Microsoft Locale Builder

You can create custom Windows locales easily by using the official Microsoft utility called Microsoft Locale Builder.

A Windows locale controls how your computer manages regional settings—including language rules, currency formatting, date/time layouts, text sorting, and calendar options. While Microsoft ships Windows with hundreds of default configurations, the Locale Builder tool allows you to build a personalized layout if your local dialect, specific regional preferences, or corporate guidelines aren’t fully supported out-of-the-box. 🛠️ Understanding the Two Types of Custom Locales

Before building, you must choose how your locale interacts with Windows:

Supplemental Locales: Completely new, independent configurations designed for languages or regional variants not included in the standard Windows installation.

Replacement Locales: Customized packages that overwrite specific data (like a currency symbol or date format) within an existing, native Windows locale without altering its underlying system identifier. 📝 Step-by-Step: Creating a Custom Locale Download the Tool

Download and install the latest package from the official Microsoft Locale Builder Download Page. It is compatible with Windows 10 and Windows 11. Establish a Baseline Open Locale Builder. Go to File > New.

You can start completely from scratch or choose “Base a new locale on an existing locale”. Basing your layout on a similar existing region saves massive amounts of entry time.

Customize Your Regional RulesNavigate through the software tabs to modify individual properties:

General: Define the English name, native name, and the specific ISO language/region codes (e.g., en-US or custom variants).

Formats: Adjust how decimals, grouping symbols, and negative numbers appear.

Currency: Change your preferred currency symbol, native currency name, and formatting rules.

Time & Date: Choose exactly how calendars display text. Remember to properly escape standard text characters with single quotes if you are creating unique text-based date separators (e.g., yyyy’year’M’month’). Build and Install the Locale Package

Once you are satisfied with the configuration, click Build > Build MSI Window Installer.

Locale Builder will generate a standard .msi installation package.

Double-click the generated .msi file on your computer to install your new custom rules directly into the Windows operating system registry. Activate Your Custom Locale

Open your Windows Control Panel and select Clock, Language, and Region (or Region in Windows ⁄₁₁).

Your custom installer makes the new option visible in the standard dropdown lists. Select your custom locale to apply it as your new system default. ⚠️ Important Rules for System Stability

When designing a replacement locale, Microsoft enforces strict guardrails to maintain system reliability:

Do Not Edit Sort Orders: You cannot alter core Windows text-sorting behavior.

Preserve Native Calendars: If you change the default calendar system (e.g., shifting to the Gregorian calendar), you must keep the original native calendar variant included in the fallback list.

If you would like to proceed with setting up a unique layout, tell me: What specific language or region are you trying to build?

Are you looking to change text layouts or formatting details like dates and currencies?

Do you need to deploy this locale across multiple enterprise computers? Custom Locales – Win32 apps – Microsoft Learn