Stay in range.Every single day.
Coagly is the free warfarin and INR tracker for iPhone and Android. It logs your results, reminds you of the exact dose you are due today, and shows you the one number your clinic actually judges control by — your time in therapeutic range.
Informational only — never change a dose on the basis of this. Want your time in range too? It is free as well.
Built around the two things that actually matter
Never missing a dose, and never missing a blood draw. Everything else is interpretation — and interpretation is worth nothing if the safety net has a hole in it.
Log every INR result
Enter a reading in seconds and see it labelled against your own target range — in colour and in words, never colour alone. Only have a PT in seconds? Coagly converts it.
Reminders that name your dose
Warfarin is not one pill a day. Your reminder carries the exact amount due today and rewrites itself the moment your prescription changes.
Never miss a blood draw
Appointment reminders for your next INR test, so the interval your clinic agreed is the interval you actually keep.
Time in therapeutic range
The measure your clinic judges control by, calculated with the Rosendaal method and updated as you log.
Home screen widgets
Today's dose, your next test and your last five weeks of adherence — one tap from the home screen.
Full history, CSV export
Every entry back to your first, exportable for your appointment. Free for everyone, not a Pro feature.
Import from another app
Already tracking elsewhere? Bring your INR and dose history in from CSV so you are not starting from zero.
Your data stays yours
Your history is on your device and exportable at any time. No account required to track your own health.
See it before you install it
Every reading labelled in plain language. Every reminder carrying the right number.
Four minutes to set up. Then it stays out of your way.
Set your target range
Tell Coagly the range your prescriber gave you — 2.0 to 3.0, 2.5 to 3.5, or whatever is on your record. Every reading is judged against it from then on.
Enter your weekly schedule
Warfarin doses often differ by weekday. Enter yours once and Coagly builds your reminders and your dose history around it.
Log results and doses
Mark a dose taken from the home screen. Log an INR result when it arrives, with a note about anything that changed.
See what your clinic sees
Your trend, your adherence and your time in therapeutic range update automatically. Export the lot as CSV for your appointment.
Work out your time in range right now — no download
The same calculations Coagly runs on your phone, free in your browser. Nothing is uploaded; everything happens on your own device.
TTR calculator
Enter your past INR results and get your time in therapeutic range, calculated with the Rosendaal linear interpolation method clinics use — plus a chart of your readings against your target band.
Open the calculator →PT to INR converter
Got a prothrombin time in seconds instead of an INR? Enter it with your lab's normal mean and ISI and get the INR, checked against your target range.
Convert a PT →INR test planner
Work out when your next blood draw is due from your testing interval, and download a calendar file with a reminder already attached.
Plan your next test →The safety net is free. Permanently.
Most INR apps make you pay to log a dose or set a reminder. Coagly does not, and will not.
Free forever
- Dose tracking and weekly schedules
- Daily dose reminders naming your current dose
- Appointment reminders for your next INR test
- Every INR reading, logged and charted
- Time in therapeutic range and adherence
- Home screen widgets
- Full history back to your first entry
- CSV export and CSV import
Coagly Pro
An optional subscription for people who want to go deeper into their own numbers.
- Built-in INR dose calculator
- Deeper trend and variability insights
Interpretation tools — never your basic safety net. Your reminders, your history and your export are never behind the paywall.
Straight answers to the questions warfarin actually raises
Written for patients, not for clinicians. Each one ends with how to handle it day to day.
Normal INR range chart
A clear INR range chart: what a normal INR is without warfarin, target ranges on warfarin by condition, and what your…
Read the guide →Time in therapeutic range
What time in therapeutic range means, what a good TTR score is, and how the Rosendaal method works — with a free TTR…
Read the guide →Missed a warfarin dose
What to do if you miss a warfarin dose: the 12-hour rule, why you must never double up, how it affects your INR, and…
Read the guide →INR too high
What a high INR means, the bleeding symptoms that matter, when a reading needs a same-day call, and the common causes…
Read the guide →INR too low
What a low INR means, why it rarely causes symptoms, the most common causes of an INR below range, and what your…
Read the guide →Warfarin foods & vitamin K
Which foods affect warfarin, a practical vitamin K food list, and why keeping your intake steady works better than…
Read the guide →PT to INR conversion
How to convert prothrombin time in seconds to INR, the ISI formula explained, why labs differ, and a free converter…
Read the guide →How often to test INR
How often INR should be tested when starting warfarin, once stable, and after a dose change — and why testing more…
Read the guide →Warfarin & antibiotics
Why antibiotics raise INR on warfarin, which ones interact most, how soon to retest, and what to tell the doctor…
Read the guide →Weekly dose schedule
Why warfarin doses differ from day to day, how alternating schedules and half tablets work, and how to keep track…
Read the guide →Alcohol & warfarin
How alcohol affects INR on warfarin, why binge drinking is the real risk, what moderate means, and how to drink…
Read the guide →INR self-testing at home
How home INR testing works, what a CoaguChek meter costs, how accurate self-testing is, and why self-testers spend…
Read the guide →INR history for your doctor
What to record alongside every INR result, how to present your history at an appointment, and how to export a…
Read the guide →Frequently asked questions
Is Coagly free?
