The 1800 rule estimates how many mg/dL one unit of rapid insulin lowers your blood glucose. Enter your total daily dose to see the factor.
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How the 1800 rule works
Divide 1800 by your total daily insulin units. The result is the approximate glucose drop produced by one unit of rapid acting insulin, used for correction doses before meals or at bedtime.
When to use corrections
Corrections address glucose above target, not food. They are usually given with meals or at intervals of at least three hours to avoid insulin stacking.
Understanding your result
- A factor under 30 means each unit moves glucose a lot, typical of insulin resistance
- 30 to 60 is a common adult factor
- Above 60 reflects high sensitivity and small correction doses
Safety reminder
Correction scales belong to your personal care plan. Confirm any change with your diabetes clinician before adjusting doses.