Enter your systolic and diastolic reading to see your blood pressure category under the 2017 ACC/AHA Hypertension Guideline, plus your Pulse Pressure and Mean Arterial Pressure (MAP).
Blood pressure is written as two numbers — systolic (top, pressure when your heart beats) over diastolic (bottom, pressure between beats) — measured in mmHg. The 2017 ACC/AHA guideline groups readings into five categories: Normal, Elevated, Stage 1 Hypertension, Stage 2 Hypertension, and Hypertensive Crisis. When your two numbers fall into different categories, the higher category is used for your overall result. This calculator also works out your Pulse Pressure and Mean Arterial Pressure (MAP), two extra numbers doctors sometimes use to understand a reading further.
⚕️ Medical Notice: This calculator is a screening and educational tool only. Blood pressure must be measured correctly and interpreted by a qualified clinician alongside your medical history. If your reading is very high or you feel unwell, seek medical care. Consult your GP for medical advice.
| Category | Systolic | Diastolic | Status |
|---|
Your systolic and diastolic readings are each checked against the 2017 ACC/AHA category ranges. If the two numbers land in different categories, the reading as a whole is classified using whichever number places you in the higher category — this is why a reading like 120/80 mmHg, which looks "normal" at a glance, is actually Stage 1 Hypertension (the diastolic value of 80 sits in the Stage 1 range of 80–89, which outranks the systolic value's Elevated range).
These are the official adult blood pressure categories published in the 2017 ACC/AHA Hypertension Guideline, along with the informally-cited Low Blood Pressure range.
| Category | Systolic (mmHg) | Diastolic (mmHg) | |
|---|---|---|---|
| Low (Hypotension)* | Below 90 | or | Below 60 |
| Normal | Below 120 | and | Below 80 |
| Elevated | 120–129 | and | Below 80 |
| Stage 1 Hypertension | 130–139 | or | 80–89 |
| Stage 2 Hypertension | 140 or above | or | 90 or above |
| Hypertensive Crisis | Above 180 | and/or | Above 120 |
*Low Blood Pressure is not a formal category in the 2017 ACC/AHA guideline but is commonly cited informationally.
Pulse Pressure is the gap between your systolic and diastolic numbers (Systolic − Diastolic). A typical healthy Pulse Pressure is roughly 40–60 mmHg. A pulse pressure that widens with age is a recognised cardiovascular risk marker, often reflecting stiffening of the arteries.
Mean Arterial Pressure (MAP) estimates the average pressure in your arteries across a full heartbeat cycle: MAP = Diastolic + ⅓ × (Systolic − Diastolic). A normal MAP is roughly 70–100 mmHg. MAP is used clinically to assess whether organs, particularly the brain, heart and kidneys, are likely receiving adequate blood flow.
Blood pressure is the force your blood exerts against the walls of your arteries as your heart pumps. It is recorded as two numbers in millimetres of mercury (mmHg): systolic pressure (the higher number, taken when the heart contracts) over diastolic pressure (the lower number, taken when the heart relaxes between beats). A reading of 120/80 mmHg is read as "120 over 80". Blood pressure is typically measured with an inflatable cuff placed around the upper arm, either manually with a stethoscope or automatically with a digital monitor.
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Low Blood Pressure (Hypotension) | Below 90 | Below 60 |
| Normal | Below 120 | Below 80 |
| Elevated | 120–129 | Below 80 |
| Stage 1 Hypertension | 130–139 | 80–89 |
| Stage 2 Hypertension | 140 or higher | 90 or higher |
| Hypertensive Crisis | Above 180 | Above 120 |
Because systolic and diastolic pressure are assessed against separate ranges, it is common for the two numbers to fall into different categories. The 2017 ACC/AHA guideline resolves this by classifying the overall reading using whichever number places it in the more severe category. For example, a reading of 125/88 mmHg has a systolic value of 125 (Elevated range) and a diastolic value of 88 (Stage 1 range) — because Stage 1 is the higher category, the overall reading is classified as Stage 1 Hypertension. This rule is why two people can each have one "normal-looking" number yet receive different overall categories.
