What should I look for in a blood sugar tracking app?

Disclosure up front: we make a free blood sugar tracking app, so we are not a neutral party and this page is not a ranking of competitors. What follows is the criteria we would apply to any of them, including ours — judge every app against it, ours included.

What actually matters

Logging has to be fast. If entering a reading takes more than a few seconds, you will stop doing it within a fortnight. This is the feature that determines whether an app is useful at all, and it is the hardest to judge from a screenshot.

Context tags. A number without context is close to useless. The ability to tag a reading as fasting, pre-meal or post-meal — and to note the meal, exercise, illness, stress or sleep alongside it — is what turns a column of figures into a pattern you can act on.

A clean export or report. Ten minutes with a clinician goes a lot further with a one-page summary than with a phone screen you scroll. Look for PDF or CSV export.

Averages and time in range, not just a list. Seven-, thirty- and ninety-day averages, and an estimated A1c, are what actually change decisions.

Both units. mg/dL and mmol/L, switchable.

A clear privacy policy you can find before installing. Health data is sensitive. Look specifically for whether data is shared with third parties or used for advertising.

Works offline, and does not force an account to see your own readings.

What matters less than the marketing suggests

AI insights and predictions. Usually pattern-matching presented confidently. Useful only insofar as the underlying log is complete.

Gamification and streaks. Pleasant for some, irrelevant to control.

Enormous food databases. Impressive, rarely used consistently. Most people log a small repertoire of meals.

Social feeds. A privacy surface with limited benefit.

The one genuine red flag

Be wary of any app offering insulin dosing recommendations unless it is a regulated medical device with clearance in your country. Dose calculation is a medical function, and getting it wrong causes hypoglycemia. A logbook is not the same as a dosing tool, and apps that blur the line are worth avoiding.

Similarly, no app can measure blood glucose through a phone camera or a fingerprint sensor. Anything claiming to is not doing what it says.

If you use a CGM

The app that ships with your sensor will usually beat a general logger for the glucose data itself. What a separate log can still add is context — meals, exercise, medication — and a combined view for appointments. Check whether an app you are considering imports from Dexcom, Libre or Apple Health before assuming it will.

The honest summary

Most tracking apps are broadly similar, and the differences that matter are speed of entry and whether the export is any good. Try one for two weeks; if you are still logging at the end of it, that is the right app for you.

And a log is only worth keeping if someone reads it. Bring it to your next appointment — a fortnight of readings with timings and context turns a vague description into something a clinician can act on.