Data Storage Converter (KB, MB, GB, TB, KiB, MiB…)
Free digital storage converter — bits, bytes, KB, MB, GB, TB, PB and the binary IEC versions (KiB, MiB, GiB, TiB). Clears up the 1000-vs-1024 confusion.
Pick “from” and “to” units, type a value. Handles both decimal (KB, MB, GB, TB, PB) and binary (KiB, MiB, GiB, TiB, PiB) prefixes, plus bits.
Two families, same letters (annoyingly)
| Prefix | Decimal (SI) | Binary (IEC) |
|---|---|---|
| Kilo / Kibi | 1 KB = 10³ B = 1,000 | 1 KiB = 2¹⁰ B = 1,024 |
| Mega / Mebi | 1 MB = 10⁶ B = 1,000,000 | 1 MiB = 2²⁰ B = 1,048,576 |
| Giga / Gibi | 1 GB = 10⁹ B | 1 GiB = 2³⁰ B ≈ 1.074 × 10⁹ B |
| Tera / Tebi | 1 TB = 10¹² B | 1 TiB = 2⁴⁰ B ≈ 1.1 × 10¹² B |
The IEC names (KiB, MiB, GiB, TiB) exist precisely to disambiguate. When hardware says “1 TB” and your OS says “931 GB”, the disk maker means decimal and the OS means binary — it’s the same drive.
Bits vs bytes
1 byte = 8 bits
File sizes use bytes. Network speeds use bits (Mbps, Gbps). A 100 Mbps internet connection peaks at ~12.5 MB/s of file download — before any protocol overhead.
Worked examples
-
1 GB in MB
1 GB = 1,000 MB
-
1 GiB in MiB
1 GiB = 1,024 MiB
-
1 TB in GiB — the disk vs OS gap
1 TB = 931.3225746155 GiB
Frequently asked questions
Why is my 1 TB drive only 931 GB in my OS?
Disk manufacturers use **decimal** units: 1 TB = 1,000,000,000,000 bytes. Most operating systems display in **binary** units (often confusingly labelled with the same letters): 1 TiB = 1,099,511,627,776 bytes. So 1 "TB" of disk = ~931 GiB on screen. Nothing is broken — just two definitions of "the same letters".
What's the difference between KB and KiB?
1 KB = 1,000 bytes (SI prefix, kilo = 1000). 1 KiB = 1,024 bytes (IEC binary prefix, kibi = 2¹⁰). The MB/MiB, GB/GiB, TB/TiB pairs work the same way. The unambiguous IEC names ("KiB", "MiB", "GiB") were standardised in 1998 specifically to remove the confusion.
Which one should I use?
Storage hardware (HDDs, SSDs, NVMe) labels capacity in **decimal**. RAM, OS file sizes, and most file managers use **binary**. Network rates use decimal (1 Mbps = 1,000,000 bits/s). For your own writing: pick the one your audience expects and label it explicitly.
Bits vs bytes for network speeds?
Network speeds are typically in bits per second (Mbps, Gbps), while file sizes are in bytes. Divide by 8 to go from bits to bytes. A 100 Mbps line transfers ~12.5 MB/s peak, before protocol overhead.
How precise are the conversions?
All factors are exact powers of 10 or 2. Internal arithmetic is full double-precision (~15 significant digits); the display shows up to ten fractional digits with trailing zeros stripped.
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