Free Blood Sugar Log and HbA1c Estimator
Log your fasting and after-meal readings on your own phone, see 7, 14 and 30-day trends and an estimated HbA1c, and print a copy for your doctor. It is free, private and needs no account.
This tool is for education only. It is not a diagnosis or a treatment plan. Never stop or change a prescribed medicine without your doctor. Nothing you enter is stored or sent anywhere.
Printable weekly blood sugar log
Prefer paper? Print this page for a simple weekly table, or use the log above and choose Print or save as PDF for a copy with your own numbers.
| Day | Fasting | Before lunch | 2 h after lunch | Before dinner | 2 h after dinner | Bedtime | Notes |
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How and when to test
- Fasting: first thing in the morning, before food or drink other than water.
- After a meal: exactly 2 hours after you start eating.
- Wash and dry your hands first, and use a fresh strip that matches your meter.
- Test at the times your doctor suggests; more readings are not always better.
- Write down what you ate, whether you exercised or missed a medicine, so patterns are easy to spot.
How the estimated HbA1c is worked out
When your last 14 days hold at least 28 readings across at least 10 different days, the log averages them and applies the ADAG formula: estimated HbA1c = (average glucose in mg/dL + 46.7) ÷ 28.7. For example, an average of 154 mg/dL gives 7.0%.
This is an estimate from your readings, not a lab HbA1c. Finger-prick logs taken mostly fasting can read lower than your lab result, so use it to spot trends and always rely on your lab report.
Your data stays on your phone
Readings are saved only in this browser on your own device, in one entry named sk_log_v1. Nothing is sent to a server. Clearing your browser data deletes them, so export a CSV or print a copy from time to time.
Common questions
Log at least 28 readings over 10 days in two weeks. The log then averages them and applies the ADAG formula to show an estimate.
It is an estimate. Home readings are snapshots, and fasting-heavy logs often read lower than a lab HbA1c, which reflects about three months.
Many doctors suggest fasting 80 to 130 mg/dL and under 180 mg/dL two hours after a meal for adults with diabetes. Your doctor sets your own targets; you can change them in the log settings.
Only in your browser, on your device. We cannot see it, and clearing your browser data deletes it. Use Export CSV or Print for a backup.
Yes. Print or save as PDF for a table and chart, or export a CSV.