Normal blood pressure reading: chart and what the numbers mean
A normal blood pressure reading for most adults sits below about 120/80 mmHg, and many guidelines regard anything under 130/85 mmHg as acceptable. This guide gives you the commonly used ranges in one chart, explains the two numbers, and shows how to measure at home so your readings mean something.
Key takeaways
- Blood pressure is written as two numbers in mmHg: systolic over diastolic, for example 118/76.
- Many guidelines call a reading below roughly 120/80 mmHg optimal and a repeated reading of 140/90 mmHg or above high.
- One reading tells you very little. A pattern across several days tells you far more.
- Rest for five minutes, sit with your back supported and keep the cuff at heart level before you measure.
- Your GP reads your numbers in the context of your age, health and medicines, so share your home log with them.
What is a normal blood pressure reading?
For most healthy adults, a normal blood pressure reading is below about 120/80 mmHg. Many guidelines also describe readings up to roughly 129/84 mmHg as still within the normal range, which is why you will see slightly different cut-offs in different places.
The unit is mmHg, short for millimetres of mercury. It is the same unit your GP, your clinic nurse and the screen on a home monitor all use, so the numbers are easy to compare wherever you are measured.
Blood pressure is not one fixed number. It rises when you climb stairs, run for a taxi or argue with a loved one, and it falls when you rest. A reading that sits in the healthy range most of the time is what people mean when they say their pressure is normal.
What does a blood pressure chart look like?
The chart below shows the ranges that are commonly used for adults. Guidelines draw the lines in slightly different places, so treat it as a map and not as a verdict. Your GP interprets your readings in context.
A reading counts in the higher band if either number falls in it. For example, 118/92 mmHg is classed by its diastolic number, not its systolic one.
| Category | Systolic (top number) | Diastolic (bottom number) |
|---|---|---|
| Low reading to discuss with your GP if you feel unwell | below about 90 | below about 60 |
| Optimal or normal | below about 120 | below about 80 |
| Normal to high-normal | about 120 to 139 | about 80 to 89 |
| High (grade 1 range) | about 140 to 159 | about 90 to 99 |
| High (grade 2 range) | about 160 to 179 | about 100 to 109 |
| Very high, seek urgent care if you also feel unwell | 180 or above | 110 or above |
A diagnosis of high blood pressure is normally made from several readings on different days, not from one measurement. If your numbers sit in the higher bands, book a visit with your GP and bring your log.
What do the two blood pressure numbers mean?
The top number is systolic pressure. It is the force in your arteries each time your heart beats and pushes blood out. The bottom number is diastolic pressure, the force while your heart rests between beats and refills.
Both matter. Doctors and nurses often pay particular attention to the systolic number in people over 50, because it tends to rise gradually as arteries become less flexible with age.
You may also hear about pulse pressure, which is simply the gap between the two numbers. Your GP may look at it alongside your pulse rate, but for everyday home checking, the two main numbers and a steady routine are what count.
Does one high reading mean I have high blood pressure?
No. One high reading usually means you were rushed, anxious, cold, in pain or had just had coffee. Clinic nurses even have a name for a bump that happens only in a medical setting, and many people notice their numbers are lower at home.
What matters is the pattern. Take your blood pressure at the same times over several days and write each result down. If most of the numbers sit in the higher bands, that is the moment to see your GP.
If you take a reading and it is 180/110 mmHg or above, sit quietly for five minutes and measure again. If it is still that high, or you also have chest pain, a severe headache, shortness of breath, confusion, weakness on one side of the body or trouble speaking, seek urgent medical care straight away.
How do I measure my blood pressure at home properly?
Use an upper-arm monitor with a cuff that fits your arm. A cuff that is too small gives readings that run high, and wrist monitors are more sensitive to arm position. Ask the pharmacist to check the cuff size when you buy one.
Follow the same routine each time so your readings can be compared. These steps are widely recommended:
- Skip coffee, tea, cigarettes and exercise for 30 minutes beforehand, and go to the toilet first.
