To convert MB to GB, divide the number of megabytes by 1,000 if you follow the decimal (SI) standard used by storage makers, macOS and iOS. Divide by 1,024 if you follow the binary convention used by Windows and RAM. So 5,000 MB is 5 GB in decimal, or about 4.88 GB in binary.
I get this question more than almost any other unit question: “Is a gigabyte 1000 MB or 1024 MB?” The honest answer is that both numbers are in use today, and which one is “right” depends on who is doing the counting. Your phone box, your laptop and your mobile data plan may each be using a different rule.
In this guide, I will walk you through the MB to GB conversion step by step, show you exactly where each standard is used, and explain the MB vs MiB difference that causes most of the confusion. If you work with files, storage or data bundles, this is one of those small skills that saves you real headaches. It sits right alongside the other everyday calculations I keep handy on a set of free online unit converters.
By the end, you will know how many MB make a GB in any situation, why your new 1 TB drive shows up as 931 GB, and how to do the math in your head in a few seconds.
What Are MB and GB?
A megabyte (MB) is a unit of digital information equal to one million bytes in the decimal system, or 1,048,576 bytes in the binary system. A gigabyte (GB) is one thousand times larger: one billion bytes in decimal, or 1,073,741,824 bytes in binary.
Before we convert anything, it helps to be clear about the building blocks. Every unit of digital storage starts from the same two pieces:
- Bit (b): the smallest unit of data, a single 0 or 1.
- Byte (B): a group of 8 bits. One byte holds roughly one text character.
From there, the prefixes stack up:
| Unit | Symbol | Decimal value (SI) | Binary value (traditional) |
| Kilobyte | KB / kB | 1,000 bytes | 1,024 bytes |
| Megabyte | MB | 1,000,000 bytes | 1,048,576 bytes |
| Gigabyte | GB | 1,000,000,000 bytes | 1,073,741,824 bytes |
| Terabyte | TB | 1,000,000,000,000 bytes | 1,099,511,627,776 bytes |
Notice the gap between the two columns grows with every step. At the kilobyte level, the difference is only 2.4%. At the gigabyte level, it is about 7.4%. At the terabyte level, it reaches roughly 10%. That growing gap is exactly why the megabytes to a gigabyte question matters more today than it did when files were small.
To put sizes in perspective, a typical smartphone photo sits somewhere in the 2 to 5 MB range, depending on the camera and format. If you regularly resize images before sharing them, you are already managing file sizes at the MB level. A full HD movie, on the other hand, usually lands in the GB range.
Is 1 GB 1000 MB or 1024 MB?
By the official international standard, 1 GB equals 1,000 MB. In everyday computing, especially in Windows and RAM, 1 GB is still commonly treated as 1,024 MB. The 1,024 value has its own correct name: the gibibyte (GiB).
Here is how this split happened, in plain terms.
Computers work in binary, so memory chips naturally come in powers of 2. Early engineers noticed that 2 to the power of 10 (1,024) is very close to 1,000. So they borrowed the metric prefix “kilo” and used it to mean 1,024. For a couple of decades, everyone in the field understood this shortcut, and nobody minded much.
Then storage got bigger and computers went mainstream. People who knew that a kilogram is 1,000 grams and a kilometer is 1,000 meters started buying hard drives. Storage manufacturers, who never built drives in neat binary blocks, labeled their products using normal decimal math. Operating systems like Windows kept using binary math but kept the same “GB” label. Two different numbers ended up wearing the same name.
To fix this, the International Electrotechnical Commission (IEC) introduced a separate set of binary prefixes in December 1998. Under that system, a gigabyte is 10 to the power of 9 bytes, while a gibibyte (GiB) is 2 to the power of 30 bytes, which works out to 1,073,741,824 bytes. This is the root of every MB to GB disagreement you will find online.
So my practical answer is this:
- Technically correct: 1 GB = 1,000 MB, and 1 GiB = 1,024 MiB.
- Commonly used: many people and some software still say 1 GB = 1,024 MB, meaning GiB and MiB without saying so.
Both answers show up in real life. The skill is knowing which one the label in front of you is using.
How to Convert MB to GB (Step by Step)
To convert MB to GB, divide the megabyte value by 1,000 for decimal storage, or by 1,024 for binary storage. For example, 2,500 MB equals 2.5 GB in decimal and about 2.44 GB in binary.
