How this instrument works
Basal insulin is often the first insulin added to a type 2 diabetes regimen when oral medications and non-insulin injectables aren't achieving glycemic targets. This calculator estimates the starting dose only — the dose a clinician might prescribe on day one of insulin therapy — using two of the most common starting conventions described in the literature: a flat 10 units/day, and a weight-based dose of roughly 0.1-0.2 units/kg/day, higher (0.2-0.3 units/kg/day) if the patient's A1C is above 8%.
The weight-based figures here use the midpoint of each range: 0.15 units/kg/day for a standard starting dose, and 0.25 units/kg/day when A1C is above 8%. Those specific numbers, along with the flat 10-unit convention, come from Kuritzky, Reid, and Wysham's 2019 review in Clinical Diabetes on basal insulin titration for primary care providers, which in turn cites AACE/ACE guidance for the A1C-based dosing range.
This calculator is scoped narrowly on purpose. It covers only the starting dose for a patient beginning basal insulin — it does not cover the ongoing titration that follows, where the dose is adjusted every few days based on fasting glucose readings until a target is reached. That titration process requires regular glucose monitoring and a clinician's active adjustment over days to weeks, and it is a separate clinical process this calculator does not attempt to model.
This is a reference tool for prescribers initiating therapy, not a substitute for clinical judgment. Actual starting doses, and every adjustment after the first dose, should be directed by the treating clinician using the patient's full picture — glucose patterns, renal function, hypoglycemia risk, and other medications. Insulin dosing errors carry real risk of hypoglycemia, so this estimate is meant to inform a starting conversation, not to be used as a standalone prescription.
- Enter the patient's weight in kilograms (weight).
- Set A1C above 8% (highA1c) to Yes or No, based on the patient's most recent A1C result.
- Read the flat starting dose (flatStartUnits) — a common convention of 10 units/day regardless of weight or A1C.
- Read the weight-based starting dose (weightBasedStartUnits), calculated at 0.15 units/kg/day, or 0.25 units/kg/day if A1C is above 8%.
- Compare the two estimates with the prescribing clinician before selecting an actual starting dose — this calculator does not choose between them.
Worked example — three starting weights
A 70 kg patient with A1C at or below 8% has a flat starting dose of 10 units/day and a weight-based starting dose of 70 × 0.15 = 10.5 units/day — the two conventions land close together at this weight, which is common for an average-sized patient with standard glycemic control.
A 90 kg patient with A1C above 8% uses the higher weight-based multiplier: 90 × 0.25 = 22.5 units/day, well above the flat 10-unit convention. The flat 10-unit dose is really calibrated for the standard-A1C case, so at a higher A1C and higher weight, the weight-based estimate diverges from it substantially.
A smaller 60 kg patient with A1C at or below 8% has a weight-based starting dose of 60 × 0.15 = 9 units/day, close to the flat 10-unit convention — illustrating how the two starting-dose conventions tend to agree most closely near an average body weight with standard A1C.
Questions
What does this calculator estimate?
It estimates a starting dose for basal insulin when a clinician is initiating insulin therapy in a patient with type 2 diabetes — either a flat 10 units/day, or a weight-based dose of 0.15 units/kg/day (0.25 units/kg/day if A1C is above 8%). It does not estimate an ongoing or adjusted dose for a patient already on insulin.
Why doesn't this cover dose titration after starting insulin?
Titration is a separate, ongoing clinical process: after starting basal insulin, the dose is typically adjusted every few days based on fasting glucose readings, guided by a treating clinician, until a glucose target is reached. That process depends on data this calculator doesn't have — a patient's actual glucose trend over time — so it's deliberately out of scope here. This tool covers only the first prescribed starting dose.
Where do the 10 units/day and 0.15/0.25 figures come from?
They come from Kuritzky, Reid, and Wysham's 2019 review in Clinical Diabetes on basal insulin titration for primary care providers, which describes starting doses of either 10 units/day or roughly 0.1-0.2 units/kg/day, rising to 0.2-0.3 units/kg/day when A1C is above 8% (citing AACE/ACE dosing guidance). This calculator uses the midpoint of each weight-based range — 0.15 and 0.25 units/kg/day.
Why does a higher A1C call for a higher starting dose?
A higher baseline A1C generally reflects a larger gap between the patient's current glucose control and target, so starting guidance allows for a higher initial weight-based dose (0.2-0.3 units/kg/day, versus 0.1-0.2 units/kg/day) to begin closing that gap sooner, with the exact regimen still finalized through titration based on the patient's actual glucose readings.
Should a patient use this to start insulin on their own?
No. This is a reference tool for prescribers, not a patient self-dosing tool. Insulin dosing carries a real risk of hypoglycemia if a dose is too high for a given patient, and the appropriate starting dose depends on factors beyond weight and A1C — kidney function, other medications, hypoglycemia history, and more — that only a clinician evaluating the patient can weigh.
Does the flat 10-unit dose change based on A1C?
No — as implemented here, the flat starting dose stays at 10 units/day regardless of A1C, reflecting the flat convention described in the source literature. The A1C-based adjustment only applies to the weight-based estimate, which is why the two numbers can diverge substantially for a patient with a higher A1C, as in the 90 kg example above.
What inputs does the calculator need?
Just two: the patient's weight in kilograms, and whether their A1C is above 8%. Those two inputs produce both a flat starting-dose estimate and a weight-based starting-dose estimate side by side, for a clinician to weigh alongside the rest of the patient's clinical picture.
References
- Kuritzky L, et al. — Basal Insulin Titration for Primary Care Providers, Clin Diabetes, 2019;37(4):368 (PMID 31660010)
- American Diabetes Association — Standards of Care in Diabetes, 2026 (Pharmacologic Approaches)
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.