High blood pressure: your numbers and home checks

Medical disclaimer: This page is general health information for education only. It is not medical advice and is not a substitute for diagnosis or treatment by a qualified health professional. It has not been reviewed by a clinician. In an emergency, call 911 or your local emergency number.

High blood pressure means the force of blood pushing on your artery walls stays higher than it should. It is common, it often causes no symptoms, and it can be measured at home. This page explains what your numbers mean, the current US categories, how to check your blood pressure correctly, and when a reading is an emergency. It is part of our library of health conditions.

What is high blood pressure?

High blood pressure, also called hypertension, means your blood pushes against your artery walls with more force than is healthy over time.

Blood pressure is the pressure that occurs when blood pushes against the walls of your arteries, as the CDC explains in its overview of high blood pressure. Blood pressure is measured in millimeters of mercury, written as mm Hg.

US adults use a lower cutoff than many people expect. Nearly half of all US adults have high blood pressure, defined as 130/80 mm Hg or higher, according to the American Heart Association announcement of the 2025 guideline.

This page covers adults only. Blood pressure in children and during pregnancy is assessed differently and is not covered here.

For readings that are too low, see our guide to low blood pressure.

What do the two blood pressure numbers mean?

A blood pressure reading has two numbers: systolic pressure on top and diastolic pressure on the bottom, such as 128/78 mm Hg.

• Systolic pressure is the pressure against your artery walls when your heart beats.
• Diastolic pressure is the pressure against your artery walls while your heart rests between beats.
• Systolic pressure is the highest pressure in the cycle. Diastolic pressure is the lowest.
• Only one of the two numbers needs to be high for a reading to count as high.

The National Heart, Lung, and Blood Institute (NHLBI) says your blood pressure is high when you have consistent systolic readings of 130 mm Hg or higher, or diastolic readings of 80 mm Hg or higher.

One reading does not diagnose high blood pressure. Caffeine, exercise, tobacco and nerves can all affect a single reading.

What are the current US blood pressure categories?

The current US categories come from the 2025 AHA/ACC high blood pressure guideline, published August 14, 2025, which kept the 2017 thresholds.

The 2025 guideline replaces the 2017 ACC/AHA guideline. The American Heart Association states that the blood pressure criteria remain the same as the 2017 guideline. The NHLBI lists the same categories for diagnosis.

All values are in mm Hg, as shown in the American Heart Association blood pressure categories chart.

• Stage 1 and stage 2 use “or,” so one high number is enough.
• A reading of 134/76 mm Hg falls in stage 1 hypertension because of the top number.
• A reading of 118/92 mm Hg falls in stage 2 hypertension because of the bottom number.
• A clinician needs two or more readings at separate appointments to diagnose high blood pressure.

These categories apply to US adults. They do not tell you which treatment is right for you. That decision depends on your overall risk and is made with your clinician.

Why is high blood pressure called a silent condition?

High blood pressure is called silent because it usually has no warning signs or symptoms, so many people do not know they have it.

• The CDC says high blood pressure usually has no warning signs or symptoms.
• The American Heart Association says high blood pressure is often called the “silent killer.”
• About 1 in 6 US adults with high blood pressure is unaware of it, according to CDC high blood pressure facts.
• Symptoms usually do not appear until high blood pressure has caused serious health problems.

Over time, untreated high blood pressure can lead to stroke, heart attack and other forms of heart disease, kidney disease, eye damage and an aneurysm, a bulge in an artery wall, according to the NHLBI.

Feeling well does not rule out high blood pressure. The only way to know your numbers is to measure them.

How do you measure blood pressure at home correctly?

To measure blood pressure at home, rest seated for 5 minutes, support your back and arm, and take at least two readings.

These steps come from the CDC guide to measuring your blood pressure and MedlinePlus.

1. Use a cuff that goes around your upper arm. It is more accurate than wrist or finger monitors.
2. For 30 minutes before, avoid eating, drinking caffeine or alcohol, exercise and tobacco.
3. Empty your bladder.
4. Sit in a chair with your back supported for at least 5 minutes.
5. Keep both feet flat on the floor and your legs uncrossed.
6. Rest your arm on a table at chest height.
7. Place the cuff on bare skin, not over clothing. It should be snug but not too tight.
8. Stay quiet. Do not talk during the reading.
9. Take at least two readings, 1 or 2 minutes apart.
10. Write down every result in a log, and measure at the same time each day.

The 2025 guideline advises against relying on cuffless devices, including smartwatches, until they prove more accurate. Bring your monitor to an appointment so your care team can check that it matches their equipment.

Home readings help your clinician, but they do not replace a diagnosis. Some people read higher at the office because of nerves. MedlinePlus calls this “white coat syndrome.”

When is a high blood pressure reading an emergency?

A reading of 180/120 mm Hg or higher with symptoms such as chest pain or trouble speaking is an emergency. Call 911.

If your blood pressure is 180/120 and you have no symptoms, the NHLBI advises waiting 5 minutes and checking again. If the second reading is also high and you have any of these symptoms, call 911:

• A sudden, severe headache
• Difficulty breathing
• Sudden, severe pain in your abdomen, chest or back
• Numbness or weakness
• Sudden vision changes
• Problems talking

Do not wait to see whether your blood pressure comes down on its own, the American Heart Association advises. If a repeat reading stays above 180/120 without symptoms, contact your health care professional as soon as possible.

This section is not a substitute for emergency care or a clinician’s advice. Our first aid guide covers general emergency basics.

Questions to bring to your appointment

These questions can help you understand your readings and your next steps. You can also use our tips on preparing for a medical appointment. These questions are a starting point and do not replace advice from your own clinician.

• Which blood pressure category do my readings fall into, and how many readings is that based on?
• Should I check my blood pressure at home, and how often?
• Is my home monitor validated, and can we compare it with your equipment?
• Could my readings at this office be higher than at home?
• What is my overall risk of heart disease and stroke?
• Which symptoms or readings should make me call 911 or call your office?