Here is the process I use every time I do an MB to GB conversion by hand:
- Find out the context. Is the number from a storage box, a cloud plan, Windows File Explorer, a Mac, or a RAM spec? This decides the divisor.
- Pick your divisor. Use 1,000 for decimal (drives, USB sticks, SD cards, macOS, iOS, data plans). Use 1,024 for binary (Windows, RAM, many older apps).
- Divide. GB = MB ÷ divisor.
- Round sensibly. Two decimal places is plenty for everyday use.
The Decimal Formula (Base 10)
GB = MB ÷ 1,000
Example: You download a game that the store lists as 45,000 MB. Divide by 1,000 and you get 45 GB. This is the MB to GB math that matches what you see on drive boxes and in app stores.
The Binary Formula (Base 2)
GB (really GiB) = MB (really MiB) ÷ 1,024
Example: Windows shows a video folder at 6,144 MB. Divide by 1,024 and you get exactly 6 GB as Windows reports it.
Going the Other Way: GB to MB
Reverse the operation and multiply:
- Decimal: MB = GB × 1,000 (so 8 GB = 8,000 MB)
- Binary: MB = GB × 1,024 (so 8 GB = 8,192 MB)
My Quick Mental Shortcut
When I need a fast estimate for the binary result, I divide by 1,000 first and then knock off about 2.4%. For 10,000 MB, that gives 10 GB minus 0.24 GB, which lands at roughly 9.76 GB. The exact answer is 9.766 GB, so the shortcut is close enough for checking whether a file fits on a drive. For bigger numbers, people often reach for a percentage calculator to work out exactly how much of a quota they have used after converting.
MB to GB Conversion Table
This MB to GB conversion table shows common values under both standards, so you can compare the decimal (÷1,000) and binary (÷1,024) results side by side.
| Megabytes (MB) | GB (decimal, ÷1,000) | GB (binary, ÷1,024) |
| 100 MB | 0.1 GB | 0.098 GB |
| 250 MB | 0.25 GB | 0.244 GB |
| 500 MB | 0.5 GB | 0.488 GB |
| 750 MB | 0.75 GB | 0.732 GB |
| 1,000 MB | 1 GB | 0.977 GB |
| 1,024 MB | 1.024 GB | 1 GB |
| 1,500 MB | 1.5 GB | 1.465 GB |
| 2,048 MB | 2.048 GB | 2 GB |
| 2,500 MB | 2.5 GB | 2.441 GB |
| 4,096 MB | 4.096 GB | 4 GB |
| 5,000 MB | 5 GB | 4.883 GB |
| 8,192 MB | 8.192 GB | 8 GB |
| 10,000 MB | 10 GB | 9.766 GB |
| 25,000 MB | 25 GB | 24.414 GB |
| 50,000 MB | 50 GB | 48.828 GB |
| 100,000 MB | 100 GB | 97.656 GB |
A pattern worth noticing: numbers like 1,024, 2,048, 4,096 and 8,192 come out perfectly even in binary. That is a good clue. If you see a RAM or memory spec using these numbers, you can be fairly sure it is using the 1,024 rule.
What Is the Difference Between MB and MiB?
A megabyte (MB) is 1,000,000 bytes, based on powers of 10. A mebibyte (MiB) is 1,048,576 bytes, based on powers of 2. One MiB is about 4.86% larger than one MB, and the gap widens at the gigabyte and terabyte levels.
This is the cleanest way to stop the confusion. Instead of using “MB” for two different amounts, the IEC system gives each one its own name. The binary prefix definitions published by NIST list these names and values, and also point out that binary prefixes are not part of the SI metric system itself, even though their names were derived from it.
| Decimal (SI) | Value | Binary (IEC) | Value |
| Kilobyte (kB) | 1,000 bytes | Kibibyte (KiB) | 1,024 bytes |
| Megabyte (MB) | 1,000,000 bytes | Mebibyte (MiB) | 1,048,576 bytes |
| Gigabyte (GB) | 1,000,000,000 bytes | Gibibyte (GiB) | 1,073,741,824 bytes |
| Terabyte (TB) | 10^12 bytes | Tebibyte (TiB) | 1,099,511,627,776 bytes |
Useful cross-conversions I keep in mind:
- 1 GB = about 953.67 MiB
- 1 GiB = about 1,073.74 MB
- 1 GiB = 1,024 MiB exactly
- 1 GB = 1,000 MB exactly
You will see “MiB” and “GiB” mostly in Linux tools, developer software, cloud server dashboards and virtual machine settings. The Ubuntu units policy is a good example of an operating system that formally asks applications to use IEC names for base 2 values and SI names for base 10 values, so the label always matches the math.
