diff --git a/rtl/objpas/sysutils/sysstrh.inc b/rtl/objpas/sysutils/sysstrh.inc
index dfb9dfd545..67bcd40765 100644
--- a/rtl/objpas/sysutils/sysstrh.inc
+++ b/rtl/objpas/sysutils/sysstrh.inc
@@ -36,8 +36,8 @@ type
 const
   { For floattodatetime and VariantToDate }
 {$ifndef FPUNONE}
-  MinDateTime: TDateTime =  -693593.0;        { 01/01/0001 12:00:00.000 AM }
-  MaxDateTime: TDateTime =  2958465.99999999; { 12/31/9999 11:59:59.999 PM }
+  MinDateTime: TDateTime =  -693593.99999999; { 01/01/0001 12:00:00.000 AM }
+  MaxDateTime: TDateTime =  2958465.99999999;  { 12/31/9999 11:59:59.999 PM }
 
 {$if defined(FPC_HAS_TYPE_EXTENDED) or defined(FPC_HAS_TYPE_FLOAT128)}
   MinCurrency: Currency = -922337203685477.5808;