It is not technically valid to calculate an arithmetic mean as the average pH value. The arithmetic average would be defined as: ΣpH / n, whereas the true average would be defined as: -log_10[(ΣCi)/(n)], where C is the concentration of hydronium ion and n is the number of measurements. Although the difference between arithmetic average and true average may be small, there is a difference. Our tool will present both the arithmetic average and the true average, for your convenience. Furthermore, it is not valid to average pH values at or below 7 (acidic) with pH values at or above 7 (alkaline). Our tool also takes this into account and presents 2 different results, if appropriate.