how much capital gains tax ?

can anybody in the know tell me what my cgt liability would be on commercial shop sale.

bought for 349,240 euro paid 20,955 euro stamp duty 2k sol fees
if i sell for 650k euro what tax liability will i have ?

20% of the difference between sale & purchase prices incl incidentals on both transactions should give you a rough ballpark. However depending on your circumstances you may well be eligible for certain reliefs that might reduce or eliminate your liability. Professional advice would be recommended in this regard, and also in relation to other possible tax implications, eg VAT.