Peak Flow Log vs PRN Dose Timer
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Peak Flow Log
Record your peak flow readings and visualize your asthma zones. Log reliever puffs, symptoms, and triggers to track trends and generate PDF reports for your doctor. Your data stays private and works offline.
- Visualize asthma zones (Green, Yellow, Red)
- Log reliever puffs, symptoms, and triggers
- Track trends over time
- Create shareable PDF reports
- Offline functionality
- Multi-user support
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Peak Flow Log turns your daily peak-flow reading into a clear picture you and your doctor can act on. Blow into your own peak-flow meter, type in the number, and the app instantly shows your zone as a percentage of your personal best: - GREEN, YELLOW or RED at a glance, based on your own numbers - Log reliever (rescue) inhaler puffs, symptoms and triggers in one tap - See your trend over time with clear color-coded zone bands - Track more than one person, so parents can follow their child too - Create a clean PDF report to share at every appointment Built to be trustworthy: - Works fully offline. No account, no sign-in. - Your data stays on your device. Nothing is uploaded. - Export and import a backup so you never lose your history when changing phones. - One-time purchase to unlock Pro. No subscription. Free to log and see your zones. Pro unlocks the doctor PDF, unlimited profiles, full 90-day and all-time trends, and custom zone thresholds. Peak Flow Log records and visualizes readings you take with your own meter. It does not diagnose, treat, or provide medical advice, and it is not a medical device. Zones are based on a percentage of your personal best that you or your clinician set. Always follow the asthma action plan given by your doctor, and seek medical help in an emergency.
PRN Dose Timer
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When did I last take my pain reliever? When can I take it again? • Log a dose with a single "Taken" tap • Real-time countdown to your next dose • A notification when it's time for the next dose For anyone taking as-needed (PRN) medication — pain relievers, allergy medicine, etc. — who wants to avoid taking it too soon. This app does not diagnose or prescribe. Set your dose interval according to your doctor's or pharmacist's instructions. Free for 1 medication. A one-time ¥300 (or local equivalent) purchase unlocks managing multiple medications at once.
Screenshots
Verdict
The clearest difference is update cadence: PRN Dose Timer at every 3 days against Peak Flow Log's every 5 weeks. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Peak Flow Log sells 1 one-off in-app purchase and PRN Dose Timer sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
Peak Flow Log ships an update every 5 weeks, PRN Dose Timer every 3 days. Both last shipped on October 31, 2026.
| Parameter | Peak Flow Log | PRN Dose Timer |
|---|---|---|
| Price | Free | Free |
| Rating | 3.0 (1 ratings) — better | — |
| Positive reviews | 0.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 5 weeks | Every 3 days — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone | iPhone, iPad — better |
| Requires iOS | 17.0 | 17.0 |
| Further details — not scored | ||
| Size | 2 MB | 0 MB |
| Age rating | 4+ | 4+ |
| Developer | Yoshifumi Sato | keisuke haraguchi |
In-app purchases
Peak Flow Log
- Peak Flow Log Pro$3.99
PRN Dose Timer
- Unlock$1.99
