diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
--- a/libc/config/windows/entrypoints.txt
+++ b/libc/config/windows/entrypoints.txt
@@ -66,6 +66,9 @@
     libc.src.math.modf
     libc.src.math.modff
     libc.src.math.modfl
+    libc.src.math.nextafter
+    libc.src.math.nextafterf
+    libc.src.math.nextafterl
 )
 
 set(TARGET_LLVMLIBC_ENTRYPOINTS
diff --git a/libc/test/src/math/NextAfterTest.h b/libc/test/src/math/NextAfterTest.h
--- a/libc/test/src/math/NextAfterTest.h
+++ b/libc/test/src/math/NextAfterTest.h
@@ -22,12 +22,8 @@
   using MantissaWidth = __llvm_libc::fputil::MantissaWidth<T>;
   using UIntType = typename FPBits::UIntType;
 
-#if (defined(__x86_64__) || defined(__i386__))
   static constexpr int bitWidthOfType =
-      __llvm_libc::cpp::IsSame<T, long double>::Value ? 80 : (sizeof(T) * 8);
-#else
-  static constexpr int bitWidthOfType = sizeof(T) * 8;
-#endif
+      __llvm_libc::fputil::FloatProperties<T>::bitWidth;
 
   const T zero = T(FPBits::zero());
   const T negZero = T(FPBits::negZero());