Add each reading as you take it, morning and evening, for a week. You get the average the US and the UK each ask for, worked out their own way, and a page to print for your doctor.
Your week at home
Add your first readingMorning and evening, two readings a minute apart, for 7 days. The average appears here as you go — and stays in this browser only.
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Tap a reading to remove it.
An average is the number to take to your doctor, not a diagnosis, and this page cannot give you one. Do not change or stop a medicine because of it.
Methods, lines and sources checked 2026-10-10. Your readings are kept in this browser only — never in the page address, never sent anywhere.
Quick answer: measure every morning and evening for 7 days, taking two readings a minute apart each time, and average them. The American method (the AHA and AMA’s Target:BP programme) averages every reading and calls a home average of 130/80 or more high. The British method (NICE) leaves out the first day, averages the rest, and uses 135/85. This log works out both, names them, and keeps your readings in your own browser.
How to use it
Pick the day and whether it is a morning or evening reading, type the two numbers from your monitor, and press Add this reading. You can paste a pair like “128/82” into the first box. Do it twice each sitting, a minute apart. The average updates as you go, and the table shows the week with each reading as a button — tap one to remove it if you mistyped. When the week is done, Print the log for your doctor gives one page with the readings and both averages. Print it before you start and you get a blank 7-day sheet to fill in by hand.
Two methods, and they are not the same
Target:BP, the American Heart Association and American Medical Association’s programme, asks for readings “every morning and evening for seven consecutive days”, two each time, and says the systolic and diastolic readings “should be averaged” — all of them. It accepts as few as two days.
NICE, which writes the guideline the NHS follows, asks for the same routine, “at least 4 days, ideally for 7 days”, and then says: “Discard the measurements taken on the first day and use the average value of all the remaining measurements.” So the same week gives two slightly different averages. This page shows both rather than choosing one, because an average of the two methods would be a number neither of them uses.
Which line each average is compared with
The American line for a home average is 130/80: Target:BP says an average at or above it “meets criteria” for high blood pressure in someone being checked, and is “above goal” in someone already treated. Below 120/80 it calls normal “in most situations”. The British line for a home average is 135/85 — NICE uses it, together with a clinic reading of 140/90 or more, to confirm high blood pressure, and on treatment aims for below 135/85 under the age of 80 and below 145/85 from 80. NICE notes that home readings correspond to clinic ones about 5 mmHg lower, which is why its home line sits below its clinic line.
Worked example
A week of single readings, morning and evening: 142/90 and 138/88 on day one, then 134/84, 132/82, 130/82, 128/80, 133/83, 131/81, 129/79, 127/79, 131/83, 129/81, 128/80 and 126/78. All fourteen average 131/82 — at or above the American 130/80. Leave out day one, as NICE does, and the other twelve average 130/81 — below the British 135/85. Same person, same week: the two countries draw their lines in different places, and this page says so instead of hiding it. (With only one reading per sitting the page also reminds you that both methods ask for two.)
How much of the average is the monitor?
A monitor passes validation if, across the people in its study, its readings differ from the reference by no more than 5 mmHg on average, with a standard deviation of no more than 8 mmHg. A week of readings smooths out the scatter from one reading to the next, but it cannot remove a monitor’s own steady error — so an average a few points either side of a line is closer than the monitor can tell apart. The cuff matters even more: in one randomised trial, a regular cuff on an arm that needed an extra-large one read about 20 mmHg too high. The AHA recommends an upper-arm cuff monitor and says wrist and finger monitors are not recommended.
Your readings stay with you
Everything you type is kept in this browser on this device — not in the page address, not on our server, not in any analytics. Clearing your browsing data deletes it, and so does the Clear the log button. The print-out is the way to take it to your doctor.
FAQ
How do I work out my average blood pressure?
Why does NICE leave out the first day?
What home blood pressure average is too high?
How many readings do I need?
Is a reading over 180/120 in my log an emergency?
Can I print a blank blood pressure log?
Can I use a wrist monitor?
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Choosing a monitor: Wellue vs Omron, Beurer vs Omron, Oxiline 9 Pro vs Omron M6 and Omron vs Dr Trust. For a single reading on its own, the Blood Pressure Reading Checker shows the band it falls in.