Short answer
Gharar is excessive uncertainty in a contract, where a buyer or seller does not know what he is getting, whether it exists, or whether it can be delivered. The Prophet ﷺ forbade sales involving it. Small uncertainty that cannot be avoided is tolerated; serious uncertainty that leads to disputes or gambling-like outcomes makes a contract invalid.
A sale with major gharar in the item, price or delivery is invalid (fasid). Minor gharar that is customary is overlooked. Buying an unseen item is valid in the Hanafi school, with the buyer having the option to cancel when he sees it (khiyar al-ru'yah).
Other madhhabs
- Shafi'i
- In the later (relied-upon) view, selling an item neither party has seen is invalid, even with an option.
Explanation
The Prophet ﷺ "forbade the pebble sale and the gharar sale" (Muslim). The word means risk or deception. The aim is that each side knows what it gives and receives, so that trade does not become a gamble and people do not fall out.
Classical examples: selling a fish still in the sea, a bird in the air, the unborn young of an animal, or a runaway camel. Each might never be delivered.
Modern examples that scholars discuss:
- Conventional insurance, where you pay premiums for an uncertain payout. See Is insurance haram?
- Options and many derivatives. See Is options trading halal?
- Paid mystery boxes and loot boxes with random contents.
- Selling goods you do not own and may not be able to get. See Is dropshipping halal?
- A price left open, such as "pay whatever it costs at the time".
What is tolerated: the foundations of a house you cannot see, the exact amount of water you use in a public bath or gym shower, small variations in fruit. Jurists overlook uncertainty that is minor, hard to avoid and that people accept by custom.
The Hanafi school is fairly practical here. You may buy something described but unseen, such as goods online, and you have the right to return it once you see it if it is not what you expected. Clear descriptions, photos and a return policy reduce gharar further. See What are the rules of business in Islam?
The evidence
Quran, Surah An-Nisaa 4:29
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ لَا تَأْكُلُوٓا۟ أَمْوَٰلَكُم بَيْنَكُم بِٱلْبَٰطِلِ إِلَّآ أَن تَكُونَ تِجَٰرَةً عَن تَرَاضٍۢ مِّنكُمْ ۚ وَلَا تَقْتُلُوٓا۟ أَنفُسَكُمْ ۚ إِنَّ ٱللَّهَ كَانَ بِكُمْ رَحِيمًۭا ﴿٢٩﴾
O you who have believed, do not consume one another's wealth unjustly but only [in lawful] business by mutual consent. And do not kill yourselves [or one another]. Indeed, Allah is to you ever Merciful.
Real consent needs both sides to know what they are agreeing to.
Quran, Surah Al-Maaida 5:90
يَٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوٓا۟ إِنَّمَا ٱلْخَمْرُ وَٱلْمَيْسِرُ وَٱلْأَنصَابُ وَٱلْأَزْلَٰمُ رِجْسٌۭ مِّنْ عَمَلِ ٱلشَّيْطَٰنِ فَٱجْتَنِبُوهُ لَعَلَّكُمْ تُفْلِحُونَ ﴿٩٠﴾
O you who have believed, indeed, intoxicants, gambling, [sacrificing on] stone alters [to other than Allah], and divining arrows are but defilement from the work of Satan, so avoid it that you may be successful.
Major gharar turns a sale into something like gambling.
Sahih Muslim 1513
Sahih... نهى رسول الله صلى الله عليه وسلم عن بيع الحصاة وعن بيع الغرر ...
"The Messenger of Allah forbade the pebble sale and the gharar sale."
The direct basis of the prohibition of gharar.
Where the ruling is recorded
- al-Hidaya, Kitab al-Buyu', Bab al-Bay' al-Fasid; and Bab Khiyar al-Ru'ya. Sales void for gharar, and the option on seeing an unseen item.
- Minhaj al-Talibin, Kitab al-Buyu', conditions of the item sold. The Shafi'i rejection of sale of unseen goods.
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.