Printable Blood Sugar Chart & Log Sheet (Free PDF and Excel)

A blood sugar log helps you and your diabetes team see patterns that one isolated reading cannot show. The most useful record includes not only the glucose number, but also the time, relationship to food, medicine or insulin, activity, symptoms, and unusual circumstances such as illness or poor sleep.

What Should You Record in a Blood Sugar Log?

The glucose number is important, but its context often explains why it changed. A useful log may include:

• date and time;
• glucose value and unit—mg/dL or mmol/L;
• timing—fasting, before a meal, one or two hours after the first bite, bedtime, overnight, before exercise, or when symptoms occur;
• food and carbohydrate—especially unusual meals or portions;
• insulin or medication—name, dose, and timing when relevant;
• activity—type, duration, and intensity;
• symptoms—shaking, sweating, dizziness, thirst, frequent urination, nausea, or blurred vision;
• ketones during illness, persistent high glucose, or according to your sick-day plan;
• other factors—illness, infection, stress, alcohol, menstruation, poor sleep, steroid medicine, travel, or missed doses.

When Should Blood Sugar Be Checked?

The correct schedule depends on diabetes type, medicine, pregnancy, illness, hypoglycemia risk, and whether you use a continuous glucose monitor. Your healthcare professional should tell you when and how often to check.

Common times include:

• when you first wake up, before eating or drinking calories;
• before meals;
• one to two hours after the beginning of a meal;
• at bedtime;
• before driving when hypoglycemia is a concern;
• before, during, or after exercise when appropriate;
• when you have symptoms of high or low glucose;
• during illness or after a medication change;
• after treating low blood sugar, according to your plan.

People using multiple daily insulin injections, pumps, pregnancy glucose plans, or medicines that can cause hypoglycemia often need more frequent monitoring. Other people may use a short structured testing period to answer a specific question rather than testing at every possible time indefinitely.

Common Blood Sugar Targets for Many Adults

For many nonpregnant adults with diabetes, commonly used general treatment goals are:

Common Blood Sugar Targets for Many Adults

For many nonpregnant adults with diabetes, commonly used general treatment goals are:

Important: These are general treatment goals, not universal requirements. Individual targets may differ during pregnancy, in children and older adults, or in people with recurrent hypoglycemia, kidney disease, or other medical conditions.

For more detailed guidance, see our Blood Sugar Levels by Time of Day guide.

These are general treatment goals, not universal requirements. Your targets may be different if you are pregnant, a child or teenager, an older adult, have limited life expectancy, kidney or heart disease, recurrent hypoglycemia, impaired awareness, or another safety concern.

Use the blood sugar levels by time of day guide for fuller interpretation.

Normal Ranges and Diabetes Targets Are Not the Same

There is no single blood sugar range that applies to everyone throughout the day. Glucose values must be interpreted according to when they were measured and whether they are being used for diabetes diagnosis, treatment monitoring, or continuous glucose monitoring (CGM). Diagnostic thresholds and treatment targets serve different purposes and should not be used interchangeably.

Do not use a treatment target to diagnose diabetes, and do not use a diagnostic range as an insulin-dosing instruction.

How to Use the Printable Chart

1. Write your personal targets first. Include pre-meal, after-meal, bedtime, and low-glucose thresholds.
2. Use one unit consistently. Record mg/dL or mmol/L and label the unit clearly.
3. Record the timing precisely. “After lunch” is less useful than “2 hours after first bite.”
4. Add treatment information. Include insulin dose, medicine, missed dose, or timing changes.
5. Add only useful meal detail. Note carbohydrate amount, unusually large portions, alcohol, or unfamiliar food.
6. Record symptoms and treatment of lows. Include glucose used and the recheck result.
7. Review at the end of the week. Circle repeated patterns rather than reacting to one isolated value.
8. Bring the log to appointments. Do not change insulin or medicine from the chart alone unless you already have a written adjustment plan.

How to Find Useful Glucose Patterns

Look for the same problem at the same time on several days:

• High fasting readings: consider evening food, missed medicine, overnight glucose, dawn phenomenon, sleep, illness, or insufficient basal insulin.
• High after breakfast: review carbohydrate amount, morning insulin resistance, and medicine or insulin timing.
• Repeated lows before lunch: review breakfast insulin, morning activity, meal size, and timing.
• Late highs after a high-fat meal: fat and protein may delay absorption for several hours.
• Exercise-related lows: lows can occur during activity or later, including overnight.
• Unexpected changes during illness: infection, dehydration, appetite changes, and stress hormones can alter glucose.

Repeated patterns are more useful than isolated readings. Use the blood sugar log sheet guide for additional examples.

Finger-Stick Meter Readings vs. CGM Readings

Finger-Stick Meter Readings vs. CGM Readings

A blood glucose meter measures glucose in a drop of capillary blood. A continuous glucose monitor (CGM) estimates glucose in interstitial fluid and provides trends throughout the day and night.

