How to check blood pressure at home: a step-by-step guide

To take your blood pressure at home, sit quietly for 5 minutes with your back supported, feet flat, legs uncrossed, and your bare arm resting on a table at heart level. Then take two readings one minute apart, do that every morning and evening for 7 days (ideally the week before a doctor visit), and use the average.

Small setup mistakes, like crossed legs or a cuff that's too small, can push a single reading up by 5, 10, or close to 20 points without you noticing. Here's how to avoid them.

What you need

• An automatic upper-arm monitor that has been validated for accuracy. The European Society of Hypertension (ESH) recommends validated electronic upper-arm devices for home use, preferably ones that store readings.
• A cuff that fits your arm. Sizing is covered below.
• A place to write the readings down. A notebook works, so does a printable blood pressure log, so does a blood pressure app.

Step by step

1. Plan 30 minutes ahead. No exercise, caffeine, smoking, or food in the 30 minutes before you measure. Use the bathroom first.
2. Pick the right chair. A dining chair beats the couch. Sit with your back against the backrest, both feet flat on the floor, legs uncrossed.
3. Bare your arm. The cuff goes directly on skin, so take your arm out of the sleeve.
4. Rest your arm on a table so the middle of your upper arm sits at about heart level.
5. Put the cuff on following your monitor's instructions. Most devices want the left arm, with the cuff's marker over the artery on the inside of your elbow. Use the same arm every time.
6. Sit quietly for 5 minutes. No phone, no TV news, no conversation. The ESH guidance asks for 3 to 5 minutes of relaxed sitting and no talking during or between measurements.
7. Take the first reading. Stay still and quiet while the cuff inflates and deflates.
8. Wait one minute, then take the second reading.
9. Write down both numbers, the date, and the time. Then average the two.
10. Repeat in the evening. In the morning, measure before breakfast and before any blood pressure medicine, which is what the ESH protocol specifies.

Why two readings, twice a day, for a week

Blood pressure moves from minute to minute and hour to hour, so one reading is a snapshot of one moment. The ESH home protocol asks for two readings one minute apart, morning and evening, for 7 days (3 days at the very least). It then sets aside the first day and averages everything else, with at least 12 readings in total. The ESH guidelines are blunt about why: individual readings have little diagnostic accuracy.

The best time to run this week is right before an appointment, so the average reflects where you are now. After that, the ESH suggests checking two readings once or twice a week for long-term follow-up, or at least once a month.

If the first of your two readings tends to be the higher one, that's common. I wrote a separate guide on why the first blood pressure reading is often higher.

Cuff size by arm circumference

A cuff that's too small squeezes too hard and reads high. Foti and colleagues, writing in Hypertension in 2025, report that using one cuff for everyone can overestimate systolic pressure by up to 19.5 mmHg when the cuff is too small, and underestimate it by up to 3.5 mmHg when it's too large.

To find your size, wrap a soft tape measure around the middle of your upper arm, halfway between shoulder and elbow, with the arm relaxed. Then match it to the American Heart Association cuff sizes (as summarized by Palatini and Asmar):

Home monitors usually print their own range on the cuff, and many sell a separate large cuff. If your measurement falls outside the cuff's printed range, buy the right cuff before you trust the numbers.

The common mistakes, and roughly how much each one adds

Each of these pushes the reading up (except a cuff that's too big, which pushes it down). The numbers come from different studies with different methods, so treat them as ballpark figures for how much a mistake can move the result.

Cuff over clothing is the one where the evidence is mixed. Handler's 2009 table lists a range of 5 to 50 mmHg, while the 2020 meta-analysis cited by Foti and colleagues found only small differences. Guidelines still say bare arm, and it costs you nothing, so I'd stick with that.

These mistakes tend to travel together. A quick reading on the couch, legs crossed, arm in your lap, chatting with someone in the next room, can stack several of them into one number. Use the same chair, table, and arm every time and most of them go away.

Wrist or upper-arm cuff?

Use an upper-arm cuff if you can. The ESH guidelines say wrist devices are generally not recommended because they're less accurate than upper-arm devices and easier to use incorrectly.

There's one real exception. Some people have upper arms too large or too cone-shaped for any upper-arm cuff to fit well. For them, ESH says a validated wrist device may be used, and Palatini and Asmar note that wrist monitors can be a reasonable alternative, especially ones with cuffs designed for larger forearms. If you go that route, follow the device's positioning instructions exactly and use the same setup every time.

Finger cuffs, smartwatches, and other cuffless wearables are a different category, and the ESH says they shouldn't be used for home blood pressure monitoring. (Here's what Apple Watch can and can't do.)

What to do with the average

Your 7-day average is the number to bring to your doctor, along with the individual readings. The average tells them where you usually are, and the individual readings show how much you swing, especially morning versus evening (see morning vs evening blood pressure). If you want to see where a number lands on the current categories, the blood pressure category chart walks through them.

Common questions

Should I throw out the first reading?

Within a session, no. Average both readings. The ESH protocol does set aside the whole first day of a 7-day week. Whatever rule you follow, decide it before you see the numbers, and don't drop a reading because you didn't like it.

Which arm should I use?

Use whichever arm your monitor's instructions specify (usually the left), and stick with it. Switching arms from day to day adds variation you don't need.

My reading is 180/120 or higher. What should I do?

The NHLBI's advice is to wait 5 minutes and check again. If it's still that high and you have symptoms such as sudden severe pain in your chest, back, or belly, trouble breathing, a sudden severe headache, numbness or weakness, a sudden change in vision, or trouble speaking, call 911. Don't wait to see if it comes down. If it's still that high but you feel fine, call your doctor.

When should I call my doctor before my next visit?

If your averages are consistently high, or your readings keep climbing, call your doctor rather than waiting for your next routine visit. Sharing home readings with your doctor covers what to send.

How BP Log fits in

BP Log runs the two-reading routine for you: it times the minute between readings, averages them automatically, and keeps morning and evening averages separate. When you're ready for an appointment, it prints a doctor visit report with a summary and every reading split into AM and PM.