Peak Flow Diary: Asthma Log

Your asthma nurse gave you a peak flow meter and an action plan with three numbers on it. Peak Flow Diary is where the readings go.

YOUR ZONES, NOT SOMEBODY ELSE'S
• Enter the personal best and the green and yellow thresholds from your own written action plan
• Every reading is shown against those numbers, as a percentage of your best
• Change your personal best after a review appointment and your whole history is re-banded against the new number — nothing is frozen at what it meant last year

Peak Flow Diary does not work out a "predicted" peak flow for you from your age and height. It has no opinion about what your reading should be. The numbers come from you and your clinician, and the app says so on the report.

A DIARY YOU WILL ACTUALLY KEEP
• Log a reading in a couple of taps: the number, and whether it was before or after your reliever
• Optional puffs taken, wheeze, cough, breathlessness and waking in the night
• A daily reminder so the diary is a trend and not a handful of readings taken on bad days
• Readings grouped by day, each with its colour, so a bad fortnight is visible at a glance

THE TREND, DRAWN PROPERLY
• 30 days, 90 days or a year
• Your own thresholds drawn on the chart as lines, so you can see where readings crossed them
• Morning and evening readings both plotted — the daily swing is a real signal, and averaging it away hides it

A REPORT YOU CAN HAND OVER
• Export a PDF or a CSV covering the last 90 days, and share it by email or messaging
• Every reading with its time, its percentage, its zone, whether it was after a reliever, and your notes
• The report states the personal best and thresholds it was measured against, and that you entered them — so whoever reads it knows exactly where the zones came from

FOR MORE THAN ONE PERSON Keep a separate diary per person, with their own best and their own thresholds. Useful if you are a parent tracking a child.

PRIVATE AND OFFLINE
• No account, no login, no cloud
• Your readings stay on your phone
• Nothing is uploaded and nothing is sold

FREE AND PREMIUM The diary itself is free forever: unlimited readings, unlimited zones, the chart and the reminders. Premium adds unlimited PDF and CSV exports, extra people, and removes the ads.

A RECORD, NOT A DIAGNOSIS Peak Flow Diary is a diary. It is not a medical device, it does not diagnose anything, and it does not tell you what to do. It shows the readings you entered against the thresholds you entered.

If you are struggling to breathe, if your reliever is not helping, or if a reading has dropped into your red zone, follow your action plan and get medical help. Do not wait to log it here first.

Blow. Write it down. Take it to your appointment.

Recent changes:
• Premium prices load reliably. If the store can’t be reached, the Premium screen now says so instead of loading forever
• Easier to read in dark mode
• Editing a reading no longer moves or duplicates it
• The medical disclaimer can be reopened from Settings
• Dates are shown in your language’s format
• Ads wait for your privacy choice before loading