Convert UTF8 to KOI8
Convert UTF8 encoding to KOI-8 and KOI8-R encodings. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Convert UTF8 to KOI8
- 1. Paste the UTF-8 text. Type or paste the text you want re-encoded, such as Russian words or plain ASCII like Hi, into the input pane.
- 2. Choose a Separator. Enter the character placed between each output byte to match the format your target KOI8 or KOI8-R system expects for its byte sequences.
- 3. Copy the KOI8 hex bytes. The output pane shows each character's KOI8 or KOI8-R byte value in hex, ready to send to a system still expecting this older Cyrillic encoding.
When to use Convert UTF8 to KOI8
Convert UTF8 to KOI8 produces byte values in the KOI8 or KOI8-R encodings that predate UTF-8 as the standard way Russian and other Cyrillic text was represented on Unix systems. It is aimed at anyone generating data for a legacy Russian-language mail or Usenet system.
- Recreating a legacy Russian Usenet or FidoNet message. You are reproducing historical Cyrillic text exchanges from a Unix system that predates widespread UTF-8 adoption, and need KOI8-R byte values for accuracy.
- Testing a mail gateway's KOI8-R fallback support. You maintain a mail relay that still needs to interoperate with older Russian systems expecting KOI8-R, and want sample byte sequences to verify compatibility.
- Generating reference bytes for a KOI8 decoder you wrote. You are implementing a decoder for the KOI8 family of encodings and want known-good byte values for a handful of Cyrillic test characters.
Examples
ASCII
Input
Hi
Output
48 69
Cyrillic
Input
Привет
Output
F0 D2 C9 D7 C5 D4
About the Convert UTF8 to KOI8 tool
Convert UTF8 to KOI8 runs as plain JavaScript in your browser tab, with no server behind it. Convert UTF8 encoding to KOI-8 and KOI8-R encodings. Whatever you put in stays on your device from start to finish.
The tool is part of EditSafely's UTF-8 Tools section, 69 single-purpose utilities built around the same idea: open the page, get the result, keep your data to yourself.
You can shape the output with the Separator setting, and the result refreshes the moment you change it. 2 worked examples further down the page show exactly what the tool produces for real inputs.
That local-first design has practical benefits beyond privacy. The tool keeps working on a flaky connection once the page has loaded, results are instant because nothing round-trips to a server, and it is safe to use with confidential material.
Frequently asked questions
Does Convert UTF8 to KOI8 cost anything?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
No data leaves your device. The whole tool is JavaScript that runs inside your browser tab, so there is no upload, no server-side processing and no log of what you did. If you disconnect from the internet after the page loads, it keeps working.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
Nothing to install and no account needed. Open the page in any up-to-date browser, including on a phone or tablet, and the tool is ready.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.