How to Take Blood Pressure Manually
By the BP Monitor Lab editorial team · Written from manufacturer documentation and published guidance, not from our own device testing · Updated: October 5, 2026
Manual measurement is the method every automatic monitor is judged against, and it depends on the skill of the person doing it. Both of those things are true at once, and the reason is the same: the accuracy lives in the operator.
What this page is. An explanation of how the auscultatory method works and where it goes wrong, written for people who want to understand it. It is not a training course, and reading it will not make you competent to measure blood pressure for clinical decisions. If you are monitoring your own blood pressure at home, the right tool is a validated automatic monitor, not a stethoscope.
What the Auscultatory Method Actually Is
A cuff is inflated around the upper arm until it squeezes the brachial artery shut and blood stops flowing through it. The pressure is then let down slowly. As soon as the cuff pressure drops just below the peak pressure in the artery, blood starts jetting through the narrowed vessel in bursts, and those bursts make a sound you can hear with a stethoscope placed over the artery.
The pressure on the gauge when those sounds first appear is the systolic reading. Keep letting the pressure down and the artery stays open for more of each heartbeat, until eventually it never fully closes and the sound stops. The pressure when the sound disappears is the diastolic reading. That is the whole idea. Everything else is care.
Korotkoff Sounds, in Five Phases
The sounds are named after Nikolai Korotkoff, who described them in 1905, and they are conventionally split into five phases. Only two of them are recorded.
| Phase | What you hear | What it marks |
|---|---|---|
| I | The first clear tapping sounds appear | Systolic pressure |
| II | A softer, swishing quality | Nothing recorded |
| III | Crisper and louder tapping returns | Nothing recorded |
| IV | The sound suddenly becomes muffled | Nothing recorded |
| V | Sound disappears completely | Diastolic pressure in adults |
Phases II, III and IV exist to be listened through, not written down.
The Equipment
- • A sphygmomanometer. The cuff plus a pressure gauge. Mercury columns were the old standard and have largely been retired on environmental grounds, so aneroid dial gauges are what most people meet now.
- • A stethoscope. The bell or the diaphragm sits over the brachial artery, below the lower edge of the cuff and not underneath it.
- • A cuff that fits. The sizing rules are identical to the automatic case, and a cuff that is too small reads high whether a machine or a person is reading it. See cuff sizing.
- • A calibration check. Aneroid gauges drift. The American Heart Association's 2019 statement says they need calibrating every 2 to 4 weeks if handheld, and every 6 months if wall-mounted.
How It Is Done
The preparation is the same as for any reading: five minutes seated and quiet, back supported, feet flat, arm bare and supported at heart height. Our technique guide covers that part in full, and none of it becomes optional because a person is holding the gauge.
- 1. Find the pulse first. Feel the radial pulse at the wrist, inflate until it disappears, and note that pressure. This is the palpated estimate.
- 2. Inflate 20 to 30 mmHg above that. That is the range the American Heart Association's 2019 statement gives.
- 3. Place the stethoscope over the brachial artery, in the crook of the elbow, below the cuff rather than tucked under it.
- 4. Deflate at 2 mmHg per second. Slower than feels natural. The statement says a rate faster than 2 to 3 mmHg per second makes the sounds hard to place.
- 5. Record phase I and phase V to the nearest even number, without rounding to the nearest five or ten.
- 6. Wait 1 to 2 minutes before repeating. That is the gap the statement asks for between readings.
Where Manual Measurement Goes Wrong
These are limits of the method named in the AHA's 2019 statement on measuring blood pressure.
- • Deflating too fast. Faster than 2 to 3 mmHg per second, the sounds become hard to place.
- • Terminal digit preference. People round to a favourite digit, such as a zero or a five, without noticing.
- • Hearing. The observer has to be able to hear the sounds. The statement lists hearing as part of observer training.
- • Expectation. The statement calls this observer bias, and says it matters most when readings are taken by hand.
- • An uncalibrated gauge. Aneroid dials lose calibration, especially when handled roughly.
Why Validation Studies Still Use It
If manual measurement is this error-prone, it is fair to ask why it is the reference. The answer is that the errors above are operator errors, not method errors, and a validation study controls for them with trained observers and calibrated equipment. A stethoscope and a mercury column were the reference standard for office blood pressure for decades. That is what an automatic monitor is measured against when it is tested to ISO 81060-2, which asks for a mean difference within 5 mmHg and a standard deviation of no more than 8 mmHg. None of those controls exist on a kitchen table.
So Should You Learn It?
If you are monitoring your own blood pressure, no. A validated automatic monitor removes the hearing, the timing and the reading judgement in one go, and the guidance that asks for home measurement assumes exactly that kind of device.
It is worth learning if you are being taught it as part of clinical training, if a clinician has specifically asked you to use one, or simply because you want to understand what the machine on your table is imitating. That last reason is a good one, and it is most of why this page exists. For a side-by-side of the two approaches, see manual versus digital monitors.
Where this comes from
Guideline and evidence last checked: 2026-10-05. We publish what these sources say. Where they decline to give a rule, we say that instead of inventing one.
- •Measurement of Blood Pressure in Humans: A Scientific Statement From the American Heart Association (2019), American Heart Association, 2019-03-04
- •Home Blood Pressure Monitoring, American Heart Association
Frequently Asked Questions
How do you take blood pressure manually?
You inflate a cuff above the point where the brachial pulse disappears, then let the pressure down slowly while listening over the artery with a stethoscope. The pressure at which tapping sounds first appear is the systolic reading. The pressure at which they disappear is the diastolic reading. This is called the auscultatory method, and doing it accurately takes training and practice.
What are Korotkoff sounds?
They are the sounds heard through a stethoscope over the brachial artery as a blood pressure cuff deflates, named after Nikolai Korotkoff. They are described in five phases. Phase I is the first appearance of clear tapping, which marks systolic pressure. Phase V is the point where the sounds disappear, which marks diastolic pressure in adults.
Is manual blood pressure more accurate than an automatic monitor?
In trained hands under good conditions it is the reference method, which is why validation studies compare automatic monitors against it. It takes training: the observer has to let the cuff down, listen and read the gauge at the same time. For home use the American Heart Association recommends an automatic upper arm monitor.
How fast should you deflate the cuff?
Slowly, at 2 mmHg per second. The American Heart Association's 2019 statement says a rate faster than 2 to 3 mmHg per second makes it hard to place the sounds.
What equipment do you need to take blood pressure manually?
A sphygmomanometer, which is the cuff with a pressure gauge, and a stethoscope. Aneroid gauges are the common type now that mercury devices have largely been retired for environmental reasons. Aneroid gauges drift over time and need periodic calibration checks against a known reference.
Should I buy a manual blood pressure kit for home use?
For almost everybody monitoring their own blood pressure at home, no. A validated automatic upper arm monitor gives more reliable numbers with far less that can go wrong, and it removes the hearing and timing judgements that make manual measurement hard. Manual kits make sense if you are being trained to use one, or a clinician has asked you to.
Why do some readings end in a zero?
That is terminal digit preference, and it is a well-documented bias in manual measurement. People unconsciously round to the nearest zero or five when reading a dial, which clusters recorded readings on round numbers. It is one of the reasons automatic devices are preferred in research and increasingly in clinics.