Free blood pressure calculator
Find your blood pressure category in two seconds. Enter your top (systolic) and bottom (diastolic) numbers and the calculator returns your 2017 ACC/AHA category — Normal, Elevated, Stage 1, Stage 2, or Hypertensive Crisis — and tells you which reading is driving it, updated live, as you type.
On this page17 sections
| Category | Systolic | Diastolic |
|---|---|---|
| Normal | Less than 120 | and Less than 80 |
| Elevated | 120 – 129 | and Less than 80 |
| Hypertension Stage 1 | 130 – 139 | or 80 – 89 |
| Hypertension Stage 2 | 140 or higher | or 90 or higher |
| Hypertensive Crisis | Higher than 180 | and/or Higher than 120 |
This classifies one reading and is not a diagnosis. How accurate is this?
Results are estimates. Consult a professional.
What is your blood pressure category?
Your blood pressure category is the band a single reading falls into — Normal, Elevated, Hypertension Stage 1, Hypertension Stage 2, or Hypertensive Crisis. A reading has two numbers, systolic over diastolic, written like 120/80 mm Hg. This blood pressure calculator takes those two numbers and tells you which of the five categories you are in under the 2017 American College of Cardiology / American Heart Association (ACC/AHA) guideline — the standard US clinicians use today.
The category matters more than the raw numbers. The same band carries the same meaning whether you measured it at home or at a clinic, and it is the first thing a doctor uses to decide whether your blood pressure needs watching, a lifestyle change, medication, or — in rare cases — emergency care. Enter your top and bottom numbers above and the calculator returns your category instantly, along with which of the two readings is driving it.
Systolic vs. diastolic — what each number means
Every blood pressure reading is two numbers because your heart creates two different pressures with each beat. Knowing which is which makes the category make sense.
So a reading of 118/76 means the pressure peaks at 118 when the heart beats and falls to 76 when it rests. Both numbers are checked against the category bands; if they disagree, the higher-risk one wins — explained below.
Definitions follow the American Heart Association: systolic is 'the pressure your blood is pushing against your artery walls when the heart beats', diastolic is the pressure 'while the heart muscle rests between beats'.Blood pressure categories chart (AHA 2017)
The 2017 ACC/AHA guideline sorts adult blood pressure into five categories. Note the joiners: Normal and Elevated need BOTH numbers in range, while the hypertension stages trigger if EITHER number is high. This is the exact chart the calculator above uses.
| Category | Systolic (mm Hg) | Diastolic (mm Hg) | |
|---|---|---|---|
| Normal | Less than 120 | and | Less than 80 |
| Elevated | 120 – 129 | and | Less than 80 |
| Hypertension Stage 1 | 130 – 139 | or | 80 – 89 |
| Hypertension Stage 2 | 140 or higher | or | 90 or higher |
| Hypertensive Crisis | Higher than 180 | and/or | Higher than 120 |
Source: 2017 ACC/AHA guideline, as published by the American Heart Association, 'Understanding Blood Pressure Readings'.
Which category applies when the two numbers disagree?
It is common for the top and bottom numbers to fall in different bands. The rule is simple and is set by the guideline itself: you are placed in the higher (more severe) of the two categories. The calculator applies this automatically and tells you which reading was responsible.
- 135/75 — systolic 135 is Stage 1, diastolic 75 is Normal. Result: Stage 1 (systolic-driven).
- 118/85 — systolic 118 is Normal, diastolic 85 is Stage 1. Result: Stage 1 (diastolic-driven).
- 145/85 — systolic 145 is Stage 2, diastolic 85 is Stage 1. Result: Stage 2 (systolic-driven).
A worked example using the blood pressure calculator
David, 52, takes his blood pressure at home and gets 134/86 mm Hg. He wants to know what category that is and whether he should worry. Here is exactly how the calculator classifies it.
Step 1 — Place the systolic number
His top number is 134. On the chart, 130–139 is Hypertension Stage 1. So systolic alone points to Stage 1.
Step 2 — Place the diastolic number
His bottom number is 86. On the chart, 80–89 is also Hypertension Stage 1. So diastolic alone also points to Stage 1.
Step 3 — Take the higher category
Both numbers land in Stage 1, so there is no tie to break — David's reading is Hypertension Stage 1. If only one number had been high, that number would have set the category on its own.
Now see what that means for David. A single Stage 1 reading is not a diagnosis — he should re-measure on several mornings and, if it stays there, ask his doctor about diet, activity, and whether his 10-year cardiovascular risk warrants medication. The next section spells out the action for each category.
What to do for each blood pressure category
Knowing your category is only useful if you know what it asks of you. Here is the general guidance for each band. None of this replaces your own clinician's advice, which accounts for your age, history, and other risks.
- Normal (under 120/80) — keep it there. Maintain a heart-healthy diet, regular activity, and a healthy weight, and recheck at least yearly.
