Normal blood pressure is a reading below 120/80 mm Hg. That means the top number (systolic) stays under 120 and the bottom number (diastolic) stays under 80. These thresholds, reaffirmed in the 2025 joint guidelines from the American Heart Association and American College of Cardiology, apply to all adults regardless of age.
What the Two Numbers Mean
A blood pressure reading gives you two numbers, written as one over the other (like 115/75). The top number, systolic pressure, measures the force in your arteries each time your heart beats and pushes blood outward. The bottom number, diastolic pressure, measures the force in your arteries between beats, when your heart is resting and refilling.
Both numbers matter. If either one climbs above the normal range, the reading gets classified in a higher category.
Blood Pressure Categories for Adults
Current guidelines break blood pressure into four levels:
- Normal: below 120 systolic and below 80 diastolic
- Elevated: 120 to 129 systolic and below 80 diastolic
- Stage 1 hypertension: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic or 90 or higher diastolic
If your systolic and diastolic numbers fall into two different categories, the higher one is the one that counts. So a reading of 135/75 would be classified as stage 1 hypertension because the top number is in that range, even though the bottom number looks fine.
Does Normal Change With Age?
Older guidelines used different thresholds for people over 65, setting the bar at 150/80 rather than 140/90. The current guidelines no longer make that distinction. The same categories apply whether you’re 35 or 75, based on large-scale trial data that included patients across age groups without separating outcomes by an age cutoff.
That said, blood pressure does tend to rise with age as arteries become stiffer. Many older adults have readings in the elevated or stage 1 range even when they’re otherwise healthy. The thresholds don’t change, but management decisions take overall health and other risk factors into account.
When Blood Pressure Is Too Low
A reading below 90/60 is generally considered low blood pressure. Not everyone with numbers in that range feels unwell. Some people run naturally low without any symptoms. The concern is when low pressure causes noticeable problems: dizziness, lightheadedness, blurred vision, fatigue, trouble concentrating, or fainting.
Context matters more than the number itself. A sudden drop of just 20 points in systolic pressure, say from 110 down to 90, can be enough to make you feel faint even though 90 isn’t dramatically low on paper. Extremely low pressure can lead to shock, which involves confusion, cold and clammy skin, rapid shallow breathing, and a weak pulse. That’s a medical emergency.
Your Reading Can Vary Throughout the Day
Blood pressure isn’t a fixed number. It follows a natural daily cycle: higher during the daytime when you’re active and lower at night while you sleep. This pattern is driven by your autonomic nervous system, the part of your nervous system that regulates things like heart rate and digestion without you thinking about it. Physical activity, stress, caffeine, meals, and even a full bladder can all push readings up temporarily.
This is why a single reading doesn’t tell the whole story. A better picture comes from multiple readings taken on different days, ideally at the same time and under similar conditions.
White Coat and Masked Hypertension
Some people consistently read high at the doctor’s office but normal at home. This is called white coat hypertension, and it affects 15% to 30% of people who show elevated readings in a clinical setting. The anxiety of a medical visit is enough to push numbers up.
The opposite problem also exists. Masked hypertension means your numbers look fine in the office but run high during everyday life. This is harder to catch and potentially more dangerous because it can go undetected for years. Home monitoring or wearing a 24-hour ambulatory blood pressure device can reveal both patterns.
How to Get an Accurate Reading at Home
If you’re checking your blood pressure at home, small details make a real difference in accuracy. The CDC recommends the following steps:
- Timing: Don’t eat or drink anything for 30 minutes beforehand.
- Bladder: Empty it before you sit down.
- Rest: Sit in a chair with back support for at least 5 minutes before measuring. Both feet flat on the floor, legs uncrossed.
- Arm position: Rest your arm on a table so the cuff sits at chest height.
- Cuff fit: Place it on bare skin, snug but not tight.
- Silence: Don’t talk during the measurement.
Skipping any of these can inflate your reading by several points. Crossing your legs, for instance, can add enough pressure to push a borderline reading into the next category. Taking two or three readings a minute apart and averaging them gives a more reliable result than relying on a single measurement.