Read a Peak-Flow Log as Session Bests, Not Averages — Free
Three attempts in, one number out — but which one? Keep the largest attempt per session separate from the others before you compare sessions, and the log stays inspectable instead of collapsing into a guessed average.
The proof surface
Repeat-reading tools such as a thermometer spread check describe dispersion inside one session. This strip selects the best attempt per session first, then compares those bests, keeping the discarded attempts visible. It does not interpret lung function, adjust technique or replace an action plan.
InputSession code | first attempt L/min | second attempt L/min | third attempt L/min; session-best review mark (l/min)
Rare deviceRepeat-reading tools such as a thermometer spread check describe dispersion inside one session. This strip selects the best attempt per session first, then compares those bests, keeping the discarded attempts visible. It does not interpret lung function, adjust technique or replace an action plan.
Output artifactHighest session best with row-by-row context
Cost$0 local calculation · no card, paid key, subscription or signup · proposed filing price is not for sale
Sample, not your facts: Illustrative inputs: Mon | 380 | 400 | 390; Tue | 410 | 395 | 405. Session-best review mark (L/min) = 420. Highest session best: 410 L/min best. All records are invented.
Before using the peak-flow strip
Use readings from your own device and your own recording session; L/min values from different devices or units are not comparable rows. Enter every attempt you actually recorded, not a corrected or remembered value, and keep the order only if your own notes depend on it — the strip treats the three cells as an unordered set. A session means one sitting of attempts under the same conditions; attempts taken hours apart belong to different sessions. The review mark is your own threshold for looking at a row again; it is not a medical limit, a personal best target or a green/amber/red zone. Nothing here evaluates whether readings are medically reassuring or concerning.
Why the flat version breaks
Averaging attempts and calling it the reading
An average blends the attempt you are meant to keep with the ones you are meant to discard under a best-of convention. If your own instructions say something other than keep-the-best, follow your instructions and treat this strip as a sorting aid only. Either way, never present an average as though it were the best.
Comparing bests across different devices
Two devices can disagree systematically, and a unit you assume is L/min may be another scale. A rise that appears after switching devices may belong to the device. Keep one device per log, or label device changes in your private notes before drawing any conclusion from the numbers.
Reading a single session as a trend
One line is one observation. A good session does not establish control, and a poor one does not establish deterioration, because effort, posture, time of day and technique all move the number. The strip surfaces the arithmetic; only a qualified person with your history can weigh what it means.
How to work the peak-flow strip
Keep attempts together as one session
Record the attempts you took in one sitting on one line with an anonymous session code. If you change technique, posture or device between attempts, either start a new session code or keep a private note, because the strip assumes the three cells share conditions. It cannot recover a distinction you did not record.
Transcribe displayed values exactly
Type the plain L/min numbers as displayed, without units, commas or corrections. If your device shows fewer decimal places than you are tempted to add, keep the displayed precision. A missing attempt is a missing observation — leave the session out rather than repeating another number to fill the cell.
Compare session bests, not mixed quantities
The strip takes the largest of the three attempts for each session, then reports the highest session best. Do not substitute an average or a first attempt for the best in your own notes, because those answer different questions. Across sessions, a best can rise while most attempts fall; the row workings keep both facts visible.
Take the log, not the verdict, to the right person
Bring the dated sessions and your own questions to your clinician, asthma educator or the professional who owns your action plan. Ask how they would like best-of-session readings recorded and compared. A marked row is a reason to open a conversation, never a reason to change medicines or ignore symptoms on your own.
What the peak-flow strip separates
Question
Before
Inspect this instead
Averaging attempts and calling it the reading
An average blends the attempt you are meant to keep with the ones you are meant to discard under a best-of convention. If your own instructions say something other than keep-the-best, follow your instructions and treat this strip as a sorting aid only. Either way, never present an average as though it were the best.
Transcribe displayed values exactly
Comparing bests across different devices
Two devices can disagree systematically, and a unit you assume is L/min may be another scale. A rise that appears after switching devices may belong to the device. Keep one device per log, or label device changes in your private notes before drawing any conclusion from the numbers.
Compare session bests, not mixed quantities
Reading a single session as a trend
One line is one observation. A good session does not establish control, and a poor one does not establish deterioration, because effort, posture, time of day and technique all move the number. The strip surfaces the arithmetic; only a qualified person with your history can weigh what it means.
