Mercu
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A home blood pressure diary that turns a week of cuff readings into the average your doctor asks for.
Mercu is an iPhone diary for the readings you take with your own blood pressure cuff. Type systolic, diastolic and pulse in three taps or import them read-only from Apple Health, follow the 7-day home protocol doctors ask for, and share a PDF report. Mercu works offline, needs no account and does not measure blood pressure — your cuff does.
Download Mercu on the App Store
What Mercu does
- 7-day home protocolTwo readings every morning and evening for seven days. Mercu leaves out day 1, counts at most two readings per sitting and shows the final average once 12 readings are in.
- Fast entry for any cuffThree wheels for systolic, diastolic and pulse, plus arm, position and context like before meds or after coffee.
- Report for your doctorA PDF with the average, morning and evening averages, highest and lowest reading, a chart and every reading. CSV export too. Made on the iPhone and shared only by you.
- Apple Health, read-onlyBring in readings your Bluetooth cuff (Omron, Withings, Qardio) saves to Apple Health. Readings you also typed within two minutes are skipped, so nothing counts twice.
- AHA or ESC rangesEach reading shows its range on the ACC/AHA 2017 or ESC/ESH 2018 scale you choose, with the source named. No diagnosis.
- Morning and evening remindersLocal notifications at the times you pick. Nothing leaves your phone.
Guides
- How to Keep a Home Blood Pressure Log for Your Doctor on iPhone
Log cuff readings for a week and bring your doctor a clear PDF. - How to Average Home Blood Pressure Over 7 Days
The 7-day home protocol, the rule for day 1, and how Mercu calculates it. - Is There an iPhone App That Measures Blood Pressure? What Works Instead
Why phone cameras can't measure blood pressure, and how to track it properly. - How to Get Omron or Withings Readings From Apple Health Into a Doctor Report
Import Bluetooth cuff readings from Apple Health and share them as a PDF.
Price
Free: log readings, see the latest reading with its range and a 7-day chart. Mercu Plus — the 7-day protocol average, doctor PDF, CSV export, Apple Health import and 30/90-day charts — is $6.99 per month with a 3-day free trial, or $29.99 per year (US prices).
Frequently asked questions
Does Mercu measure blood pressure with the phone camera?
No. No iPhone app can measure blood pressure with the camera or a finger. Mercu records the numbers from your own cuff.
Which cuff should I use?
A validated upper-arm cuff is the most accurate; wrist cuffs work too. Any brand works with manual entry; Bluetooth cuffs that write to Apple Health can be imported.
Is my data uploaded?
No. Readings stay on your iPhone. Mercu has no account and no server; reports leave the phone only when you share them.
Can I use Mercu for a parent?
Yes. Choose 'for a parent or partner' at the start and put their name on the report in Settings.
Why is day 1 left out of the average?
Home monitoring protocols leave out the first day because readings are often higher at the start. You can include it in Settings.
How do I cancel?
Settings › Apple ID › Subscriptions › Mercu. Cancel at least 24 hours before renewal.
Free to download on the App Store.