Zakat is due once a year on wealth you've held above the nisab threshold for a full lunar year (hawl). It isn't a tax on income — it's a percentage of what you still have sitting in savings, gold, or investments at the point zakat becomes due.
The standard rate is 2.5% of total zakatable wealth. This tool uses the gold-based nisab (85 grams), the measure most UAE residents use in practice. Some scholars apply the silver-based threshold instead, which is lower and brings more people into zakat eligibility — if you're unsure which applies to you, a local fatwa body or your mosque can advise on your specific situation.
One thing people often miss: savings accounts count, not just cash in hand. So does gold jewelry you own but don't wear daily, and the current market value of stocks or crypto — not what you originally paid for them.