Blood Glucose Converter
Convert blood glucose between mg/dL and mmol/L instantly, check ADA fasting and post-meal ranges, and estimate HbA1c from average glucose. Free, private, in-browser.
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What is Blood Glucose Converter?
The Blood Glucose Converter translates readings between mg/dL and mmol/L — the two unit systems used by meters and labs worldwide — using the exact molar-mass factor of 18.0156. It also classifies values against American Diabetes Association (ADA) reference ranges for fasting, post-meal, and random tests, and converts between HbA1c and estimated average glucose (eAG) with the ADAG formula. Everything is computed locally in your browser.
Key Benefits
- Convert meter and lab readings between US (mg/dL) and international (mmol/L) units instantly
- See where your reading falls against ADA normal, prediabetes, and diabetes thresholds
- Estimate HbA1c from average glucose — and average glucose from HbA1c — with the ADAG formula
- Avoid mental-math errors from the commonly rounded multiply-by-18 shortcut
- Keep health data private with fully offline, in-browser processing
Common Use Cases
- •Interpret lab results from abroad that report mg/dL while your meter uses mmol/L
- •Compare your readings with US-based health websites, apps, and research papers
- •Prepare for doctor visits by pre-checking which ADA range your values fall into
- •Convert HbA1c targets (e.g. below 7%) into the average glucose numbers your CGM shows
- •Double-check readings when traveling between countries with different units
How to Convert Blood Glucose Units
- Enter your reading: Type a glucose value from your meter or lab report, such as 99 mg/dL or 5.5 mmol/L.
- Pick the units: Choose the unit you have (mg/dL or mmol/L) and the unit you want. Use the swap button to reverse the direction.
- Set the reading context: Select fasting, 2 hours after a meal, or random so the reading is compared against the correct ADA thresholds.
- Read the result: See the converted value, its range classification, and the estimated HbA1c. You can also enter an HbA1c value to get the average glucose (eAG).
Key Features
- Exact bidirectional conversion: 1 mmol/L = 18.0156 mg/dL based on glucose molar mass (180.156 g/mol).
- ADA reference classification for fasting, 2-hour post-meal, and random readings.
- HbA1c to estimated average glucose (eAG) calculator using the ADAG study formula.
- Color-coded status badges for low, normal, prediabetes, and diabetes ranges.
- Quick-reference ADA range table covering FPG, OGTT, and HbA1c thresholds.
- Runs entirely in your browser — lab values never leave your device.
Frequently Asked Questions
How do I convert mg/dL to mmol/L?
Divide the mg/dL value by 18.0156. For example, 90 mg/dL ÷ 18.0156 ≈ 5.0 mmol/L. The factor comes from the molar mass of glucose (180.156 g/mol): 1 mmol/L equals exactly 18.0156 mg/dL.
Why do the US and Thailand use different glucose units?
The US, Japan, and a few other countries report glucose in mg/dL (mass concentration), while most of the world — including Thailand, the UK, Europe, Canada, and Australia — uses mmol/L (molar concentration). Both measure the same thing, just in different units, which is why labs and meters abroad can look wrong until converted.
What is a normal blood glucose range?
Per the American Diabetes Association: fasting plasma glucose of 70–99 mg/dL (3.9–5.5 mmol/L) is normal, 100–125 mg/dL (5.6–6.9 mmol/L) suggests prediabetes, and 126 mg/dL (7.0 mmol/L) or above on two occasions supports a diabetes diagnosis. Two hours after a meal, under 140 mg/dL (7.8 mmol/L) is considered normal.
How is HbA1c related to average glucose?
The ADAG study established the formula eAG (mg/dL) = 28.7 × HbA1c − 46.7. For example, an HbA1c of 6.5% corresponds to an estimated average glucose of about 140 mg/dL (7.8 mmol/L). Individual variation of roughly ±0.5% HbA1c is normal.
Is this tool medical advice?
No. This converter performs unit conversion and range lookup for education only. Diagnosis and treatment decisions must always be made with a healthcare professional who can consider your full clinical picture.