How to use a pulse oximeter at home

Follow these instructions to make sure the pulse oximeter gives an accurate reading:

Before you start make sure you:

  • Remove any nail polish or false nails
  • Warm your hand if cold.
  • Have been resting for at least five minutes before taking your measurement.

Once you have done the above:

  • Rest your hand on your chest at heart level and hold still.
  • Switch the pulse oximeter on and place it on your finger. It works best on your middle or index finger. It should not be used on your ear.
  • The reading takes time to steady. Keep the pulse oximeter in place for at least a minute, or longer if the reading keeps changing.
  • Record the highest result once the reading has not changed for five seconds.
  • Be careful to identify which reading is your heart rate and which is your oxygen level.


95% and 99%
is an ideal blood oxygen level

94% or 93%
Ring your GP or 111 as soon as possible if your blood oxygen level is 94% or 93% when sitting or lying down, and remains at this level after being rechecked within an hour.

92% or below
Attend your nearest A&E or call 999 immediately if your blood oxygen level is 92% or less. Check your blood oxygen level again straight away – if it’s still 92% or below, go to A&E immediately or call 999.