Sit quietly for 5 minutes with your back supported, feet flat and your bare upper arm resting at heart level, take two readings 1 minute apart, morning and evening for a week, and judge the average, where 135/85 at home matches 140/90 at the office.
I strongly encourage you to get a home blood pressure monitor. The 2025 American Heart Association guideline recommends home or 24-hour readings to confirm a diagnosis and home readings to track treatment (guideline).
Office readings can mislead. In one analysis, about 35% of people whose first office reading was 140 to 159 over 90 to 99 were under 140/90 once three readings were averaged (AHA statement).
The book's grade: SUPPORTED (works) for a validated upper-arm home cuff with your readings shared and acted on by your care team, a Start here item. That lowered the top number about 6 points at 12 months, while the cuff alone moved it about 1 point, which could have been chance (review).
Best home blood pressure monitor: what to look for
- Upper-arm and automatic. The American Heart Association recommends an automatic cuff that wraps around your upper arm, not a wrist or finger monitor, which gives less reliable readings (AHA).
- Validated. A validated cuff has passed a formal accuracy test, landing within about 5 points of careful readings by trained staff, on average (standard). In the United States, a cuff can be sold without one (paper), and "FDA cleared" on the box doesn't mean it was tested for accuracy (review). The American Medical Association keeps a list of validated devices at validatebp.org. If the cuff is for someone who is pregnant, an older adult or a child, make sure it was validated for that group.
If you're shopping for the "best" or "most accurate" home blood pressure monitor, any automatic upper-arm cuff on the validated list, in the right size for your arm, is the right kind for most adults. Compare it with the office device at your next visit.
Getting the cuff size right
The wrong size is one of the biggest errors in home readings. In one trial, people who needed a large cuff read about 5 points too high on a regular one, and people who needed an extra-large cuff read about 20 points too high. People who needed a small cuff read about 4 points too low (trial).
Measure around the middle of your upper arm with a soft tape and match it to the range printed on the cuff. Once it's on, one finger should slip easily under the top and bottom edges, and two should fit snugly.
How to check your blood pressure at home, step by step
These steps come from the American Heart Association and the CDC (CDC):
- For 30 minutes before, don't smoke, exercise or have caffeine. The CDC adds that it's best not to eat or drink anything in that half hour.
- Empty your bladder.
- Sit in a chair with your back supported, feet flat on the floor and legs uncrossed.
- Put the cuff on your bare upper arm, with the bottom edge just above the bend of your elbow.
- Rest your arm on a table so the middle of the cuff is at heart level. Prop it on a pillow if you need to.
- Sit quietly for 5 minutes. No talking, no phone, no TV.
- Take two readings, 1 minute apart, and write both down.
Mistakes that throw the number off
Across many studies, talking during a reading raised the top number by about 4 to 19 points, crossed legs by about 2 to 15, and caffeine in the past few hours by about 3 to 14 (review). In a 2024 trial, resting your hand in your lap read about 4 points higher than an arm supported on a desk, and letting the arm hang at your side read about 6.5 points higher (trial).
Which arm? Check both arms the first time, and use the higher one from then on. If one arm keeps reading 10 or more points higher, tell your doctor, since a big gap is sometimes a sign of a narrowed artery. Never use an arm with a dialysis fistula or graft. If you have an irregular heartbeat such as atrial fibrillation, ask your doctor how much to trust a home cuff.
When and how often to check your blood pressure at home
Trend your averages, not single readings. For a new diagnosis, before a check-up, or after a new medicine or a big change in habits, do a home week. That means two readings in the morning and two in the evening, for 7 days (AHA statement). Take the morning readings before breakfast and coffee. If a week is too much, 3 days captures most of the useful information (study).
Once your numbers are steady and at goal, you don't need to check every day. In two British trials of people with controlled blood pressure on stable medicine, a home week about once a year was enough for people well below their goal, and about every 6 months for people closer to it (trials). Your doctor may want more.
What your home blood pressure numbers mean
The 2025 guideline sorts office readings into four groups (guideline):
- Normal: under 120 and under 80.
- Elevated: 120 to 129, and under 80.
- Stage 1 high blood pressure: 130 to 139, or 80 to 89.
- Stage 2 high blood pressure: 140 or higher, or 90 or higher.
If your two numbers fall in different groups, the higher one counts, so 126/86 is stage 1.
Home readings are judged a little differently. At 130/80, home and office numbers line up. At higher levels, home cutoffs run a little lower, so a home average of 135/85 matches an office reading of 140/90.
Your goal is set with your doctor. The guideline's main goal for most adults is under 130/80, and I use it so the numbers stay consistent. Your doctor may use 140/90 instead, and that isn't wrong, since each goal rests on evidence from real trials.
