Maximum Integer Size of REG_DWORD in Regedit

The Windows Registry utilizes various data types to store configuration settings, with REG_DWORD being one of the most widely used formats for numerical and boolean values. This article covers the maximum integer size that can be stored in a REG_DWORD value within Regedit, detailing its bit architecture, numerical limits in decimal and hexadecimal notations, and what happens when those limits are exceeded.

The Maximum Integer Size for REG_DWORD

A REG_DWORD (Registry Double Word) is a 32-bit (4-byte) numerical value. Because it is 32 bits in length, the maximum unsigned integer value it can store is 4,294,967,295.

In hexadecimal notation, this maximum limit is represented as 0xFFFFFFFF.

Value Ranges for REG_DWORD

Depending on whether the system or application reads the value as signed or unsigned, the supported ranges are:

When editing a REG_DWORD in Windows Regedit, the interface allows you to toggle between Hexadecimal and Decimal entry modes:

If you attempt to enter a number larger than 4294967295 in decimal mode, Regedit will display an error message stating that the entered value is too large for a DWORD.

Handling Larger Values: REG_QWORD

If a configuration setting requires an integer larger than 4,294,967,295, the Windows Registry uses the REG_QWORD (Quad Word) data type.