A good blood pressure reading is below 120/80 mmHg. That first number (systolic) measures the force when your heart beats, and the second number (diastolic) measures the pressure between beats. Both numbers matter, and staying under that 120/80 threshold puts you in the “normal” category with the lowest cardiovascular risk.
Blood Pressure Categories for Adults
The American Heart Association and American College of Cardiology define four categories based on your readings:
- Normal: below 120/80 mmHg
- 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
If your two numbers fall into different categories, the higher one determines your classification. So a reading of 135/75 counts as Stage 1 hypertension because the top number is in that range, even though the bottom number looks fine.
These categories aren’t just labels. Each step up corresponds to a measurable increase in the risk of heart attack, stroke, and heart failure. A large meta-analysis of over 38,000 patients found that getting systolic pressure below 120 (versus below 140) reduced stroke risk by 19%, heart failure risk by 25%, and cardiovascular death by 26%.
When Blood Pressure Is Too Low
There is a floor. A reading below 90/60 mmHg is generally considered low blood pressure, or hypotension. Symptoms include dizziness, blurred vision, fatigue, trouble concentrating, and fainting. Even a drop of just 20 points in your systolic number can trigger those symptoms if it happens quickly, such as going from 110 down to 90.
Severe hypotension can lead to shock, which involves confusion, cold and clammy skin, rapid shallow breathing, and a weak pulse. This is a medical emergency. But for most people searching “what should blood pressure be,” low readings aren’t the concern. If you consistently feel lightheaded or faint, that’s worth investigating regardless of what the numbers say.
Targets for Older Adults
The general 120/80 target applies broadly, but the conversation gets more nuanced after age 65. A major NIH-funded trial called SPRINT found that lowering systolic pressure below 120 in adults 50 and older significantly reduced cardiovascular disease and death. That’s encouraging, but pushing blood pressure lower also comes with trade-offs: the same body of research shows intensive targets increase the rate of hypotension episodes and fainting.
For older adults, the right target depends on overall health, other medical conditions, and how well someone tolerates treatment. Someone who is 75 and otherwise fit may benefit from aggressive targets, while someone the same age with frequent falls or multiple chronic conditions might do better with a slightly higher threshold. This is genuinely one of those cases where the optimal number varies from person to person.
Targets for People With Diabetes
If you have type 2 diabetes, most major medical organizations recommend a blood pressure target below 130/80 mmHg. This is stricter than the old standard of 140/90 because diabetes already raises cardiovascular risk, and tighter blood pressure control helps offset that. The American Diabetes Association, ACC/AHA, and several international bodies all converge on that 130/80 number for people at higher cardiovascular risk.
For older adults with diabetes, the targets loosen slightly. Some guidelines recommend below 140/90 for people over 70 and below 150/90 for those over 80, reflecting the increased risk of side effects from aggressive treatment in that age group.
How to Get an Accurate Reading
Your blood pressure fluctuates throughout the day, so technique matters more than most people realize. A poorly taken reading can easily be off by 10 to 20 points, which is enough to push you from “normal” into “hypertension” on paper.
The CDC recommends sitting in a comfortable chair with your back supported for at least five minutes before taking a reading. Rest your arm on a table at chest height with the cuff against bare skin, not over a sleeve. The cuff should be snug but not tight. Don’t talk during the measurement.
Take two or three readings a minute apart and average them. A single reading is a snapshot, not a diagnosis. If you’re monitoring at home, morning readings before coffee or medication tend to give the most consistent baseline.
White Coat Hypertension
Some people consistently read high in the doctor’s office but normal everywhere else. This is called white coat hypertension, and it’s common enough that guidelines account for it. The pattern typically shows office readings at or above 140/90 while 24-hour ambulatory monitoring (wearing a portable cuff throughout the day) shows a normal average below 130/80.
A clinically significant “white coat effect” means your office reading exceeds your daytime average by 20 points systolic or 10 points diastolic. If your doctor suspects this, they may ask you to monitor at home or wear an ambulatory cuff for 24 hours. Home readings above 135/85 during waking hours are considered elevated, which is slightly lower than the 140/90 office cutoff because the stress of a clinical setting is removed.
White coat hypertension isn’t entirely harmless. It may signal a tendency toward sustained high blood pressure over time. But it does mean a single high reading at the clinic shouldn’t be the sole basis for treatment decisions.
What the Numbers Mean for Children
Blood pressure norms for children and teenagers aren’t fixed numbers like they are for adults. Instead, they’re based on percentiles that account for age, sex, and height. A reading at or above the 95th percentile for a child’s demographic group is considered high. Because kids’ blood vessels and hearts are still growing, a “normal” number for a 6-year-old would look very different from a normal number for a 16-year-old. Pediatricians use reference charts to interpret these readings, so there’s no single number to memorize for children.