AkCalculators

Data storage units explained — how to convert between bits, bytes, KB, MB, GB, and beyond

Modern computing uses many prefixes and sometimes-confusing conventions when reporting file sizes and storage capacity. This page is a practical guide and converter for all common data storage units. Use this tool to convert quickly and accurately between bits, bytes, SI prefixes (KB, MB, GB) and binary prefixes (KiB, MiB, GiB), as well as larger units like TB, PB, and EB.

Bits vs Bytes — the fundamental difference

Bit (b) is the smallest unit of data — it can be 0 or 1. A Byte (B) typically equals 8 bits. When working with file sizes, storage, or network throughput, make sure you compare the same base unit (bits vs bytes) — bandwidth often uses bits per second (e.g., Mbps) while file sizes use bytes (e.g., MB).

SI prefixes vs binary prefixes — why there’s confusion

Two prefix systems are widely used:

• SI prefixes (decimal): KB = 1,000 bytes, MB = 1,000,000 bytes, GB = 1,000,000,000 bytes. These are favored by storage device manufacturers (HDD/SSD vendors often advertise in decimal units).
• Binary prefixes (IEC): KiB = 1,024 bytes, MiB = 1,024×1,024 bytes, GiB = 1,024³ bytes. Operating systems and many technical tools historically report sizes using these binary multiples.

Because of this mismatch, a 500 GB drive (advertised as 500,000,000,000 bytes) will typically show up as ~465.66 GiB in an operating system that reports in GiB. Knowing which system your tool or OS uses avoids confusion.

Canonical conversion method used by this tool

This converter uses bytes as the bridge unit internally. Conversions follow two steps:

1. Convert input to bytes (accounting for bit/byte and SI vs binary multipliers).
2. Convert bytes to target unit.

This reduces chaining error and makes the conversion accurate for any pair of units.

Quick conversion table (reference)

Common real-world examples

Example 1 — File download: A 5 MB image (advertised MB decimal) is how many MiB?

5 MB = 5,000,000 bytes. In MiB: 5,000,000 / 1,048,576 ≈ 4.768 MiB.

Example 2 — Disk capacity: A 1 TB drive (decimal) reported by OS in TiB looks smaller. Convert 1 TB to TiB:

1 TB = 1,000,000,000,000 bytes. TiB = 1,099,511,627,776 bytes. 1,000,000,000,000 / 1,099,511,627,776 ≈ 0.9095 TiB (≈ 0.91 TiB).

Example 3 — Bits vs bytes for network: An ISP claims 100 Mbps (megabits per second). A file of 100 MB (megabytes) will take how long to download at full 100 Mbps?

100 MB = 800 Mb (megabits) if MB here equals 1,000,000 bytes. At 100 Mbps, time = 800 / 100 = 8 seconds (theoretical, ignoring overhead).

Best practices — avoid these mistakes

• Check the unit system: Confirm whether values are reported in decimal (KB) or binary (KiB). This is the most common source of mismatch.
• Mind bits vs bytes: Network speeds use bits; file sizes use bytes. Don’t mix them accidentally.
• Avoid rounding early: Keep full precision while computing and round the final display to a sensible number of decimal places.
• When sizing storage: Account for file system overhead and reserved space — real usable bytes are slightly less than raw bytes.

How developers and system admins use this tool

Developers use storage converters to estimate transfer times, pick correct buffer sizes, or compare package sizes (MB vs MiB). System administrators use it to reconcile reported disk sizes and to calculate backups, replication datasets, and cloud storage costs where vendors charge by decimal GB/TB.

FAQ

Conclusion

This Data Storage Converter helps you convert accurately between bits, bytes, decimal and binary prefixes, and the large-scale units used in modern storage planning. Bookmark it for quick file size checks, bandwidth calculations, and storage capacity comparisons.