€5,210 is not a tax credit or a 0% tax band - it's a tax exemption earnings threshold. If you earn more than this in a year then you pay 20% on any amount up to €29,400 (20% of the full €29,400 if your earnings are greater than or equal to €29,400) and then 42% on any amount above this. Once you come up with a gross tax figure you subtract your tax credits (as stated on your annual statement of tax credits - common tax credits are listed [broken link removed]) to get a net tax figure which is the amount that you actually pay in tax. Don't forget that you also pay PRSI (4%) and health levy (2%) on most of your income - see [broken link removed]. PRSI/health levy are not refundable through a P50 claim. [broken link removed] is useful for figuring this stuff out but it seems to have been exhibiting problems with the display of calculations recently and, unfortunately, Karl has not yet responded to bug reports on this. Does that make more sense to you? Perhaps if you post your own figures (e.g. how much you have earned and how much of the year you will not be working) then somebody can crunch the numbers for you (assuming Karl's calculator is still not working properly)?