Yes. Coagly is free to download, and dose tracking, your daily dose reminder, appointment reminders for your next INR test, your full history and CSV export are free forever. Coagly Pro is an optional subscription that adds an INR dose calculator and deeper trend insights — interpretation tools, never your basic safety net. Missing a dose because a reminder sat behind a paywall is a real risk, not a place to upsell you.
What is a normal INR range?
There is no single normal INR. Without an anticoagulant it sits around 0.8 to 1.2. On warfarin, the usual target is 2.0 to 3.0 for atrial fibrillation, DVT and pulmonary embolism, and 2.5 to 3.5 for most mechanical heart valves. Your own range is set by your prescriber, and every reading should be judged against it.
What is time in therapeutic range, and what is a good score?
Time in therapeutic range (TTR) is the share of your days — not your tests — spent inside your target range. It predicts outcomes far better than any single reading. Above 70% is generally regarded as good control, 65% is the common quality benchmark, and below 60% is treated as poor control. Coagly calculates yours automatically using the Rosendaal method clinics use.
What should I do if I miss a dose of warfarin?
If you remember within about 12 hours of your usual time on the same day, take it and carry on normally. If more time has passed, skip it and take only your normal dose today. Never double up to catch up. If you have missed two or more days, contact your anticoagulation clinic. Always record the date — your clinic will want it.
My INR is too high — how worried should I be?
Above your range means a raised bleeding risk, though most people feel nothing at all. Readings of 5.0 or above warrant contacting your clinic the same day even without symptoms, and any head injury needs assessment regardless of your number. Antibiotics, illness, alcohol and eating less vitamin K than usual are the most common causes of a spike.
Which foods should I avoid on warfarin?
Fewer than most people expect. Warfarin needs a steady vitamin K intake rather than a low one, so cutting greens out entirely tends to make control worse rather than better. The bigger problem is swinging — weeks of salads followed by weeks without. Large or regular amounts of cranberry juice and supplements such as St John’s wort are worth avoiding.
Does my warfarin dose change from day to day?
Often, yes, and it is entirely normal. The weekly total you need rarely divides evenly into available tablet strengths, so clinics build a weekly pattern — 5 mg some days, 2.5 mg others. It is also the biggest source of dosing errors, which is why Coagly's reminder names today's actual amount and rewrites itself the moment your prescription changes.
Can I convert a PT in seconds to an INR?
Yes. INR = (patient PT ÷ your lab's normal mean PT) raised to the power of the reagent's ISI. Both the normal mean and the ISI belong to the lab that ran your test and are usually printed on the report. Coagly will do the conversion when you log a result, and there is a free converter on this site.
How often should I get my INR tested?
Every 2 to 4 days when starting warfarin, then weekly to fortnightly while stabilising, and typically every 4 weeks once stable — sometimes stretched to 8 or 12 weeks with a long track record. Testing more often reliably improves time in range: roughly 50 to 60% of patients stay in range with monthly testing versus 77 to 85% with weekly testing.
Can I get my data out of Coagly?
Yes, and it is free. Your complete history exports as CSV reaching back to your very first entry — readings, target ranges, notes and dose history. You can also import existing history from another app by CSV, so you are not starting from zero. A record you cannot get out is not a record.
Is Coagly available on Android?
Yes. Coagly is on Google Play for Android and on the App Store for iPhone and iPad, in English and Spanish. The iOS version requires iOS 16.4 or later. The free web tools on this site — the TTR calculator, PT to INR converter and test planner — also work in any browser on any device, with no install at all.
Does Coagly tell me what dose to take?
No, and deliberately so. Coagly is a tracking and organisation tool. It records what you were prescribed, reminds you of it and shows you your trends, but dosing decisions belong to your prescriber and your anticoagulation clinic. Never change a warfarin dose on the basis of an app.
DownloadGet Coagly free
Dose tracking, daily reminders and appointment reminders are free forever. Because missing a dose over a paywall is a real risk, not a place to upsell you.
iPhone, iPad and Android · iOS 16.4 or later · English and Español · Free with an optional Coagly Pro subscription