Normal blood pressure is less than 120/80 mmHg. That first number (systolic) measures the force when your heart beats, and the second (diastolic) measures the force when your heart rests between beats. The 2025 guidelines from the American Heart Association and American College of Cardiology confirm this threshold remains unchanged.
Blood Pressure Categories for Adults
Your reading falls into one of four categories:
- 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
Notice that elevated blood pressure only involves the top number creeping up. Once either number crosses into a higher range, the higher category applies. So a reading of 118/85 counts as stage 1 hypertension even though the top number looks fine.
How Blood Pressure Changes With Age
Children have significantly lower blood pressure than adults. A healthy one-year-old boy typically reads around 80/34 mmHg, while a one-year-old girl averages about 83/38. By age 17, those numbers climb to roughly 118/67 for boys and 111/66 for girls, approaching adult ranges. Pediatric blood pressure is evaluated against percentile charts that account for age, sex, and height, so a single cutoff like 120/80 does not apply to children.
In adults, blood pressure tends to rise gradually with age, particularly the systolic number. This happens because arteries stiffen over time. The 120/80 threshold still defines “normal” regardless of age, though your doctor may weigh your overall cardiovascular risk when deciding how aggressively to manage a borderline reading.
Blood Pressure During Pregnancy
The normal range during pregnancy is the same: below 120/80 mmHg. What changes is the level of concern. Readings at or above 140/90 after 20 weeks of pregnancy, in someone who previously had normal pressure, signal gestational hypertension. This condition raises the risk of preeclampsia, a serious complication involving organ damage. Pregnant individuals with readings in that range are typically monitored more closely and may be started on blood pressure medication.
Why Your Reading Fluctuates
Blood pressure is not a fixed number. It follows a daily cycle, dropping 10% to 20% during sleep and rising sharply in the early morning hours. In some people, that morning surge can be dramatic: one study documented swings of roughly 70 mmHg in systolic pressure between nighttime lows and morning peaks. Stress, caffeine, a full bladder, and even the way you sit during a reading all shift the number.
This is why a single high reading does not necessarily mean you have hypertension. Doctors look at patterns over multiple visits, or use 24-hour ambulatory monitors to capture the full picture. People whose pressure does not drop by at least 10% during sleep, called “nondippers,” face higher cardiovascular risk even if their daytime numbers look acceptable.
What Pulse Pressure Tells You
Pulse pressure is simply your systolic number minus your diastolic number. For a reading of 120/80, pulse pressure is 40, which is considered healthy. A wide pulse pressure (consistently above 60) can indicate stiff arteries, while a very narrow one may suggest the heart is not pumping effectively. It is a useful additional signal your doctor can read from the same two numbers you already have.
Other Types of Normal Pressure
Eye Pressure
Normal pressure inside the eye ranges from 10 to 20 mmHg. Readings above that range, with no other symptoms, are classified as ocular hypertension, a risk factor for glaucoma. Eye pressure is measured during a standard eye exam using a quick, painless air puff or a small probe that touches the cornea. Unlike blood pressure, you cannot feel changes in eye pressure, which is why routine screening matters.
Pressure Inside the Skull
The brain sits in a closed space, and the fluid surrounding it normally exerts 7 to 15 mmHg of pressure in adults. When that pressure exceeds 20 mmHg, it can compress brain tissue and reduce blood flow. Sustained pressure above 40 mmHg is considered life-threatening. This type of pressure is only measured in clinical settings, usually after a head injury or when conditions like swelling or fluid buildup are suspected.
Atmospheric Pressure
Standard atmospheric pressure at sea level is 1013.25 hectopascals (also called millibars), or 14.7 pounds per square inch, or 29.92 inches of mercury. This is the weight of the air column above you pressing down on every surface. It decreases with altitude, which is why your ears pop on a plane and why weather maps track pressure changes to predict storms. The International Space Station maintains its interior at the same 14.7 psi as Earth’s surface so astronauts can breathe and move normally.