diff --git a/src/include/OpenImageIO/fmath.h b/src/include/OpenImageIO/fmath.h
index ea31eb43ce..6db6376f08 100644
--- a/src/include/OpenImageIO/fmath.h
+++ b/src/include/OpenImageIO/fmath.h
@@ -911,20 +911,11 @@ convert_type<float,uint8_t> (const float *src, uint8_t *dst, size_t n,
 
 
 #if defined(_HALF_H_) || defined(IMATH_HALF_H_)
+// Specialize for half only if half.h is included prior to fmath.h
 template<>
-OIIO_UTIL_API
-void convert_type<half,float> (const half *src, float *dst, size_t n,
-                               float /*_min*/, float /*_max*/);
-template<>
-OIIO_UTIL_API
-void convert_type<float,half> (const float *src, half *dst, size_t n,
-                               half /*_min*/, half /*_max*/);
-
-#if OIIO_FMATH_HEADER_ONLY
-// Not just the declarations, give the definitions here.
-template<>
-void convert_type<half,float> (const half *src, float *dst, size_t n,
-                               float /*_min*/, float /*_max*/)
+inline void
+convert_type<half,float> (const half *src, float *dst, size_t n,
+                          float /*_min*/, float /*_max*/)
 {
 #if OIIO_SIMD >= 8 && OIIO_F16C_ENABLED
     // If f16c ops are enabled, it's worth doing this by 8's
@@ -944,7 +935,7 @@ void convert_type<half,float> (const half *src, float *dst, size_t n,
 }
 
 template<>
-void
+inline void
 convert_type<float,half> (const float *src, half *dst, size_t n,
                           half /*_min*/, half /*_max*/)
 {
@@ -964,7 +955,6 @@ convert_type<float,half> (const float *src, half *dst, size_t n,
     while (n--)
         *dst++ = *src++;
 }
-#endif /* if OIIO_FMATH_HEADER_ONLY */
 #endif /* if defined(IMATH_HALF_H_) */
 
 #endif /* ifndef __CUDA_ARCH__ */
diff --git a/src/libutil/CMakeLists.txt b/src/libutil/CMakeLists.txt
index 2a159e449b..e7c6447c75 100644
--- a/src/libutil/CMakeLists.txt
+++ b/src/libutil/CMakeLists.txt
@@ -4,7 +4,7 @@
 
 set (libOpenImageIO_Util_srcs argparse.cpp benchmark.cpp
                   errorhandler.cpp farmhash.cpp filesystem.cpp
-                  fmath.cpp filter.cpp hashes.cpp paramlist.cpp
+                  filter.cpp hashes.cpp paramlist.cpp
                   plugin.cpp SHA1.cpp
                   strutil.cpp sysutil.cpp thread.cpp timer.cpp
                   typedesc.cpp ustring.cpp xxhash.cpp)
@@ -15,9 +15,6 @@ if (CMAKE_COMPILER_IS_GNUCC)
 endif ()
 
 if (CMAKE_UNITY_BUILD)
-    # If unity builds are occurring, fmath.cpp MUST be compiled alone. But the
-    # rest can be built together if in group mode.
-    set_property (SOURCE fmath.cpp APPEND PROPERTY SKIP_UNITY_BUILD_INCLUSION TRUE)
     set_source_files_properties (${libOpenImageIO_Util_srcs}
                                  PROPERTIES UNITY_GROUP utilsrc)
 endif ()
diff --git a/src/libutil/fmath.cpp b/src/libutil/fmath.cpp
deleted file mode 100644
index 647f60d5c7..0000000000
--- a/src/libutil/fmath.cpp
+++ /dev/null
@@ -1,11 +0,0 @@
-// Copyright Contributors to the OpenImageIO project.
-// SPDX-License-Identifier: Apache-2.0
-// https://github.com/AcademySoftwareFoundation/OpenImageIO
-
-#include <OpenImageIO/half.h>
-
-// Force the full implementation of all fmath functions, which will compile
-// some callable versions here.
-#define OIIO_FMATH_HEADER_ONLY 1
-
-#include <OpenImageIO/fmath.h>