A healthy blood oxygen level is between 95% and 100% . This means that the amount of oxygen circulating in the blood is sufficient for the needs of every cell in the body. Blood oxygen levels are measured using a pulse oximeter, which is a small device that clips onto a finger or another part of the body and shines a light into the tiny blood vessels to measure the oxygen from the light thats reflected back. For most people, a normal pulse oximeter reading for oxygen saturation level is between 95% and 100% . However, people with certain conditions, such as COPD, may need to maintain their blood oxygen at a different level, and their healthcare provider will let them know what levels are acceptable. Its important to note that pulse oximeters are not always accurate, and actual blood saturation levels may be 2% to 4% higher or lower than what the oximeter reads. If you have symptoms such as shortness of breath, chest pain, coughing or wheezing, confusion, headache, rapid heartbeat, or a blue discoloration of your nail beds, skin, and mucus membranes, you should get immediate medical attention, even if your pulse oximeter reading is normal.