A　quantitative　characterization　method　is　introduced　for　estimating　surface　crack　depth　using　Rayleigh　waves　in　pitch-catch　mode　by　electromagnetic　acoustic　transducers　(EMATs).　The　method　employs　the　experimentally　determined　reflection　and　transmission　coefficients　of　Rayleigh　waves　scattered　at　a　surface　crack,　which　will　be　compared　to　the　reference　curves　obtained　from　two-dimensional　finite　element　method　(FEM)　simulations　based　on　variable　crack　depth.　Three　EMAT　couples　with　different　centre　frequencies　were　employed　to　extend　the　measuring　range,　and　to　implement　the　quantitative　characterization　of　crack　depth.　The　reference　curves　and　measurement　results　were　verified　to　be　repeatable　with　great　accuracy,　which　shows　a　maximum　error　of　17%　with　crack　depth　ranging　from　0.2-3.0　mm.