Experimental and theoretical uncertainties in top-quark mass measurements at the Tevatron and the LHC

Since the discovery of the top-quark at the Tevatron collider in 1995, enormous efforts have been devoted to the precise determination of its properties and in particular of its mass, mtop. Together with precision electroweak measurements, mtop can be used to check the mtop-mW-mH relations within the Standard Model and to constrain the allowed mass range for heavy particles predicted by Standard Model extensions. In this paper a review of the current experimental and theoretical uncertainties affecting the top-quark mass measurements at the Tevatron and the LHC is provided: strategies and techniques adopted to evaluate the main systematic uncertainties within the various experiments are summarised and compared, highlighting, when appropriate, complementarities and differences which are important ingredients to set the basis of a future world mtop combination.