Saving score is calculated during relearning. When you relearn something you can calculate the amount of information that you have retained in your memory from previous learning period.. it can be calculated in two ways depending on whether you are learning based on number of trials or based on time..

The formula for calculate savings is (based on no. of trials)

savings = (no. of trials for original learning)-(no. of trials for relearning)/(no. of trials for original learning) x 100

so if you took you 5 trials to understand the information originally and when you were relearning it took you 2

the savings would be:

savings = 5-2/5 x 100 = 60%

This means that 60% of the information was retained from original learning..

a saving score based on time would be the same thing expect substitute time for no. of trials

savings = (time for original learning)-(time for original relearning)/(time for original learning) x 100

say that you were memorized 10 keywords for a particular chapter in your psych class.. it took you 10 mins to fully memorize the first time while it took 1 minute when you were relearning the same glossary two weeks later.. the savings would be:

savings = 10-1/10 x 100 = 90%

this means that 90% of the info was retained from the first time you learnt the 10 keywords.