Comments on: Nifty Tricks with the Rule of 72, 71, 70, 69.3, 114, 144 and My Favorites, 1.5 and 1,080,000 http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/ Money Management and Personal Finance | The Dough Roller Mon, 13 Feb 2012 05:44:53 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: sindy http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/comment-page-1/#comment-25417 sindy Thu, 14 Oct 2010 07:03:55 +0000 http://www.doughroller.net/2007/09/10/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/#comment-25417 Intresting facts, are you sure? Intresting facts, are you sure?

]]> By: Jerry Felix http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/comment-page-1/#comment-19563 Jerry Felix Fri, 23 Apr 2010 17:57:31 +0000 http://www.doughroller.net/2007/09/10/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/#comment-19563 Hi. Glad you found Felix's Corollary and the Millionaire's Estimation handy. This is to answer your question "Where does the 7 come from?" when you have three 8-year periods at 9%: The amount accumulated in the first 8 years (principal and interest) will double in the second eight years, and double again in the third eight years. So that's doubling twice (or 4 times the original), which accounts for 4 of the 7 in question. The amount accumulated in the second eight years (principal and interest) will double during the third eight years. So that's another 2 of the 7. And finally, the amount accumulated in the third eight years (principal and interest) makes up the 7th of the 7. Hope that helps! - Felix, of "Felix's Corollary" "You can earn roughly 50% on your money, by spreading a planned investment over N annual payments at a rate of R%, if NxR = 72" - JF Hi. Glad you found Felix’s Corollary and the Millionaire’s Estimation handy.

This is to answer your question “Where does the 7 come from?” when you have three 8-year periods at 9%:

The amount accumulated in the first 8 years (principal and interest) will double in the second eight years, and double again in the third eight years. So that’s doubling twice (or 4 times the original), which accounts for 4 of the 7 in question.

The amount accumulated in the second eight years (principal and interest) will double during the third eight years. So that’s another 2 of the 7.

And finally, the amount accumulated in the third eight years (principal and interest) makes up the 7th of the 7.

Hope that helps!

- Felix, of “Felix’s Corollary”

“You can earn roughly 50% on your money, by spreading a planned investment over N annual payments at a rate of R%, if NxR = 72″ – JF

]]> By: Jon http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/comment-page-1/#comment-1096 Jon Mon, 08 Oct 2007 14:57:02 +0000 http://www.doughroller.net/2007/09/10/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/#comment-1096 Another little trick will let you calculate your savings assuming a steady contribution plus compound interest. Say you want to save $4k per year for 30 years and earn 10% interest. How much money will you have at the end? The trick is that adding $4k per year is like getting 10% interest on $40k. So we can set the base principle to $40k and ignore the yearly addition of $4k. Then subtract the magical $40k at the end. $40k * 1.1^30 - $40k = $657k Another little trick will let you calculate your savings assuming a steady contribution plus compound interest.

Say you want to save $4k per year for 30 years and earn 10% interest. How much money will you have at the end? The trick is that adding $4k per year is like getting 10% interest on $40k. So we can set the base principle to $40k and ignore the yearly addition of $4k. Then subtract the magical $40k at the end.

$40k * 1.1^30 – $40k = $657k

]]> By: the baglady http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/comment-page-1/#comment-937 the baglady Wed, 19 Sep 2007 16:45:22 +0000 http://www.doughroller.net/2007/09/10/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/#comment-937 hmm! logarithms are magically delicious! hmm! logarithms are magically delicious!

]]> By: paidtwice http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/comment-page-1/#comment-878 paidtwice Tue, 11 Sep 2007 19:01:33 +0000 http://www.doughroller.net/2007/09/10/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/#comment-878 All I can say is.... whoa. All I can say is….

whoa.

]]> By: Karen @ Simply A Musing Blog http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/comment-page-1/#comment-870 Karen @ Simply A Musing Blog Tue, 11 Sep 2007 01:12:57 +0000 http://www.doughroller.net/2007/09/10/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/#comment-870 My husband has never shared some of these with me - and he's securities licensed! Great information, thanks! My husband has never shared some of these with me – and he’s securities licensed! Great information, thanks!

]]> By: Brian http://www.doughroller.net/investing/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/comment-page-1/#comment-867 Brian Mon, 10 Sep 2007 20:09:58 +0000 http://www.doughroller.net/2007/09/10/nifty-tricks-with-the-rule-of-72-71-70-693-114-144-and-my-favorites-15-and-1080000/#comment-867 Holy cow. My brain nearly exploded from all the numbers. Although I can see some of those methods saving time if you get used to using them, I think my feeble mind will stick with the rule of 72! Holy cow. My brain nearly exploded from all the numbers. Although I can see some of those methods saving time if you get used to using them, I think my feeble mind will stick with the rule of 72!

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