A normal blood pressure reading is below 120/80 mmHg. That means the top number (systolic) stays under 120 and the bottom number (diastolic) stays under 80. Once either number climbs above those thresholds, your cardiovascular risk starts to increase, even if you feel perfectly fine. The 2025 guidelines from the American Heart Association and American College of Cardiology reaffirmed these targets for adults.
What the Two Numbers Mean
The top number, systolic pressure, measures the force your blood exerts against artery walls each time your heart contracts and pushes blood out. The bottom number, diastolic pressure, measures the pressure that remains between beats, when your heart is briefly resting. Both numbers matter, though systolic pressure tends to rise more noticeably with age and carries more weight in assessing long-term risk for heart attack and stroke.
Blood Pressure Categories for Adults
There are four categories, and they apply to anyone age 13 and older:
- 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
If your systolic and diastolic fall into two different categories, the higher category is the one that counts. So a reading of 135/72 would be classified as Stage 1 hypertension because the top number falls in that range, even though the bottom number looks normal.
Elevated blood pressure is not yet hypertension, but it signals that your numbers are trending in the wrong direction. Without changes, most people in this range eventually cross into Stage 1.
Targets for Specific Health Conditions
If you have diabetes, chronic kidney disease, or other conditions that make your heart and blood vessels more vulnerable, your doctor will likely aim for a systolic reading below 130. For people with kidney disease and significant protein in their urine, some guidelines now push that target even lower, to below 120 systolic, based on evidence that tighter control reduces the risk of kidney failure and cardiovascular events.
Blood Pressure in Children
Children under 13 don’t use the same fixed numbers adults do. Instead, their readings are compared to percentiles based on age, sex, and height. A reading below the 90th percentile for their demographic group is considered normal. Once they hit age 13, the standard adult categories apply: below 120/80 is normal, and anything at or above 130/80 qualifies as Stage 1 hypertension.
Blood Pressure During Pregnancy
Pregnancy changes the equation. Gestational hypertension is diagnosed when blood pressure reaches 140/90 or higher on two separate readings at least four hours apart, in someone who had normal readings before 20 weeks of pregnancy. Severe-range readings, 160 systolic or 110 diastolic, require prompt medical attention. Preeclampsia involves those same elevated pressures combined with signs of organ stress, such as protein in the urine, low platelet counts, or liver problems. These thresholds are deliberately more conservative because high blood pressure during pregnancy poses acute risks to both parent and baby.
When Blood Pressure Becomes Dangerous
A reading above 180 systolic or above 120 diastolic is considered a hypertensive crisis. This is split into two levels of severity. In a hypertensive urgency, the numbers are extremely high but there’s no immediate organ damage. You might feel a headache, some anxiety, or nothing at all. In a hypertensive emergency, those extreme pressures are actively harming organs, potentially causing stroke, heart attack, kidney failure, or fluid in the lungs. Symptoms can include chest pain, severe headache, vision changes, confusion, or difficulty breathing.
Your Numbers Can Vary More Than You Think
Blood pressure is not a fixed number. It fluctuates throughout the day, dropping 10% to 20% while you sleep and rising in the morning. Exercise, stress, caffeine, a full bladder, and even conversation can temporarily push it higher. This is why a single reading doesn’t tell the full story.
Two common patterns make diagnosis tricky. White coat hypertension occurs when your readings run high at the doctor’s office but are normal the rest of the time. This affects 25% to 30% of people seen at hypertension clinics, and it can lead to unnecessary treatment if not caught. Masked hypertension is the opposite: your readings look fine in the office but run high at home or at work. This is estimated to affect 15% to 30% of people and is more dangerous because it often goes undetected. Home monitoring or wearing a 24-hour blood pressure monitor can identify both patterns.
Getting an Accurate Reading at Home
A surprising number of blood pressure readings are inaccurate because of simple technique errors. Small changes in positioning can shift your results by several points in either direction. To get a reliable number:
- Sit quietly for five minutes before taking a reading. No talking, no scrolling your phone.
- Position your arm correctly. Your back should be supported, feet flat on the floor, legs uncrossed. Rest your arm on a table so the middle of the cuff sits at heart level. If your arm hangs below your heart, the reading will be artificially high. If it’s raised above your heart, it will read low.
- Use the right cuff size. A cuff that’s too small for your arm will give a falsely high reading. The inflatable bladder inside the cuff should wrap around at least 80% of your upper arm. Most home monitors come with a standard adult cuff designed for arm circumferences of 27 to 34 cm. If your arm is larger, you need a wide-range or large cuff.
- Take at least two readings spaced a minute apart, and average them. The first reading is typically the highest.
When you first start monitoring at home, check both arms. It’s normal for one arm to read slightly higher. Use the arm with the higher number for all future readings.