Enter a whole byte count to get decimal KB using 1,000 bytes and the matching binary KiB using 1,024 bytes.
Advanced options
Uses 1 KB = 1,000 bytes. Use this result when KB follows the decimal meaning of kilo.
Uses 1 KiB = 1,024 bytes. Use this result when the source explicitly says KiB or uses the binary convention.
Table of contents
How to use our Bytes to KB Converter
- Copy the whole number labeled Bytes or B from file details, a log, command output, API response, or storage report.
- Enter the number in Bytes (B). You can type normal comma groups such as 1,024 and may add B, byte, or bytes after the number.
- Click Calculate to see decimal kilobytes first, where 1 KB equals 1000 bytes, followed by binary kibibytes, where 1 KiB equals 1024 bytes.
- Use the KB result for a decimal SI source. Use the KiB result when the source explicitly says KiB or uses a 1024-byte binary convention.
- Sanity-check the result: 1,024 bytes should be 1.024 KB and exactly 1 KiB.
Definitions
Byte (B): A unit of digital information. This converter takes a nonnegative whole count of bytes.
Kilobyte (KB): A decimal data unit equal to 1000 bytes. The SI prefix kilo means 1000. [1]
Kibibyte (KiB): A binary data unit equal to 1024 bytes, which is 2 to the 10th power bytes.
Decimal places: Digits displayed after the decimal point. This setting changes the displayed result, not the conversion itself.
Common mistakes and quick fixes
Mistake: Treating KB and KiB as the same unit.
Fix: Use KB for 1000 bytes and KiB for 1024 bytes. Check the unit named by the source.
Mistake: Entering a fractional amount such as 1.5 bytes.
Fix: Enter a whole number. This converter accepts complete byte counts only.
Mistake: Using comma groups incorrectly, such as 1,01.
Fix: Put commas between groups of three digits, such as 1,024 or 12,345.
Mistake: Copying bits instead of bytes.
Fix: Check the letter case. Uppercase B means bytes, while lowercase b means bits.
Mistake: Seeing 0 after rounding a small nonzero conversion.
Fix: Choose more decimal places or use Auto formatting to show the small value.
Limitations & Key Assumptions / Boundary Conditions
- The input must be a whole byte count from 0 through 9,007,199,254,740,991 so JavaScript number math can keep the entered count exact.
- This is a unit conversion only. It does not include file-system allocation, compression, metadata, transfer overhead, or manufacturer storage reporting.
- Use decimal KB for a 1000-byte SI convention. Use KiB only when the source explicitly uses KiB or a 1024-byte binary convention.
- A fixed decimal-place setting can round a displayed value. Auto formatting keeps useful digits while removing trailing zeros.
Methodology
Conversion method
The calculator checks that the entry is a nonnegative whole number of bytes, then divides the same unrounded byte count by each unit factor.
decimal KB = bytes / 1000
binary KiB = bytes / 1024
Decimal KB appears first because the SI prefix kilo means a factor of 1000. [1] KiB is a separate binary prefix equal to 1024 bytes.
Worked example
For 1,024 bytes, 1,024 divided by 1000 is 1.024 KB. The same 1,024 divided by 1024 is 1 KiB. The byte count is unchanged; only the unit factor differs.
Display rounding
The calculator keeps the unrounded values for both conversions and applies the selected decimal-place setting only when it displays them. If a nonzero value rounds to 0, the result identifies the higher precision needed to show it.