Bytes to KB, MB, GB and TB Converter
Need to convert bytes to KB, MB, GB or TB? Enter any value, pick your units, and choose binary (1024 — what your operating system shows) or decimal (1000 — what the box on the hard drive says). The two systems are exactly why a "1 TB" drive shows up as ~931 GB in Windows or macOS. Below the calculator you'll find the exact conversion factors, a full reference chart, and the formula so you can check any conversion by hand.
1 GB = 1,024 MB in the binary system (used by operating systems) or 1,000 MB in the decimal system (used by drive manufacturers). Each step up the ladder — bytes → KB → MB → GB → TB — multiplies by 1,024 (binary) or 1,000 (decimal). So 1 GB = 1,073,741,824 bytes in binary, and a drive sold as 1 TB shows about 931 GB because the OS counts in binary.
When to use this calculator
- Convert a file size you see in a file manager (KB, MB) to GB and back
- Figure out why a 1 TB drive only shows ~931 GB of usable space
- Estimate how many photos, songs or videos fit on a given storage size
- Plan storage allocation, backups and data transfers as a developer or sysadmin
- Convert between decimal (manufacturer) and binary (OS) sizes for accurate capacity
Worked example: convert 1 GB to MB (binary)
- Goal: how many MB are in 1 GB using the binary system (1024).
- Convert GB to bytes: 1 GB × 1024 × 1024 × 1024 = 1,073,741,824 bytes.
- Convert bytes to MB: 1,073,741,824 ÷ (1024 × 1024) = 1,024 MB.
- In decimal (1000), the same 1 GB would equal 1,000 MB.
How it works
2 min readBytes to KB, MB, GB, TB: the exact conversion factors
Storage units climb in steps. Each step up multiplies by 1024 in the binary system (what your operating system uses) or by 1000 in the decimal system (what drive manufacturers print on the box). A byte itself is 8 bits.
| Unit | Binary (1024) | Decimal (1000) |
|---|---|---|
| 1 KB | 1,024 bytes | 1,000 bytes |
| 1 MB | 1,024 KB = 1,048,576 bytes | 1,000 KB = 1,000,000 bytes |
| 1 GB | 1,024 MB = 1,073,741,824 bytes | 1,000 MB = 1,000,000,000 bytes |
| 1 TB | 1,024 GB = 1,099,511,627,776 bytes | 1,000 GB = 1,000,000,000,000 bytes |
Quick conversion chart (binary, 1024)
| From | To MB | To GB | To TB |
|---|---|---|---|
| 1 GB | 1,024 MB | 1 GB | 0.000977 TB |
| 5 GB | 5,120 MB | 5 GB | 0.00488 TB |
| 10 GB | 10,240 MB | 10 GB | 0.00977 TB |
| 50 GB | 51,200 MB | 50 GB | 0.0488 TB |
| 100 GB | 102,400 MB | 100 GB | 0.0977 TB |
| 500 GB | 512,000 MB | 500 GB | 0.488 TB |
| 1 TB | 1,048,576 MB | 1,024 GB | 1 TB |
The formula
To convert any value, first turn it into bytes, then divide into the target unit:
where base is 1024 (binary) or 1000 (decimal), and the index is B = 0, KB = 1, MB = 2, GB = 3, TB = 4.
Binary vs decimal — why it matters
This mismatch is why a 1 TB drive shows up as about 931 GB once your OS measures it in binary.
Frequently asked questions
How many MB are in a GB?
In binary (used by Windows, macOS and Linux), 1 GB = 1,024 MB. In decimal (used by manufacturers), 1 GB = 1,000 MB. Pick your system in the calculator to see either result.
How many bytes are in 1 GB?
In binary, 1 GB = 1,073,741,824 bytes (1024 × 1024 × 1024). In decimal, 1 GB = 1,000,000,000 bytes. The binary value is what your operating system actually counts.
How many GB are in 1 TB?
In binary, 1 TB = 1,024 GB. In decimal, 1 TB = 1,000 GB. That gap is why a drive sold as 1 TB shows roughly 931 GB of usable space after your OS measures it in binary.
Why does my 1 TB hard drive show only 931 GB?
Manufacturers label drives in decimal: 1 TB = 1,000,000,000,000 bytes. Windows and macOS report storage in binary, where 1 TB = 1,099,511,627,776 bytes. So 1,000,000,000,000 ÷ 1,073,741,824 ≈ 931 GB. No space is missing — it's just two different counting systems.
What is the difference between KB and KiB?
KB (kilobyte) traditionally means 1,000 bytes (decimal), while KiB (kibibyte) strictly means 1,024 bytes (binary). The IEC introduced KiB, MiB and GiB to remove the ambiguity, but most operating systems still display 'KB' while counting in 1024.
How many KB are in an MB?
In binary, 1 MB = 1,024 KB. In decimal, 1 MB = 1,000 KB. To convert MB to KB, multiply by 1,024 (binary) or 1,000 (decimal).
How do I convert MB to GB?
Divide the number of MB by 1,024 in binary, or by 1,000 in decimal. For example, 2,048 MB ÷ 1,024 = 2 GB (binary), or 2,000 MB ÷ 1,000 = 2 GB (decimal).
What is a byte and how does it relate to bits?
A byte is 8 bits and is the fundamental unit of computer storage. File sizes are measured in bytes (and KB, MB, GB, TB), while network and internet speeds are usually measured in bits per second (Mbps, Gbps). 1 byte = 8 bits.
Should I use binary or decimal for my conversion?
Use binary (1024) when you want to match what your operating system shows for files, RAM and disk usage. Use decimal (1000) when you're reading a manufacturer's advertised capacity or network transfer speed. The calculator lets you switch between both.