Pulse Oximeter Readings Chart (Printable PDF)

A pulse oximeter shows what share of your red blood cells are carrying oxygen, so a healthy adult’s number sits close to the top of the scale. Your device shows SpO2 by shining light through your finger. What matters most is not one exact value but which band your reading falls into, from normal through mildly low to an emergency. For a healthy adult resting at sea level, 95 to 100% is normal, 92 to 94% is mildly low and worth checking with a doctor, and anything below 92% calls for prompt attention. Below 90% needs medical care, and below 85% is urgent.

The right band depends on who is being measured. People with long-term lung disease often have a lower personal target of 88 to 92%, and babies and people living at altitude have different normal numbers.1Respirology. Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: ‘Swimming between the flags’2PubMed Central. Effects of high altitude on respiratory rate and oxygen saturation reference values in healthy infants and children younger than 2 years in four countries: a cross-sectional study The clip on your finger can also be fooled by cold hands, some nail polish, darker skin and smoke from fires or faulty heaters.3PubMed Central. The impact of skin tone on performance of pulse oximeters used by NHS England COVID Oximetry @home scheme: measurement and diagnostic accuracy study4Biomedical Signal Processing and Control. Analysing the effects of cold, normal, and warm digits on transmittance pulse oximetry5PubMed. The effect of nail polish on pulse oximetry6PubMed Central. Carbon Monoxide Poisoning: Diagnosis, Prognostic Factors, Treatment Strategies, and Future Perspectives

Pulse Oximeter Readings Chart for Adults

Print this and keep it next to the device.

17Open Critical Care. What are the indications for supplemental oxygen therapy?Sources draw the line between “mild” and “needs care” slightly differently, some at 92% and some at 90%.18Healthify. Pulse oximeter – adult19Gwinnett Pulmonary & Sleep. Decoding Pulse Oximetry Readings Treat 92% as your point to act, because it is the stricter of the common cutoffs.

The percentage does not tell you how much air you are moving or how hard you are working to breathe. Someone can breathe very fast and hard to hold a normal number, so a normal reading does not rule out a problem if they look distressed. A single reading is only a snapshot, and the pattern over several checks tells you more than any one number.

When a reading looks low, treat it as a reason to recheck, not to panic. Warm the hand, sit still, and measure again after a minute. Write down the number, the time, and what the person was doing, so a doctor can see the trend. A drop of a few points from the person’s usual level matters even if the number is still inside the normal band. Breathlessness, confusion, chest pain or bluish lips need urgent help whatever the number says.

On your printed copy, add the person’s own usual reading and any target range a doctor gave. Write the doctor’s phone number beside the lower bands, along with when to call emergency services. Add a log column for date, time and reading, and mark the sheet clearly if the person has COPD so a different target is used.

When to Call a Doctor or Go to the ER

For most adults with a sudden illness, guidelines start oxygen when the reading falls below 92%.20Respirology. Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: ‘Swimming between the flags’ Hospitals then aim to keep the reading between 92 and 96%, not at 100%.21Respirology. Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: ‘Swimming between the flags’

When you call the doctor, say the reading, how long it has stayed there, and whether it changes with rest. Mention fever, cough, breathlessness, and any lung or heart condition. Say whether you rechecked with warm hands and no nail polish. It also helps to ask what number should make you go to hospital next time.

Low oxygen can be silent. Some people, notably during COVID-19, have dangerously low oxygen without feeling short of breath.22Acute Care Testing. Asymptomatic severe hypoxemia is an important feature of COVID-19 for some patients; mechanisms discussed and prognosis examined

The opposite problem exists too. Carbon monoxide from fires, heaters or car exhaust makes the device read normal or high even when the person is poisoned.23PubMed Central. Carbon Monoxide Poisoning: Diagnosis, Prognostic Factors, Treatment Strategies, and Future Perspectives24PubMed. Pulse oximetry in severe carbon monoxide poisoning If there is headache, dizziness or nausea in a home with fuel-burning appliances, get to emergency care whatever the reading says.

Some signs override any number:

  • Struggling to speak in full sentences, or breathing fast at rest
  • Blue or grey lips, face or nail beds
  • New confusion, drowsiness, or being hard to wake
  • Chest pain or a racing heart with breathlessness

While you wait for help, sit the person upright rather than lying flat, since that usually makes breathing easier. Stay with them, keep them calm, and keep the oximeter handy to report the reading to the call handler. Don’t give food or drink if they are breathing hard, and don’t make them walk to the car.

Target Readings for People With COPD

For COPD and other long-term breathing failure, guidelines give oxygen below 88% and aim for 88 to 92%.25Respirology. Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: ‘Swimming between the flags’ The lower target is deliberate. People hospitalized with a COPD flare-up died least often at readings of 88 to 92%, and readings even slightly higher, at 93 to 96%, were linked with more deaths.26PubMed. Oxygen therapy and inpatient mortality in COPD exacerbation

In some people with long-term lung disease, extra oxygen can lead to carbon dioxide building up in the blood, which is part of why a higher number is not the goal. A reading of 95% or more is not automatically reassuring in someone with COPD who is on supplemental oxygen.

If you have COPD, use your own doctor’s target range, not the 95% normal line, as your all clear. Don’t turn up home oxygen to chase a higher number without advice. A drop below your usual range, or below 88%, is the sign to call. Note your usual reading on a good day so you can see a flare-up starting.

Oxygen can also drop while you walk and recover by the time you stop, so checking only after exercise can miss that dip. Ask your doctor whether to check during activity.

Normal Readings for Children and Babies

Healthy children at sea level usually read between 97 and 100%, with about half at 100%.27PubMed Central. Normative pulse oximetry values in healthy children The average is about 99% from infancy to age 5, and readings below about 96.5% are unusual.28PubMed. Reference values for oxygen saturation by pulse oximetry in healthy children at sea level in Chennai A child reading in the low 90s at sea level deserves a call to the doctor. The adult cutoffs shouldn’t be applied to a child, so check what is normal for their age.

