Comments on: Mysql rounding for currency format http://www.imranulhoque.com/mysql/mysql-rounding-for-currency-format/ Fri, 03 Feb 2012 12:09:44 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Paul Carpenter http://www.imranulhoque.com/mysql/mysql-rounding-for-currency-format/comment-page-1/#comment-5637 Paul Carpenter Tue, 07 Jun 2011 11:44:10 +0000 http://www.imranulhoque.com/?p=138#comment-5637 Anyone using floats to store monetary values that are then used in calculations to create totals and taxes, is asking for trouble. This is the difference between resolution and accuracy. The classic examples with floats is partials equivalent no powers of 2 - 1/3, 1/5, 1/6, 1/7........ I have seen the results in many places like dailywtf and pictures of parking charge machines giving totals of $4.18e96 (yes x 10 to the power 96) to never use any float format for anything monetary in normal usage. The only time floats are useable is for working out national debt, where the second by second differences between actual and calculated vary so much any figure is a best estimate. Anyone using floats to store monetary values that are then used in calculations to create totals and taxes, is asking for trouble.

This is the difference between resolution and accuracy. The classic examples with floats is partials equivalent no powers of 2 – 1/3, 1/5, 1/6, 1/7……..

I have seen the results in many places like dailywtf and pictures of parking charge machines giving totals of $4.18e96 (yes x 10 to the power 96) to never use any float format for anything monetary in normal usage.

The only time floats are useable is for working out national debt, where the second by second differences between actual and calculated vary so much any figure is a best estimate.

]]> By: imran http://www.imranulhoque.com/mysql/mysql-rounding-for-currency-format/comment-page-1/#comment-1613 imran Thu, 12 Nov 2009 08:54:11 +0000 http://www.imranulhoque.com/?p=138#comment-1613 you are kind of correct. Thanks :-) you are kind of correct. Thanks :-)

]]> By: Will http://www.imranulhoque.com/mysql/mysql-rounding-for-currency-format/comment-page-1/#comment-1593 Will Tue, 10 Nov 2009 12:38:34 +0000 http://www.imranulhoque.com/?p=138#comment-1593 ... except, of course, that nobody would ever store monetary values as a float, because that would be wrong. … except, of course, that nobody would ever store monetary values as a float, because that would be wrong.

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