How many bytes are in a kilobyte?

In the SI decimal standard (used by storage manufacturers and most networking tools), 1 kilobyte (KB) = 1000 bytes. In the IEC binary standard (used by most operating systems), 1 kibibyte (KiB) = 1024 bytes. The two standards produce slightly different results for the same byte count.

Why does my OS show a different KB value than the file spec?

Storage manufacturers advertise capacity in SI (1 KB = 1000 bytes), while Windows and many other operating systems calculate using binary (1 KiB = 1024 bytes) but label the result as "KB". This discrepancy grows larger at higher magnitudes — a 1 GB drive shows roughly 954 MiB in Windows.

Which definition should I use?

Use SI (1 KB = 1000 bytes) when working with storage specs, network throughput, and most developer APIs. Use binary (1 KiB = 1024 bytes) when interpreting values reported by operating systems or when doing low-level bit/byte arithmetic in binary systems.

What is a kibibyte (KiB)?

Kibibyte is the IEC 80000-13 standard term for exactly 1024 bytes. It was introduced to remove ambiguity from the overloaded "kilobyte" label, which historically referred to both 1000 and 1024 bytes depending on context.

Can I convert values larger than kilobytes here?

This tool focuses on the byte-to-kilobyte step. For larger conversions (KB to MB, MB to GB, etc.) use the related tools linked below.

Bytes to Kilobytes Converter

Name: Bytes to Kilobytes Converter
Availability: InStock
Author: Nham Vu

Enter a byte value and instantly get kilobytes (KB, decimal SI) and kibibytes (KiB, binary IEC), plus a quick-reference table.

Enter Bytes

Bytes (B)

SI vs Binary: KB (kilobyte) = 1000 bytes — used by storage manufacturers and networking. KiB (kibibyte) = 1024 bytes — used by operating systems.

Result

Enter a byte value to see the conversion.

Quick-Reference Table

Bytes (B)	KB (÷ 1000)	KiB (÷ 1024)
500	0.5 KB	0.488281 KiB
1,000	1 KB	0.976563 KiB
1,024	1.024 KB	1 KiB
4,096	4.096 KB	4 KiB
10,000	10 KB	9.765625 KiB
65,536	65.536 KB	64 KiB
100,000	100 KB	97.65625 KiB
1,000,000	1,000 KB	976.5625 KiB

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Summary

Enter a byte value and instantly get kilobytes (KB, decimal SI) and kibibytes (KiB, binary IEC), plus a quick-reference table.

How it works

Enter any number of bytes in the input field.
The converter divides the byte count by 1000 to get kilobytes (SI decimal).
It also divides by 1024 to get kibibytes (IEC binary) as a secondary reference.
Results update instantly as you type.
The quick-reference table below shows common byte counts converted to both KB and KiB.
Use the copy button next to each result to copy the value to your clipboard.

Use cases

Check how large a file is in KB before uploading to a size-limited service.
Compare storage specs (SI KB) with what your OS reports (binary KiB).
Convert packet or payload sizes from bytes to kilobytes for documentation.
Verify data transfer sizes in API responses and bandwidth calculations.
Understand why a "1 KB" file in Windows shows slightly fewer than 1000 bytes.
Cross-reference byte values in binary protocol fields against human-readable KB.

Frequently Asked Questions

Last updated: 2026-07-22 · Reviewed by Nham Vu