Reference charts
Blood Pressure Chart: What the Numbers Mean
A blood pressure reading is two numbers in millimetres of mercury (mmHg): systolic, the pressure while the heart beats, over diastolic, the pressure while it rests between beats. The table shows the American Heart Association's categories for adults. When the two numbers fall in different rows, the higher row applies.
Updated . Educational reference, not medical advice.
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Educational only. A single reading can't diagnose or rule out high or low blood pressure.
Reference Data
| Category | Systolic (top) | And / or | Diastolic (bottom) |
|---|---|---|---|
| Normal | Less than 120 | and | Less than 80 |
| Elevated | 120–129 | and | Less than 80 |
| Stage 1 hypertension | 130–139 | or | 80–89 |
| Stage 2 hypertension | 140 or higher | or | 90 or higher |
| Severe hypertension / hypertensive emergency | Higher than 180 | and/or | Higher than 120 |
Source: American Heart Association blood pressure categories (heart.org, reviewed Aug 2025); NCHS Data Brief No. 364.
How to read this chart
Read the row for each number, then take the higher category. A reading of 128/84 is stage 1, because 84 is in the stage 1 diastolic range even though 128 is only in the elevated systolic range.
The AHA splits the top row by symptoms. Above 180/120 with no symptoms it calls severe hypertension and says to contact your health care professional; above 180/120 with chest pain, shortness of breath, back pain, numbness, weakness, a change in vision or difficulty speaking it calls a hypertensive emergency and says to call 911.
These categories describe readings. Only a clinician can diagnose high or low blood pressure, normally from repeated measurements, and the chart sets no lower cut-off.
Blood pressure by age
The categories are the same at every adult age, but high readings get more common as you get older. In NHANES 2017–2018, 5,199 US adults had their blood pressure measured up to three times after five minutes of seated rest. Using the 130/80 threshold (or taking blood pressure medicine), 22.4% of people aged 18–39 had hypertension, 54.5% of those aged 40–59 and 74.5% of those 60 and over. Below 60 it was more common in men than women (31.2% vs 13.0% at 18–39). The AHA notes that systolic pressure tends to rise with age as large arteries stiffen, and that it says more about heart disease risk after 50.
Why a single reading can mislead
NHANES averaged up to three readings taken 30 seconds apart after rest, and guidelines base diagnosis on more than one visit. Talking, a full bladder, an unsupported arm or a cuff that is the wrong size can all shift a home reading. For how cuffless watches and rings compare with a cuff, see blood pressure watches and are wrist monitors accurate. The gap between the two numbers has its own name, pulse pressure.
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Frequently asked questions
What is a normal blood pressure?
The AHA calls a reading normal when systolic is under 120 and diastolic is under 80 mmHg.
Is 130/80 high blood pressure?
130/80 sits in the AHA's stage 1 hypertension range (130–139 systolic or 80–89 diastolic). One reading is not a diagnosis; a clinician confirms it with repeat measurements.
What is normal blood pressure by age?
The AHA uses the same adult categories at every age. What changes is how common high readings are: in NHANES 2017–2018, 22.4% of adults aged 18–39, 54.5% aged 40–59 and 74.5% aged 60+ met the 130/80 definition of hypertension.
Which number matters more, systolic or diastolic?
Either can put a reading in a higher category. The AHA says systolic tells more about heart disease risk for people over 50, as it tends to rise with age.
References
- American Heart Association. Understanding blood pressure readings (last reviewed Aug 14, 2025). www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings
- Ostchega Y, Fryar CD, Nwankwo T, Nguyen DT. Hypertension prevalence among adults aged 18 and over: United States, 2017–2018. NCHS Data Brief No. 364; 2020. www.cdc.gov/nchs/products/databriefs/db364.htm
- Whelton PK, et al. 2017 ACC/AHA high blood pressure guideline. J Am Coll Cardiol 2018;71(19):e127–e248. doi.org/10.1016/j.jacc.2017.11.006