Clinical tool

Insulin Calculations

Weight-based insulin dosing.

WeightkgStarting factoru/kg/day0.3–0.4 if insulin-sensitive or elderly; 0.5 typical; 0.6+ if insulin-resistant

These are starting estimates for initiating or reviewing a regimen, not a prescription. Real requirements vary widely and are established by titration against glucose monitoring, not by formula. Reduce the starting factor in renal or hepatic impairment, the elderly, and anyone with hypoglycaemia unawareness. The 100 and 500 rules were derived for type 1 diabetes on multiple daily injections and apply poorly to type 2 on mixed regimens. Do not use this for DKA or HHS — those need a fixed-rate weight-based infusion per protocol, which is a different calculation entirely. Insulin is a high-risk medicine: check every dose against local policy and prescribe in units written in full.

For practising medics only. Clinical tools support judgement, they do not replace it. Always verify results against current guidelines and the patient in front of you.