Abstract: A special purpose digital computer requiring minimal data storage capabil for continually calculating the numerical average of a predetermined number of sampled data values. The average I.sub.n + 1 is calculated according to the equation: ##EQU1## WHEREIN I.sub.n is the nth average stored; andX.sub.n + 1 is the (n + 1) sample input.A new value for the average of all previously sampled data is calculated upon receipt of each new sample thereby eliminating the storing of past sampled data values. The prior calculated average is multiplied by the previous number of data samples and the product is added to a new sample. The resultant sum is divided by the sequence number of the new sample and the quotient, which represents the new average, is placed in data storage.