A. Delayed retirement credits are calculated each month you delay taking benefits beyond your full retirement age, which is 66 for people born from 1945 to 1954 and rises by 2 months each year until it reaches age 67 for people born after 1960.
You will get an extra 2/3 of 1% of your full retirement benefit for each month you delay after your birthday month, adding up to an extra 8% for each full year you wait till age 70!
The clock starts from the month you reach full retirement age.