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Self Health Pharmacist

Blood Pressure Reading Checker

Type the two numbers from your monitor. You get the band the American guideline puts them in, what the UK would call the same reading — the two lines are ten points apart — and which of your two numbers decided it.

mmHg
mmHg

You can paste the pair into the first box — “128/82” goes into both.

Where was it taken?

It changes the UK threshold: the NHS uses a lower one for home readings, because home readings run lower.

Whose reading is it?
years

Only used to show the national average at that age, which is not a target.

Compare with

A reading taken at home

128/82 — High blood pressure, stage 1 (US guideline)The bottom number is what puts this reading in that band.

Each number on its own scale, against the American bands.

    What people actually measure, by age — an average, not a target
    AgeAllMenWomen

    One reading is not a diagnosis, and this page cannot give you one. If your readings are high, or you feel unwell, take the numbers to your doctor or pharmacist.

    Thresholds and sources checked 2026-09-22.

    Quick answer: in the United States a reading is normal under 120 and under 80, elevated at 120–129 with a bottom number under 80, stage 1 at 130–139 or 80–89, and stage 2 at 140 or more, or 90 or more. Above 180 or above 120 needs attention today. In the UK the line is 140/90 at a surgery and 135/85 at home — so a reading the American guideline calls stage 1 hypertension may not be called high at all by the NHS. Both lines are shown here, because averaging two national guidelines would produce a threshold nobody published.

    How to use it

    Type the two numbers — or paste the pair into the first box and it will split them. Say where the reading was taken, because the UK uses a lower threshold for home readings. Optionally put in an age to see the national average at that age, which is a description of a population and not a target.

    Which of your two numbers decides the answer

    This is the part that surprises people. If the top and bottom numbers fall in different categories, the higher category is the one that counts. So 119/85 is stage 1 hypertension on the strength of the bottom number alone, even though the top number is normal. The drawing under the answer marks the number that decided it.

    Two countries, ten points apart

    The American Heart Association and the American College of Cardiology define hypertension as 130/80 and above — a definition their 2025 guideline kept from 2017. The NHS, following NICE, uses 140/90 in a clinic and 135/85 at home. A reading of 134/84 is therefore stage 1 hypertension in one country and not high in the other, for the same person on the same morning.

    Neither is a mistake. They are different lines drawn for different reasons, and both are published. What a page should not do is average them into a number that appears in no guideline — so this one shows both, names them, and lets the difference be visible.

    A single reading is not a diagnosis

    The NIH puts it plainly: “You will need two or more blood pressure readings at separate medical appointments to diagnose high blood pressure.” Blood pressure moves all day — with the time, the room, a conversation, a cup of coffee, a full bladder. That is why home monitoring is done as a series, and why the useful thing to take to an appointment is a week of readings, not one.

    The cuff can move your reading further than a category is wide

    In a randomised crossover trial, using the usual regular-size cuff on people who actually needed a large cuff read about 5 mmHg too high, and about 20 mmHg too high on people who needed an extra-large one. On people who needed a small cuff it read about 4 mmHg too low. Twenty points is more than the whole distance between normal and stage 2. Measure your upper arm, and check it against the range printed on your own monitor’s cuff.

    Worked examples

    118/76. Normal in the US guideline, not high in the UK, and both numbers agree.

    128/82. Stage 1 in the US — decided by the bottom number — and not called high by the NHS at all. This is exactly the band where the two guidelines disagree.

    142/88. Stage 2 in the US, high in the UK. The top number decides it.

    186/94. Above the 180/120 line: no symptoms, wait five minutes and measure again, then call your doctor if it is still that high; with a sudden severe headache, difficulty breathing, chest or back pain, numbness, a change in vision or trouble speaking, call 911 (UK: 999) instead of waiting.

    Blood pressure “by age”

    Search for a blood pressure chart by age and you will find tables suggesting that higher numbers are fine once you are older. They are not thresholds — they are averages, and the categories do not move with age. The table under the checker is the national survey figure: American adults aged 18–39 averaged 115/69, those 40–59 averaged 123/75, and those 60 and over averaged 136/68, with men and women differing in both directions. Plenty of the people in that survey had untreated high blood pressure; their readings are in the average too.

    FAQ

    What is a normal blood pressure?
    In the American guideline, less than 120 systolic and less than 80 diastolic. The NHS describes an ideal range of about 90/60 to 120/80 and calls a reading high from 140/90 at a surgery or 135/85 at home. Both lines are shown on this page.
    Is 130/80 high blood pressure?
    In the United States, yes: 130–139 systolic or 80–89 diastolic is stage 1 hypertension under the AHA/ACC guideline. In the UK it is under the NHS’s 140/90 line and would not be called high, though at home it is close to the 135/85 line. A single reading is not a diagnosis either way.
    My top number is fine but my bottom number is high. Which counts?
    The higher category counts. A reading of 119/85 is stage 1 hypertension in the US guideline because of the bottom number, even though the top number is inside normal.
    What blood pressure is dangerous?
    Higher than 180 systolic or higher than 120 diastolic. The NIH’s own instruction: with no symptoms, wait five minutes and measure again, and if it is still that high call your provider. If the second reading is also high and you have a sudden severe headache, difficulty breathing, severe pain in the abdomen, chest or back, numbness or weakness, a sudden change in vision or problems talking, call 9-1-1 (UK: 999). Do not wait to see if it comes down on its own.
    What is a normal blood pressure by age?
    The categories do not change with age — an older person’s 140/90 is stage 2 hypertension just as a younger person’s is. What changes is the average: 115/69 at 18–39, 123/75 at 40–59 and 136/68 at 60 and over in the US national survey. An average is what people have, not what is healthy.
    Why is the reading at home lower than at the doctor’s?
    It usually is, which is why the NHS sets a lower home threshold (135/85) than its clinic one (140/90). A reading that is high in the surgery and normal at home has a name — white-coat hypertension — and it is one of the reasons doctors ask for home readings.
    What is low blood pressure?
    The NHS calls a reading under 90/60 low. It does not always need treatment, but tell a doctor if you get lightheadedness, dizziness, blurred vision, nausea, weakness or fainting with it.
    Can I use this for a child?
    No, and the tool will not try. Children’s readings are compared with percentile tables for their age, sex and height rather than the adult categories, so a child’s numbers need their own doctor and their own chart.

    More from the site

    On the monitors themselves: Wellue vs Omron, Beurer vs Omron, Omron vs Dr Trust and Oxiline 9 Pro vs Omron M6, and how an oximeter differs from a blood pressure monitor.