To check blood pressure manually, you need an aneroid sphygmomanometer (a cuff with an attached pump and gauge) and a stethoscope. You inflate the cuff above your expected systolic pressure, then slowly release the air while listening for the sounds of blood flowing through the artery at your inner elbow. The first sound you hear marks your systolic (top) number, and the point where sounds disappear marks your diastolic (bottom) number. With the right setup and technique, you can get readings just as accurate as those taken in a clinic.
Equipment You Need
A manual blood pressure kit has four parts: an inflatable cuff that wraps around your upper arm, a rubber bulb pump you squeeze to inflate it, a pressure gauge (the round dial with numbers), and a stethoscope. These are sold together in most pharmacies and medical supply stores, typically for $20 to $40.
Before you start, check that the gauge needle rests exactly at zero when the cuff is deflated and the valve is open. If it doesn’t, the gauge is out of calibration and your readings will be off. Aneroid gauges should be checked for calibration every six months, since the internal mechanism can drift with regular use or if the device gets bumped around.
Choosing the Right Cuff Size
Cuff size matters more than most people realize. A cuff that’s too small can add 2 to 10 mmHg to your reading, potentially making a normal number look like high blood pressure. Measure the circumference of your upper arm at the midpoint between your shoulder and elbow, then match it to the cuff:
- Small adult: 26 cm or less
- Standard adult: 27 to 34 cm
- Large adult: 35 to 44 cm
- Extra-large adult: over 44 cm
Most kits come with a standard adult cuff. If your arm falls outside that range, order the correct size separately.
How to Prepare for an Accurate Reading
Small details in your positioning can swing a reading by dozens of points. Sit in a chair with a back support (not a couch) and rest quietly for at least five minutes before measuring. Place your feet flat on the floor with your legs uncrossed. Rest the arm you’ll measure on a table so it sits at heart level, and relax it completely.
Avoid caffeine, exercise, and smoking for at least 30 minutes beforehand. Don’t talk during the measurement. Even passively listening to a conversation can add around 10 mmHg to the result. And always place the cuff on bare skin. Measuring over a sleeve, depending on fabric thickness, can inflate your reading by up to 50 mmHg.
Step-by-Step Measurement
Wrap the cuff snugly around your upper arm, about one inch above the bend of your elbow. Most cuffs have an arrow or marker labeled “artery.” Line that up with the inside of your arm, roughly where you’d feel a pulse just above the elbow crease. That’s where the brachial artery runs, close to the skin’s surface along the inner front of your bicep.
Place the stethoscope earpieces in your ears and press the flat side of the chest piece gently over the brachial artery, just below the lower edge of the cuff. You shouldn’t hear anything yet.
Close the valve on the rubber bulb by turning the small knob clockwise until it’s snug. Squeeze the bulb rapidly to inflate the cuff until the gauge reads about 30 points above your usual systolic pressure. If you don’t know your usual number, inflating to 180 mmHg is a reasonable starting point for most people. You can also estimate by inflating until you can no longer feel a pulse at your wrist, then adding 30 mmHg.
Now slowly open the valve by turning the knob counterclockwise. You want the needle to drop at a steady rate of about 2 mmHg per second, which works out to roughly one small tick mark on the dial per second. This is the part that takes practice. If you release air too fast, you’ll miss the sounds. Too slow, and the pressure against your arm becomes uncomfortable and can skew the reading.
Listening for the Sounds
As the cuff deflates, you’re listening for a specific sequence of sounds created by blood starting to push through the compressed artery. These are called Korotkoff sounds, and only two moments matter for your reading.
The first clear tapping or snapping sound you hear is your systolic pressure, the top number. Note the gauge reading at that exact moment. This is the pressure at which blood first begins to flow past the cuff with each heartbeat.
Keep deflating at the same steady rate. The tapping sounds will continue, changing in quality as you go. Eventually, the sounds will disappear completely into silence. The gauge reading at the last sound you hear, right before that silence, is your diastolic pressure, the bottom number. This represents the pressure in your arteries between heartbeats, when the heart is at rest.
Once you’ve noted both numbers, open the valve fully to release all remaining air and remove the cuff. Your blood pressure is recorded as systolic over diastolic, for example, 124/78 mmHg.
Tips for Consistent Results
Take two or three readings, waiting one to two minutes between each. Your first reading tends to run slightly higher due to the novelty of cuff inflation, so averaging the second and third gives a more reliable number. Always measure on the same arm. It’s normal for readings to differ slightly between arms, but tracking from a consistent side helps you spot real trends.
If you need to repeat a measurement immediately because you missed a sound or deflated too quickly, fully deflate the cuff and wait at least a minute. Re-inflating against a partially pressurized cuff traps blood in the forearm and throws off accuracy.
Rest the gauge in the open palm of your cuffed hand so you can read it clearly while keeping your arm relaxed on the table. Trying to hold the gauge in your free hand while also squeezing the bulb and managing the valve is awkward and often leads to a jerky deflation rate.
What Your Numbers Mean
The 2025 guidelines from the American Heart Association and American College of Cardiology define four categories based on the numbers you get:
- Normal: below 120/80 mmHg
- Elevated: 120 to 129 systolic with diastolic still below 80
- Stage 1 hypertension: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic, or 90 or higher diastolic
If your systolic and diastolic numbers fall into two different categories, the higher category applies. For example, a reading of 132/76 counts as Stage 1 hypertension because the systolic number is in that range, even though the diastolic is normal. A single high reading doesn’t necessarily mean you have hypertension. Blood pressure fluctuates throughout the day, and a pattern across multiple readings on different days gives a much clearer picture than any one measurement.