How much ATP is produced in Krebs cycle?

The Krebs cycle produces 1 direct ATP (or GTP) per cycle turn through substrate-level phosphorylation. Through oxidative phosphorylation, 3 NADH contribute approximately 7.5 ATP and 1 FADH₂ contributes about 1.5 ATP, bringing the total to approximately 10 ATP equivalents per cycle. As each glucose molecule yields two turns of the Krebs cycle (via two acetyl-CoA molecules), the total ATP yield per glucose molecule is about 20 ATP equivalents.