Blood pressure log: your readings, kept on your own device

Before you measure

The Centers for Disease Control and Prevention (CDC) gives this checklist for a reading you can trust:

• Don’t eat or drink anything 30 minutes before.
• Empty your bladder first.
• Sit in a comfortable chair with your back supported for at least 5 minutes before the reading.
• Put both feet flat on the ground and keep your legs uncrossed.
• Rest the arm with the cuff on a table at chest height.
• The cuff goes against bare skin, not over clothing, snug but not too tight.
• Do not talk while the reading is being taken.

The CDC also says to measure at the same time every day and to take at least two readings, 1 or 2 minutes apart; smoking, alcohol, caffeine or exercise in the 30 minutes before can make a reading higher. The American Heart Association says to use a monitor with a cuff for the upper arm, not the wrist or a finger, and to take the monitor to an appointment so someone can check it against the office’s. We read these on the CDC page Measuring your blood pressure and the association’s page Home blood pressure monitoring on October 6, 2026. How often to measure is for you and your doctor to settle.

The chart this page uses

Under each reading the page names the row of the American Heart Association’s blood pressure chart that it falls in. The rows, in the association’s numbers:

• Normal: top number less than 120 and bottom number less than 80.
• Elevated: top 120 to 129 and bottom less than 80.
• Stage 1 hypertension (high blood pressure): top 130 to 139 or bottom 80 to 89.
• Stage 2 hypertension (high blood pressure): top 140 or higher or bottom 90 or higher.
• Higher than 180 and/or higher than 120: the association calls this severe hypertension when there are no symptoms, and a hypertensive emergency (call 911) when it comes with chest pain, shortness of breath, back pain, numbness, weakness, a change in vision or difficulty speaking.

The association’s own note under the chart: only a doctor or other medical professional can confirm a high blood pressure diagnosis, and they can also check whether your blood pressure is too low. It also says that a single high reading is not an immediate cause for alarm: take it a second time, write both down, and check with your healthcare professional. The National Heart, Lung, and Blood Institute, a federal institute, says that for children younger than 13, readings are instead compared with readings common for children of the same age, sex and height, and that a diagnosis takes two or more readings at separate medical appointments. We read the chart on the association’s page Understanding blood pressure readings and the institute’s page High blood pressure: diagnosis on October 6, 2026. They are those organizations’ words, shortened; we added no numbers of our own.

How it works

• A reading asks for the two numbers, the day and the time. The pulse, where it was taken and a note are optional.
• My readings lists them, newest first, each with the chart row it falls in. Change puts one back in the boxes; Remove takes it out.
• Looking back gives the average of the last 7 days and the last 30, mornings and evenings apart, the lowest and highest top number, and a bar for each recent reading.
• Print my sheet makes a table of your last 24 readings with empty rows to fill in by hand.

What this page can’t do

• It measures nothing. It only knows the numbers you type, and a typing slip looks the same to it as a real reading.
• It does not diagnose high or low blood pressure and is not treatment. Naming a row of a chart is not a diagnosis.
• It does not say what your numbers ought to be. Your doctor may have given you a different goal from the chart, and that goal is the one that counts.
• It is no reason to change a medicine. The American Heart Association says not to stop taking blood pressure medication without checking with your healthcare professional, whatever your home readings are.
• It does not know about pregnancy. If you are pregnant or gave birth recently, ask your own care team which numbers matter for you and when to call.
• It cannot remind you. It has no alarm and sends no message.
• The log does not move to another phone or computer by itself. Print it, download it, or use My data on this device to carry a backup across.

Where the idea comes from

A blood pressure log is ordinary advice: the CDC’s first tip for measuring at home is to use one, and the American Heart Association says a record of readings taken over time gives a more complete picture than one measurement. Many monitors and phone apps keep such a log on a company’s computers. This page does the arithmetic and keeps nothing anywhere but here. It is not any clinic’s official form, and no doctor or nurse has looked at it.