Insulin Dosing

Decision-support tool. The final dose is the clinical responsibility of the treating doctor. All glucose values on this page are mmol/L, and all doses assume regular human (soluble) insulin — Actrapid / Insugen-R.

Timing: regular human insulin has an onset of about 30 minutes and peaks at 2–4 hours, so give it 30 minutes before the meal. Giving it with food produces a post-meal spike followed by a late hypoglycaemia as the peak arrives after the glucose has cleared.

1Total daily dose (TDD)

Everything below is derived from the TDD, so start here.

Current TDD (unit/day)

Add up every unit of basal and bolus insulin the patient takes in 24 hours.

Dose rounding

2ICR and ISF

Enter a TDD above to derive these.

Where these numbers come from

ICR = 450 ÷ TDD, and ISF = 83 ÷ TDD. The 83 is the mmol/L constant, equivalent to the 1500 rule used with mg/dL.
These are the constants for regular human (soluble) insulin — Actrapid / Insugen-R, the prandial insulin stocked in MOH facilities. Rapid-acting analogues use different constants (500 and 100) and are not covered here.
Both are starting estimates only. Refine them against the patient's glucose logs: persistent post-meal highs suggest the ICR is too large, and corrections that overshoot suggest the ISF is too small.

3Correction and meal bolus

Current BG (mmol/L)

Target BG (mmol/L)

Carbohydrate (g)

Insulin on board (unit)

Defaults to 0 — enter manually unless a pump or CGM app reports it.

ISF override (mmol/L per unit)

ICR override (g per unit)

Enter current BG, target BG, and an ISF and ICR to see the bolus.