Storage Unit Converter

About the Storage Unit Converter

Storage units can be confusing because two different standards exist: binary (base-1024) used by operating systems and decimal (base-1000) used by drive manufacturers. A "1 TB" hard drive marketed using decimal units actually shows roughly 931 GiB in your OS because it uses binary units internally. This discrepancy has caused confusion for decades and even led to class-action lawsuits against drive manufacturers.

This converter lets you enter a value in any storage unit—from bytes all the way up to petabytes—and see the equivalent in every other unit. Toggle between binary (KiB, MiB, GiB, TiB, PiB) and decimal (KB, MB, GB, TB, PB) systems to understand exactly how your storage is measured. Whether you're provisioning cloud storage, sizing a RAID array, or simply trying to understand why your new SSD shows less space than advertised, this converter gives you precise answers.

When This Page Helps

Drive manufacturers, cloud providers, and operating systems all measure storage differently. This converter eliminates guesswork by showing exact conversions in both binary and decimal systems simultaneously. It's essential for capacity planning, purchase decisions, and understanding the real usable space on any storage device.

How to Use the Inputs

1. Enter the storage value you want to convert.
2. Select the source unit (B, KB, MB, GB, TB, or PB).
3. Choose binary (1024) or decimal (1000) base.
4. View the converted values in all other units.
5. Toggle between binary and decimal to compare the difference.
6. Use the results for capacity planning or purchase decisions.

Example Calculation

Tips & Best Practices

• Hard drive manufacturers use decimal (1000-based) units, which is why drives appear smaller in your OS.
• RAM is always measured in binary units (1024-based) because memory addresses are powers of 2.
• Cloud providers typically bill in binary GiB but may advertise in decimal GB—check the fine print.
• IEC prefixes (KiB, MiB, GiB) were introduced in 1998 to eliminate ambiguity.
• When estimating storage needs, always add 10-20% overhead for filesystem metadata.
• Network speeds use decimal (1 Gbps = 1,000,000,000 bits/sec), so download sizes differ from file sizes.

Understanding Binary vs Decimal Storage

The binary system uses powers of 1024 because computer memory is organized in powers of 2. Each step up multiplies by 1024: bytes to KiB, KiB to MiB, MiB to GiB. The decimal system uses clean powers of 1000, making it easier for marketing but creating a growing gap at higher units.

The Gap Gets Bigger

At the kilobyte level, the difference between binary and decimal is only 2.4%. At the terabyte level, it grows to nearly 10%. A "4 TB" external drive shows about 3.63 TiB in your OS—a difference of roughly 370 GiB. At the petabyte scale, the gap exceeds 12.6%.

Practical Applications

When provisioning cloud storage or building a NAS, always calculate in the same unit system your platform uses. Most Linux and Windows systems report in binary units. macOS switched to decimal units in Snow Leopard (10.6) to match drive labels. Always verify which system your tools and platforms use before making purchasing decisions.

Frequently Asked Questions

• Why does my 1 TB drive show only 931 GB?

  Drive manufacturers use decimal units where 1 TB = 1,000,000,000,000 bytes. Your operating system uses binary units where 1 GiB = 1,073,741,824 bytes. Dividing 1,000,000,000,000 by 1,073,741,824 gives approximately 931 GiB. No data is missing—it's just measured differently.

• What is the difference between GB and GiB?

  GB (gigabyte) in the decimal/SI system equals exactly 1,000,000,000 bytes. GiB (gibibyte) in the binary/IEC system equals 1,073,741,824 bytes (1024³). The difference is about 7.4% and grows larger at higher units.

• Which standard should I use for cloud storage?

  Most cloud providers (AWS, Azure, GCP) bill in GiB (binary), even though marketing materials may say "GB." Always check the pricing documentation. AWS explicitly states pricing per GB-month where 1 GB = 2^30 bytes (which is technically 1 GiB).

• Is RAM measured in binary or decimal?

  RAM is always measured in binary units. When you buy 16 GB of RAM, you get exactly 16 × 1,073,741,824 = 17,179,869,184 bytes. This is because RAM chip capacities are always powers of 2 due to how memory addressing works.

• Why do network speeds use decimal but file sizes use binary?

  Network engineers adopted SI decimal prefixes (1 Mbps = 1,000,000 bits/sec) while computer scientists used powers of 2. A 100 Mbps connection transfers 100,000,000 bits per second, which is 11.92 MiB/sec, not 12.5 as you might expect with pure binary math.

• How do I convert between bits and bytes?

  There are 8 bits in 1 byte. To convert bits to bytes, divide by 8. To convert bytes to bits, multiply by 8. Network speeds are in bits per second while file sizes are in bytes, so divide your connection speed by 8 to get the file transfer rate.