What is a good oxygen level after surgery?

80-100 mm hg. Normal po2 is 80-100 mm hg which is the partial pressure of oxygen in blood. If your asking about o2 saturation, then 94-100%.
92 % plus.... In all patients, but certainly in post op patients, we'd like to see oxygen saturation of at least 92%. Supplemental oxygen may be necessary, at least for a short time. Good pulmonary toilet and breathing exercises are also employed. Good luck.