Meter and CGM readings may differ when:

• Glucose is changing rapidly.
• The sensor is newly inserted or under pressure.
• Meter strips are expired, damaged, or poorly stored.
• Hands are not clean and dry before testing.
• Either device is outside its expected accuracy range.

Confirm a CGM reading with a finger-stick meter when symptoms do not match the sensor reading, the device instructs you to check, or you suspect the sensor is inaccurate. Record whether a value came from a meter or CGM when that distinction matters.

What Is a Good CGM Time in Range?

Time in Range (TIR) is the percentage of time your CGM glucose readings stay within a specified target range. For many nonpregnant adults with type 1 or type 2 diabetes, the commonly recommended CGM target range is 70–180 mg/dL (3.9–10.0 mmol/L).

A common treatment goal is to spend more than 70% of the time within this range, equivalent to approximately 17 hours per day.

However, time-in-range goals should be individualized. Older adults with complex health conditions, people experiencing frequent hypoglycemia, pregnant individuals, and others with specific medical needs may require different glucose ranges or targets.

Important: Time in Range should not be evaluated alone. Time spent below 70 mg/dL, particularly below 54 mg/dL, is also important for assessing treatment safety. Review CGM trends with your diabetes care team rather than changing insulin doses based on the percentage alone.

For additional information about glucose targets throughout the day, see Blood Sugar Levels by Time of Day.

What Should You Record During Low Blood Sugar?

What Should You Record During Low Blood Sugar?

Blood glucose below 70 mg/dL (3.9 mmol/L) is a low-glucose alert level that generally requires prompt action. Glucose below 54 mg/dL (3.0 mmol/L) is considered clinically significant hypoglycemia and requires immediate treatment.

How Should You Treat Low Blood Sugar?

If you are awake, able to swallow safely, and your blood glucose is low, follow your individualized hypoglycemia treatment plan. For many adults, the following approach is appropriate:

1. Take approximately 15 grams of fast-acting carbohydrate, such as glucose tablets, glucose gel, or about 120 mL (4 ounces) of regular juice.
2. Wait 15 minutes, then check your blood glucose again.
3. If glucose remains below 70 mg/dL, repeat treatment and recheck after another 15 minutes.
4. Once glucose has recovered, follow your diabetes care plan. If your next meal is not soon, a snack may help prevent another low, particularly when insulin or certain diabetes medicines remain active.

Important: The amount of carbohydrate needed may differ depending on your treatment, especially if you use an automated insulin delivery system. Follow the instructions provided by your diabetes team.

What Information Should You Record?

After treating the low glucose episode, document:

• The glucose reading and time of the episode.
• Symptoms such as sweating, shaking, dizziness, or confusion.
• Possible causes, including delayed meals, insulin, physical activity, or alcohol.
• The carbohydrate treatment used and approximate amount.
• The glucose recheck result and time.
• Whether assistance from another person or glucagon was required.

Severe hypoglycemia: A person experiencing severe confusion, seizures, unconsciousness, or an inability to swallow safely requires emergency assistance. Give glucagon if available and call emergency services. Never give food or drink by mouth to someone who cannot swallow safely. Severe hypoglycemia is defined by the need for assistance from another person, not solely by a particular glucose reading.

Repeated hypoglycemia episodes require a review of your diabetes treatment plan with your healthcare professional. For additional guidance, see Is My Blood Sugar Too High or Too Low?.

High Blood Sugar, Ketones, and Sick Days

High blood glucose (hyperglycemia) should be interpreted according to the glucose level, timing, symptoms, diabetes treatment, and whether the reading is improving or rising. A single elevated reading does not always indicate an emergency, but persistent hyperglycemia or symptoms of illness may require prompt medical attention.

When Should You Contact Your Diabetes Care Team?

Follow your individualized sick-day plan and contact your diabetes care team when:

• Blood glucose remains above your personal target despite following your prescribed correction or treatment plan.
• Readings are repeatedly high or continue rising, particularly during illness.
• Blood glucose is around 250 mg/dL (13.9 mmol/L) or higher during illness, especially if you use insulin, and you need guidance about ketone testing or treatment.
• You detect ketones and are unsure how to interpret or manage the result.
• You have difficulty maintaining your usual food or fluid intake or are uncertain how to manage diabetes medication during illness.

People with type 1 diabetes, insulin deficiency, or a history of diabetic ketoacidosis may need earlier ketone testing and more urgent medical advice. Follow your personal sick-day instructions rather than waiting for a specific glucose threshold.

When Is High Blood Sugar a Medical Emergency?

Seek immediate emergency medical evaluation if you develop symptoms suggesting diabetic ketoacidosis (DKA) or another serious hyperglycemic emergency, including:

• Persistent vomiting or severe abdominal pain.
• Deep, rapid, or difficult breathing.
• Fruity-smelling breath, especially with other symptoms.
• Confusion, marked drowsiness, fainting, or reduced consciousness.
• Severe dehydration or inability to keep fluids down.
• High blood ketones (approximately 3.0 mmol/L or higher) or large urine ketones.

