Case Converter
Convert text to UPPER, lower, Title Case or Sentence case, with correct Turkish i/İ and ı/I handling when you need it.
This tool runs entirely in your browser. What you enter is not sent to a server, not saved and not stored in cookies.
A paragraph typed with Caps Lock on, an all-caps Excel column, a list that needs title case… This tool converts text to the case you need in one click, and applies the Turkish i/İ and ı/I rule correctly when you need it.
How to use it
- Paste your text into the left box.
- Choose UPPER, lower, Title Case, Sentence case or invert.
- For Turkish text keep Turkish rules; choose English for English text.
- Copy the result.
Frequently asked questions
Why is there a Turkish mode?
Turkish has dotted i/İ and dotless ı/I. English rules turn “istanbul” into “ISTANBUL” instead of “İSTANBUL”. With Turkish rules each letter keeps its own pair.
Which words stay lower case in Title Case?
In English, short articles, conjunctions and prepositions such as a, an, the, and, of, in, to, unless they open the title. In Turkish, conjunctions such as ve, ile, veya, de/da, ki.
What does Sentence case do?
It capitalises only the first letter of each sentence and lower-cases the rest. You may need to fix proper nouns by hand.
Can I convert an Excel column?
Yes. Copy and paste the column; line breaks are kept. Copy the result and paste it back into the column.
Why a separate Turkish mode?
Turkish has two i’s: dotted i/İ and dotless ı/I. Most converters use English rules, so “istanbul” becomes “ISTANBUL” instead of “İSTANBUL”, and “IŞIK” becomes “işik” instead of “ışık”. With Turkish rules selected, every letter keeps its own pair.
Title Case rules
- Turkish: every word starts with a capital, except the conjunctions ve, ile, veya, ya da, de, da, ki, mi and similar short words in the middle of the title.
- English: short articles, conjunctions and prepositions (a, an, the, and, or, of, in, on, to…) stay lower case unless they open the title.