Average Blood Pressure Calculator

Q: What is a good average blood pressure number?

For most adults, a healthy average is below 120/80 mmHg . 1 That is about 16.0/10.7 kPa. 120 to 129 on top with under 80 on the bottom is Elevated. 1 130/80 or higher is high blood pressure. 1 Home averages are judged the same way, but many doctors treat a home average of 135/85 mmHg as the line where office readings would be 140/90. 4

Q: How do I convert mmHg to kPa?

Divide mmHg by 7.5 to get kPa. Multiply kPa by 7.5 to go back. 120/80 mmHg = 16.0/10.7 kPa 130/80 mmHg = 17.3/10.7 kPa 140/90 mmHg = 18.7/12.0 kPa Some devices in Europe and China show kPa instead of mmHg.

Q: Why do my left and right arms give different readings?

A small gap is normal. A steady gap of 10 mmHg or more counts as meaningful, and it shows up in about 3.6% of the general population. 8 Check both arms the first time, then always use the arm with the higher number. 4 A large gap can be caused by a blocked artery in the arm, so tell your doctor. 8

Q: What blood pressure reading is a medical emergency?

A reading higher than 180/120 mmHg needs urgent attention. 1 Wait 1 minute and take it again. 1 Still higher than 180/120 with no symptoms? Call your doctor right away. 1 With chest pain, shortness of breath, back pain, numbness, weakness, vision changes, or trouble speaking, call emergency services now. 1

Average Blood Pressure Calculator

American Heart Association blood pressure categories with the matching row marked
Category	Systolic (mmHg)		Diastolic (mmHg)
Normal (Green)	Below 120	and	Below 80
Elevated (Yellow)	120 – 129	and	Below 80
High — Stage 1 (Orange)	130 – 139	or	80 – 89
High — Stage 2 (Red)	140 – 180	or	90 – 120
Hypertensive Crisis (Dark Red / Alert)	Higher than 180	or	Higher than 120

Introduction

One blood pressure reading does not tell the whole story. Your numbers change all day. They go up when you move, feel stress, or drink coffee. That is why doctors look at an average blood pressure taken over several days, not a single check.

The Average Blood Pressure Calculator takes your morning and evening readings for up to 14 days, adds them up, and returns one average, such as 131.2 / 83.4 mmHg. You can work in mmHg or kPa.

The calculator also shows:

Average systolic (the top number) and average diastolic (the bottom number)
Pulse pressure, the gap between the two numbers
Mean arterial pressure (MAP), the average pressure in your arteries during one heartbeat
Your blood pressure category based on American Heart Association (AHA) ranges: Normal, Elevated, Stage 1, Stage 2, or Hypertensive Crisis

By default, Day 1 readings are left out of the average. Standard home monitoring practice drops the first day.³ Those numbers often run high while people are still new to the cuff. You can turn that setting off with one click.

You also get a step-by-step solution, a chart of your daily averages, and a day-by-day table. Bring these results to your next doctor visit. This tool is for learning and tracking only. It is not a diagnosis. Always talk to your doctor about your numbers.

How to use our Average Blood Pressure Calculator

Enter your home blood pressure readings for each day, morning and evening. The calculator gives you your average systolic and diastolic blood pressure, your pulse pressure, your mean arterial pressure (MAP), and your blood pressure category based on American Heart Association ranges.

Pressure Unit: Pick mmHg or kPa. All readings you type and all results will use this unit. If you switch units, your numbers are converted for you.

Days of Monitoring: Type how many days you tracked, from 1 to 14. The table adds or removes rows to match.

Day 1 Readings: Leave this switch on to drop Day 1 from your average. The first day often reads high, so home monitoring routines usually skip it. Turn the switch off if you want every day counted.

Systolic: In each row, type the top number of your reading. It must be between 60 and 299 mmHg.

Diastolic: In the same row, type the bottom number. It must be between 40 and 199 mmHg and lower than your systolic number, or that row is skipped.

Add Day and Remove Last Day: Use these buttons to change how many days show in the table without retyping your other readings.

Clear All Readings: Empties every box so you can start a new set of readings.

Calculate: Press this to see your average blood pressure, the step-by-step math, a daily trend chart, and a per-day summary.

Reset: Puts the calculator back to the 7-day sample readings in mmHg.

What Is Average Blood Pressure?

Blood pressure is the force of your blood pushing on the walls of your arteries. It is written as two numbers, like 128/82. The top number is systolic pressure, the push when your heart beats. The bottom number is diastolic pressure, the push when your heart rests between beats. Most readings are given in mmHg (millimetres of mercury), but some countries and devices use kPa (kilopascals).

