A probabilistic estimation of fatigue crack life of a component is provided. A plurality of representations of the component is defined from material property scatter data and flaw-size scatter data, wherein each representation is defined by one possible material condition and flaw-size condition associated with the component. For each representation, a component location is selected and a determination is made whether said individual representation fails after a given number of cycles N, based on the calculation of a crack growth in the selected location. The crack growth is calculated on the basis of the material condition and the flaw-size condition in the selected location. Failure of the individual representation is determined if the crack growth is determined to be unstable. The sum total of the number of the representations that failed after N cycles is determined. A probability of failure of the component after N cycles is then determined.