# Blood sugar converter (mg/dL to mmol/L)

> Glucose from mg/dL to mmol/L and back, and HbA1c to estimated average glucose (eAG) and IFCC mmol/mol, with ADA categories.

操作できるページ：https://www.calcopenly.com/ja/health/blood-sugar-converter
分野：健康とフィットネスの計算機

Glucose converts between units through its molar mass: 1 mmol/L is 18.016 mg/dL (180.16 g/mol ÷ 10), which many meters and tables round to 18. HbA1c converts to estimated average glucose (eAG) with the ADAG regression, eAG in mg/dL = 28.7 × A1c − 46.7, and to IFCC units in mmol/mol with the NGSP–IFCC master equation. Results are placed in the American Diabetes Association (ADA) categories.

People use it to read results reported in the other unit, such as a US meter against a UK lab report. 100 mg/dL is 5.55 mmol/L, the fasting level where ADA's prediabetes range begins, and an HbA1c of 7 % corresponds to an eAG of 154 mg/dL (8.6 mmol/L) and 53 mmol/mol.

The categories are population thresholds for laboratory tests confirmed by repeat testing, not for a single meter reading. eAG is a regression estimate (R² = 0.84 in the 507-person ADAG study), so an individual's measured average can differ, and anaemia or haemoglobin variants can distort HbA1c.

## 入力

- **単位換算** (選択肢：Glucose mg/dL → mmol/L, Glucose mmol/L → mg/dL, HbA1c → estimated average glucose, Estimated average glucose → HbA1c)
- **Glucose**
- **Glucose**
- **HbA1c**: NGSP/DCCT percent, as reported in the US.
- **Estimated average glucose**
- **Average glucose unit** (選択肢：mg/dL, mmol/L)
- **mg/dL per mmol/L** (選択肢：18.016, 18)

## 結果

- 結果 — 主な結果
- Unit of the result
- Estimated average glucose (mmol/L) (mmol/L)
- HbA1c (IFCC) (mmol/mol)
- If this is a fasting reading (ADA)
- HbA1c category (ADA)

## 計算式

$$
\text{mg/dL} = \text{mmol/L} \times 18.016 \qquad \text{eAG}_{\text{mg/dL}} = 28.7 \times \text{A1c} - 46.7 \qquad \text{IFCC} = \frac{\text{A1c} - 2.152}{0.09148}
$$

## 計算例

### Boundary: 100 mg/dL → mmol/L

- 単位換算: Glucose mg/dL → mmol/L
- Glucose: 100 mg/dL
- **結果: 5.55 mmol/L**
- **If this is a fasting reading (ADA): Prediabetes**
- 照合元：Python 3.8 decimal: 100 / 18.016 = 5.5506; ADA fasting 100–125 mg/dL is prediabetes

### 7.0 mmol/L → mg/dL with factor 18

- 単位換算: Glucose mmol/L → mg/dL
- Glucose: 7.0 mmol/L
- mg/dL per mmol/L: 18
- **結果: 126 mg/dL**
- **If this is a fasting reading (ADA): Diabetes range**
- 照合元：NGSP eAG table pairs 126 mg/dL with 7.0 mmol/L (factor 18); ADA fasting ≥ 126 mg/dL is diabetes range

### 7.0 mmol/L → mg/dL with factor 18.016

- 単位換算: Glucose mmol/L → mg/dL
- Glucose: 7.0 mmol/L
- **結果: 126.11 mg/dL**
- 照合元：Python 3.8 decimal: 7.0 × 18.016 = 126.112

### HbA1c 7% → eAG

- 単位換算: HbA1c → estimated average glucose
- HbA1c: 7%
- **結果: 154.2 mg/dL**
- **HbA1c (IFCC): 53 mmol/mol**
- **Estimated average glucose (mmol/L): 8.6 mmol/L**
- **HbA1c category (ADA): Diabetes range**
- 照合元：NGSP table: 7% ↔ 154 mg/dL, 8.6 mmol/L, 53 mmol/mol; ADAG 28.7 × 7 − 46.7 = 154.2

### Boundary: HbA1c 5.7%

- 単位換算: HbA1c → estimated average glucose
- HbA1c: 5.7%
- **結果: 116.89 mg/dL**
- **HbA1c category (ADA): Prediabetes**
- 照合元：Python 3.8 decimal: 28.7 × 5.7 − 46.7 = 116.89; ADA A1c 5.7–6.4% is prediabetes

