Active Insulin (IOB) Estimator

Insulin on Board (IOB), or active insulin, is the amount of rapid-acting insulin still working in your body from a previous bolus. This tool estimates IOB using a simplified linear decay model over a given Duration of Insulin Action (DIA).

Why It Matters

Ignoring IOB leads to "insulin stacking"—taking correction doses while previous insulin is still active, which inevitably causes severe hypoglycemia. Always subtract IOB from your calculated Correction Factor dose.