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Oxygen Saturation (SpO2) Calculator

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Enter your pulse oximeter reading to check which category it falls into.

Oxygen Saturation (SpO2) Calculator

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Category
Normal
Applies to a healthy adult at sea level. People with chronic lung conditions may have a different doctor-set target range. This is informational only, not a diagnosis.

The classification

Normal: 95-100% Low (consult a doctor): 90-94% Very Low (seek care): under 90%
Example

A reading of 98% falls squarely in the Normal range (95-100%).

Step-by-step guide

  1. Warm your hands if they're cold, and remove any nail polish or artificial nails on the finger you'll use - both can interfere with an accurate reading.
  2. Clip the pulse oximeter onto a fingertip and stay still for 10-15 seconds while it stabilizes.
  3. Enter the SpO2 percentage shown (not the pulse rate number) above.

What can cause a falsely low reading

Before treating a low reading as a genuine medical concern, it's worth ruling out common measurement issues: cold fingers reduce blood flow to the fingertip and can drag the reading down, nail polish (especially dark colors) can block the sensor's light, a poorly fitted or loose clip introduces motion artifact, and cold environments or Raynaud's-type circulation issues can all produce an artificially low number that doesn't reflect your actual blood oxygen level.

Common mistakes

Reading the pulse rate number instead of the SpO2 percentage - a pulse oximeter displays two different numbers, and mixing them up leads to comparing the wrong value against these ranges.
Not accounting for altitude - people living at high elevation naturally run somewhat lower SpO2 readings as a normal baseline, since there's less oxygen in the air to begin with.

Frequently asked questions

Does age affect the normal SpO2 range?

Not as much as heart rate does, though older adults' readings can drift slightly toward the lower end of normal as lung elasticity naturally decreases with age - a reading of 94-95% may be a normal baseline for some healthy older adults.

Do people with COPD or lung disease use the same normal range?

Not necessarily - some people with chronic lung conditions have a doctor-set target range that's lower than the standard healthy-adult range, often around 88-92%. Follow your own doctor's specific target if you have one.

Why might my reading look low even though I feel fine?

Cold hands, nail polish, poor circulation, or a loosely fitted sensor can all cause an artificially low reading. Try warming your hands and rechecking with a properly fitted sensor before assuming the number reflects a real problem.

Does living at high altitude change what's normal?

Yes - people who live at high elevation typically have a somewhat lower baseline SpO2 than this calculator's sea-level-based range, since there's less available oxygen in the air at altitude.

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