How to Export Your FreeStyle Libre Data From LibreView as a CSV and Analyze It

To export FreeStyle Libre data from LibreView, sign in at libreview.com on a desktop browser, choose Download glucose data, complete the verification and save the CSV file. You can then drop that file onto the free CGM report at https://healthosx.com/glucose and get an AGP, time in range, GMI, variability, biggest rises and an overnight view in your browser, with no account and no upload.

How do I export my FreeStyle Libre data from LibreView as a CSV and analyze it?

Do this on a computer, not the phone app. Sign in at libreview.com with the account your FreeStyle Libre app uploads to. If you use LibreLink or Libre 3, the app normally syncs readings to LibreView automatically, so your data should already be there.

Look for Download glucose data in the main menu or under Reports. The exact place depends on your LibreView version and region. Complete the verification, choose a date range if the screen offers one, and save the file. It downloads as a .csv, usually with columns for device, timestamp, record type and glucose value in mg/dL or mmol/L.

The CSV may contain both scan glucose values and historic glucose values. The report tool only needs the timestamp and reading columns. LibreView keeps the units and date format from your account, so a mmol/L account exports mmol/L. The free report reads both units and common date styles.

Open https://healthosx.com/glucose on the same computer, drag the CSV onto the file area or select it. The file is read by your browser on your device. Nothing is uploaded. In a few seconds you get a set of glucose patterns.

What the report actually tells you

Before reading the output, hold two numbers. A CGM reads interstitial fluid, not blood, so it trails a finger-prick by roughly 5 to 15 minutes. And healthy adults without diabetes still spend about 3 hours a day above 140 mg/dL. A rise after a meal is not automatically a problem.

The report gives you:

• AGP (ambulatory glucose profile): all your days laid on one 24-hour clock. The middle line is your median. The darker band holds the middle half of your readings, the lighter band holds 90%. A narrow band means your days look similar at that hour; a wide band means they differ a lot.
• Time in range: the standard 70-180 mg/dL band was set by an international consensus for people with diabetes. For context, studies of adults without diabetes find most of the day inside a tighter 70-140 mg/dL band.
• GMI: 3.31 + 0.02392 x your average glucose in mg/dL. It estimates the A1C that usually matches that average. It is most reliable with 14 or more days of data and is not a lab A1C.
• Variability (CV): how spread out your readings are around your average. Lower is steadier.
• Biggest rises and overnight: the report marks your largest glucose excursions and flags short overnight dips that recover quickly, which are often compression lows from lying on the sensor.

The CSV gives you glucose patterns, not moment-to-moment truth. Use it for time in range and post-meal rises, not for insulin dosing or a single correction.

What the CSV cannot tell you

The LibreView CSV is a record of sensor readings. It does not contain your meals, workouts, stress or insulin doses unless you log them in the app and export a report that includes them. A glucose rise after a meal can come from the food, the meal's size, what you did before, or a sensor warmup. You will see the curve but not the cause.

The common mistake is to read one meal spike as a problem or one overnight dip as a real low. A single meal can push glucose above 140 mg/dL without disease. A compression low is not your glucose.

The sensor reads fluid under the skin, not blood. After a meal, blood glucose rises first and the interstitial reading follows by 5 to 15 minutes. So the exact peak time on the CSV may be a little late. The first day of a new sensor is usually the least reliable. Sleeping on the sensor can push tissue fluid away and create a fast, sharp drop called a compression low; it usually recovers as soon as you roll over. The report marks short overnight dips that recover quickly as possible compression, but it cannot prove the cause.

This analysis is for pattern finding and wellness, not diagnosis. If you have diabetes, your time-in-range goals, medication and insulin decisions need to come from your own care team, not from a CSV report.

What if my LibreView menu has no Download glucose data?

Use a desktop browser, or a mobile browser in desktop mode. The phone-sized view often hides it. If the option is missing or greyed out, check that your LibreLink or Libre 3 app is signed in and syncing to the same LibreView account. A new sensor or a long gap can also take a few minutes to appear. If you still cannot find it, look for a Download or Export option under a reports or data section; the label changes slightly between regions.

The CSV itself is just rows. Most analysis tools, including the free report at https://healthosx.com/glucose, only need a column with a time and a column with a glucose value. If you have a Dexcom Clarity, Stelo, Lingo or SiBionics export, or an Apple Health export that contains glucose, the same report reads those too.

What to do next

Drop the CSV into the free CGM report and read the AGP before you change anything. The file never leaves your device. If you do not have a sensor yet, HealthOS Sensor is a 30-day continuous glucose kit for $70 with the app, no membership, where shipping is available, at https://healthosx.com/glucose/sensor.