Blood Sugar 248 mg/dl — Too High? Fasting & After Eating
Where 248 mg/dl sits — adjust to your situation
248 mg/dl as a fasting reading
Diabetes range
A fasting reading of 126 mg/dl or higher falls into the diabetes range. Diagnosis requires a repeat test on another day — take this result to your doctor.
Fasting = no food for at least 8 hours, typically first thing in the morning. More on fasting readings.
248 mg/dl after eating
Diabetes range
A reading of 200 mg/dl or more two hours after a meal falls into the diabetes range and should be confirmed with your doctor.
Guidelines measure 2 hours after the start of a meal. More on post-meal readings.
Measured right after exercise?
There is no official range for readings taken during or just after a workout, so the two classifications above do not apply to them. How exercise moves blood sugar.
How 248 mg/dl compares to a typical day
Typical day without diabetes; your reading is the horizontal line — above anything a typical day produces, even right after meals.
What to do with a reading of 248 mg/dl
Book a doctor's appointment to confirm with a lab test (fasting glucose or A1C). If you are already diagnosed, this reading belongs in your log for your care team.
What actually moves the number: How to lower blood sugar, Foods that steady your glucose and Exercise and blood sugar.
Save this reading
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Questions about 248 mg/dl
Is 248 mg/dl blood sugar normal?
It depends on when you measured. Fasting, 248 mg/dl is diabetes range (normal fasting range: 70–99 mg/dl). Two hours after a meal it is diabetes range (normal post-meal range: 70–139 mg/dl).
What is 248 mg/dl in mmol/L?
248 mg/dl equals 13.8 mmol/L. Divide mg/dl by 18 to convert (used in the UK, Canada, Australia and most of Europe).
Does one reading of 248 mg/dl mean I have diabetes?
No single home reading is a diagnosis. Guidelines require a second abnormal lab result, either a different test from the same blood draw or a repeat on another day (fasting glucose, an oral tolerance test, or A1C). But a reading like this is exactly the reason those tests exist — take it to your doctor.
How accurate is a home reading of 248 mg/dl?
Home meters are allowed an error of ±15 mg/dl below 100 mg/dl and ±15 % from 100 up (ISO 15197), so a displayed 248 can correspond to a true value anywhere from 211 to 285 mg/dl. Fasting, that window crosses the 250 mg/dl line — a single home reading of 248 cannot settle which side you are truly on. That is a lab-test question, not a meter question.
What A1C would 248 mg/dl correspond to?
If 248 mg/dl were your average glucose over three months, it would work out to an A1C of about 10.3 % — at or above the 6.5 % diabetes threshold. A single reading is not an average — but the conversion shows what this level would mean as a habit. How the two measures relate: A1C and blood sugar.
BloodSugarEasy — blood sugar reading report
Reading: 248 mg/dl (13.8 mmol/L)
Fasting classification: Diabetes range · After-meal classification: Diabetes range
Reference: ADA criteria, reviewed 2026-08-21 · https://bloodsugareasy.com/blood-sugar-248/
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