2-3 months (Standard A1C period)
1 month (Approximate)
Weekly average
Estimated A1C
–
Average Blood Glucose: –
Note: This is an estimate. Actual A1C tests measure glycated hemoglobin directly.
Understanding Blood Sugar and A1C
The relationship between average blood glucose levels and A1C (HbA1c) is crucial for diabetes management. A1C provides a long-term view of blood sugar control, reflecting your average blood glucose over the past 2-3 months.
What is A1C?
A1C, or hemoglobin A1C (HbA1c), measures the percentage of hemoglobin proteins in your blood that have glucose attached to them. When glucose levels are higher, more glucose attaches to hemoglobin. Since red blood cells live for about 3 months, the A1C test reflects your average blood sugar over that period.
The A1C Formula: The most commonly used formula is: A1C = (Average Glucose + 46.7) รท 28.7 (when glucose is in mg/dL)
A1C Target Ranges
Normal (Non-diabetic): Below 5.7%
Prediabetes: 5.7% to 6.4%
Diabetes: 6.5% or higher
Diabetes Control Goal: Below 7% (for most adults with diabetes)
Tight Control: Below 6.5% (for some individuals without significant hypoglycemia risk)
Blood Glucose to A1C Conversion
Understanding the relationship between daily blood glucose readings and A1C helps you interpret your glucose monitoring results. Here are approximate conversions:
A1C 5%: Average glucose ~97 mg/dL (5.4 mmol/L)
A1C 6%: Average glucose ~126 mg/dL (7.0 mmol/L)
A1C 7%: Average glucose ~154 mg/dL (8.6 mmol/L)
A1C 8%: Average glucose ~183 mg/dL (10.2 mmol/L)
A1C 9%: Average glucose ~212 mg/dL (11.8 mmol/L)
A1C 10%: Average glucose ~240 mg/dL (13.4 mmol/L)
Why This Calculator is Useful
This calculator helps you:
Estimate your A1C based on continuous glucose monitoring or frequent blood sugar checks
Set realistic blood glucose targets to achieve desired A1C levels
Track progress between A1C lab tests
Understand how daily glucose readings translate to long-term control
Motivate better diabetes management through immediate feedback
Factors Affecting A1C Accuracy
Several factors can affect A1C readings:
Anemia: Can falsely lower A1C results
Recent blood transfusions: May affect accuracy
Hemoglobin variants: Genetic variations can interfere with some A1C tests
Kidney disease: May affect red blood cell lifespan
Vitamin deficiencies: Iron or vitamin B12 deficiency can impact results
Using Both Metrics for Optimal Control
The best diabetes management combines both daily glucose monitoring and periodic A1C testing. Daily glucose checks show immediate responses to food, exercise, and medication, while A1C provides the bigger picture of overall control. Together, they offer comprehensive insight into your diabetes management.
Important: Always consult with your healthcare provider about your A1C targets and diabetes management plan. Individual goals may vary based on age, duration of diabetes, presence of complications, and other health conditions.