Expect your readings to bounce. In those British trials, most of a typical person's home readings landed within about 10 points above or below their own average, so 128 one morning and 146 the next can be ordinary (trials).
White-coat and masked high blood pressure
White-coat hypertension means high readings in the office and normal ones at home. It shows up in about 15% to 30% of people with high office readings (AHA statement). Untreated, it carried about 36% more risk of heart and stroke events than truly normal blood pressure in a large review, and it can turn into lasting high blood pressure (review). If you have it, keep working on your habits and do a home week every year.
Masked hypertension runs the other way, normal in the office and high at home. In a large 2024 review, about 18% of people had it (review), and it carried about 70% more risk of heart and stroke events than normal readings (review). Because the office number looks fine, it takes home or 24-hour readings to find it.
When home and office numbers don't agree, your doctor may order a 24-hour monitor, a cuff you wear for a day and a night that also shows what your blood pressure does while you sleep (guideline).
When to call your doctor
- Over 180 on top or 120 on the bottom with no symptoms: wait at least 1 minute and take it again. If it's still that high, contact your doctor's office as soon as possible, or the on-call line if it's closed. If you can't reach a person or get seen that day, go to urgent care.
- Over 180/120 with symptoms such as chest pain, shortness of breath, back pain, numbness, weakness, a change in vision or trouble speaking: call 911. The AHA says, "Do not wait to see whether your blood pressure comes down on its own" (AHA). Call 911 for stroke signs even if your reading isn't high.
- Low readings with dizziness or fainting: call the same day. Low numbers without symptoms are usually fine, but call within a week or two about a run of them.
- A home-week average above your goal: call within a week or two.
Never stop or change a blood pressure medicine because of a home reading.
If checking makes you anxious, stick to the schedule, repeat a high reading only once, and put the cuff away.
Are wrist monitors and smartwatches accurate enough?
Use a wrist cuff only if your arm truly won't fit any arm cuff, after asking your doctor, and hold your wrist exactly at heart level.
Smartwatches and other cuffless devices aren't ready for blood pressure decisions. The guideline recommends against using them to diagnose or manage high blood pressure (guideline). The book grades them UNLIKELY TO HELP for that job. A high number on your watch means it's time to check with a real cuff.
If a home cuff isn't for you
Some people can't afford a cuff, can't work one, or don't want one in the house.
- Nurse visits. Ask whether your office does quick blood pressure checks with a nurse. Your doctor should judge your blood pressure on the average of readings from at least two visits, never one (guideline).
- Pharmacy and store kiosks. A 2025 expert review found kiosk readings ran close to office readings on average, but it called their usefulness uncertain because the studies varied so much (review). The built-in cuff may also be the wrong size for your arm. Treat a kiosk number like any other single reading.
- Help with the cost. Ask your insurance plan, pharmacy or health savings account whether a cuff is covered, and whether your doctor's office loans them out.
- A 24-hour monitor (above).
Bottom line
Use a validated, automatic upper-arm cuff in the right size, follow the 7 steps, and take two readings morning and evening for a week. Judge the average, and remember that 135/85 at home matches 140/90 at the office. Home readings also catch white-coat and masked high blood pressure, which office visits miss. Share your averages with your doctor, because the cuff helps only when someone acts on the numbers.
Questions people ask
How do I check my blood pressure at home correctly?
No caffeine, smoking or exercise for 30 minutes, then empty your bladder. Sit with your back supported, feet flat and legs uncrossed, with the cuff on your bare upper arm at heart level. Rest quietly for 5 minutes, then take two readings 1 minute apart and write both down.
What is a normal blood pressure reading at home?
Under 120/80 is normal on office readings. At home, the 130/80 goal lines up with the office number, and a home average of 135/85 matches 140/90 at the office, the start of stage 2.
Why is my blood pressure higher at the doctor's office?
High in the office and normal at home is called white-coat hypertension, and it shows up in about 15% to 30% of people with high office readings. A home week sorts it out. It still carries extra risk, so keep up your habits and repeat a home week every year.
How often should I check my blood pressure at home?
Do a home week after a new diagnosis or any change. Once you're steady and at goal, a home week once or twice a year may be enough, unless your doctor wants more.
What you can do with those numbers
Your Blood Pressure by the Numbers, coming soon, grades what moves the number, from aerobic exercise (SUPPORTED, about 8 points in people with high blood pressure) to isometric handgrip training (SUPPORTED, for office readings) to checking many times a day (NO EVIDENCE). Start with how to lower blood pressure naturally, or read does coffee raise blood pressure?