We present and discuss an algorithm that reliably determines the period and phase of RHEED intensity oscillations. Based on multiple running averages of the data, this algorithm is not affected by damping or rapid arbitrary changes of the average intensity on a time scale larger than the growth oscillations. It is therefore suitable for a general and precise determination of the deposited layer thickness, at least in homoepitaxy. An additional pre-filtering running average allows the removal of the periodic modulation induced in pulsed laser deposition (PLD). (C) 2016 Elsevier B.V. All rights reserved.