Blood Sugar Converter
Convert a blood glucose reading between mg/dL and mmol/L, and see where it falls on the standard fasting and 2-hour post-meal (OGTT) reference ranges.
Input
The unit your reading is already in.
Which reference ranges to use for the category below — fasting and post-meal thresholds differ.
Output
| Test | Category | Range |
|---|---|---|
| No data yet | ||
General reference figures, not medical advice. Glucose ranges vary by lab, individual, pregnancy status, and medication — this tool cannot diagnose diabetes or hypoglycemia. Talk to a clinician about your own results.
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/blood-sugar-converter \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"value": "100",
"unit": "mgdl",
"readingType": "fasting"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `blood-sugar-converter` tool (Blood Sugar Converter) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/blood-sugar-converter/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="Blood Sugar Converter — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
Convert a blood glucose reading between mg/dL (the US convention) and mmol/L (used almost everywhere else), and see where it falls on the standard reference ranges published by the American Diabetes Association (ADA).
How to use it
- Enter your glucose value and pick the unit it's already in.
- Pick the reading type — Fasting (8+ hours without food) or 2-hour post-meal (the oral glucose tolerance test, or OGTT). This matters: the same number means something different depending on when it was measured.
- Read the converted value in both units, the category for your reading type, and the full reference table below it.
The conversion runs entirely in your browser as you type — nothing is uploaded to a server.
How the conversion works
The two units measure the same thing — glucose concentration in blood — using a fixed molar-mass conversion:
mg/dL = mmol/L × 18.0182
mmol/L = mg/dL ÷ 18.018218.0182 is the molar mass of glucose (C₆H₁₂O₆) in g/mol, which is also the mg/dL-per-mmol/L conversion factor for this specific molecule.
Why does the category depend on reading type?
The ADA defines separate threshold sets for a fasting reading and a 2-hour post-meal (OGTT) reading, because blood glucose is expected to rise after eating:
| Category | Fasting | 2-Hour Post-Meal (OGTT) |
|---|---|---|
| Normal | Below 100 mg/dL (5.5 mmol/L) | Below 140 mg/dL (7.8 mmol/L) |
| Prediabetes | 100–125 mg/dL (5.5–7.0 mmol/L) | 140–199 mg/dL (7.8–11.0 mmol/L) |
| Diabetes range | 126 mg/dL (7.0 mmol/L) and above | 200 mg/dL (11.1 mmol/L) and above |
A reading of 140 mg/dL, for example, is squarely "prediabetes" if it was taken fasting, but still "normal" if it was taken two hours after a meal. Picking the wrong reading type for your number is a common source of confusion — this tool asks first so it always applies the right set.
Anything below roughly 70 mg/dL (3.9 mmol/L) is treated as hypoglycemia (low blood sugar) regardless of when it was measured; below 54 mg/dL (3.0 mmol/L) is flagged separately as a level that's considered a medical emergency if the person is symptomatic.
Is this medical advice?
No. These are general public reference ranges, not a diagnosis. Normal ranges vary by lab, by individual, during pregnancy, and with certain medications — only a clinician interpreting your specific results, ideally alongside an A1C test and your medical history, can tell you what your numbers mean for you.