Most of the questions that come across a pharmacy counter now arrive holding a device. A fingertip oximeter says 94. A cuff says 138 over 86. A ring says you had forty minutes of deep sleep. The question is always the same one: is that number all right? These free tools answer it for one reading at a time — what the official range is, where your number sits against it, and how much of the number is the device rather than you. Nothing to sign up for, nothing to install, and nothing you type ever leaves your phone or computer.
Reading Checkers
A number from your own device in — what it means, what the official range is, and how much of it is the device.
- Oxygen Level (SpO2) CheckerWhat your oximeter reading means — and how much of the number is the device.
- Blood Pressure Reading CheckerYour reading in the US bands and the UK’s — they are ten points apart.
- Deep & REM Sleep CheckerYour tracker’s deep and REM numbers, and what is actually published about them.
- Overnight Oximetry Report ReaderThe four numbers on an overnight report, read line by line.
- Pulse Rate Checker & CounterCount your pulse, then see the published range for that age.
- HRV Checker: RMSSD vs SDNNYour HRV against the published figure that actually matches your device.
Where the numbers come from
Every range on these pages is quoted from the body that published it — the NHS, the British Thoracic Society, the FDA, the American Heart Association, the American Academy of Sleep Medicine, ASHA, NIOSH and peer-reviewed research — with the date we last checked it printed next to the answer. Where two official bodies draw the line in different places, and they often do, you see both lines and who drew each one. Nothing is averaged into a number nobody published.
The part other pages leave out: the device’s own error
A consumer pulse oximeter is allowed to be a few points out. A blood-pressure cuff that is the wrong size can be out by more than the gap between two categories. A sleep tracker is estimating your sleep stages from movement and heartbeat, not measuring them. So every reading tool here shows the band your number really sits in, not just the number, and says what makes that band wider — cold hands, nail polish, moving, the wrong cuff, a loose ring.
Where a tool stops
These are tools, not a diagnosis, and none of them will tell you what is wrong. They tell you what a published range is and where a reading falls against it. If a tool shows you a warning, it is shown at the top of the answer, in words, with who to call — and if you feel unwell, that matters more than any number on any screen. Ring your doctor, or the emergency services, rather than re-testing until you get a reading you like.
Built to be read
The type on these tools is larger than on most of the web, every button is big enough to press with a thumb, and no answer depends on telling red from green. That is deliberate: many people using a home oximeter or a blood-pressure monitor are reading it without their glasses.
Share an answer, or keep it
Every result has its own link. Copy link saves exactly what you entered, so you can send a reading to a family member, or open it again at the doctor’s surgery without writing it down.
Put a tool on your own site
Every tool has an Embed button. It gives you a short piece of code to paste into a page — a patient group, a pulmonary rehab page, a hearing charity’s resources — and the tool works there exactly as it does here, free, with a credit line linking back.
More from the site
The tools read the numbers. For the devices themselves — which oximeter, which CPAP mask, which sleep tracker, and what the features are actually worth — start with the latest guides.