Your average blood pressure is the mean of many readings taken over several days. One single reading does not tell the whole story. Blood pressure changes all day long with stress, sleep, food, salt, caffeine, exercise, and even the drive to the clinic. Averaging many readings smooths out these ups and downs and gives a much truer picture of your heart health.

Why Home Monitoring Uses 7 Days

Heart doctors usually ask people to check their blood pressure at home for 7 days in a row, twice each day, once in the morning and once in the evening.³ The first day is normally thrown out.³ First-day readings are often higher while you are still getting used to the cuff and the routine. The remaining days are averaged to get your true home blood pressure.³

Other Numbers That Matter

Pulse pressure = systolic − diastolic. It shows how stiff your arteries are. A wide gap (over about 60 mmHg) can be a warning sign, especially in older adults.
Mean arterial pressure (MAP) = diastolic + (pulse pressure ÷ 3).⁵ This is the average pressure in your arteries during one full heartbeat. Doctors like MAP to stay around 70 to 100 mmHg, because organs such as the kidneys and brain need steady pressure to get enough blood.

Blood Pressure Categories

The American Heart Association sorts adult blood pressure into these groups: Normal (under 120/80), Elevated (120 to 129 systolic and under 80 diastolic), Stage 1 high blood pressure (130 to 139, or 80 to 89), Stage 2 high blood pressure (140 or more, or 90 or more).¹ Readings higher than 180, or higher than 120, are a hypertensive crisis and need medical help right away.⁴

Tips for Accurate Readings

Sit quietly for 5 minutes first, with your back supported and feet flat on the floor.⁴
Rest your arm on a table so the cuff is at heart level.²
Skip caffeine, smoking, and exercise for 30 minutes before you measure.²
Empty your bladder first, and do not talk during the reading.⁴
Use the same arm and the same time of day each time.
Take two readings a minute apart and use the pattern over days, not one number.²

High blood pressure often has no symptoms, which is why it is called the "silent killer." Over time it can damage the heart, brain, kidneys, and eyes. Tracking your average at home helps you and your doctor spot problems early and see if lifestyle changes or medicine are working. Home numbers help, but they are not a diagnosis. Always share your results with a healthcare professional.

Formulas used

Average Systolic Pressure

\bar{S} = \frac{\sum_{i=1}^{n} S_i}{n}

Average Diastolic Pressure

\bar{D} = \frac{\sum_{i=1}^{n} D_i}{n}

Pulse Pressure

PP = \bar{S} - \bar{D}

Mean Arterial Pressure ⁵

MAP = \bar{D} + \frac{PP}{3} = \bar{D} + \frac{\bar{S} - \bar{D}}{3}

Daily Average (per day, morning and evening)

\bar{S}_{day} = \frac{\sum S_{day}}{m}, \quad \bar{D}_{day} = \frac{\sum D_{day}}{m}

Unit Conversion between kPa and mmHg

P_{\text{mmHg}} = P_{\text{kPa}} \times 7.5006157584566, \quad P_{\text{kPa}} = \frac{P_{\text{mmHg}}}{7.5006157584566}

Frequently asked questions

What is a good average blood pressure number?

For most adults, a healthy average is below 120/80 mmHg.¹ That is about 16.0/10.7 kPa.

120 to 129 on top with under 80 on the bottom is Elevated.¹
130/80 or higher is high blood pressure.¹

Home averages are judged the same way, but many doctors treat a home average of 135/85 mmHg as the line where office readings would be 140/90.⁴

Why is my blood pressure higher in the morning?

Your body releases hormones like cortisol and adrenaline as you wake up. They make your heart beat harder and your vessels tighten, so pressure climbs. This is called the morning surge.

Blood pressure usually peaks in the late morning, dips in the afternoon, and falls lowest while you sleep. That is why morning and evening readings are both taken and then averaged.

Should I take two readings each time and average them?

Yes. Take two readings one minute apart at each sitting, then average those two before writing the number down.²

The first reading of a session is often the highest. If the two are more than 5 mmHg apart, take a third and average all of them.

Is home blood pressure lower than at the doctor's office?

Often, yes. For many people, readings taken at the clinic are higher than their average outside it.⁸ How big the gap is depends on the level: home and clinic readings match at 120/80 and 130/80 mmHg, and the difference opens up above that.⁸

Because of this gap, a home average of 135/85 mmHg is treated like 140/90 mmHg in a clinic.⁴

What is white coat hypertension?

