What is first stable product in Calvin cycle?

The first stable product in the Calvin cycle is a 3-carbon compound called 3-phosphoglycerate (3-PGA). During the light-independent reactions of photosynthesis, carbon dioxide (CO₂) is initially fixed into a 5-carbon compound called ribulose-1,5-bisphosphate (RuBP) with the help of the enzyme RuBisCO (Ribulose-1,5-bisphosphate carboxylase/oxygenase).