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4 October 2021

How to buy the best pulse oximeter

Looking for a pulse oximeter to use at home? We explain the features you should be looking out for before you buy one.
Rebecca Jakeman

Pulse oximeters are small medical devices that let you keep tabs on key health measures – such as your blood oxygen levels and pulse rate – at home, and share them with your doctor or clinician if needed.

Here, we explain how much pulse oximeters typically cost, the key features worth looking for and how to decide if buying one is right for you.

We also advise on the best places to buy one, and include links to our expert pulse oximeter reviews so you can see which models we recommend.

If you just want to see the pulse oximeters we've tested, head straight to our pulse oximeter reviews.

Do I need a pulse oximeter?

If you need a pulse oximeter, your doctor will usually advise you to buy one. You might not even need to buy it yourself, as it might be supplied by the NHS, depending on your condition and circumstances.

Pulse oximeters are useful monitoring devices to have at home for certain groups of people, such as those who are prone to respiratory failure, suffer from a chronic respiratory condition, or require oxygen therapy. For these patients, a drop in oxygen levels could point to something much more serious.

During the pandemic, some doctors have suggested buying pulse oximeters to test your oxygen levels at home as a precaution, in case you become severely unwell with Covid-19. Trials are ongoing, but if you're unwell, it's important not to rely on these devices without advice from a medical professional.

If you're concerned about your respiratory health and think a pulse oximeter would be beneficial, speak to a medical professional first. Pulse oximeters are not a substitute for medical advice, and any at-home monitoring should be part of a clear health-management plan.

Find out more about the debate over pulse oximeters and Covid-19.

How much do pulse oximeters cost?

Pulse oximeters typically cost around £15-30, although prices can vary from £5-50. You don't necessarily have to pay more to get a great model; some of our Best Buys cost less than £20. 

But if you're after particular features (such as a perfusion index function or a larger, OLED screen), the extra functionality will usually cost you more.

You'll need to account for the cost of batteries too, as all of the pulse oximeters we've tested use them - usually AAA, but you may come across some that use AA. The charge can run down quite quickly, especially if you're using it regularly, so it's worth making sure you always have spare batteries to hand if your rely on regular readings.

Head over to our AAA battery reviews to find out which brands we recommend. 

Pulse oximeter features to look for

While our in-depth reviews can tell you which Best Buy pulse oximeters provide the speediest, most accurate readings – and are most comfortable to use – you might still be baffled by some of the jargon and terminology used. 

We've listed some of the phrases you might see when you're looking for a pulse oximeter, and what they mean:

  • SpO2 reading A measurement of how much oxygen is in your blood. Every pulse oximeter has this feature, as it's the main thing they're designed to measure. A Spo2 reading of less than 92% (or 88% for those with chronic obstructive pulmonary disease) can suggest that someone is seriously ill and needs immediate medical attention.
  • Pulse rate The number of times your heart beats per minute. For a healthy adult, this is usually around 60-100bpm. On most pulse oximeters this is displayed as a number, but it can also be in the form of a bar graph or plethysmographic waveform (a continuous curve showing your heart rate).
  • Perfusion index Usually only pricier pulse oximeters will have this feature. It measures the ratio of pulsating to non-pulsating blood in your finger, and is used as an indication of how strong your blood flow is. Most people are unlikely to need this on a regular basis, and we don't test it in our lab.
  • Display orientation Some pulse oximeters give you the option to rotate the display so it's easier to read when the device is on your finger. 
  • OLED screen Most devices have basic LCD screens, but a handful have slightly more advanced OLED screens. 

How to buy the best digital thermometer - we give typical costs plus pros and cons of different types to help you choose


Where to buy a pulse oximeter

Once you've decided to buy a pulse oximeter, make sure you choose a seller with a good reputation. Check their returns policy and have a look at some user reviews before you buy. Our online shopping advice guide has some more handy hints and tips.

Most pharmacies, including Boots, Lloyds and Superdrug, sell a handful of pulse oximeters. Generalist retailers such as Amazon and Argos do too.

You'll likely find a wider selection online, but it's worth sticking to known brands or sellers you recognise. Any pulse oximeters marketed as 'medical devices' should display a valid CE, CE UKNI or UKCA mark. Those that aren't certified medical devices must have a disclaimer to explain as such. 

For more information on purchasing medical-grade devices, take a look at the MHRA advice website and our guide on how to avoid fake and dangerous products

Discover which retailers you can trust in our expert guide on the best and worst shops.

How to use a pulse oximeter effectively

If you've been told by a medical professional that you should use a pulse oximeter at home, you need to make sure you're using it as effectively as possible to get the most accurate picture of your health.

Make sure you thoroughly read the instructions that come with your pulse oximeter, but as a general guide, these tips can help to get accurate readings:

  1. Make sure you wash your hands thoroughly before using the pulse oximeter. The finger you are going to use shouldn't have any nail varnish or a false nail on it, as these make it hard to obtain an accurate reading.
  2. Ensure your hand is warm to the touch,  then sit down and let it rest on your chest for about five minutes before switching the pulse oximeter on.
  3. Attach the clip of the pulse oximeter onto your index finger (the finger next to your thumb) or your middle finger, and wait for the readings to appear on the screen.
  4. Once the numbers have stopped changing and reached a steady average, record your readings. You can then remove the pulse oximeter and put it away until you need it next.

If you ever encounter readings that look slightly out of the ordinary (a little too high or low), take a break before repeating the steps listed above. If it happens again, you should contact your medical provider for further assistance.

For more tips, check the NHS guide to treating Covid at home or this useful NHS video guide to using a pulse oximeter.

Pulse oximeters compared

It's important that a pulse oximeter does its job accurately and efficiently, and is easy for you to use and understand.

We check all these things in our independent tests, and we buy products ourselves from the shops so they're exactly what you could buy. Any pulse oximeters that fail at their core job of measuring blood oxygen accurately are automatic Don't Buys which we recommend avoiding.

Find out more about the pulse oximeters that give accurate readings by heading to our pulse oximeter reviews.