I am a salaried person, how will I calculate the total amount of money at the end of the year because of eg. if I get some money in the eleventh month or even 6th month it is difficult to keep track monthly

Assalaamu `alaykum waRahmatullahi Wabarakatoh

Your Zakaat year will commence as soon as you have the minimum Nisaab of Zakaat. For example let us assume that the minimum Nisaab is $500. On the 1^st of Rajab 1428 you become the owner of $500 therefore your Zakaat year would commence on the 1^st of Rajab 1428 and end on the 1^st Rajab 1429. 

What would then happen is on the 1^st Rajab 1429 you will calculate your total assets, deduct your liabilities and give 2.5 % of that difference in Zakaat (if the amount exceeds the Nisaab). If after deducting the liabilities the total assests are lesser than Nisaab, Zakaat will not be necessary. There is no need to calculate the amounts every month.

And Allah knows best

Checked and Approved by:

Mufti Emraan Vawda
Darul Iftaa