High Blood Pressure

A single high blood pressure reading is common and usually not an emergency. Blood pressure is judged on a pattern of correctly taken readings, not one number.

Before reacting to the number, check the circumstances. A cuff that is too small, talking during the reading, crossing your legs, recent caffeine, rushing in from outside, pain, anxiety, or the white-coat effect can all push a reading up.

Reading explorer

This tool places a reading into published NICE/ESC threshold categories. It does not diagnose high blood pressure, calculate cardiovascular risk, or decide treatment.

Enter both numbers

The explorer will show the threshold category and what that category means.

Sources are shown with the category.

The interactive explorer needs JavaScript. The same categories and routes are shown here as static HTML.

Reading pattern

Category used here

What it means

Any high reading with chest pain, severe breathlessness, fainting, new confusion, one-sided weakness, or feeling acutely unwell

Urgent symptoms with the reading

Call 999 now. Symptoms matter more than the number.

Clinic reading below 120 and below 80

Optimal office range

This sits in the lowest ESC/ESH office category.

Clinic reading 120-129 or 80-84

Normal office range

This is above optimal but still below the high-normal office category.

Clinic reading 130-139 or 85-89

High-normal office range

This is not the same as diagnosed hypertension, but it is close to the threshold used for clinic hypertension.

Clinic reading 140-159 or 90-99

Grade 1 hypertension range

A single clinic reading in this range usually needs confirmation with repeated or out-of-office readings.

Clinic reading 160-179 or 100-109

Grade 2 hypertension range

This is a higher range; arrange prompt review through your GP or NHS 111 if you are unsure where to go.

Clinic reading 180 or above, or 110 or above

Grade 3 hypertension range

This is a very high range. If you feel well, seek urgent medical advice rather than waiting for a routine appointment.

Clinic systolic 140-179 with diastolic below 90

Isolated systolic hypertension range

The top number is in a hypertension range while the bottom number is not; the systolic range sets the grade.

Home average below 120 and below 70

Non-elevated home range

This sits below the ESC elevated home category.

Home average 120-134 or 70-84

Elevated home range

ESC uses this range for elevated home blood pressure.

Home average 135-149 or 85-94

Home hypertension confirmation range

NICE and ESC use lower home thresholds than clinic thresholds.

Home average 150 or above, or 95 or above

Higher home hypertension range

This is a higher home average range and should be discussed promptly with a clinician.

When a high reading is urgent

If a high reading comes with chest pain, severe breathlessness, fainting, new confusion, one-sided weakness, or you feel acutely unwell, call 999.

If you feel well but the reading is very high, arrange urgent medical advice through your GP or NHS 111 rather than waiting for a routine appointment.

Why one reading can mislead

Blood pressure moves from minute to minute. The first reading is often higher than later readings, especially if you have just sat down, are worried about the result, or are using a cuff that does not fit your arm.

A better question is whether repeated, properly taken readings show the same pattern. That is why clinicians usually look for repeated clinic readings, home readings, or ambulatory monitoring before labelling someone with hypertension.

How home readings differ from clinic readings

Home readings are usually taken sitting quietly in a familiar setting. Clinic readings may be higher because the room, timing, and stress of being measured can change the result.

For that reason, home and daytime ambulatory readings are interpreted with lower thresholds than clinic readings. If you keep a home diary, the average is more useful than the highest single number.

Evidence behind the categories

Real data

The office-reading categories used in the explorer are the ESC/ESH categories: optimal is below 120 and below 80, normal is 120-129 or 80-84, high-normal is 130-139 or 85-89, grade 1 hypertension is 140-159 or 90-99, grade 2 is 160-179 or 100-109, and grade 3 is 180 or above or 110 or above.

These categories describe a reading range; they do not diagnose a person from one measurement.

Source: Williams B, Mancia G, Spiering W, et al. 2018 ESC/ESH Guidelines for the management of arterial hypertension. European Heart Journal 2018;39(33):3021-3104. doi:10.1093/eurheartj/ehy339

Real data

Clinic and home readings are not interpreted on identical cut-offs. The 2024 ESC guideline defines elevated office BP as 120-139 or 70-89 and hypertension as office BP of 140 or above or 90 or above; it states that an average home BP of 135/85 is equivalent to an office BP of 140/90 for diagnosing hypertension.

This is why a home average can cross a threshold at a lower number than a clinic reading.

Source: McEvoy JW, McCarthy CP, Bruno RM, et al. 2024 ESC Guidelines for the management of elevated blood pressure and hypertension. European Heart Journal 2024;45(38):3912-4018. doi:10.1093/eurheartj/ehae178

NICE NG136 uses the same UK principle: clinic readings are confirmed with ambulatory or home monitoring where appropriate, and very high readings with concerning symptoms need same-day assessment.

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