tag:blogger.com,1999:blog-4011252463639388552.post1551199087522830530..comments2024-07-02T09:02:56.543-04:00Comments on JTB World Blog: Understanding Floating Point Precision in AutoCAD, Excel, etc.JTB Worldhttp://www.blogger.com/profile/02249678064305703202noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-4011252463639388552.post-81963738733218237282008-08-02T10:00:00.000-04:002008-08-02T10:00:00.000-04:00Restored commentsKevin said... Wikipedia's arti...Restored comments<BR/><BR/>Kevin said...<BR/><BR/> Wikipedia's article http://en.wikipedia.org/wiki/Double-precision on double-precision floating point values will show you that they use 64 bits, not 65. One bit is used for the sign of the number. Eleven are used for the exponent (with an assumed offset to include negative exponents). the remaining 52 bits are used for the mantissa, so there are 53 bits of precision since the first bit (before the decimal) is always 1 for a non-zero number.<BR/><BR/> Using 53 bits of precision leaves you theoretically with 15.95 reliable decimal digits. Compare this to single precision at 7.22 digits.<BR/> July 25, 2008 <BR/><BR/>JTB World said...<BR/><BR/> One bit, called the hidden bit or the implied bit, can be omitted if all numbers are required to be normalized according to the IEEE 754 standard.<BR/> Here you also see the implied bit mentioned.<BR/> http://support.microsoft.com/kb/78113JTB Worldhttps://www.blogger.com/profile/02249678064305703202noreply@blogger.com