If a Hypertensive Crisis reading is accompanied by any of the symptoms above, seek emergency medical care immediately. If the reading is very high but you have no symptoms, wait a few minutes and retest, then contact your doctor promptly if it remains elevated.
What do the blood pressure category numbers mean?
Blood pressure is written as two numbers: systolic (the pressure when your heart beats) over diastolic (the pressure when your heart rests between beats), measured in millimetres of mercury (mmHg). For example, a reading of 120/80 mmHg means a systolic pressure of 120 and a diastolic pressure of 80. The 2017 ACC/AHA guideline groups these readings into categories from Normal through to Hypertensive Crisis.
Why is my blood pressure classified as a higher category than I expected?
When your systolic and diastolic readings fall into different categories, the 2017 ACC/AHA guideline classifies your overall reading using whichever number places you in the higher category. For example, a reading of 120/80 mmHg has a systolic value in the Elevated range but a diastolic value of 80 in the Stage 1 range, so the overall classification is Stage 1 Hypertension.
What is a normal blood pressure reading?
A normal blood pressure reading is a systolic pressure below 120 mmHg and a diastolic pressure below 80 mmHg (commonly written as below 120/80 mmHg). Both numbers need to be in the normal range for a reading to be classified as Normal under the 2017 ACC/AHA guideline.
What is considered high blood pressure (hypertension)?
Under the 2017 ACC/AHA guideline, Stage 1 Hypertension starts at a systolic reading of 130–139 mmHg or a diastolic reading of 80–89 mmHg. Stage 2 Hypertension is a systolic reading of 140 mmHg or above, or a diastolic reading of 90 mmHg or above. Readings above 180/120 mmHg are considered a Hypertensive Crisis.
What is Pulse Pressure & Mean Arterial Pressure (MAP)?
Pulse Pressure is the difference between your systolic and diastolic readings (systolic minus diastolic) and typically falls between about 40 and 60 mmHg in healthy adults. Mean Arterial Pressure (MAP) estimates the average pressure in your arteries during one heartbeat cycle, calculated as diastolic plus one-third of the pulse pressure, with a typical healthy range of roughly 70 to 100 mmHg.
What should I do if my reading shows Hypertensive Crisis?
A reading above 180 mmHg systolic and/or above 120 mmHg diastolic is considered a Hypertensive Crisis. If you also have symptoms such as chest pain, shortness of breath, sudden vision changes, or a severe headache, seek emergency medical care immediately. If you have no symptoms, wait a few minutes and retest, then contact your doctor promptly if the reading remains this high.
Can one blood pressure reading diagnose high blood pressure?
No. A single reading does not diagnose hypertension. Blood pressure naturally varies throughout the day and can be affected by stress, recent activity, caffeine, posture, and cuff size. A diagnosis of hypertension generally requires multiple elevated readings taken on separate occasions, confirmed by a healthcare professional.
What counts as low blood pressure (hypotension)?
Low blood pressure, or hypotension, is generally considered a systolic reading below 90 mmHg or a diastolic reading below 60 mmHg. This is not a formal category in the 2017 ACC/AHA guideline, but it is commonly cited informationally. Low blood pressure can be normal for some people, but if it comes with dizziness, fainting, or blurred vision, it should be discussed with a doctor.
How should I measure my blood pressure accurately at home?
For an accurate reading, sit quietly and rested for at least five minutes with your back supported and feet flat on the floor, use a correctly sized cuff positioned at heart level, avoid caffeine, exercise, and smoking for 30 minutes beforehand, and avoid talking during the measurement. Take two or three readings a minute apart and use the average.
Does this calculator diagnose high blood pressure?
No. This calculator is an educational screening tool that categorises a blood pressure reading against the 2017 ACC/AHA guideline and calculates Pulse Pressure and Mean Arterial Pressure. It does not diagnose hypertension or any other medical condition. Always have your blood pressure measured properly and interpreted by a qualified healthcare professional.