Soak dried chickpeas in one liter (4 cups) of water for about 10 hours (you can leave them to soak overnight).
Discard soaking water and rinse the chickpeas.
Place chickpeas into a saucepan and cover with 1 liter (4 cups) of water.
Cover the saucepan with a lid and bring to the boil. Then decrease the heat to low-medium and simmer for 60 to 90 minutes (until chickpeas are tender).
Once the chickpeas are cooked, turn the heat off and leave them to cool down completely in their cooking water.
Using a slotted spoon, remove chickpeas from the cooking water. And there you are : this chickpea cooking water is your aquafaba! You should get about ½ liter (2 cups) of aquafaba.
Notes
Please keep in mind that the nutritional information is calculated using a nutrition facts calculator. It is a rough estimate and can vary greatly based on products used.