Zakat al Fitr: 1 Saa’ is a measure of VOLUME. Not a measure of WEIGHT.

بِسْمِ اللهِ الرَّحْمٰنِ الرَّحِيْمِ

• A Prophetic saa’ ( صاع ) is not a weight measurement. It was and still is a measurement of volume.
• 1 Saa’ is equal to 4 Mudd.
• 1 Saa’ converted to the commonly used Litre today is calculated at being 3L.
• 1 Mudd is therefore 0.75L or 750ml.
• Defining 1 Saa’ as simply a single weight is INCORRECT. Food types differ, so a KG (weight) of dates will be different in volume to rice of the same KG (weight).

For an exceptionally detailed article with evidences from the Qur’aan, the Sunnah, the understanding of the Salaf, and the sayings of some of the great scholars, please READ: https://www.bakkah.net/en/zakat-fitr-measurements-saa-three-litres-mudd.htm