Blood Pressure Range Chart: What Your BP Numbers Mean

A blood pressure reading is two numbers, and each one tells you something different. Below are the questions people ask most often about those numbers, in roughly the order they ask them. Each answer starts with the short version.

What do the two numbers mean?

The top number is systolic pressure, the pressure in your arteries when the heart beats. The bottom number is diastolic pressure, the pressure when the heart relaxes between beats.

A reading written as 128/78 is said "128 over 78" and is measured in millimetres of mercury (mm Hg). Both numbers matter: if either one is high, that is enough to place you in a higher category. With age, arteries tend to stiffen, so the top number often rises while the bottom one stays the same or even falls.

What is normal blood pressure?

For adults, normal blood pressure is below 120 for the top number and below 80 for the bottom number. The 2025 guideline from the American Heart Association and American College of Cardiology groups readings like this:

Category	Top number (systolic)	Bottom number (diastolic)	What it means for you
Normal	Below 120	and below 80	Keep up healthy habits and keep checking from time to time.
Elevated	120 to 129	and below 80	Not yet high BP, but a signal to work on diet, activity and weight.
Stage 1 high BP	130 to 139	or 80 to 89	Talk to your doctor. Lifestyle changes for everyone; medicines for some, depending on overall risk.
Stage 2 high BP	140 or higher	or 90 or higher	See your doctor. Medicines are usually advised along with lifestyle changes.
Severe	180 or higher	or 120 or higher	Recheck after 5 minutes. If still this high, get urgent medical care; go immediately if there is chest pain, breathlessness, weakness, or trouble with vision or speech.

If your two numbers fall into different categories, the higher category applies. A single high reading is not a diagnosis; high blood pressure is confirmed with repeated readings, often including readings taken at home.

What should my BP be if I am on treatment?

Most adults being treated for high blood pressure are advised to aim for below 130/80, unless their doctor advises a different target.

Your target may be different if you are elderly and frail, feel dizzy on standing, or have other illnesses. Do not change or stop your tablets because one reading is high or low; write it down and discuss it at your visit. Treatment options are explained on our high blood pressure page.

Why does high BP matter if I feel fine?

Because high blood pressure usually causes no symptoms while it slowly damages the arteries, heart, brain and kidneys.

Over the years it raises the risk of heart attack, stroke, heart failure, kidney disease and eye problems. Narrowed heart arteries may later need tests such as angiography, explained in angiography vs angioplasty. Headache or giddiness is not a reliable sign of high BP. Only a measurement can tell you.

How do I measure BP correctly at home?

Follow the same routine every time: rested, seated, arm supported, the right cuff on a bare arm, and two readings a minute apart.

For 30 minutes before, avoid tea, coffee and other caffeine, smoking and exercise.
Empty your bladder.
Sit quietly for 5 minutes with your back supported, feet flat on the floor and legs uncrossed. Do not talk or use your phone.
Rest your arm on a table so the cuff is at the level of your heart.
Wrap the cuff around your bare upper arm, not over a sleeve, and make sure it is the right size for your arm.
Take 2 readings, 1 minute apart, and write both down with the date and time.

Measuring at about the same times each day makes readings easier to compare.

Which BP machine should I buy?

For home use, an automatic machine with an upper-arm cuff, tested (validated) for accuracy, is the usual choice.

Wrist and finger devices are generally less reliable. Cuff size matters: a cuff that is too small for your arm can show a falsely high reading. Bring your machine to a clinic visit once, so its readings can be compared with the clinic's.

Why is my reading different every time?

Blood pressure changes naturally through the day, so small differences between readings are normal.

It rises with stress, pain, talking, a full bladder, cold, caffeine and activity, and is usually lower during sleep. Some people read higher in the clinic than at home, often called the white-coat effect; others read normal in the clinic but high at home, called masked hypertension. That is why a pattern of home readings over several days tells your doctor more than any single number.

When is high BP an emergency?

A reading of 180/120 or higher needs action: wait 5 minutes and measure again. If it is still that high, get urgent medical care.

Do not wait to recheck. Call 108 or 112 immediately if a high reading comes with chest pain, breathlessness, weakness or numbness, change in vision, or difficulty speaking. These can be signs of a heart attack, a stroke or other organ damage. Keep our emergency page saved, and read what to do in the first hour of a heart attack.

Is low blood pressure a problem?

A low reading is mainly a concern when it comes with symptoms such as dizziness, fainting, blurred vision or unusual tiredness.

There is no single number that is too low for everyone. If you take BP tablets and feel giddy on standing, sit or lie down, check your BP, note the reading and tell your doctor. Do not stop your medicines on your own.

How can I keep track of my readings?

Write every reading down, or use the free BP diary on this site.

The BP diary keeps your readings on your own phone; they are not sent to the clinic. Open it at your visit to show the doctor how your numbers have moved. When you are ready for a review, book an appointment and bring your record along.

Sources

For understanding only — the right test or treatment is decided after examination.

Blood Pressure Numbers Explained: Range Chart and Home Checks