There is even a third, odd variant. The classic “1.44 MB” floppy disk mixed both systems: 1.44 × 1,000 × 1,024 bytes. It is a fun reminder that the confusion around the megabyte goes back decades, as the megabyte definitions on Wikipedia show.
Why Does My 1 TB Drive Show Only 931 GB?
A 1 TB drive holds 1,000,000,000,000 bytes. Windows divides that by 1,073,741,824 (binary GB), which gives about 931.32. Nothing is missing. The same bytes are being measured with a bigger unit, so the number looks smaller.
This is the single most common complaint I hear, and it is the clearest real-world example of why MB and GB conversion has two answers.
Here is what different advertised sizes look like when an operating system reports them in binary:
| Advertised capacity (decimal) | What a binary system shows |
| 16 GB | about 14.90 GB |
| 32 GB | about 29.80 GB |
| 64 GB | about 59.60 GB |
| 128 GB | about 119.21 GB |
| 256 GB | about 238.42 GB |
| 500 GB | about 465.66 GB |
| 1 TB | about 931.32 GB |
| 2 TB | about 1,862.65 GB |
On top of this unit difference, formatting and the operating system itself take up some space, so your usable free space will be a little lower still.
Apple explains this clearly in its support note on how storage capacity is measured on Apple devices. Storage makers use the decimal system, which is why packaging often states that 1 GB equals 1 billion bytes. Apple also notes that older software, such as iOS 10 and earlier and OS X Leopard and earlier, reported storage in binary. Newer Apple systems report in decimal, which is why a Mac shows numbers closer to the box.
This difference has even ended up in court. Drive makers including Western Digital and Seagate faced lawsuits over capacity labels and settled them. A later US case went in favor of the manufacturers, with the court treating the decimal definition as the preferred one for trade. You can find a summary of that history on the gigabyte page on Wikipedia.
Which Devices and Systems Use 1000 vs 1024?
Storage makers, macOS, iOS and most networking use 1,000. Windows File Explorer and RAM specs use 1,024. Linux tools vary, but well-behaved ones label binary values as MiB or GiB.
Here is my working reference:
| Where you see the number | Rule used | How many MB make a GB here |
| Hard drive, SSD, USB, SD card packaging | Decimal | 1,000 |
| macOS (10.6 Snow Leopard and later) | Decimal | 1,000 |
| iOS (iOS 11 and later) | Decimal | 1,000 |
| Windows File Explorer | Binary, labeled “GB” | 1,024 |
| RAM modules (for example “8 GB RAM”) | Binary | 1,024 |
| Internet speeds (Mbps, Gbps) | Decimal, in bits | 1,000 |
| Linux command-line tools (ls, du, df) | Often binary by default | 1,024 |
| Cloud and server dashboards | Varies, check for “GiB” | Depends on label |
My tip: if you ever compare a file size on Windows with the same file on a Mac, expect the Mac number to be a little higher. Neither computer is wrong. They are counting in different units.
MB vs Mb: Don’t Mix Up Bytes and Bits
A capital “B” means bytes, a lowercase “b” means bits. One byte is 8 bits, so 1 MB equals 8 Mb. Internet speeds are usually quoted in megabits per second (Mbps), while file sizes are quoted in megabytes.
This mix-up catches people out all the time, especially with internet packages and mobile data.
Say your connection runs at 100 Mbps. That is 100 megabits per second, which is only 12.5 megabytes per second. To download a 1 GB file (1,000 MB, or 8,000 megabits), it takes about 80 seconds in ideal conditions. Real-world speeds are usually lower because of network overhead and congestion.
Quick bit and byte reference:
- 1 MB = 8 Mb
- 1 GB = 8 Gb
- 100 Mbps ÷ 8 = 12.5 MB per second
- 1 Gbps ÷ 8 = 125 MB per second
The same caution applies to file encoding. When developers turn files into text with Base64 encoding, the output grows by roughly 33%. So a 3 MB image can become about 4 MB once encoded, which matters when you are working near an upload limit.
