> What is the formula for duration in finance?

What is the formula for duration in finance?

Posted at: 2014-12-05 
i need the formula to calculate a t-note that has coupon rate, par value, and ytm

thx!

Reading notes from here http://finance.thinkanddone.com/

There are two types of durations

1) Macaulay's duration

2) Modified duration

Modified duration is found as ratio of 1st derivative of bond price over the bond price

Calculating the duration(s) is time consuming when done manually, it is much easier to find the duration given par value, coupon, rate, ytm, and years to maturity by plugging in these values in two one of the following two online calculators

http://finance.thinkanddone.com/online-b...

http://finance.thinkanddone.com/online-b...

The first one will return the duration, the second one will show you how the duration is calculated showing each step

Macaulay's duration amends the modified duration by an extra interest factor of (1+i) where i is the YTM

i need the formula to calculate a t-note that has coupon rate, par value, and ytm

thx!