Blood Sugar 58 mg/dl — Too Low? What It Means
Where 58 mg/dl sits — adjust to your situation
58 mg/dl as a fasting reading
Low (hypoglycemia)
A fasting reading below 70 mg/dl counts as hypoglycemia. If you feel shaky, sweaty or confused, treat it right away with fast-acting carbohydrates.
Fasting = no food for at least 8 hours, typically first thing in the morning. More on fasting readings.
58 mg/dl after eating
Low (hypoglycemia)
Below 70 mg/dl after a meal is unusual and counts as hypoglycemia — worth discussing with your doctor, especially if it happens repeatedly.
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 58 mg/dl compares to a typical day
Typical day without diabetes; your reading is the horizontal line — below the band a typical day stays in.
What to do with a reading of 58 mg/dl
Use the 15-15 rule: 15 g of fast carbohydrates, wait 15 minutes, re-test. Repeat until you are above 70 mg/dl, then eat a small snack with protein.
Save this reading
Stored only in your browser on this device. See the privacy policy for what analytics records when you allow it. Build a history you can chart, print for your doctor, or export.
Questions about 58 mg/dl
Is 58 mg/dl blood sugar normal?
It depends on when you measured. Fasting, 58 mg/dl is low (hypoglycemia) (normal fasting range: 70–99 mg/dl). Two hours after a meal it is low (hypoglycemia) (normal post-meal range: 70–139 mg/dl).
What is 58 mg/dl in mmol/L?
58 mg/dl equals 3.2 mmol/L. Divide mg/dl by 18 to convert (used in the UK, Canada, Australia and most of Europe).
How accurate is a home reading of 58 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 58 can correspond to a true value anywhere from 43 to 73 mg/dl. If you have symptoms, treat it as a low now; if you feel fine, wash and dry your hands and recheck.
BloodSugarEasy — blood sugar reading report
Reading: 58 mg/dl (3.2 mmol/L)
Fasting classification: Low (hypoglycemia) · After-meal classification: Low (hypoglycemia)
Reference: ADA criteria, reviewed 2026-08-21 · https://bloodsugareasy.com/blood-sugar-58/
Printed: