## Home Blood Pressure Average Calculator (NICE 7-Day Method) URL: https://www.cardilogai.com/guides/home-blood-pressure-average-calculator Author: The CardiLog Team · Published: 2026-10-17 · Updated: 2026-10-17 Doctors judge home blood pressure by the average of a week of readings, not by one number. This home blood pressure average calculator follows the method NICE sets out for diagnosis: two readings morning and evening for up to 7 days, with the first day left out. ### Short answer Take 2 readings a minute apart, morning and evening, for at least 4 days and ideally 7. Leave out the first day, then average the rest, systolic and diastolic separately. NICE and the 2024 ESC guideline both treat a home average of 135/85 or higher as hypertension. ### How to collect the readings NICE (the UK's guideline body) sets out a specific routine for home monitoring when it's used to confirm high blood pressure: - Each time you measure, sit down and take 2 readings at least 1 minute apart. - Measure twice a day, ideally in the morning and the evening. - Keep going for at least 4 days, ideally 7. - Leave out the first day's readings and average all the rest. The 2024 European (ESC) guideline is close but not identical: 2 readings 1–2 minutes apart, morning and evening, for at least 3 days and up to 7, with all readings averaged. It doesn't ask you to leave out the first day. The calculator lets you choose either way. If your doctor has given you a schedule, use theirs. For the routine itself (how to sit, cuff position, what to avoid beforehand), see our guide to [taking an accurate measurement at home](https://www.cardilogai.com/guides/how-to-take-accurate-blood-pressure-measurements). ### How the average is worked out The maths is plain arithmetic, done separately for each number: - Add up all the systolic (top) readings you're keeping and divide by how many there are. - Do the same for the diastolic (bottom) readings. - Write the result as systolic/diastolic, rounded to whole numbers. A full NICE week gives 28 readings (2 per session, 2 sessions a day, 7 days). With the first day left out, 24 go into the average. Missing the odd session is fine; the average is still taken over the readings you have. Don't average away a reading that worried you. If any single reading is 180/120 or higher, deal with that reading first (see below). ### What the thresholds mean for a home average Home thresholds sit below clinic ones because readings at home tend to be lower. NICE says home averages correspond to clinic readings 5 mmHg lower. How the main guidelines read a home average: - NICE: 135/85 to 149/94 is stage 1 hypertension; 150/95 or higher is stage 2. - ESC 2024: 135/85 or higher is hypertension; 120 to 134 systolic or 70 to 84 diastolic is elevated; under 120/70 is non-elevated. - ACC/AHA 2017 (US): its table of matching values puts 130/80 at home level with stage 1 (130/80 in clinic), and 135/85 at home level with 140/90 in clinic. Either number can cross a threshold on its own. A home average of 128/86, for example, is in the NICE stage 1 range because of the diastolic. These labels are how guidelines describe readings; your doctor decides what they mean for you, alongside the rest of your health. ### Single high readings still matter An average is the right tool for a diagnosis, but it can hide one dangerous number. If a reading is 180/120 or higher, wait a minute and measure again. If it's still that high, contact your doctor. If you also have chest pain, shortness of breath, weakness, vision changes or trouble speaking, call emergency services. The calculator flags any reading at that level as soon as you type it, whatever the average says. ### Keeping a running average in CardiLog A week of numbers on paper is fine for one diagnosis. If you're tracking for longer, the CardiLog app works out averages for you and charts them over 7, 30 and 90 days, so you can see whether the average is drifting. Its PDF report includes your readings and averages for your doctor. Tagging each reading Home or Clinic lets CardiLog compare the two: with at least 5 home and 3 clinic readings, it flags a clinic average 10 mmHg or more above your home one, which is the pattern described on our [white coat syndrome](https://www.cardilogai.com/use-cases/white-coat-syndrome) page. ### What makes a home average count - Two readings, a minute apart: One reading can be off for many reasons. Two seated readings at least a minute apart smooth out some of that, and both go into the average. - Morning and evening: Blood pressure moves through the day. Measuring at both ends of it gives a fairer picture than measuring whenever you remember. - Several days, not one: NICE asks for at least 4 days and ideally 7. ESC 2024 asks for at least 3, and up to 7 if the result is close to a threshold. - The right threshold for home numbers: Home readings run lower than clinic readings, so home thresholds are lower too: 135/85 at home lines up with 140/90 in a clinic. ### FAQ #### How many readings do I need for a reliable home average? NICE asks for 2 readings morning and evening for at least 4 days, ideally 7, then leaves out the first day. A full week gives 24 readings to average. ESC 2024 accepts 3 days as a minimum and asks for up to 7 when the average is near a threshold. #### Should I leave out the first day of readings? NICE says to. The 2024 ESC guideline averages all the days instead. The calculator leaves day one out by default and lets you include it, so you can match whichever method your doctor uses. #### What is a normal home blood pressure average? Under 135/85 is below the home threshold for hypertension in both NICE and ESC 2024. The US ACC/AHA table treats under 120/80 at home as the equivalent of normal. Your doctor may set a personal target. #### Does the calculator save or send my readings? No. The average is worked out in your browser as you type, and nothing is sent anywhere or stored. Reloading the page clears it. #### Can the CardiLog app work out my average for me? Yes. CardiLog averages your logged readings, charts them over 7, 30 and 90 days, and includes averages in the PDF report you can share with your doctor. ### Sources - [NICE NG136: Hypertension in adults, recommendations (1.2.7) and terms used](https://www.nice.org.uk/guidance/ng136/chapter/Recommendations) - [McEvoy JW et al. 2024 ESC Guidelines for the management of elevated blood pressure and hypertension. Eur Heart J 2024;45:3912 (Table 5)](https://academic.oup.com/eurheartj/article/45/38/3912/7741010) - [Corresponding clinic, home and ambulatory values from the 2017 ACC/AHA guideline (Hypertension 2019, table 2)](https://pmc.ncbi.nlm.nih.gov/articles/PMC6392041/table/T2) - [American Heart Association: Monitoring your blood pressure at home](https://www.heart.org/en/health-topics/high-blood-pressure/understanding-blood-pressure-readings/monitoring-your-blood-pressure-at-home) - [CDC: Measuring Your Blood Pressure](https://www.cdc.gov/high-blood-pressure/measure/index.html)