diff --git a/include/fast_float/float_common.h b/include/fast_float/float_common.h
index 3ddf5f8..8854d91 100644
--- a/include/fast_float/float_common.h
+++ b/include/fast_float/float_common.h
@@ -9,7 +9,8 @@
        || defined(__amd64) || defined(__aarch64__) || defined(_M_ARM64) \
        || defined(__MINGW64__)                                          \
        || defined(__s390x__)                                            \
-       || (defined(__ppc64__) || defined(__PPC64__) || defined(__ppc64le__) || defined(__PPC64LE__)))
+       || (defined(__ppc64__) || defined(__PPC64__) || defined(__ppc64le__) || defined(__PPC64LE__)) \
+       || defined(__EMSCRIPTEN__))
 #define FASTFLOAT_64BIT
 #elif (defined(__i386) || defined(__i386__) || defined(_M_IX86)   \
      || defined(__arm__)                                        \