### eAG 126 mg/dL → HbA1c

- 単位換算: Estimated average glucose → HbA1c
- Estimated average glucose: 126
- Average glucose unit: mg/dL
- **結果: 6.02 %**
- **HbA1c (IFCC): 42 mmol/mol**
- 照合元：Python 3.8 decimal: (126 + 46.7) / 28.7 = 6.0174; (6.0174 − 2.152) / 0.09148 = 42.25. NGSP table: 6% ↔ 126 mg/dL, 42 mmol/mol

## よくある質問

### How do you convert mg/dL to mmol/L?

Divide by 18, or 18.016 exactly, from glucose's molar mass of 180.16 g/mol; to go from mmol/L to mg/dL, multiply. So 100 mg/dL is 5.55 mmol/L and 7.0 mmol/L is 126 mg/dL. The US mostly reports glucose in mg/dL, while the UK, Canada and Australia use mmol/L. The factor applies only to glucose; cholesterol and other substances have their own factors.

### What is a normal blood sugar level?

For a fasting test, ADA classes below 100 mg/dL (5.6 mmol/L) as normal, 100–125 mg/dL (5.6–6.9 mmol/L) as prediabetes and 126 mg/dL (7.0 mmol/L) or more, confirmed by repeat testing, as diabetes. Two hours into a 75 g glucose tolerance test the cut-offs are 140 and 200 mg/dL (7.8 and 11.1 mmol/L). For people treated for diabetes, ADA calls a reading below 70 mg/dL (3.9 mmol/L) level 1 hypoglycaemia and below 54 mg/dL (3.0 mmol/L) level 2.

### What does an HbA1c of 7 % mean?

It corresponds to an estimated average glucose of 154 mg/dL (8.6 mmol/L) over roughly the previous three months, by the ADAG equation 28.7 × 7 − 46.7, and to 53 mmol/mol in IFCC units. ADA's diagnostic threshold for diabetes is 6.5 % (48 mmol/mol), and below 7 % is the goal ADA suggests for many non-pregnant adults with diabetes, adjusted to the individual.

### What HbA1c level is prediabetes?

From 5.7 % to below 6.5 % (39 to 47 mmol/mol) in the ADA criteria, with 6.5 % (48 mmol/mol) or higher, confirmed, in the diabetes range. By the ADAG equation, 5.7 % corresponds to an average glucose of 117 mg/dL (6.5 mmol/L) and 6.5 % to 140 mg/dL (7.8 mmol/L). HbA1c can mislead in anaemia, pregnancy, after blood loss or transfusion, and with some haemoglobin variants.

### 「Blood sugar converter (mg/dL to mmol/L)」の精度はどのくらいですか？

精度は入力値と計算方法の前提に依存します。十進演算には有効数字50桁を使いますが、推定、数値計算手法、元データの精度はそれより低い場合があります。表示の丸め処理でこれらの制約がなくなるわけではありません。 独立した出典の解答と照合した計算例：7。 例えば、「Boundary: 100 mg/dL → mmol/L」はPython 3.8 decimal: 100 / 18.016 = 5.5506; ADA fasting 100–125 mg/dL is prediabetesと照合しています。

### この計算方法の出典は何ですか？

Nathan DM et al. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008;31(8):1473–1478; NGSP — HbA1c and estimated average glucose (eAG) table; NGSP — IFCC standardization of HbA1c (master equation); American Diabetes Association. Standards of Care in Diabetes—2025, sections 2 (diagnosis) and 6 (glycemic goals and hypoglycemia). Diabetes Care 2025;48(Suppl 1).

## 出典

- [Nathan DM et al. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008;31(8):1473–1478](https://diabetesjournals.org/care/article/31/8/1473/28589/Translating-the-A1C-Assay-Into-Estimated-Average)
- [NGSP — HbA1c and estimated average glucose (eAG) table](https://ngsp.org/A1ceAG.asp)
- [NGSP — IFCC standardization of HbA1c (master equation)](https://ngsp.org/ifccngsp.asp)
- [American Diabetes Association. Standards of Care in Diabetes—2025, sections 2 (diagnosis) and 6 (glycemic goals and hypoglycemia). Diabetes Care 2025;48(Suppl 1)](https://diabetesjournals.org/care/issue/48/Supplement_1)

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