diff --git a/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs b/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs
index f26c783e47..39363beae3 100644
--- a/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs
+++ b/src/Windows/Avalonia.Win32/Interop/UnmanagedMethods.cs
@@ -1909,7 +1909,7 @@ namespace Avalonia.Win32.Interop
                     var result = ImmGetCompositionString(hIMC, dwIndex, (IntPtr)bufferPtr, (uint)bufferLength);
                     if (result >= 0)
                     {
-                        return Encoding.Unicode.GetString(bufferPtr, bufferLength);
+                        return Encoding.Unicode.GetString(bufferPtr, result);
                     }
                 }
             }