Reference

Conversion rules

Every case where the converter did something other than a plain letter substitution — what, and why.

Most letters map straight onto one another. The rules below describe the places where they do not: where one letter is written two ways depending on position, where two letters merge into one, or where a stretch of text should not be touched at all. The converter shows each such decision beside your result.

Latin to Cyrillic

The rules applied when converting Latin text into Cyrillic.

A word-initial “e” becomes Cyrillic “э”.
After a vowel, “e” also becomes “э”.
After a consonant, “e” becomes “е” instead.
In loanwords the pair “ts” collapses into the single letter “ц”.
Where “t” and “s” meet at a morpheme boundary the result is “тс”, not “ц”.
In some Russian loanwords the letter “s” is written “ц”.
The mark in “oʻ” and “gʻ” is part of the letter itself (U+02BB), not an apostrophe.
The tutuq belgisi (U+02BC) is written “ъ” in Cyrillic.
When “s” and “h” are pronounced separately the result is “сҳ”, not “ш”.
In Russian loanwords the soft sign dropped by the Latin spelling is restored.
In Russian loanwords the hard sign ъ, which Latin drops, is restored: obyekt → объект.
The pairs “yo”, “yu”, “ya” fold back into the single letters “ё”, “ю”, “я”.

Cyrillic to Latin

The reverse direction — there are more rules here, because Cyrillic has letters with no letter of their own in Latin.

A word-initial “е” is written “ye”.
After a vowel, “е” also becomes “ye”.
After “ъ” or “ь”, “е” is read as “ye”.
An “е” standing at a compound or morpheme boundary is also written “ye”.
After a consonant, “е” is a plain “e”.
Between two vowels, “ц” is written “ts”.
A word-initial “ц” is written “s”.
A word-final “ц” is also written “ts”.
After a consonant, “ц” is written “s”.
A “ц” on a prefix boundary is decided by word structure rather than by its neighbouring letters.
The cluster “сц” is taken as a unit and becomes “ss”: сценарий → ssenariy.
A doubled “ц” is likewise treated as one cluster rather than two independent letters.
The hard sign “ъ” becomes the tutuq belgisi in Latin.
After “ў”, the hard sign is still the tutuq mark — never the digraph mark.
The soft sign (ь) is not written in the Latin script.
The letters “я” and “ю” after a consonant follow their own rule.
The cluster “сҳ” is not “sh”: the “s” and “h” stay apart.
The letter “щ” is written “shch”.

Capitalisation

Which form is chosen when a letter combination becomes a capital.

A word written entirely in capitals stays capitalised after conversion.
A word starting with a capital keeps that capital in the result.
Inside an acronym both letters of a digraph are capitalised.

Protected text

Stretches that must not be converted: links, email addresses, formulas and foreign-language runs. They are left exactly as they were.

Links (URLs) are never converted.
DOI identifiers are left untouched.
Email addresses are left alone.
ISSN, ISBN and similar identifiers do not change.
Roman numerals are preserved as written.
Formulas, chemical symbols and statistical notation are not converted.
Whole runs of English or Russian stay in their own script.

Automatic corrections

Before converting, the text is cleaned — wrong apostrophes are repaired and invisible characters removed.

Incorrect apostrophes were replaced: U+02BB for oʻ/gʻ, U+02BC for the tutuq belgisi.
The text was normalised to Unicode NFC — text pasted from Word or a PDF can spell one letter with two codepoints.
Invisible characters — zero-width spaces and the like — were removed.

How a decision is reached

For each word the converter checks the lexicon first, then the rules, and finally a direct letter match.

The word was found in the exception lexicon — proper nouns, place names and loanwords come from there.
A plain one-to-one mapping. Around 90% of any text goes this way and is never listed.
No mapping exists for this character, so it was passed through unchanged.

See it on your own text

Paste your text into the converter — it shows which of the rules above fired, and where, beside the result.