A new function (calc IEU) is now available in the latest version of the R Luminescence package (version 0.4.2). The calc IEU function can be used to calculate an equivalent dose (De)value for a given dose distribution using the Internal External Uncertainty (IEU) model. The IEU model is used in luminescence dating to determine a De value for a partially-bleached sample by calculating the weighted mean from the well bleached part of a partially-bleached population. The new calc IEU function automates the calculation of the IEU model so that the results are produced rapidly and reproducibly. This is advantageous as the user can easily perform sensitivity tests of the model in response to changing input parameters.