It is when your blood pressure is high at the doctor's office but normal at home.⁴ Nerves at the clinic push the numbers up.

Among people with a high office reading, 15% to 30% turn out to have it.⁸ A 7-day home average is the best way to spot it. Most studies find it adds little heart risk on its own, but keep tracking.⁸

What is masked hypertension?

It is the opposite of white coat hypertension. Your readings look fine at the clinic but are high at home or at work.⁴

It is dangerous because it goes unnoticed. Stress at work, smoking, salt, and poor sleep can all push home numbers up. Only home or 24-hour monitoring finds it.⁴

How do I convert mmHg to kPa?

Divide mmHg by 7.5 to get kPa. Multiply kPa by 7.5 to go back.

120/80 mmHg = 16.0/10.7 kPa
130/80 mmHg = 17.3/10.7 kPa
140/90 mmHg = 18.7/12.0 kPa

Some devices in Europe and China show kPa instead of mmHg.

What does it mean if only my top number is high?

A high systolic number with a normal diastolic number is called isolated systolic hypertension. It is the most common type of high blood pressure in people over 60.

It happens when the large arteries get stiff with age. It still counts as high blood pressure and still needs treatment, even if the bottom number looks fine.

Why do my left and right arms give different readings?

A small gap is normal. A steady gap of 10 mmHg or more counts as meaningful, and it shows up in about 3.6% of the general population.⁸

Check both arms the first time, then always use the arm with the higher number.⁴ A large gap can be caused by a blocked artery in the arm, so tell your doctor.⁸

What blood pressure reading is a medical emergency?

A reading higher than 180/120 mmHg needs urgent attention.¹

Wait 1 minute and take it again.¹
Still higher than 180/120 with no symptoms? Call your doctor right away.¹
With chest pain, shortness of breath, back pain, numbness, weakness, vision changes, or trouble speaking, call emergency services now.¹

What is a healthy pulse pressure?

Pulse pressure is the top number minus the bottom number. A normal pulse pressure is about 40 mmHg.⁶

Over 60 mmHg often means stiff arteries and a higher risk of heart problems, especially after age 60. A pulse pressure below 25% of the top number is narrow, which can happen when the heart is not pumping well.⁶

Does a fast heart rate mean high blood pressure?

No. Heart rate and blood pressure are two different things. Your pulse can double during exercise while blood pressure rises only a little.

You cannot guess one from the other. Track both numbers, but judge your blood pressure by the cuff reading alone.

How fast can lifestyle changes lower blood pressure?

Most changes show up in your average within 2 to 8 weeks. Typical drops in the top number:

Losing 10 lb (4.5 kg): about 5 mmHg.
Cutting salt to under 1,500 mg a day: 5 to 6 mmHg.⁴
150 minutes of walking a week: 5 to 8 mmHg.⁴
Less alcohol: about 4 mmHg.⁴

Keep measuring, because the weekly average shows progress better than one reading.

Can I still have high blood pressure if I feel fine?

Yes. High blood pressure usually has no symptoms at all, which is why it is called the silent killer.⁷

Many people feel healthy for years while the pressure quietly damages the heart, kidneys, brain, and eyes. Regular readings are the only way to know.

Sources

Understanding Blood Pressure Readings. American Heart Association. Accessed September 26, 2026.

Monitoring Your Blood Pressure at Home. American Heart Association. Accessed September 26, 2026.

Hypertension in adults: diagnosis and management (NG136): Recommendations. National Institute for Health and Care Excellence. 2019;recommendation 1.2.7. Accessed September 26, 2026.

Whelton PK, Carey RM, Aronow WS, Casey DE Jr, Collins KJ, Dennison Himmelfarb C, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Hypertension. 2018;71:e13-e115. doi:10.1161/HYP.0000000000000065. Accessed September 26, 2026.

DeMers D, Wachs D. Physiology, Mean Arterial Pressure. StatPearls. StatPearls Publishing, NCBI Bookshelf. 2023. Accessed September 26, 2026.

Homan TD, Bordes SJ, Cichowski E. Physiology, Pulse Pressure. StatPearls. StatPearls Publishing, NCBI Bookshelf. Accessed September 26, 2026.

High blood pressure. NHS. Accessed September 26, 2026.

Muntner P, Shimbo D, Carey RM, Charleston JB, Gaillard T, Misra S, et al. Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association. Hypertension. 2019;73(5). Sections: Interarm Differences; White-Coat Hypertension and White-Coat Effect; Table 11. doi:10.1161/HYP.0000000000000087. Accessed October 7, 2026.

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