diff --git a/include/float.h b/include/float.h
index 35b28f2c..24b7410b 100644
--- a/include/float.h
+++ b/include/float.h
@@ -38,6 +38,7 @@
 #define LDBL_MAX_EXP 16384
 #define LDBL_MAX 1.18973149535723176502e+4932L
 #define LDBL_MAX_10_EXP 4932
+#define DECIMAL_DIG 21
 
 #elif defined __aarch64__ || defined __riscv
 /*
@@ -53,6 +54,7 @@
 #define LDBL_MAX_EXP 16384
 #define LDBL_MAX 1.18973149535723176508575932662800702e+4932L
 #define LDBL_MAX_EXP 16384
+#define DECIMAL_DIG 36
 
 #else
 
@@ -66,6 +68,7 @@
 #define LDBL_MAX_EXP 1024
 #define LDBL_MAX 1.7976931348623157e+308L
 #define LDBL_MAX_10_EXP 308
+#define DECIMAL_DIG 17
 
 #endif