How to Uppercase Turkish Text with Dotted and Dotless I

A Turkish heading can lose a meaningful dot during an uppercase conversion. If izmir becomes IZMIR, the result is not the Turkish uppercase spelling İZMİR. Check the language rules before accepting an automatic result.

This guide uses short city labels to separate the behavior of the Case Converter from an explicitly Turkish conversion. Keep the original text so you can check each changed letter.

Identify the two different letter pairs

In Turkish casing, dotted lowercase i pairs with dotted uppercase İ. Dotless lowercase ı pairs with uppercase I. A conversion that maps both lowercase letters to plain I loses that distinction.

JavaScript provides locale-specific casing for this purpose. The MDN toLocaleUpperCase reference explains that Turkish mappings can differ from the default Unicode case mappings.

Reproduce the default conversion with a short label

1. Open the Case Converter and enter the following in Your text, with one space between the labels and no final newline.

izmir ısparta

2. Select UPPERCASE.
3. Read the Result before copying it. The current output is:

IZMIR ISPARTA

The counter shows two words and 13 characters for the input. Equal input and output lengths do not establish correct language-specific spelling: the letters in IZMIR still need attention.

The tool currently uses JavaScript toUpperCase() for this mode and offers no locale selector. That method takes no locale argument, as shown in the MDN toUpperCase reference. This comparison identifies the limitation; the site control does not perform the Turkish operation in the next section.

Apply Turkish casing to the saved original

For a short heading, correct the letters in your destination editor while checking the original. The intended result for our two labels is:

İZMİR ISPARTA

For a repeated text-processing task in an existing JavaScript environment, specify the locale explicitly:

const original = "izmir ısparta";
const display = original.toLocaleUpperCase("tr");
console.log(display);
// İZMİR ISPARTA

Run this on a copy of the original, then review the returned text before saving it. The example calculates a new string; it does not update your CMS, translate the labels or choose a heading style. For a list with one label per line, test that your surrounding import and export steps preserve those lines too.

Do not replace every uppercase I with İ afterward. In this example, that would damage ISPARTA, which came from a dotless lowercase letter. If the original i ı has already become I I, that output alone cannot tell you which source letter occupied each position. Return to the saved original instead of guessing.

Check lowercase conversion separately

Lowercasing an uppercase label is another operation, not a reliable undo button. When your workflow specifically needs Turkish lowercase text, JavaScript also accepts an explicit locale:

const original = "İ I";
console.log(original.toLocaleLowerCase("tr"));
// i ı

The MDN toLocaleLowerCase reference documents the Turkish distinction. Avoid a chain of uppercase and lowercase conversions to reconstruct spelling. Preserve the untouched source and choose the intended display conversion directly.

Review the heading in its final location

Before publishing, compare every dotted and dotless letter against the saved text. Check both labels in our sample, rather than accepting a result because the first word looks right. Read the heading in the font used on the page, where a small dot can be easy to overlook.

Keep code identifiers, URLs and filenames out of a prose casing batch. Their exact spelling may serve a different purpose. Apply Turkish conversion only to text whose language and editorial requirements call for it; a mixed-language list needs its entries reviewed individually.

If your goal is sentence case rather than all capitals, follow the heading capitalization workflow and review names separately. Finish by copying the approved heading into its publishing field and checking that exact saved version. A correct language mapping is one part of that editorial review.