A good blood pressure reading is below 120/80 mm Hg. That first number (120) measures the force on your artery walls when your heart beats, and the second number (80) measures the pressure between beats, when your heart is resting. If both numbers fall under those thresholds, your blood pressure is considered normal by current clinical guidelines.
Blood Pressure Categories by the Numbers
The 2025 clinical guidelines break blood pressure into four categories:
- Normal: below 120 systolic and below 80 diastolic
- Elevated: 120 to 129 systolic with diastolic still below 80
- Stage 1 hypertension: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic or 90 or higher diastolic
Only one number needs to be high for a reading to count as elevated or hypertensive. So a reading of 138/75 qualifies as stage 1 hypertension even though the bottom number looks fine. That said, a single high reading doesn’t mean you have high blood pressure. The diagnosis comes from a pattern of elevated readings over time.
What Each Number Tells You
The top number, systolic pressure, reflects how hard your heart pushes blood out with each beat. The bottom number, diastolic pressure, reflects the baseline pressure in your arteries while your heart refills between beats. Both matter, but the top number becomes especially important after age 50. As you get older, large arteries stiffen and plaque builds up, which tends to push systolic pressure higher while diastolic pressure may stay the same or even drop.
This pattern is common enough to have its own name: isolated systolic hypertension. Many older adults will see a reading like 145/72, where only the top number is elevated. That top number still carries real cardiovascular risk and typically needs attention.
When Blood Pressure Is Too Low
A reading below 90/60 mm Hg is generally considered low blood pressure. But unlike high blood pressure, low readings are only a concern if they cause symptoms. Some people walk around at 95/58 and feel perfectly fine.
Symptoms of blood pressure that’s too low for your body include dizziness, lightheadedness, blurred vision, fatigue, trouble concentrating, and fainting. Even a drop of just 20 mm Hg from your usual reading can make you feel dizzy. If you experience confusion, cold and clammy skin, rapid shallow breathing, or a weak pulse, that suggests a dangerous drop that needs emergency care.
Targets for Older Adults and Chronic Conditions
For most adults, below 120/80 is the goal. A large NIH-funded trial called SPRINT found that getting systolic pressure below 120 in adults age 50 and older significantly reduced the risk of cardiovascular disease and death. That finding applies to many older adults, though individual targets sometimes vary depending on other health conditions and overall fitness.
People with chronic kidney disease have a similar target: systolic pressure below 120. However, evidence is less clear for certain subgroups, including those who also have diabetes or advanced kidney disease with significant protein in the urine. In those cases, a doctor will typically set a personalized target.
How to Get an Accurate Reading
Blood pressure fluctuates throughout the day, so how you measure it matters as much as the number itself. A reading taken after rushing up the stairs or drinking coffee can look 10 to 20 points higher than your true resting level. The CDC recommends the following steps for an accurate measurement:
- Timing: Don’t eat, drink, smoke, exercise, or consume caffeine for 30 minutes beforehand.
- Preparation: Empty your bladder, then sit in a comfortable chair with your back supported for at least 5 minutes before measuring.
- Position: Keep both feet flat on the floor, legs uncrossed. Rest your arm on a table so the cuff sits at chest height.
- Cuff fit: Place the cuff on bare skin, not over clothing. It should be snug but not tight.
- Silence: Don’t talk while the reading is being taken.
Skipping even one of these steps can throw off your results enough to move you into a different category.
Why Home Readings Can Differ From the Doctor’s Office
About 14% of people have what’s called white coat hypertension: their blood pressure reads high at the doctor’s office but is normal at home. The stress and unfamiliarity of a clinical setting can push numbers up temporarily. If your only high readings happen in a medical office, you may not actually have hypertension.
The opposite problem is more dangerous. Roughly 10% of people have masked hypertension, meaning their blood pressure looks normal at the doctor’s office but runs high the rest of the time. Among people already taking blood pressure medication who appear well-controlled at office visits, the rate of masked hypertension jumps to over 40%. These people are effectively undertreated because their doctor sees reassuring numbers during appointments.
This is why home monitoring is so valuable. A home blood pressure monitor used consistently over days or weeks gives a much more complete picture than occasional office visits. If you’re tracking at home, take readings at the same time each day, following the preparation steps above, and bring a log to your appointments.
When a Reading Is an Emergency
A blood pressure of 180/120 or higher is a hypertensive crisis. If you see that number and also have chest pain, shortness of breath, severe headache, blurred vision, seizures, or symptoms of a stroke, call 911 immediately. That combination signals potential organ damage and requires emergency treatment. A reading of 180/120 without those symptoms is still serious and needs prompt medical evaluation, but the immediate danger is lower.