diff --git a/SConstruct b/SConstruct
index 46942ca3b41..5ad4b614ca1 100644
--- a/SConstruct
+++ b/SConstruct
@@ -167,7 +167,7 @@ opts.Add("p", "Platform (alias for 'platform')", "")
 opts.Add(BoolVariable("tools", "Build the tools (a.k.a. the Godot editor)", True))
 opts.Add(EnumVariable("target", "Compilation target", "debug", ("debug", "release_debug", "release")))
 opts.Add(EnumVariable("arch", "CPU architecture", "auto", ["auto"] + architectures, architecture_aliases))
-opts.Add(EnumVariable("float", "Floating-point precision", "default", ("default", "32", "64")))
+opts.Add(EnumVariable("float", "Floating-point precision", "32", ("32", "64")))
 opts.Add(EnumVariable("optimize", "Optimization type", "speed", ("speed", "size", "none")))
 opts.Add(BoolVariable("production", "Set defaults to build Godot for use in production", False))
 opts.Add(BoolVariable("use_lto", "Use link-time optimization", False))
diff --git a/modules/mono/README.md b/modules/mono/README.md
index ebbc6b0f80d..366777cfc19 100644
--- a/modules/mono/README.md
+++ b/modules/mono/README.md
@@ -43,3 +43,13 @@ This option ensures the packages will be added to the specified local NuGet
 source and that conflicting versions of the package are removed from the
 NuGet cache. It's recommended to always use this option when building the
 C# solutions during development to avoid mistakes.
+
+# Double Precision Support (REAL_T_IS_DOUBLE)
+
+Follow the above instructions but build Godot with the float=64 argument to scons
+
+When building the NuGet packages, specify `--float=64` - for example:
+```sh
+./modules/mono/build_scripts/build_assemblies.py --godot-output-dir ./bin \
+    --push-nupkgs-local ~/MyLocalNugetSource --float=64
+```
diff --git a/modules/mono/build_scripts/build_assemblies.py b/modules/mono/build_scripts/build_assemblies.py
index fa3be684bdc..6f66ce9efa7 100755
--- a/modules/mono/build_scripts/build_assemblies.py
+++ b/modules/mono/build_scripts/build_assemblies.py
@@ -195,7 +195,7 @@ def run_msbuild(tools: ToolsLocation, sln: str, msbuild_args: [str] = None):
     return subprocess.call(args, env=msbuild_env)
 
 
-def build_godot_api(msbuild_tool, module_dir, output_dir, push_nupkgs_local):
+def build_godot_api(msbuild_tool, module_dir, output_dir, push_nupkgs_local, float_size):
     target_filenames = [
         "GodotSharp.dll",
         "GodotSharp.pdb",
@@ -216,6 +216,8 @@ def build_godot_api(msbuild_tool, module_dir, output_dir, push_nupkgs_local):
         args = ["/restore", "/t:Build", "/p:Configuration=" + build_config, "/p:NoWarn=1591"]
         if push_nupkgs_local:
             args += ["/p:ClearNuGetLocalCache=true", "/p:PushNuGetToLocalSource=" + push_nupkgs_local]
+        if float_size == "64":
+            args += ["/p:GodotFloat64=true"]
 
         sln = os.path.join(module_dir, "glue/GodotSharp/GodotSharp.sln")
         exit_code = run_msbuild(
@@ -256,9 +258,9 @@ def build_godot_api(msbuild_tool, module_dir, output_dir, push_nupkgs_local):
     return 0
 
 
-def build_all(msbuild_tool, module_dir, output_dir, godot_platform, dev_debug, push_nupkgs_local):
+def build_all(msbuild_tool, module_dir, output_dir, godot_platform, dev_debug, push_nupkgs_local, float_size):
     # Godot API
-    exit_code = build_godot_api(msbuild_tool, module_dir, output_dir, push_nupkgs_local)
+    exit_code = build_godot_api(msbuild_tool, module_dir, output_dir, push_nupkgs_local, float_size)
     if exit_code != 0:
         return exit_code
 
@@ -269,6 +271,8 @@ def build_all(msbuild_tool, module_dir, output_dir, godot_platform, dev_debug, p
     )
     if push_nupkgs_local:
         args += ["/p:ClearNuGetLocalCache=true", "/p:PushNuGetToLocalSource=" + push_nupkgs_local]
+    if float_size == "64":
+        args += ["/p:GodotFloat64=true"]
     exit_code = run_msbuild(msbuild_tool, sln=sln, msbuild_args=args)
     if exit_code != 0:
         return exit_code
@@ -277,6 +281,8 @@ def build_all(msbuild_tool, module_dir, output_dir, godot_platform, dev_debug, p
     args = ["/restore", "/t:Build", "/p:Configuration=Release"]
     if push_nupkgs_local:
         args += ["/p:ClearNuGetLocalCache=true", "/p:PushNuGetToLocalSource=" + push_nupkgs_local]
+    if float_size == "64":
+        args += ["/p:GodotFloat64=true"]
     sln = os.path.join(module_dir, "editor/Godot.NET.Sdk/Godot.NET.Sdk.sln")
     exit_code = run_msbuild(msbuild_tool, sln=sln, msbuild_args=args)
     if exit_code != 0:
@@ -300,6 +306,7 @@ def main():
     parser.add_argument("--godot-platform", type=str, default="")
     parser.add_argument("--mono-prefix", type=str, default="")
     parser.add_argument("--push-nupkgs-local", type=str, default="")
+    parser.add_argument("--float", type=str, default="32", choices=["32", "64"], help="Floating-point precision")
 
     args = parser.parse_args()
 
@@ -321,6 +328,7 @@ def main():
         args.godot_platform,
         args.dev_debug,
         args.push_nupkgs_local,
+        args.float,
     )
     sys.exit(exit_code)
 
diff --git a/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.props b/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.props
index 59ce1da17b0..04592571063 100644
--- a/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.props
+++ b/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.props
@@ -62,7 +62,7 @@
   </PropertyGroup>
 
   <PropertyGroup>
-    <GodotRealTIsDouble Condition=" '$(GodotRealTIsDouble)' == '' ">false</GodotRealTIsDouble>
+    <GodotFloat64 Condition=" '$(GodotFloat64)' == '' ">false</GodotFloat64>
   </PropertyGroup>
 
   <!-- Godot DefineConstants. -->
diff --git a/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.targets b/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.targets
index aad4ea4553a..bff9760b324 100644
--- a/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.targets
+++ b/modules/mono/editor/Godot.NET.Sdk/Godot.NET.Sdk/Sdk/Sdk.targets
@@ -10,9 +10,9 @@
     <!--
     Define constant to determine whether the real_t type in Godot is double precision or not.
     By default this is false, like the official Godot builds. If someone is using a custom
-    Godot build where real_t is double, they can override the GodotRealTIsDouble property.
+    Godot build where real_t is double, they can override the GodotFloat64 property.
     -->
-    <DefineConstants Condition=" '$(GodotRealTIsDouble)' == 'true' ">GODOT_REAL_T_IS_DOUBLE;$(DefineConstants)</DefineConstants>
+    <DefineConstants Condition=" '$(GodotFloat64)' == 'true' ">GODOT_REAL_T_IS_DOUBLE;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
 
   <!-- C# source generators -->
diff --git a/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj b/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj
index aae7a5ebfa8..5827d3e5919 100644
--- a/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj
+++ b/modules/mono/glue/GodotSharp/GodotSharp/GodotSharp.csproj
@@ -36,6 +36,7 @@
   </ItemGroup>
   <PropertyGroup>
     <DefineConstants>$(DefineConstants);GODOT</DefineConstants>
+    <DefineConstants Condition=" '$(GodotFloat64)' == 'true' ">REAL_T_IS_DOUBLE;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="ReflectionAnalyzers" Version="0.1.22-dev" PrivateAssets="all" IncludeAssets="runtime; build; native; contentfiles; analyzers" />
diff --git a/modules/mono/glue/GodotSharp/GodotSharpEditor/GodotSharpEditor.csproj b/modules/mono/glue/GodotSharp/GodotSharpEditor/GodotSharpEditor.csproj
index ebf09aab7b0..5d69ad8ec69 100644
--- a/modules/mono/glue/GodotSharp/GodotSharpEditor/GodotSharpEditor.csproj
+++ b/modules/mono/glue/GodotSharp/GodotSharpEditor/GodotSharpEditor.csproj
@@ -25,6 +25,7 @@
   </PropertyGroup>
   <PropertyGroup>
     <DefineConstants>$(DefineConstants);GODOT</DefineConstants>
+    <DefineConstants Condition=" '$(GodotFloat64)' == 'true' ">REAL_T_IS_DOUBLE;$(DefineConstants)</DefineConstants>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\GodotSharp\GodotSharp.csproj">