What is normal blood pressure?

AHA 2017 defines Normal as less than 120 systolic AND less than 80 diastolic (e.g., 115/75). Elevated is 120-129 systolic AND less than 80 diastolic. Anything 130/80 or higher is hypertension.

What does the top and bottom number mean?

Systolic (top) is the pressure when your heart contracts and pumps blood. Diastolic (bottom) is the pressure when your heart relaxes between beats. Both matter — the higher of the two determines your blood pressure category.

What is Mean Arterial Pressure (MAP)?

MAP = Diastolic + (Systolic − Diastolic) / 3. It represents the average pressure during one cardiac cycle and is what actually perfuses your organs. Normal range is 70-100 mmHg. MAP below 60 means inadequate organ perfusion.

What is pulse pressure?

Pulse pressure is the difference between systolic and diastolic (e.g., 120/80 has pulse pressure of 40). Normal range is 30-50. Widening pulse pressure above 60 is an indicator of arterial stiffness and cardiovascular risk, especially in adults over 60.

When should I worry about high blood pressure?

Consult a doctor if you consistently measure 130/80 or higher (Stage 1 hypertension). Seek IMMEDIATE medical attention if 180/120 or higher (Hypertensive Crisis), especially with chest pain, shortness of breath, vision changes, severe headache, or numbness.

Can I lower blood pressure naturally?

Yes, especially for Elevated and Stage 1: reduce sodium (under 2,300 mg/day, ideally 1,500), DASH diet, exercise 150 min/week moderate intensity, lose weight if overweight, limit alcohol, manage stress, sleep 7-9 hours. Stage 2 usually needs medication.

What is white coat syndrome?

Elevated BP readings at the doctor's office due to anxiety, even though home readings are normal. Affects 15-30% of people. Home monitoring or 24-hour ambulatory monitoring gives more accurate values.

How accurate are home BP monitors?

Validated upper-arm cuff monitors are accurate within ±5 mmHg when used correctly. Wrist monitors are less reliable. Take 2-3 readings 1 minute apart and average them. Bring your home monitor to your doctor occasionally to verify against their device.

Blood Pressure Calculator

Blood pressure is reported as two numbers: systolic (top, when heart contracts) over diastolic (bottom, when heart relaxes). The American Heart Association (AHA) 2017 guidelines define five categories: Normal (<120/80), Elevated (120-129/<80), Hypertension Stage 1 (130-139/80-89), Hypertension Stage 2 (≥140/≥90), and Hypertensive Crisis (≥180/≥120). The Mean Arterial Pressure (MAP) — calculated as Diastolic + (Systolic − Diastolic)/3 — represents the average pressure during one cardiac cycle and is what perfuses your organs.

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calendar_today Updated: September 2025

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monitor_heartBlood Pressure Reading

Systolic (top)

Diastolic (bottom)

Enter both numbers from your BP reading (mmHg)

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tips_and_updates Tips

• Take readings at the same time daily for accurate trends
• Sit quietly for 5 minutes before measuring
• Use both arms initially; future readings on the higher arm
• Avoid caffeine, exercise, and smoking 30 min before
• Average 2-3 readings 1 minute apart
• White coat syndrome can elevate BP at the doctor's office
• Home monitoring is more accurate than single office readings

medical_information

Medical disclaimer. This calculator is for informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read here.

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Reviewed against authoritative guidelines

Last updated September 2025

Formulas, categories and healthy ranges align with American Heart Association.

How to Use the Blood Pressure Calculator

Enter systolic

Enter diastolic

Bottom number from your BP reading.

Read category and recommendations

AHA 2017 classification + risk + actions.

The Formula

MAP normal range is 70-100 mmHg. Below 60 indicates inadequate organ perfusion. Pulse pressure normally 30-50 mmHg; widening pulse pressure (>60) is a marker of arterial stiffness and cardiovascular risk in older adults. The category is determined by the HIGHER classification of either systolic or diastolic.