Take the log, not the verdict, to the right person
This peak-flow strip replaces a manual count or calculation, not source verification or the responsible person’s review.
Run it on the samples, right here
FIRST-LOAD
HYPOTHESIS / PROTOTYPE — checkout unavailable. Calculation is local. A draft is saved automatically in this browser profile when storage is available; Reset to sample clears it. Optional Pro history stores only five summaries and has its own deletion control. State links encode your inputs and can remain in browser history, clipboard or recipients’ records; share only non-sensitive rows. Optional external AI formatting leaves this device. The required site analytics beacon reports page activity; shared URLs contain encoded inputs. Do not treat an encoded URL as private. The calculator has no input-collection endpoint.
Observation sorting only, not diagnosis, monitoring advice or treatment. Follow your own written action plan and the instructions of the clinician or educator who provided the meter; seek appropriate care for concerning symptoms instead of relying on this log.
Data note: The peak-flow strip processes Session code | first attempt L/min | second attempt L/min | third attempt L/min locally. Starter/sample selection and Run compute in this tab; no input is sent by the calculator. A local draft may be saved; explicit state-link sharing or optional external AI formatting can disclose inputs. Use non-sensitive labels.
Go deeper: the companion app files the same reading as a paper ticker strip
The article demo above runs without limits. The companion app keeps a local history, exports the rows as CSV, prints the peak-flow strip reading, and holds your drafts on this device — one complete free app run; the proposed $4 one-time filing layer is not for sale.
The peak-flow strip answer stays complete for free. The proposed $4 one-time filing layer adds row CSV, print and five local reading summaries, not hidden answers. Checkout is unavailable; the article demo remains unlimited.
Observation sorting only, not diagnosis, monitoring advice or treatment. Follow your own written action plan and the instructions of the clinician or educator who provided the meter; seek appropriate care for concerning symptoms instead of relying on this log.
What this is built on
Method: The strip takes the largest of the three attempts for each session, then reports the highest session best. Do not substitute an average or a first attempt for the best in your own notes, because those answer different questions. Across sessions, a best can rise while most attempts fall; the row workings keep both facts visible.
All sample records, dates, quantities and labels are invented. No outside policy, contract, rate, clock offset, measurement or accessibility standard is represented as verified.
Google’s official pricing documentation, fetched 2026-10-01, says AI Studio is free in available regions. Optional formatting may require a Google account; manual local entry requires none. Limits can change and free-tier content may be used to improve products. Do not send private records.
Before: three attempts per session blurred into one vague number. After: each session keeps its best attempt, and session bests stay comparable.
Monday's three attempts give a session best of 400 L/min; Tuesday's give 410. The strip reports the highest session best, 410, and keeps each session's discarded attempts visible in the row workings. Neither session exceeds the supplied 420 L/min review mark, so nothing is flagged. Choosing the best before comparing sessions is a sorting convention you supplied, not a clinical rule, and the number says nothing about what caused it.
One session with attempts of 250, 245 and 250 gives a best of 250 L/min, which is also the summary because only one session was entered. The average of the three attempts would be about 248.3, a different quantity the strip deliberately does not report. A single session cannot show change between sessions, so treat this as one observation, not a trend.
Two equal highest attempts still give one session best of 330 L/min. Repeated identical displays may reflect the device rounding, so a tidy set is not evidence of precision. The boundary case checks that a best is selected when attempts tie, not that the readings were repeated correctly. Technique, posture and device instructions remain outside this log.
Optional AI formatting, never the calculation
Manual entry completes this peak-flow strip for free without signup. If available to you, the free AI Studio interface linked in the sources may format fictional or non-sensitive notes; external access may require an account. No API key or AI call is built into this tool. Free-tier content may be used to improve products. Review each cell and transcribe it to the labeled row schema; do not paste the JSON object into the row box.
Format only these fictional or non-sensitive notes for a peak-flow strip. Return strict JSON shaped as {"rows": [{"label": "string", "cells": ["string", "string", "string"]}], "setting": "string"}. The columns are Session code | first attempt L/min | second attempt L/min | third attempt L/min; the setting is Session-best review mark (L/min). Keep all supplied strings and quantities exactly; do not calculate, infer missing entries, invent dates or add advice. If any required value is missing, return an empty rows array and ask me for it separately. I will verify every cell against my source and manually transcribe rows using vertical bars before running the local calculator.
An AI response is not executed, fetched or trusted as a result. Missing values remain questions; the strict local parser checks the rows you actually enter.