Zakat is the third of the five pillars. Everything on the other giving page is voluntary; this is the part that is owed — worked out on savings rather than on what you earn, and paid once a year.
If you have just become Muslim and are carrying debt, this may not apply to you at all this year. Read it to understand what it is, not as a bill.
And establish prayer and give zakāh, and whatever good you put forward for yourselves - you will find it with Allāh. Indeed Allāh, of what you do, is Seeing.
Grounded with quran.ai: fetch_translation(2:110, en-sahih-international)
It appears beside prayer again and again, which tells you how it is regarded: not charity in the sense of a kind extra, but a duty on wealth in the same breath as the duty of prayer.
The two kinds you will meet
Zakat on wealth, sometimes called zakat al-mal. Paid once a year on savings you have held, once they pass a set threshold. This is the one people usually mean by “zakat”.
Zakat al-fitr, paid at the end of Ramadan, for every member of a household, so that nobody is without food on Eid. Small, fixed, and separate from the one above.
Zakat al-fitr, as it was given
Allah's Messenger (ﷺ) enjoined the payment of one Sa' of dates or one Sa' of barley as Zakat-ul-Fitr on every
Muslim slave or free, male or female, young or old, and he ordered that it be paid before the people
went out to offer the `Id prayer. (One Sa' = 3 Kilograms approx.)
Narrated Ibn `Umar:
Show the Arabic
حَدَّثَنَا يَحْيَى بْنُ مُحَمَّدِ بْنِ السَّكَنِ، حَدَّثَنَا مُحَمَّدُ بْنُ جَهْضَمٍ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ جَعْفَرٍ، عَنْ عُمَرَ بْنِ نَافِعٍ، عَنْ أَبِيهِ، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ فَرَضَ رَسُولُ اللَّهِ صلى الله عليه وسلم زَكَاةَ الْفِطْرِ صَاعًا مِنْ تَمْرٍ، أَوْ صَاعًا مِنْ شَعِيرٍ عَلَى الْعَبْدِ وَالْحُرِّ، وَالذَّكَرِ وَالأُنْثَى، وَالصَّغِيرِ وَالْكَبِيرِ مِنَ الْمُسْلِمِينَ، وَأَمَرَ بِهَا أَنْ تُؤَدَّى قَبْلَ خُرُوجِ النَّاسِ إِلَى الصَّلاَةِ.
Source: Sahih al-Bukhari, hadith 1451 — in the Book of Obligatory Charity Tax (Zakat)
Note who it covers — every person in the household, young and old — and when it is due: before people go out to the Eid prayer, so it arrives in time to be of use that day. The measure named is a sa' of dates or barley. What that comes to where you live, this year, is a question for the section below.
Zakāh expenditures are only for the poor and for the needy and for those employed for it and for bringing hearts together [for Islām] and for freeing captives [or slaves] and for those in debt and for the cause of Allāh and for the [stranded] traveler - an obligation [imposed] by Allāh. And Allāh is Knowing and Wise.
Grounded with quran.ai: fetch_translation(9:60, en-sahih-international)
Worth reading that list slowly, because one of the eight is those in debt. If you have arrived at this page assuming zakat is something you will only ever pay, the Qur'an names circumstances in which a person receives it instead. Whether that describes you is not something a web page can tell you — but it is worth knowing the question exists before you decide the answer.
What Rafīq will not work out for you
The threshold, the rate, whether your debts come off the total, whether your pension or your house counts, and what you owe this year. None of it appears on this page, and that is deliberate.
People act on numbers. A wrong figure here would not merely misinform somebody — it would change what they hand over, or convince them they owe nothing when they do. Those answers depend on your circumstances and on positions our scholarly board has not settled for us to publish, so they belong with a knowledgeable person.
That includes the question most people in this country actually have: what a mortgage means for any of it. It is a real question, scholars differ on it, and it is not one Rafīq is going to answer for you in either direction.
In practice this is a short conversation. Any mosque can point you to someone, and many run a zakat desk or use a calculator prepared by scholars — which is the right kind of tool for it, prepared by people who can stand behind the figures.