Tax is normally calculated using the ‘cumulative basis’. This means that each pay day, all earnings and all tax credits from 1 January of that year are accumulated. This is to ensure you have paid the correct amount of tax and you have received the benefit of all your tax credits.
You may receive a Tax Credit Certificate (TCC) on the week 1 basis (also known as the ‘non-cumulative basis’). This means that your employer will deduct Income Tax (IT) from your pay on a week-to-week basis. Your yearly tax credits and rate bands are not backdated to the 1 January and do not accumulate for each pay period. Your employer cannot make any refunds of IT that may be due to you until a ‘cumulative’ TCC is issued.
You can contact Revenue to find out why you are on the week 1 basis, by:
If you are still on the week 1 basis at the end of the year, you must submit a Form 12. You can find a Form 12 in ‘PAYE Services’ in myAccount. We will then review your tax position for the year.