During this pandemic, there are many people who are suffering from proper oxygen levels. To measure the oxygen we use a tiny device that usually slides over your fingertip or clips on the ear lobe and uses infrared light refraction to measure your oxygen level. The pulse oximeter measures blood oxygen saturation (Sp02) level that indicates what percentage of blood is saturated. In simple words, it shows us an estimation of oxygen that is been carried by the red blood cells. The oxygen saturation level is measured in percentage (%) and heart rate in (bpm). The normal oxygen range should be 95-100% and for heart rate, the normal condition ranges from 70 to 100 bpm. If there is any slight decrease or increase in the value then it indicates an abnormality. Sometimes the oximeter also indicates heart attack or its severity in acute settings such as cardinal infraction and may have prognostic implications. When baseline oxygen saturation by pulse oximeter is <93 then we can suspect the patient can have the chances of a heart attack. If a person is suffering from COVID then they must check their oxygen level every 4 hours.