- Sit in a chair with your back supported, feet flat on the floor and legs uncrossed.
- Rest quietly for five minutes without talking or looking at your phone.
- Rest your bare upper arm on a table so the cuff sits level with your heart.
- Take two readings one minute apart and write down both, or the average.
- Measure at similar times each day, for example morning before breakfast and evening before supper, for about a week before a GP visit.
Where can I get my blood pressure checked in South Africa?
Blood pressure checks are easy to find. Your local clinic, your GP's rooms and the in-store health stations that many pharmacies offer all measure blood pressure, often within minutes and sometimes during a wellness day at work or a community event.
Medical aid schemes frequently include a blood pressure screening in their wellness benefits, so it is worth asking your scheme what it covers. If you prefer a quick check while doing your shopping, a pharmacy station is convenient, and the pharmacist can tell you when a result is worth taking to your GP.
A home monitor is a sensible purchase if you have been told your pressure runs high, if high blood pressure runs in your family or if you want a private record between visits. Bring the monitor along to your next appointment so your GP can compare it with their own device.
What can make my blood pressure reading go up or down?
Blood pressure naturally swings through the day. It is usually lowest while you sleep, climbs when you wake and tends to be higher in the afternoon. Knowing this helps you read your log with a calm head.
Several everyday things can push a reading up for a while:
- Caffeine, nicotine and a recent argument or stressful phone call
- A full bladder, which can add a noticeable bump to a reading
- Cold weather, such as a winter morning on the Highveld
- Talking during the measurement or having your arm unsupported
- Some cold and flu remedies, pain tablets and other medicines, so mention everything you take when you see your GP
What should I do with my readings?
Keep a simple log with the date, time, both numbers and your pulse. A notebook works as well as an app. Bring it to your GP so they can see the pattern and not just a single number from the day of the visit.
If your readings are in the healthy range, keep up the habits that got you there: regular movement, a sensible amount of salt, a healthy weight, limited alcohol and good sleep. A yearly check is a sensible habit, and more often if you are over 40 or have a family history of high blood pressure.
If your readings are higher than you would like, you are not alone and there is plenty you can do. Our guide on how to lower blood pressure naturally lists everyday steps, and the guide on what causes high blood pressure explains the common drivers. Whatever you choose, keep taking any prescribed medicine exactly as your GP directed.
Frequently asked questions
What is a normal blood pressure reading by age?
The commonly used target below about 120/80 mmHg applies to most adults. Blood pressure tends to creep up with age, and your GP may set a slightly different goal for you depending on your health, other conditions and medicines. Ask what your personal target is.
Is 130/80 a normal blood pressure reading?
A reading of 130/80 mmHg sits just above the optimal range and is described as high-normal by many guidelines. One reading is not a diagnosis. Measure again on different days, keep a log and discuss the pattern with your GP.
What blood pressure is too low?
A reading below about 90/60 mmHg is commonly considered low. Many people have low readings and feel well. If you feel dizzy, faint or unusually tired, or you take blood pressure tablets, speak to your GP or pharmacist.
When is the best time of day to measure blood pressure?
Choose times you can repeat daily, such as in the morning before breakfast and again in the evening. Sit quietly for five minutes first. Using the same arm, the same chair and the same routine makes your readings easier to compare.
Do home blood pressure monitors give accurate readings?
Upper-arm monitors with a correctly sized cuff are generally reliable when used properly. Take yours to your next GP or clinic visit and measure alongside their device so you can see how closely the two agree.
Which arm should I use to measure my blood pressure?
Use the same arm each time. At your first check, measuring both arms is useful, and if one arm reads consistently higher, use that one and tell your GP. Always rest the arm on a table with the cuff at heart level.
Can I stop my tablets if my readings are normal?
No. Normal readings on treatment often mean the medicine is doing its job. Keep taking prescribed medicine exactly as directed and only change your dose after speaking to your GP.