- Elevated (120–129 / under 80) — not yet hypertension, but a warning. Lifestyle changes now (less salt, more movement, weight loss if needed) can stop it progressing.
- Stage 1 (130–139 or 80–89) — confirm with repeat readings. Your doctor will recommend lifestyle changes and may prescribe medication depending on your overall cardiovascular risk.
- Stage 2 (140+ or 90+) — usually treated with one or more blood-pressure medications in addition to lifestyle changes. See a clinician.
- Hypertensive Crisis (over 180 and/or over 120) — wait a few minutes and re-measure. If it stays this high, contact your doctor immediately; with symptoms, call 911.
How to measure your blood pressure correctly
Your category is only as good as the reading you feed it. A sloppy measurement can shift you a whole band. The American Heart Association recommends an automatic, cuff-style, upper-arm monitor and the following routine.
- Prepare. Don't smoke, drink caffeine, or exercise for 30 minutes beforehand, and empty your bladder first.
- Rest. Sit quietly for at least 5 minutes before you measure — no talking, no phone.
- Sit correctly. Back supported, feet flat on the floor, legs uncrossed.
- Position your arm. Rest it on a table so the cuff is at heart level; put the cuff on bare skin, not over a sleeve.
- Take two readings. Measure twice, a minute apart, at the same time each day, and record the average.
When high blood pressure is an emergency
A reading over 180/120 mm Hg is a hypertensive crisis. What you do next depends on whether you have symptoms.
- No symptoms — wait five minutes and re-measure. If it is still over 180/120, contact your doctor right away (hypertensive urgency).
- With symptoms — if you also have chest pain, shortness of breath, back pain, numbness or weakness, a change in vision, or difficulty speaking, call 911 immediately. Do not wait to re-measure (hypertensive emergency).
Does normal blood pressure change with age?
A common question is whether older adults are 'allowed' a higher number. The answer from the 2017 guideline is no — the cut-offs for high blood pressure are the same at every adult age. The goal of under 120/80 applies whether you are 30 or 70.
What does change with age is the typical reading. Arteries stiffen over the decades, so systolic pressure tends to drift up while diastolic can fall — which is why the top number becomes the more important one after about age 50. A rising systolic with a falling diastolic (a wide 'pulse pressure') is itself a cardiovascular risk marker. The bands below describe what is common by age, not a different healthy target.
| Life stage | What's typical | Healthy target |
|---|---|---|
| Young adults (20s–30s) | Often comfortably under 120/80 | Under 120/80 |
| Middle age (40s–50s) | Systolic creeps up; watch for the 130/80 line | Under 120/80 |
| Older adults (60+) | Higher systolic is common but not 'normal' | Under 120/80* |
*Some clinicians individualise targets for frail or very elderly patients. The 2017 ACC/AHA diagnostic cut-offs themselves do not change with age. Ask your provider what your personal goal is.
What about low blood pressure (hypotension)?
The ACC/AHA categories only describe normal-to-high blood pressure — they have no 'too low' band. Clinically, a reading under about 90/60 mm Hg is considered low blood pressure, or hypotension. On its own a low number is often fine, and even healthy in very fit people.
It only becomes a concern when it causes symptoms — dizziness, light-headedness, fainting, blurred vision, or fatigue — especially on standing up. If a low reading comes with those symptoms, it is worth a conversation with a clinician, because it can point to dehydration, medication effects, or an underlying issue. This calculator focuses on the AHA categories and so reports very low readings as 'Normal' rather than flagging hypotension.
How accurate is this blood pressure calculator?
The classification is exact. The calculator applies the published 2017 ACC/AHA cut-offs without rounding or interpolation, and uses the guideline's own 'higher category wins' rule when your two numbers disagree. For any reading you enter, it returns the same category a clinician reading the AHA chart would.
What it cannot do is diagnose you. A category from a single reading is a screen, not a diagnosis: real-world blood pressure swings through the day, and hypertension is confirmed only on the average of multiple readings across separate visits. The calculator also does not account for medication, pregnancy, or conditions that change your personal target. Treat the result as a starting point for a conversation with a healthcare professional.
Data sources and methodology
All category cut-offs come from the 2017 ACC/AHA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults, as summarised by the American Heart Association in 'Understanding Blood Pressure Readings'. The measurement routine follows the AHA's home-monitoring guidance, and the emergency thresholds follow the AHA's hypertensive-crisis advice.
American Heart Association — Understanding Blood Pressure Readings (2017 ACC/AHA categories).American Heart Association — Monitoring Your Blood Pressure at Home.Frequently asked questions about the free blood pressure calculator
About this blood pressure calculator
This blood pressure calculator runs entirely in your browser. Your readings never leave your device — nothing is sent to a server, logged, or shared. It matches your systolic and diastolic numbers against the 2017 ACC/AHA category bands and applies the guideline's 'higher category wins' rule when the two disagree, updating instantly as you type.
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