Blood pressure is written as two numbers separated by a forward slash: the top number (systolic) over the bottom number (diastolic), measured in millimeters of mercury. A reading of 120/80, spoken as “120 over 80,” means the pressure in your arteries is 120 mmHg when your heart beats and 80 mmHg when it rests between beats. That format is the same whether you’re jotting it on a sticky note or filling out a formal log for your doctor.
The Standard Format
Always write the systolic (higher) number first and the diastolic (lower) number second, with a slash between them. So if your monitor reads 134 on top and 82 on the bottom, you write 134/82. You can add “mmHg” after the numbers if you want to be precise, but most home logs leave it off since blood pressure is always measured in the same unit.
If your monitor also displays a pulse rate, write that separately. A typical entry might look like: 134/82, pulse 72. Keeping the blood pressure numbers and pulse distinct prevents any confusion when you or your doctor review the log later.
What Else to Record With Each Reading
The numbers alone are useful, but context makes them far more valuable. The American Heart Association’s log template and Stanford Medicine’s tracking sheet both include the same core columns: date, time of day, blood pressure, pulse, and a notes field. At minimum, record the date and time with every reading. Blood pressure naturally fluctuates throughout the day, so a reading of 128/78 at 7 a.m. tells a different story than the same number at 10 p.m.
The notes column is where you flag anything that might have affected the reading. Useful things to jot down:
- Which arm you used. Readings can differ between arms, and consistency matters for tracking trends.
- Whether you’d had caffeine, alcohol, or exercise within the previous 30 minutes. All three can temporarily raise your numbers.
- Medication timing. Note if you took the reading before or after your blood pressure medication, since the difference can be significant.
- Stress or unusual circumstances. A rough commute, a bad night of sleep, or a stressful phone call right before measuring is worth noting.
Setting Up a Simple Log
You don’t need a special app or printed form, though both exist. A notebook, spreadsheet, or even your phone’s notes app works fine as long as you keep the same columns each time. A basic table might look like this:
Date | Time | BP | Pulse | Notes
6/12 | 7:15 AM | 126/82 | 68 | Before meds, left arm
6/12 | 9:30 PM | 118/76 | 64 | Left arm, after walk
If you prefer a printed version, the American Heart Association offers a free downloadable PDF log. Many pharmacies also hand them out. Whatever format you choose, the key is sticking with it so you build a consistent record over time.
How Many Readings to Record
The American Heart Association recommends taking two readings in the morning before eating or taking medication, and two readings at bedtime. For each pair, sit quietly, take the first reading, wait a minute or two, then take the second. Write down both. Your doctor will typically look at the average rather than any single number.
If you’re tracking blood pressure for a specific reason, like adjusting medication or confirming a new diagnosis, a common clinical approach is to record twice-daily readings for seven consecutive days each month. Once your numbers are well controlled and stable, you can scale back. Research published in the Journal of Hypertension found that for people whose blood pressure is consistently below target, repeating a week of monitoring once every 12 months is reasonable. If your numbers sit closer to the treatment threshold, every six months is more appropriate.
Knowing What Your Numbers Mean
Writing down your blood pressure is more useful when you understand what you’re looking at. Under the most recent clinical guidelines, the categories break down like this:
- Below 120/70: Non-elevated. This is the range associated with the lowest cardiovascular risk.
- 120 to 139 systolic or 70 to 89 diastolic: Elevated. Not yet hypertension, but worth watching and a reason to keep logging.
- 140/90 or higher: Hypertension. Persistent readings at this level typically prompt treatment discussions.
When you review your log, look at the overall trend rather than fixating on any single reading. One high number after a stressful day is different from a pattern of high numbers across weeks.
Getting Accurate Numbers to Write Down
A perfectly kept log is only as good as the measurements going into it. The CDC recommends sitting in a comfortable chair with your back supported for at least five minutes before taking a reading. Both feet should be flat on the floor with your legs uncrossed. Rest the arm wearing the cuff on a table so it sits at chest height. Avoid smoking, caffeine, alcohol, and exercise for 30 minutes beforehand, and empty your bladder first.
These details matter more than people realize. Crossing your legs can add several points to both numbers. A full bladder can raise systolic pressure. Talking during the reading inflates results. If you know you skipped the rest period or had coffee 10 minutes before, note that in your log so you can interpret the reading in context.
Sharing Your Log With Your Doctor
Bring your log to every appointment, whether it’s on paper or your phone. Structured, consistent records let your doctor spot trends and make medication decisions with real data instead of relying on a single in-office reading, which can be artificially high from the stress of being in a clinic. If your log spans several weeks or months, it helps to calculate the average of your morning readings and evening readings separately. Most spreadsheet apps can do this automatically, but even a rough mental average gives your doctor a useful summary.
If you’ve been tracking virtually during telehealth visits, your home log becomes especially important. Research from a Canadian study found that blood pressure often goes undocumented during virtual appointments simply because there’s no in-office measurement being taken. Having your own written record fills that gap and keeps your care on track.