Blood pressure readings: what your numbers mean

The two numbers

A reading such as 120/80 mm Hg ("120 over 80") has two parts. The top number (systolic) is the pressure when the heart pumps; the bottom number (diastolic) is the pressure when the heart fills between beats. (NHLBI, 2024) (NHLBI, 2025) Blood pressure changes through the day with what you are doing. (NHLBI, 2024)

The ranges for adults

In the table, "or" means either number on its own puts a reading in that row. The NHLBI says research shows a top number above 120 can harm health over time, and that readings above 180/120 are dangerously high and need medical attention right away. (NHLBI, 2025) Talk to your provider if your readings are consistently above 120/80. (NHLBI, 2025)

By age: why "normal" does not change

There is no separate, higher normal range for older adults: the NHLBI uses the same adult categories at every age. (NHLBI, 2025) What changes is the risk. Blood pressure tends to rise with age as blood vessels thicken and stiffen. Men are more likely than women to develop high blood pressure through middle age, while in older adults women are more likely to. (NHLBI, 2024) High blood pressure is also more common in Black adults, who tend to develop it earlier in life. (NHLBI, 2024)

Children younger than 13 are different: their readings are compared with what is common for children of the same age, sex and height. (NHLBI, 2025) More on checks for 12 to 17 year olds: teen health screenings.

How to get an accurate reading

The NHLBI's steps, for the office or at home: (NHLBI, 2025)

• No exercise, coffee or smoking for 30 minutes before.
• Empty your bladder first.
• Sit in a chair and relax for at least 5 minutes, feet flat on the floor.
• Do not talk while resting or during the reading.
• Put the cuff on a bare arm, with the arm resting on a table at heart level.
• Use a cuff of the right size: one too small or too big changes the reading.

The USPSTF says readings should be taken on the upper arm with a validated, accurate device, seated, after 5 minutes of rest. (USPSTF, 2021) The 2025 AHA/ACC guideline, as summarized by its companion article, does not recommend cuffless devices for diagnosing or managing high blood pressure. (Hypertension, 2025)

One high reading is not a diagnosis

• The NHLBI says diagnosing high blood pressure takes two or more readings at separate appointments. (NHLBI, 2025)
• The USPSTF recommends confirming a high office reading with measurements outside the clinic before treatment: a 24-hour ambulatory monitor, or home readings with an automated device, taken for example 1 to 2 times a day or a week. (USPSTF, 2021) The 2025 guideline also recommends home monitoring to confirm a suspected diagnosis. (Hypertension, 2025)
• White coat high blood pressure: readings are higher at the doctor's office than at home or in a pharmacy. Masked high blood pressure: readings are lower at the office than elsewhere. Comparing office and home readings helps find both. (NHLBI, 2025)

How often to check

The USPSTF recommends screening all adults 18 and older (grade A). It suggests a yearly check from 40, and yearly at any adult age for people at increased risk, such as Black adults, people with high-normal blood pressure, and people with overweight or obesity. Adults 18 to 39 who are not at increased risk and had a normal reading before can be checked every 3 to 5 years. (USPSTF, 2021) The NHLBI says everyone age 3 or older should have their blood pressure checked by a provider at least once a year. (NHLBI, 2025) Full details: blood pressure screening. To write your numbers down, use the wallet card on know your numbers. Pregnant? Blood pressure is checked at every prenatal visit, with its own cutoffs: preeclampsia screening.

Questions people ask

What is a normal blood pressure for my age?

For adults, the NHLBI uses the same ranges at every age: a healthy reading is less than 120/80 mm Hg, and blood pressure is high when readings are consistently 130 or higher on top or 80 or higher on the bottom. Blood pressure tends to rise with age, but the healthy range does not. Children under 13 are compared with children of the same age, sex and height. (NHLBI, 2025) (NHLBI, 2024)

Is 130/80 high blood pressure?

In the NHLBI categories, a top number of 130 to 139 or a bottom number of 80 to 89 is stage 1 high blood pressure, if your readings are consistently in that range. One reading does not make a diagnosis. (NHLBI, 2025)

Does one high reading mean I have high blood pressure?

No. The NHLBI says a diagnosis needs two or more readings at separate appointments, and the USPSTF recommends confirming a high office reading with measurements outside the clinic, at home or with a 24-hour monitor, before treatment starts. (NHLBI, 2025) (USPSTF, 2021)

How often should I get my blood pressure checked?

For screening, the USPSTF suggests every year from 40, and every year at younger ages for people at increased risk; adults 18 to 39 not at increased risk with a normal reading before can be checked every 3 to 5 years. The NHLBI says everyone 3 or older should be checked at least once a year. (USPSTF, 2021) (NHLBI, 2025)

Are smartwatch or cuffless blood pressure readings accurate enough?

The 2025 AHA/ACC guideline, as summarized by its companion article, does not recommend cuffless devices for diagnosing or managing high blood pressure, and recommends validated cuffs instead. (Hypertension, 2025)

Related

• Blood pressure screening: who needs it and how often
• Know your numbers
• Screenings if you have high blood pressure
• Heart screenings by age
• Blood pressure in pregnancy: preeclampsia screening