Healthy newborns average about 97%, with a normal spread from 94 to 100%.29Pediatric Pulmonology. Pulse oximetry: What’s normal in the newborn nursery? Readings creep up slightly each day after birth. Crying lowers a baby’s reading by about 1 point, so measure while the baby is calm or asleep.30Pediatric Pulmonology. Pulse oximetry: What’s normal in the newborn nursery?

Many adult fingertip clips don’t fit small fingers and give unreliable numbers. Consumer devices and phone apps tested on children varied widely and did poorly in infants.31PubMed Central. The Accuracy of Readily Available Consumer-Grade Oxygen Saturation Monitors in Pediatric Patients For a sick baby, rely on breathing, feeding, color and alertness, and call a doctor rather than trusting the clip. Keep the child still and warm, because a wriggling child makes the reading jump.

To judge a sick child beyond the number, watch how hard they are working to breathe: flaring nostrils, skin pulling in between the ribs, or grunting. Notice whether they are feeding or drinking normally, alert and responsive, and of normal color.

Why Your Reading Might Be Wrong

Cold fingers get less blood flow, which weakens the signal and makes the reading inaccurate.32Biomedical Signal Processing and Control. Analysing the effects of cold, normal, and warm digits on transmittance pulse oximetry A cold-hand reading is most often falsely low or no reading at all, which can cause needless worry. In children, skin below about 30°C was the clearest sign the reading would be wrong.33PubMed. Effect of peripheral perfusion on accuracy of pulse oximetry in children

Warming the hand improved signal quality up to fourfold.34Biomedical Signal Processing and Control. Analysing the effects of cold, normal, and warm digits on transmittance pulse oximetry Rub the hands together, or hold them in warm water briefly and dry them, before rechecking. The earlobe can work better than the finger when circulation is poor, but only with some sensors, and ordinary home devices are finger clips.35Anesthesiology News. Earlobes Better for Pulse Oximetry When Peripheral Perfusion Is Poor36PubMed. Pulse oximeter probes. A comparison between finger, nose, ear and forehead probes under conditions of poor perfusion

Nail polish matters because the light passes through the nail. Black, blue, green and brown-red polish can lower the reading, while red and purple caused less change.37PubMed. The effect of nail polish on pulse oximetry Gel manicures can push readings up or make them unreliable, especially in dark colors.38PubMed Central. The effects of gel-based manicure on pulse oximetry Thick artificial coverings can interfere too. Remove polish from one finger with remover before measuring. If you can’t, try turning the clip sideways so the light crosses the sides of the fingertip, but treat that result with caution.

Oximeters tend to read higher on darker skin, on average 0.6 to 1.5 points above the true level.39PubMed Central. The impact of skin tone on performance of pulse oximeters used by NHS England COVID Oximetry @home scheme: measurement and diagnostic accuracy study The gap grows as oxygen falls, reaching about 3.5 points at very low levels.40PubMed. Effects of skin pigmentation on pulse oximeter accuracy at low saturation Someone with darker skin reading 92 to 94% may truly be lower, so act a little sooner.

To tell a real drop from a bad reading, look for steadiness. A good reading holds for several seconds, while a bouncing number points to a poor signal. Many devices show a pulse wave or bar, and a weak, irregular one means you shouldn’t trust the number. Check that the pulse shown matches the pulse you feel at the wrist. If a recheck on another warm finger is normal, the first reading was probably wrong.

How to Take an Accurate Reading at Home

Follow these steps in order:

The middle or index finger usually gives the best signal, since it tends to have good blood flow and fits the clip well. Avoid a finger that is cold, injured, swollen, or wearing a ring or polish. If you are tracking trends, use the same finger and hand each time so changes reflect the person rather than the finger.

A useful log starts with measuring at the same times each day, such as morning and evening. Record each reading alongside symptoms like breathlessness or fever, and take the log to appointments so the doctor sees the trend. Replace the batteries when readings start failing to appear.

Readings During Sleep, With Age, and at Altitude

Healthy adults average about 96% overnight.44PubMed Central. The uses of overnight pulse oximetry Repeated drops of 4 points or more, five or more times an hour, can point to a sleep breathing problem such as sleep apnea.45PubMed Central. The uses of overnight pulse oximetry If a device logs frequent overnight dips, or you snore and wake tired, ask about a sleep test.

Many basic home devices aren’t designed for overnight use and may slip off or leave gaps, and a gap is not proof of a dip. Overnight readings can raise suspicion, but a proper diagnosis needs a sleep test arranged by a doctor. Loud snoring, pauses in breathing that a partner notices, and gasping or choking at night are worth mentioning, as are waking unrefreshed, morning headaches and daytime sleepiness. Raise these even if the daytime reading is normal.

A slightly lower oxygen level is a normal part of aging.46PubMed. Oxygen saturation levels in the well elderly: altitude makes a difference Even so, a reading below 95% still deserves a check rather than being put down to age.

Higher altitude means thinner air, so readings fall.47PubMed Central. The Use of Pulse Oximetry in the Assessment of Acclimatization to High Altitude Young children averaged about 98% near sea level but about 90% at very high altitude in Peru.48PubMed Central. Effects of high altitude on respiratory rate and oxygen saturation reference values in healthy infants and children younger than 2 years in four countries: a cross-sectional study

On a mountain trip the sea-level bands don’t apply, and readings in the high 80s to low 90s are to be expected up high. They often improve over a few days as the body adjusts. Headache, breathlessness at rest, or confusion matter more than the number, and going down is the main treatment for serious altitude sickness.