Improving Your A1C
To lower your A1C and improve blood sugar control:
Monitor blood glucose regularly and track patterns
Follow a balanced, carbohydrate-controlled diet
Engage in regular physical activity (aim for 150 minutes per week)
Take medications as prescribed
Manage stress through relaxation techniques
Get adequate sleep (7-9 hours per night)
Stay hydrated and avoid sugary beverages
Work closely with your diabetes care team
var currentUnit = 'mgdl';
function switchUnit(unit) {
currentUnit = unit;
var mgdlBtn = document.getElementById('mgdlBtn');
var mmolBtn = document.getElementById('mmolBtn');
var unitLabel = document.getElementById('unitLabel');
var avgGlucoseInput = document.getElementById('avgGlucose');
if (unit === 'mgdl') {
mgdlBtn.classList.add('active');
mmolBtn.classList.remove('active');
unitLabel.textContent = 'Unit: mg/dL (common in USA)';
avgGlucoseInput.placeholder = 'Enter average glucose in mg/dL';
avgGlucoseInput.value = '154';
} else {
mmolBtn.classList.add('active');
mgdlBtn.classList.remove('active');
unitLabel.textContent = 'Unit: mmol/L (common in UK, Canada, Australia)';
avgGlucoseInput.placeholder = 'Enter average glucose in mmol/L';
avgGlucoseInput.value = '8.6';
}
}
function calculateA1C() {
var avgGlucoseInput = document.getElementById('avgGlucose').value;
var resultDiv = document.getElementById('result');
var a1cValueDiv = document.getElementById('a1cValue');
var avgGlucoseDisplay = document.getElementById('avgGlucoseDisplay');
var interpretationDiv = document.getElementById('interpretation');
if (!avgGlucoseInput || avgGlucoseInput <= 0) {
alert('Please enter a valid average blood glucose value.');
return;
}
var avgGlucose = parseFloat(avgGlucoseInput);
if (isNaN(avgGlucose) || avgGlucose <= 0) {
alert('Please enter a valid positive number for average glucose.');
return;
}
var avgGlucoseMgDl = avgGlucose;
if (currentUnit === 'mmol') {
avgGlucoseMgDl = avgGlucose * 18.018;
}
var a1c = (avgGlucoseMgDl + 46.7) / 28.7;
a1c = Math.round(a1c * 10) / 10;
a1cValueDiv.textContent = a1c.toFixed(1) + '%';
if (currentUnit === 'mgdl') {
avgGlucoseDisplay.textContent = avgGlucose.toFixed(0) + ' mg/dL';
} else {
avgGlucoseDisplay.textContent = avgGlucose.toFixed(1) + ' mmol/L (' + avgGlucoseMgDl.toFixed(0) + ' mg/dL)';
}
var interpretation = '';
var interpretationClass = '';
if (a1c < 5.7) {
interpretation = 'Normal Range: Your estimated A1C is in the normal, non-diabetic range. Continue maintaining healthy habits including balanced diet, regular exercise, and routine health check-ups.';
interpretationClass = 'normal';
} else if (a1c >= 5.7 && a1c < 6.5) {
interpretation = 'Prediabetes Range: Your estimated A1C indicates prediabetes. This is a warning sign. Lifestyle changes like improved diet, increased physical activity, and weight loss can help prevent progression to diabetes. Consult your healthcare provider.';
interpretationClass = 'prediabetes';
} else if (a1c >= 6.5 && a1c < 7.0) {
interpretation = 'Diabetes Range (Good Control): Your estimated A1C indicates diabetes, but you are maintaining relatively good control. Continue working with your healthcare team to maintain this level. Many adults with diabetes aim for A1C below 7%.';
interpretationClass = 'diabetes';
} else if (a1c >= 7.0 && a1c < 8.0) {
interpretation = 'Diabetes Range (Moderate Control): Your estimated A1C is above the typical target of 7% for most adults with diabetes. Discuss with your healthcare provider about adjusting your treatment plan, including medications, diet, and exercise.';
interpretationClass = 'diabetes';
} else if (a1c >= 8.0 && a1c < 9.0) {
interpretation = 'Diabetes Range (Poor Control): Your estimated A1C indicates poor glucose control. This increases your risk of diabetes complications. It is important to work closely with your healthcare team to improve your blood sugar management.';
interpretationClass = 'diabetes';
} else {
interpretation = 'Diabetes Range (Very Poor Control): Your estimated A1C is significantly elevated, indicating very poor glucose control. Immediate action is needed. Please consult your healthcare provider as soon as possible to review and adjust your diabetes management plan.';
interpretationClass = 'diabetes';
}
interpretationDiv.innerHTML = interpretation;
interpretationDiv.className = 'interpretation ' + interpretationClass;
resultDiv.classList.add('show');
}