What is the difference between KB and KiB?

KB (kilobyte) is a decimal unit: 1 KB = 1,000 bytes. KiB (kibibyte) is a binary unit: 1 KiB = 1,024 bytes. The IEC introduced KiB in 1998 to remove ambiguity, but many tools and OSes still use KB to mean 1,024 bytes informally.

How do I convert kilobytes to kibibytes?

Multiply by 1,000 then divide by 1,024. For example: 100 KB × 1000 / 1024 = 97.65625 KiB.

Why is 1 KB slightly less than 1 KiB?

Because 1 KB = 1,000 bytes while 1 KiB = 1,024 bytes. So one kilobyte is 24 bytes fewer than one kibibyte, making 1 KB ≈ 0.9766 KiB.

Which is larger, KB or KiB?

KiB is larger. 1 KiB = 1,024 bytes, whereas 1 KB = 1,000 bytes. The difference grows at higher magnitudes (MB vs MiB, GB vs GiB, etc.).

Does Windows use KB or KiB?

Windows File Explorer labels sizes as "KB" but actually uses 1 KB = 1,024 bytes (the binary definition). This is a common source of confusion — technically those should be labeled KiB.

Kilobyte to Kibibyte Converter

Convert kilobytes (KB, decimal: 1 KB = 1,000 bytes) to kibibytes (KiB, binary: 1 KiB = 1,024 bytes) and back.

Kilobytes to Kibibytes

1 KB = 1,000 bytes → KiB = KB × 1000 / 1024

Kilobytes (KB) Kibibytes (KiB)

Kibibytes to Kilobytes

1 KiB = 1,024 bytes → KB = KiB × 1024 / 1000

Kibibytes (KiB) Kilobytes (KB)

Conversion Formulas

KB → KiB

KiB = KB × 1000 / 1024

= KB × 0.9765625

KiB → KB

KB = KiB × 1024 / 1000

= KiB × 1.024

Common Values

Kilobytes (KB)	Kibibytes (KiB)
1 KB	0.9765625 KiB
10 KB	9.765625 KiB
100 KB	97.65625 KiB
1,000 KB	976.5625 KiB
1,024 KB	1,000 KiB

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Summary

Kilobytes (KB) and kibibytes (KiB) measure the same type of data but use different bases. One kilobyte equals exactly 1,000 bytes (SI/decimal), while one kibibyte equals exactly 1,024 bytes (IEC/binary). The conversion factor is 1 KB = 1000/1024 KiB, or about 0.9765625 KiB. This distinction matters when comparing storage device specifications (marketed in KB) with what your operating system reports (shown in KiB or KB depending on the OS).

How it works

Enter a value in either the kilobytes (KB) or kibibytes (KiB) field.
The converter applies the exact ratio: 1 KB = 1000/1024 KiB.
For KB to KiB: multiply the KB value by 1000, then divide by 1024.
For KiB to KB: multiply the KiB value by 1024, then divide by 1000.
The result updates instantly as you type, with up to 10 significant digits shown.

Use cases

Reconcile hard drive advertised capacity (KB) with OS-reported size (KiB).
Convert file size metadata between SI and IEC notations.
Clarify storage specs when documentation mixes KB and KiB.
Understand why 1 KB of network data does not equal 1 KiB in memory.
Cross-check values from tools that use different notation standards.
Learn the difference between decimal and binary storage prefixes.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu