diff --git a/tests/core/math/big/build.bat b/tests/core/math/big/build.bat
index 16bdbc8ca..ad199d775 100644
--- a/tests/core/math/big/build.bat
+++ b/tests/core/math/big/build.bat
@@ -4,7 +4,7 @@ set PATH_TO_ODIN==..\..\..\..\odin
 set TEST_ARGS=-fast-tests
 set TEST_ARGS=-no-random
 set TEST_ARGS=
-set OUT_NAME=math_big_test_library
+set OUT_NAME=math_big_test_library.dll
 set COMMON=-build-mode:shared -show-timings -no-bounds-check -define:MATH_BIG_EXE=false -vet -strict-style
 echo ---
 echo Running core:math/big tests