Pulse oximeter measures oxygen carrying capacity of blood by measuring the saturation of hemoglobin with oxygen. It fluctuates with the physical activity and your cardiopulmonary health. It’s not always a constant reading and normally also it can vary from individual to individual. The normal value for SpO2 is more than 95%. However, in all circumstances it should remain more than 92%. To find out your regular SpO2 levels, you need to take your SpO2 readings four times a day approximately 6 hours apart for 5 days. This way you can find out your average SpO2 for future reference.