and internet speeds use. In the binary system some computers use, 1 GiB is 1,024 MiB. Windows uses 1,024 but writes GB and MB, which is where the confusion comes from.
How many GB are in a TB?
1,000 GB in a terabyte, and 1,024 GiB in a tebibyte. So a 2 TB drive holds 2,000 GB, which a computer counting in 1024s shows as 1,862.65 GB (really GiB).
Why does my 1 TB drive only show 931 GB?
Nothing is missing. The maker counts 1 TB as 1,000,000,000,000 bytes. Windows divides by 1,024 three times instead of 1,000, giving 931.32, and still calls it GB. The gap grows with size: about 7% at GB and 9% at TB.
What is the difference between Mb and MB?
A small b means bits and a big B means bytes, and 1 byte is 8 bits. Internet speeds are in megabits per second (Mbps), so a 100 Mbps line downloads at most 12.5 megabytes (MB) each second.
How long does it take to download 1 GB?
Size in bits ÷ speed. 1 GB is 8,000 megabits, so at 100 Mbps it takes 80 seconds and at 1 Gbps 8 seconds, at full speed. Real downloads are often slower, so Advanced lets you set an efficiency, such as 90%.
What are KiB, MiB and GiB?
Binary units: 1 KiB is 1,024 bytes, 1 MiB is 1,024 KiB (1,048,576 bytes) and 1 GiB is 1,024 MiB (1,073,741,824 bytes). They were named so that kB, MB and GB could keep meaning 1,000, 1,000,000 and 1,000,000,000 bytes.
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