MAP = Diastolic + (Systolic − Diastolic) / 3

lightbulb Variables Explained

Systolic Pressure when heart contracts (top number)
Diastolic Pressure when heart relaxes (bottom number)
MAP Mean Arterial Pressure — average pressure perfusing organs
Pulse Pressure Systolic − Diastolic (heart's stroke output indicator)

tips_and_updates Pro Tips

Take readings at the same time daily for accurate trends

Sit quietly for 5 minutes before measuring

Use both arms initially; future readings on the higher arm

Avoid caffeine, exercise, and smoking 30 min before

Average 2-3 readings 1 minute apart

White coat syndrome can elevate BP at the doctor's office

Home monitoring is more accurate than single office readings

Blood pressure is one of the most important vital signs measured during any medical checkup, yet nearly half of American adults — approximately 116 million people — have hypertension, and many do not know it. A blood pressure reading consists of two numbers: systolic pressure (the force when your heart contracts) over diastolic pressure (the force when your heart relaxes between beats). This blood pressure calculator interprets your reading according to the American Heart Association 2017 guidelines, classifying it as Normal, Elevated, Hypertension Stage 1, Hypertension Stage 2, or Hypertensive Crisis. It also computes your Mean Arterial Pressure (MAP), which represents the average pressure perfusing your organs during a complete cardiac cycle, and your pulse pressure, which is the difference between systolic and diastolic values. Whether you are monitoring readings at home with a digital cuff, reviewing lab results before a doctor visit, or tracking trends over weeks to assess medication effectiveness, this calculator gives you an immediate, clinically-grounded interpretation of what your numbers mean and what actions the AHA recommends for your category.

AHA 2017 Blood Pressure Categories and Thresholds

The American Heart Association updated its blood pressure guidelines in 2017, lowering the threshold for hypertension from 140/90 to 130/80 mmHg. Under the current framework, Normal blood pressure is below 120/80 mmHg. Elevated is systolic 120-129 with diastolic below 80 — a warning stage requiring lifestyle changes. Hypertension Stage 1 is systolic 130-139 or diastolic 80-89, where doctors consider medication if cardiovascular risk factors are present. Hypertension Stage 2 is systolic 140+ or diastolic 90+, typically requiring medication plus lifestyle modification. Hypertensive Crisis (systolic over 180 or diastolic over 120) demands immediate medical attention. When systolic and diastolic readings fall into different categories, the higher category applies. For example, a reading of 138/78 is Stage 1 hypertension based on the systolic value alone. These thresholds are based on large-scale studies showing that cardiovascular risk begins rising continuously above 115/75 mmHg.

Mean Arterial Pressure and Why It Matters Clinically

Mean Arterial Pressure (MAP) is the weighted average pressure during one cardiac cycle, calculated as MAP = Diastolic + (Systolic − Diastolic) / 3. The formula weights diastolic more heavily because the heart spends roughly two-thirds of the cycle in relaxation. A normal MAP ranges from 70 to 100 mmHg. Below 60 mmHg, vital organs may not receive adequate blood flow — a critical threshold in emergency medicine and ICU monitoring. Above 100 mmHg indicates the heart is working harder than normal, increasing risk of organ damage over time. Pulse pressure — the difference between systolic and diastolic — is another important derived metric. Normal pulse pressure is 30-40 mmHg. A widened pulse pressure above 60 mmHg can indicate aortic stiffness, aortic regurgitation, or hyperthyroidism. A narrow pulse pressure below 25 mmHg may suggest heart failure or significant blood loss. Together, MAP and pulse pressure provide a more complete hemodynamic picture than systolic and diastolic values alone.

Tips for Accurate Home Blood Pressure Monitoring

Home blood pressure monitoring is recommended by the AHA for anyone with elevated readings, but technique errors can produce readings that are 10-20 mmHg off. First, use an upper-arm cuff validated by the Association for the Advancement of Medical Instrumentation (AAMI) — wrist and finger monitors are less accurate. Second, sit quietly for 5 minutes before measuring, with your back supported, feet flat on the floor, and arm resting on a table at heart level. Crossing legs can raise systolic pressure by 2-8 mmHg. Third, avoid caffeine, exercise, and smoking for 30 minutes beforehand. Fourth, take two readings one minute apart and average them — single readings can vary significantly. Fifth, measure at the same times daily (morning before medication and evening) to establish a reliable trend. White coat hypertension (elevated readings only at the doctor) affects 15-30% of patients, while masked hypertension (normal at the doctor but elevated at home) affects about 10%. Regular home monitoring catches both patterns and gives your physician a far more accurate picture.

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