diff --git a/include/prism/defines.h b/include/prism/defines.h
index e78c7dd75c..785361728e 100644
--- a/include/prism/defines.h
+++ b/include/prism/defines.h
@@ -136,17 +136,6 @@
 #   define PRISM_HAS_FILESYSTEM
 #endif
 
-/**
- * isinf on Windows is defined as accepting a float, but on POSIX systems it
- * accepts a float, a double, or a long double. We want to mirror this behavior
- * on windows.
- */
-#ifdef _WIN32
-#   include <float.h>
-#   undef isinf
-#   define isinf(x) (sizeof(x) == sizeof(float) ? !_finitef(x) : !_finite(x))
-#endif
-
 /**
  * If you build prism with a custom allocator, configure it with
  * "-D PRISM_XALLOCATOR" to use your own allocator that defines xmalloc,
diff --git a/src/prism.c b/src/prism.c
index bc516cbf4c..f8a05a79b8 100644
--- a/src/prism.c
+++ b/src/prism.c
@@ -4142,7 +4142,14 @@ pm_double_parse(pm_parser_t *parser, const pm_token_t *token) {
 
     // If errno is set, then it should only be ERANGE. At this point we need to
     // check if it's infinity (it should be).
-    if (errno == ERANGE && isinf(value)) {
+    if (
+        errno == ERANGE &&
+#ifdef _WIN32
+        isinf((float) value)
+#else
+        isinf(value)
+#endif
+    ) {
         int warn_width;
         const char *ellipsis;