🧬 Insulin Correction Factor / Carb Ratio
Estimates the insulin sensitivity (correction) factor and insulin-to-carbohydrate ratio from total daily dose, providing starting points for bolus dosing in intensive insulin therapy.
Insulin Correction Factor / Carb Ratio
Total daily insulin dose TDD (U/day)
Insulin type
When to use
Enter total daily dose and select rapid- or short-acting insulin; the tool returns ISF (mmol/L and mg/dL per unit) and ICR (grams per unit). Titrate both against the patient's own glucose monitoring.
How it works
Rapid-acting: ISF = 1800/TDD (mg/dL per U), ICR = 500/TDD (g per U). Short-acting: ISF = 1500/TDD, ICR = 450/TDD. ISF in mmol/L = (mg/dL value)/18.
Key points
- The 1800/500 ('rapid') and 1500/450 ('regular') rules are starting estimates derived from TDD, not validated individual targets — always refine empirically. (original synthesis · not guideline verbatim)
- Both factors scale inversely with TDD, so a recent dose change invalidates a previously derived ISF/ICR.
- Apply with caution in hypoglycemia-prone patients; specialist supervision and structured education underpin safe carb counting.
References
- Walsh J, Roberts R, Bailey T. Guidelines for optimal bolus calculator settings in adults. J Diabetes Sci Technol. 2011;5(1):129-135.
- ADA. Standards of Care in Diabetes — Pharmacologic Approaches to Glycemic Treatment. Diabetes Care. 2024;47(Suppl 1):S158-S178.
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.