Bytes Converter: Convert Between B, KB, MB, GB, TB, and PB

File sizes look different depending on who is reporting them. Your operating system says a file is 4.00 GiB, your cloud dashboard calls it 4.29 GB, and the command-line tool shows 4294967296 bytes. The discrepancy comes down to whether you measure in powers of 1000 (decimal) or 1024 (binary). Our Bytes Converter handles both modes so you always get the number you need.

Decimal vs. Binary: Why It Matters

Decimal (SI) Units

Decimal units use powers of 1000. This is the standard adopted by hard drive manufacturers, networking equipment, and the International System of Units (SI).

1 KB = 1,000 bytes
1 MB = 1,000,000 bytes
1 GB = 1,000,000,000 bytes
1 TB = 1,000,000,000,000 bytes
1 PB = 1,000,000,000,000,000 bytes

Binary (IEC) Units

Binary units use powers of 1024. Operating systems like Windows traditionally report file sizes this way, and memory (RAM) is always measured in binary.

1 KiB = 1,024 bytes
1 MiB = 1,048,576 bytes
1 GiB = 1,073,741,824 bytes
1 TiB = 1,099,511,627,776 bytes
1 PiB = 1,125,899,906,842,624 bytes

The Practical Impact

A “500 GB” hard drive holds 500,000,000,000 bytes by the manufacturer’s decimal definition. But Windows displays that as roughly 465 GiB because it divides by 1024 three times. You did not lose 35 gigabytes — the two systems simply count differently.

How to Use Our Bytes Converter

Enter a value in any unit field (B, KB, MB, GB, TB, or PB)
Select the mode — decimal (base 1000) or binary (base 1024)
Read the converted values across all other units instantly
Copy the result you need for your documentation or code

Conversion Reference

Decimal Mode (Base 1000)

Unit	Bytes
1 KB	1,000
1 MB	1,000,000
1 GB	1,000,000,000
1 TB	1,000,000,000,000
1 PB	1,000,000,000,000,000

Binary Mode (Base 1024)

Unit	Bytes
1 KiB	1,024
1 MiB	1,048,576
1 GiB	1,073,741,824
1 TiB	1,099,511,627,776
1 PiB	1,125,899,906,842,624

Common Use Cases

Scenario	Suggested Mode
Hard drive / SSD capacity	Decimal (matches manufacturer specs)
RAM size	Binary (memory is always base 1024)
Network bandwidth	Decimal (networking uses SI units)
File size on Windows	Binary (OS reports in GiB)
File size on macOS	Decimal (macOS switched to base 1000)
Cloud storage pricing	Decimal (providers use GB)
API upload limits	Varies — check the documentation

Tips

When a cloud provider says “5 GB upload limit,” they almost always mean 5,000,000,000 bytes (decimal). If your file is 4.8 GiB as shown by Windows, it is actually about 5.15 GB in decimal — and it may exceed the limit.
RAM is always binary. A “16 GB” RAM stick is actually 16 GiB (17,179,869,184 bytes) because memory addresses are powers of two.
macOS Catalina and later report file sizes in decimal units. If you share files between macOS and Windows, expect the numbers to differ slightly.
When writing technical documentation, use the IEC abbreviations (KiB, MiB, GiB) if you mean base 1024, and SI abbreviations (KB, MB, GB) if you mean base 1000. This removes all ambiguity.

Frequently Asked Questions

Why does my hard drive show less space than advertised? The manufacturer measures in decimal gigabytes (base 1000), but your OS may report in binary gibibytes (base 1024). A 1 TB drive holds exactly 1,000,000,000,000 bytes, which is about 931 GiB.

Which mode should I use? Use decimal for storage devices, network bandwidth, and cloud services. Use binary for RAM, OS-level file sizes on Windows, and any context where you see the “i” suffix (KiB, MiB, GiB).

Is 1 KB equal to 1000 or 1024 bytes? It depends on the context. The IEC standard defines 1 KB as 1000 bytes (decimal) and 1 KiB as 1024 bytes (binary). In practice, many people still use “KB” to mean 1024 bytes, which is why the confusion exists.

Does this tool handle petabytes? Yes. The converter supports the full range from bytes up to petabytes in both decimal and binary modes.

Try our free Bytes Converter to convert between B, KB, MB, GB, TB, and PB instantly.