The net requirement of assimilatory powers for the formation of 1 hexose molecules in ${\mathrm{C}}_3$ plant is:

Six turns of Calvin cycle are required to produce one molecule of glucose. Twelve ATP and twelve NADPH+H⁺ molecules are required during reduction phase where twelve 3-PGA molecules are reduced to twelve PGAL molecules and 6 ATPs are required during regeneration phase where six RuBP molecules are regenerated from ten molecules of PGAL.