Real-World Examples of MB and GB
In practical terms, 1 GB holds roughly 200 to 500 phone photos, about an hour of standard-definition video, or a few hours of normal web browsing. Exact figures depend on file quality and compression.
These are the everyday questions where a quick MB to GB check actually helps:
Photos. If your phone saves photos at around 3 MB each, 1 GB (1,000 MB) holds about 333 photos. A 64 GB phone, after the system takes its share, still fits thousands.
Video. As a rough guide, one hour of standard-definition video at 2.2 megabits per second works out to about 1 GB. HD and 4K video use far more, often several GB per hour.
Mobile data bundles. If your monthly bundle is 6 GB and you have used 4,500 MB, you have used 4.5 GB in decimal terms, leaving about 1.5 GB. Most mobile carriers count data in decimal, though it is worth checking your provider’s terms if the numbers do not seem to add up.
Email attachments. Many email services cap attachments at around 20 to 25 MB. A 0.5 GB video file (500 MB) is far over that limit, so you would need a cloud link instead.
USB transfers. A folder showing 30.5 GB in Windows is about 32.75 GB in decimal. That will not fit on a 32 GB flash drive, even though the numbers look close. This is exactly the kind of moment where knowing how many MB to make a GB saves you a failed transfer.
Disc formats. A single-layer DVD holds about 4.7 GB in decimal, which Windows shows as roughly 4.38 GB. A single-layer Blu-ray holds about 25 GB.
Common Mistakes When Converting MB to GB
The most common mistakes are using the wrong divisor for the context, confusing megabits with megabytes, and assuming a drive is faulty when it shows less capacity than the box. Each one has a simple fix.
After years of dealing with storage questions, these are the errors I see most:
- Treating 1,024 as the only correct answer. Many competing guides say 1,000 is “a mistake.” It is not. It is the official SI definition and the one storage makers use.
- Treating 1,000 as the only correct answer. Equally risky. Your Windows PC and your RAM still use 1,024, so you need that rule to read their numbers properly.
- Mixing Mb and MB. A 50 Mbps plan does not download 50 MB per second. It downloads about 6.25 MB per second.
- Comparing numbers across systems without converting. A Mac and a Windows PC will show different sizes for the same file.
- Forgetting formatting overhead. Even after converting correctly, usable space is slightly lower than the raw capacity.
- Rounding too early. If you round each file before adding them up, small errors stack. Add first, convert once, then round.
Which Conversion Should You Use?
Use 1,000 when you are dealing with drive packaging, cloud plans, data bundles, Macs and iPhones. Use 1,024 when you are reading Windows File Explorer, RAM sizes, or anything labeled MiB or GiB.
My personal rule of thumb for MB to GB is to match the number to its source. When I am buying storage, I think in decimal because that is how it is sold. When I am checking whether files will fit on a drive that Windows is reporting, I think in binary because that is how Windows measures.
If you are writing documentation, reports or technical specs, I strongly recommend using the IEC labels (MiB, GiB) whenever you mean 1,024. It costs you one extra letter and removes all doubt for your readers.
And if you are ever unsure, run the MB to GB conversion both ways. If the file fits under both results, you are safe either way.
Pros and Cons of Each Standard
The decimal system is easier for people and is the legal standard for selling storage. The binary system fits how memory hardware is built. Each has a clear place.
| Decimal (1,000) | Binary (1,024) | |
| Easy mental math | Yes | Harder |
| Matches drive packaging | Yes | No |
| Matches RAM hardware | No | Yes |
| Official SI standard | Yes | No (IEC uses separate names) |
| Used by Windows | No | Yes |
| Used by macOS and iOS | Yes | Only older versions |
Using a Memory Unit Converter
A memory unit converter lets you enter any value in bits, bytes, KB, MB, GB, TB or larger units and get the converted result instantly. It removes the risk of dividing by the wrong number or misplacing a decimal point.
The MB to GB formulas above are simple, but when I am converting large numbers, chaining several units (say, KB to TB), or double-checking a spec sheet, a converter is faster and less error-prone. A good converter should:
- Support every unit from bits up to petabytes and beyond.
- Make clear which factor it uses (1,000 or 1,024).
- Work instantly in the browser, without sign-ups.
- Let you swap the “from” and “to” units with one click.
One tip: always check which convention a converter uses before you trust a result for a purchase decision. If a tool uses 1,024, its results will match what Windows and RAM specs show, and you can multiply by about 1.074 to get the decimal GB figure printed on the box.
