Convert blood sugar

Convert glucose readings between mmol/L and mg/dL or HbA1c between IFCC mmol/mol and NGSP percent.

freeworks offlinenothing uploaded
ToolBlood Sugar Converter
Input
Output
—
Put this on your own site

The frame below runs the same code as this page, in the reader's own browser. Nothing is sent to us, and nothing is sent to you.

Pick a dark background and the text and panels follow it, so the frame stays readable on a dark page.

Preview

How it works

Glucose multiplies or divides by 18, while HbA1c follows NGSP percent = 0.09148 × IFCC mmol/mol + 2.152. For HbA1c, the ADAG regression also gives estimated average glucose as 28.7 × percent − 46.7 mg/dL; either glucose or HbA1c can be converted independently.

Formula
glucose mg/dL = glucose mmol/L × 18
estimated average glucose mg/dL = 28.7 × HbA1c % − 46.7
  • No reading defaults because an absent laboratory or meter result must not become an invented value.
  • Exactly one source unit is accepted within each conversion group to prevent contradictory duplicate inputs.

Worked example

7 mmol/L glucose, 6.5% HbA1c
One glucose reading and one HbA1c reading converted both ways
Input
											Glucose mmol per l: 7
HbA1c percent: 6.5
Output
												Glucose mmol per l: 7
Glucose mg per dl: 126
HbA1c percent: 6.5
HbA1c mmol per mol: 47.5
Estimated average glucose mmol per l: 7.77
Estimated average glucose mg per dl: 139.8

When to use this

European laboratory reports use mmol/L glucose and IFCC mmol/mol HbA1c, United States meters commonly use mg/dL and NGSP percent, and diabetes clinic summaries may place ADAG estimated average glucose beside meter logs.

Edge cases

  • Entering both unit versions of the same glucose or HbA1c reading is rejected rather than silently choosing one.
  • A spot glucose value is only unit-converted and never substituted for the multiweek average estimated from HbA1c.
  • Anaemia, haemoglobin variants, altered red-cell lifespan, pregnancy, kidney disease, and recent transfusion receive no correction even though they can alter the HbA1c-glucose relationship.

References