Short answer
Sadaqah means charity given for the sake of Allah. The word comes from sidq, truthfulness, because giving shows the truth of your faith. It covers voluntary giving of any amount to anyone, and the Prophet ﷺ said every good deed, even a smile, is sadaqah. Zakat is its obligatory form.
Voluntary sadaqah (nafl) is sunnah and greatly rewarded, with no minimum, no nisab and no fixed recipients: it may go to relatives, non-Muslims, a masjid, or even someone well off as a gift. Some sadaqah is wajib, such as zakat al-fitr, fidya, kaffarah and a vowed charity, and that must go to the poor like zakat.
The four schools agree on this.
Explanation
The Arabic sadaqah shares its root with sidq, truthfulness. Scholars explain that spending for Allah is proof that a person's faith is true. The Quran uses the word broadly: in 9:60 and 9:103 it refers to zakat itself. In everyday Muslim speech, sadaqah usually means voluntary charity.
It is wider than money. The Prophet ﷺ said every Muslim owes sadaqah, and that one who has nothing to give should do good and hold back from harm, for that is sadaqah for him. He also said that smiling at your brother is sadaqah. Removing something harmful from a path, a good word, helping someone onto their mount, and sparing people your harm are all described as sadaqah in the hadith.
There are several kinds:
- Zakat: fard, 2.5 percent of zakatable wealth, with fixed recipients.
- Wajib sadaqah: zakat al-fitr, fidya, kaffarah and charity you vowed. These go to the poor.
- Voluntary sadaqah: any amount, at any time, to any good cause.
- Sadaqah jariyah: ongoing charity such as a well, a masjid or beneficial knowledge, whose reward continues after death (see sadaqah jariyah).
Voluntary sadaqah is free of zakat's rules. You may give it to your own parents or children, to non-Muslims (see charity to non-Muslims), to a masjid's building fund, or to an animal charity. Give from lawful earnings, without reminding people of your favour, and in secret where you can, since the Quran calls hidden giving to the poor better (2:271). The four schools agree on this outline. For a side-by-side table, see zakat vs sadaqah.
The evidence
Quran, Surah Al-Baqara 2:271
إِن تُبْدُوا۟ ٱلصَّدَقَٰتِ فَنِعِمَّا هِىَ ۖ وَإِن تُخْفُوهَا وَتُؤْتُوهَا ٱلْفُقَرَآءَ فَهُوَ خَيْرٌۭ لَّكُمْ ۚ وَيُكَفِّرُ عَنكُم مِّن سَيِّـَٔاتِكُمْ ۗ وَٱللَّهُ بِمَا تَعْمَلُونَ خَبِيرٌۭ ﴿٢٧١﴾
If you disclose your charitable expenditures, they are good; but if you conceal them and give them to the poor, it is better for you, and He will remove from you some of your misdeeds [thereby]. And Allah, with what you do, is [fully] Acquainted.
Sadaqah given quietly to the poor is praised.
Quran, Surah Al-Baqara 2:261
مَّثَلُ ٱلَّذِينَ يُنفِقُونَ أَمْوَٰلَهُمْ فِى سَبِيلِ ٱللَّهِ كَمَثَلِ حَبَّةٍ أَنۢبَتَتْ سَبْعَ سَنَابِلَ فِى كُلِّ سُنۢبُلَةٍۢ مِّا۟ئَةُ حَبَّةٍۢ ۗ وَٱللَّهُ يُضَٰعِفُ لِمَن يَشَآءُ ۗ وَٱللَّهُ وَٰسِعٌ عَلِيمٌ ﴿٢٦١﴾
The example of those who spend their wealth in the way of Allah is like a seed [of grain] which grows seven spikes; in each spike is a hundred grains. And Allah multiplies [His reward] for whom He wills. And Allah is all-Encompassing and Knowing.
The reward of spending for Allah is multiplied.
Sahih al-Bukhari 1445
Sahih... فليعمل بالمعروف وليمسك عن الشر فإنها له صدقة ...
"Let him do good and hold back from harm, for that is sadaqah for him."
Doing good and holding back from harm count as sadaqah.
Jami' at-Tirmidhi 1956
Grading to be checked... تبسمك في وجه أخيك لك صدقة ...
"Your smile in the face of your brother is sadaqah for you."
Even a smile counts as sadaqah.
Where the ruling is recorded
- Radd al-Muhtar, Kitab al-Zakat, chapter on the recipients (bab al-masrif). Wajib sadaqat such as vows, kaffarah and zakat al-fitr go to the recipients of zakat; voluntary sadaqah may be given more widely.
- al-Fatawa al-Hindiyya, Kitab al-Zakat, chapter on the recipients. Voluntary sadaqah may be given to the wealthy and to relatives who cannot receive zakat.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.