Similarly, replacing the "R" in R/200 on the third line with 2.02 gives 70 on the numerator, showing the rule of 70 is most accurate for periodically compounded interests around 2%. Alternatively, the E-M rule is obtained if the second-order Taylor approximation is used directly. Continuous compounding For continuous compounding, the derivation is simpler and yields a more accurate rule: See also Exponential growth Time value of money Interest Discount Rule of 16 Rule of three (statistics) References External links The Scales Of 70 – extends the rule of 72 beyond fixed-rate growth to variable rate compound growth including positive and negative rates. Debt Exponentials Interest Rules of thumb Mathematical finance Mental calculation