Key Takeaways
- There are two valid answers. 1 GB = 1,000 MB in the decimal SI standard, and 1 GiB = 1,024 MiB in the binary IEC standard.
- The MB to GB formula is simple: divide by 1,000 (decimal) or by 1,024 (binary).
- Context decides the divisor. Drives, macOS, iOS and data plans use 1,000. Windows and RAM use 1,024.
- MiB and GiB are the precise binary names. One MiB is 1,048,576 bytes, about 4.86% more than one MB.
- A 1 TB drive showing 931 GB is normal. It is the same storage measured with a bigger unit.
- Bits are not bytes. 1 MB equals 8 Mb, which matters for internet speeds.
Conclusion
The MB to GB question has two right answers because the world never fully agreed on one. Storage makers, macOS, iOS and mobile carriers count in thousands. Windows and RAM count in 1,024s. Once you know which rule the number in front of you is using, the conversion takes seconds: divide by 1,000 or by 1,024, and you are done.
My advice is simple. Match the divisor to the source, keep bits and bytes separate, and use MiB or GiB in your own writing whenever you mean the binary value.
When you want an instant, error-free answer without doing the division yourself, try this free MB to GB converter. It handles every unit from bits up to yottabytes, uses the binary 1,024 factor that Windows and RAM specs follow, and works right in your browser with no sign-up.
Frequently Asked Questions
How many MB make 1 GB?
It depends on the standard. In the decimal system used by storage makers, macOS and iOS, 1 GB equals 1,000 MB. In the binary system used by Windows and RAM, 1 GB is treated as 1,024 MB, which is properly called a gibibyte (GiB). Both are in common use today.
How do I convert MB to GB quickly?
Divide the number of megabytes by 1,000 for decimal results, or by 1,024 for binary results. For example, 3,000 MB equals 3 GB in decimal and about 2.93 GB in binary. Pick the divisor that matches where the number came from, such as a drive box or Windows File Explorer.
Is 1 GB 1000 MB or 1024 MB?
Officially, 1 GB is 1,000 MB under the International System of Units. The value of 1,024 MB belongs to the gibibyte (GiB), a binary unit standardized by the IEC in 1998. Many people and Windows still call the 1,024 version “GB,” which is why both answers appear online.
What is the difference between MB and MiB?
A megabyte (MB) equals 1,000,000 bytes, while a mebibyte (MiB) equals 1,048,576 bytes. MB follows powers of 10, and MiB follows powers of 2. One MiB is about 4.86% larger than one MB. You will usually see MiB in Linux, developer tools and cloud dashboards.
Why does Windows show less storage than my drive box?
Drive makers measure capacity in decimal, where 1 GB is one billion bytes. Windows measures in binary, dividing by 1,073,741,824 but still labeling the result “GB.” So a 1 TB drive shows about 931 GB. No storage is missing; the same bytes are counted with a larger unit.
How many GB is 1,500 MB?
1,500 MB is exactly 1.5 GB in the decimal system. In the binary system, it is about 1.46 GB. If you are checking whether a 1,500 MB file fits on a drive that Windows reports in GB, use the binary figure to be safe.
Is a megabyte bigger than a megabit?
Yes. A megabyte is eight times bigger than a megabit because one byte contains eight bits. File sizes use megabytes (MB), while internet speeds use megabits per second (Mbps). A 100 Mbps connection transfers about 12.5 MB per second under ideal conditions.
How many megabytes to a gigabyte does my phone use?
Modern iPhones running iOS 11 or later report storage in decimal, so 1 GB equals 1,000 MB. Android phones often follow decimal reporting as well, though some apps may differ. Older iOS versions used binary math, which is why earlier iPhones showed slightly less capacity than advertised.
Does RAM use 1000 or 1024?
RAM uses the binary system, so an “8 GB” memory module holds 8 × 1,073,741,824 bytes, which is 8 GiB. Memory chips are built in powers of two, which makes the 1,024 rule a natural fit. This is one place where the traditional 1,024 definition remains standard practice.
How much is 1 GB of mobile data in MB?
Most mobile carriers count data in decimal, so 1 GB of mobile data equals 1,000 MB. Some apps on your phone may display usage in binary, which can make the numbers look slightly different. If your usage does not match your carrier’s figure, check which convention each one uses.