Some form of the golden duo of INDEX and MATCH should do it in Excel. I suspect you could do it with SUMPRODUCT too if the tax table contains sufficient data (

Some form of the golden duo of INDEX and MATCH should do it in Excel. I suspect you could do it with SUMPRODUCT too if the tax table contains sufficient data (e.g. for each band a lump-sum + progressive rate may be necessary) but it may still be an array equation (ctrl-shift-enter when entered, with curly braces displayed around it). I’m not in front of a PC so I can’t try to confirm.