Convert file sizes and storage capacity between bits, bytes, kilobytes, megabytes, gigabytes and terabytes. Both conventions are included: decimal units (1 KB = 1,000 bytes), used by drive makers, macOS and network speeds, and binary units (1 KiB = 1,024 bytes), which Windows shows as “KB”, “MB” and “GB”.
It explains everyday puzzles such as why a new 1 TB drive appears as 931 GB, how many photos fit on a 64 GB phone, or whether an attachment is under an email size limit.
How to use the Data Storage Converter tool
- Type the number you want to convert in the Value box, for example 500 with megabytes selected.
- Pick the unit you have in From and the unit you need in To.
- Read the result instantly in large type, with the exact formula used shown underneath.
- Open All data storage units to see the same value in every unit at once, or press ⇄ to swap the direction.
- Use Copy result to paste the converted number into a document, spreadsheet or message.
Why use ToolOrca Data Storage Converter
- Decimal KB/MB/GB/TB and binary KiB/MiB/GiB/TiB
- Bits and bytes for network speeds
- Explains the 1,000 vs 1,024 difference
- All units shown at once
- Handles very large numbers
- Instant and private
Decimal (1000) versus binary (1024) units
The SI prefixes kilo, mega, giga and tera mean 1,000, 1,000,000 and so on, so 1 GB = 1,000,000,000 bytes. That is how hard drives, SSDs, USB sticks and macOS count. Computer memory, however, comes in powers of two, so the IEC defined binary units: 1 KiB = 1,024 bytes, 1 MiB = 1,024 KiB and 1 GiB = 1,024 MiB. Windows uses the binary sizes but labels them KB, MB and GB.
Worked example: a “1 TB” drive holds 1,000,000,000,000 bytes. Divided by 1,024³ that is 931.323 GiB, which Windows displays as about 931 GB. Nothing is missing; it is the same number of bytes in a different unit.
Frequently asked questions
How many MB are in a GB?
In decimal units there are 1,000 MB in 1 GB. In binary units there are 1,024 MiB in 1 GiB, which Windows shows as 1,024 MB per GB.
Why does my 1 TB hard drive show 931 GB?
The maker counts 1 TB as 10¹² bytes, while Windows divides by 1,024³ and calls the result GB. 10¹² bytes is 931.323 GiB.
How many bytes are in a kilobyte?
1,000 bytes in the decimal convention, or 1,024 bytes for a binary kibibyte (KiB).
Is Mbps the same as MB/s?
No. Network speeds use megabits per second. Divide by 8 to get megabytes per second, so a 100 Mbps connection downloads about 12.5 MB/s.