Data Storage Converter
Convert bits, bytes, KB, MB, GB, TB and PB, plus binary KiB, MiB, GiB and TiB, without mixing up 1000 and 1024.
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Tool guide
What this tool does
Data Storage Converter translates file and disk sizes between decimal and binary units. It shows why a new drive looks smaller in your operating system and lets you convert lists of sizes in one go.
Storage sizes use two competing conventions. Drive makers, network engineers and the SI system count in powers of 1000, so a gigabyte is 1,000,000,000 bytes. Many operating systems and older programs count in powers of 1024 and call 1,073,741,824 bytes a gigabyte. The gap grows with each prefix, reaching almost 10% at the terabyte level, which is why a new 1 TB drive appears as about 931 GB.
This converter keeps both systems apart with the IEC names: kB, MB, GB and TB are decimal, while KiB, MiB, GiB and TiB are binary. It also includes bits and bit-based units, since a byte is 8 bits. Every value passes through the byte, so the results are exact up to the displayed precision. A dedicated panel converts an advertised drive capacity into the figures you will see in Windows or macOS. Nothing leaves your device.
How to use Data Storage Converter
- Enter a size in the Value field.
- Choose the From unit, picking decimal (GB) or binary (GiB) as appropriate.
- Choose the To unit and read the Result.
- Use the swap button and Decimal places slider as needed.
- Enter a drive size in the Advertised vs reported panel to see how operating systems display it.
- Paste a list of file sizes into Batch convert and download the results as CSV.
Tips for better results
- Windows shows binary sizes with decimal labels, so its "GB" is really GiB.
- macOS and most phone storage screens use decimal units, matching drive labels.
- A lowercase b means bits and an uppercase B means bytes: 8 Mb is 1 MB.
- Cloud quotas and RAM are usually binary in practice even when written as GB.
Common use cases
- Checking whether a set of files will fit on a USB stick, SD card or drive.
- Understanding the capacity a new SSD will show after formatting.
- Converting database and backup sizes in reports between GB and TB.
- Teaching or learning the difference between SI and IEC prefixes.
Common mistakes to avoid
- Assuming storage has been lost because a 500 GB drive shows 465 GB.
- Confusing megabits with megabytes in file size or bandwidth figures.
- Mixing decimal and binary values in the same calculation.
Frequently asked questions
Is 1 GB 1000 MB or 1024 MB?
Under the SI standard used by storage makers, 1 GB is 1000 MB. In binary terms, 1 GiB is 1024 MiB. Software that writes "1 GB = 1024 MB" is really describing GiB and MiB.
Why does my 1 TB drive show 931 GB?
The drive holds 10¹² bytes. Dividing by 1024³ gives 931.3, which Windows displays as "931 GB". The capacity is the same; only the unit differs.
How many bits are in a byte?
A byte is 8 bits, and a nibble is 4 bits. Network speeds are usually given in bits, file sizes in bytes.
What is a kibibyte?
A kibibyte (KiB) is 1,024 bytes. The IEC introduced kibi, mebi, gibi and similar prefixes in 1998 to separate binary multiples from decimal ones.
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