Calculation. Summary: This is the calculation used for figuring the yield to maturity of bonds and coupons purchased after 1984 as described in example 22. To calculate: 2 multiplied by (($100,000 divided by $38,000) raised to (1 divided by 25) power minus 1) equals 2 multiplied by (1.03946 minus 1) equals 0.07892 equals 7.892%.