Important: Diabetic ketoacidosis can sometimes develop even when blood glucose is not extremely high. This is called euglycemic diabetic ketoacidosis and is particularly relevant for people taking SGLT2 inhibitors, such as empagliflozin or dapagliflozin. Do not dismiss symptoms of ketoacidosis simply because your glucose reading is below 250 mg/dL.

What Should You Record During Illness?

If you are unwell, use your blood sugar log to record:

• Glucose readings and measurement times.
• Blood or urine ketone results, when indicated.
• Insulin or diabetes medication taken, including timing and doses.
• Fluid intake, appetite, and ability to eat or drink.
• Symptoms such as fever, nausea, vomiting, abdominal pain, or unusual breathing.
• Advice received from your healthcare professional and any treatment changes made according to your prescribed plan.

Continue essential insulin according to your sick-day plan, and ask your diabetes team how to manage other medications during illness. Do not stop basal insulin on your own. People taking SGLT2 inhibitors should follow their clinician's sick-day instructions, which commonly include temporarily withholding these medications during significant acute illness, dehydration, or reduced oral intake.

Safety reminder: Never delay urgent medical treatment to complete a blood sugar log. If you suspect diabetic ketoacidosis, seek emergency care even if your glucose reading is not markedly elevated.

For additional guidance, read Dangerous Blood Sugar Levels.

How to Prepare the Log for a Medical Appointment

Before the visit:

• bring the meter or CGM receiver, not only handwritten values;
• bring insulin and medication names, doses, and timing;
• mark severe or repeated lows;
• note missed doses, steroid use, illness, travel, or major diet changes;
• write down the two or three patterns that concern you most;
• ask whether testing frequency and targets should change.

The goal is not to prove that every reading is “good.” Honest records help your team make safer decisions.

Most Asked Questions

Should I write down every CGM reading?

No. A CGM already stores frequent readings. Use the log for insulin, meals, exercise, symptoms, illness, ketones, sensor problems, and events that help explain the pattern.

Is 70–120 mg/dL the normal range all day?

No. Glucose interpretation depends on timing and purpose. Common treatment targets, diagnostic thresholds, and CGM ranges are different concepts.

Can I change insulin from the Excel chart?

Only when your diabetes team has provided a written self-adjustment plan. The chart identifies patterns but does not prescribe insulin.

How many days should I record?

One to two weeks often reveals useful patterns, but the appropriate period depends on the clinical question. Record longer when asked by your team.

Should I record blood pressure and weight too?

You may record them in the weekly notes if they are part of your care plan, but avoid making the glucose log so complicated that you stop using it.

Can I Print the Blood Sugar Chart for Free?

Yes. Download the free printable blood sugar log (PDF) and print it for personal use. The weekly log provides space to record glucose readings, medications, meals, physical activity, symptoms, and notes for your healthcare professional.

Can I Use the Excel Blood Sugar Tracker on My Computer?

Yes. Download the Excel blood sugar tracker (ZIP), extract the Excel workbook, and open it in compatible spreadsheet software.

The tracker is designed to help you:

• Record daily blood glucose readings.
• Convert glucose values between mg/dL and mmol/L.
• Highlight low and high glucose readings.
• View glucose trends using a line chart.
• Review summaries to identify recurring patterns.

Important: Always enter your individualized glucose targets before using the tracker's summaries. The spreadsheet is an educational monitoring tool and should not be used to adjust insulin or diabetes medication without an agreed treatment plan.

Related Questions

• Why Did Glucose Rise From 91 at Bedtime to 145 in the Morning?
• What Does Blood Sugar of 196 mg/dL Two Hours After Food Mean?
• How Can I Manage High Post-Meal Blood Sugar?
• What Should I Do About Blood Sugar of 455 mg/dL?

Related Resources

• Blood Sugar Log Sheet Guide
• Normal Blood Sugar Level Chart
• Blood Sugar Levels by Time of Day
• Chart of Blood Sugar Levels
• Convert mmol/L and mg/dL
• Dangerous Blood Sugar Levels

Medical disclaimer: The downloadable files and this page provide general education. They do not prescribe testing frequency, targets, insulin doses, medication changes, or emergency treatment. Use the personal plan supplied by your healthcare professional.

References

1. American Diabetes Association: Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises—Standards of Care in Diabetes 2026
2. Centers for Disease Control and Prevention: Monitoring Your Blood Sugar
3. Centers for Disease Control and Prevention: Managing Blood Sugar
4. Centers for Disease Control and Prevention: Low Blood Sugar
5. National Institute of Diabetes and Digestive and Kidney Diseases: Managing Diabetes
6. National Institute of Diabetes and Digestive and Kidney Diseases: Continuous Glucose Monitoring