Our Methodology
Every calculator on this site implements a published, citable clinical formula — nothing proprietary, nothing invented. This page documents where each formula comes from, how we build and test the tools, and what they can and cannot do.
Four Principles
Published Formulas Only
Each tool implements formulas from clinical guidelines or peer-reviewed literature. The source is cited on the page that uses it.
Show the Math
Every result prints the exact calculation used, so users and clinicians can verify each number by hand.
Conservative Defaults
Where guidelines give ranges, defaults sit at the midpoint or the conservative end (e.g., 0.5 u/kg TDD; 0.2 u/kg for insulin-naïve Type 2).
Privacy by Design
All calculation runs in your browser. No health values you enter are transmitted or stored by us.
Formula Sources
| Formula | Definition | Primary source |
|---|---|---|
| Weight-based TDD | 0.4–0.6 u/kg/day starting range; 0.2 u/kg insulin-naïve T2 | ADA Standards of Care, Section 9 |
| Basal/bolus split | 40–50% basal, 50–60% bolus | ADA / AACE algorithms |
| 500 Rule (ICR) | ICR = 500 ÷ TDD (rapid-acting) | Walsh & Roberts, Using Insulin |
| 450 Rule (ICR) | ICR = 450 ÷ TDD (Regular insulin) | Walsh & Roberts, Using Insulin |
| 1800 Rule (ISF) | ISF = 1800 ÷ TDD (rapid-acting) | Davidson et al., Endocr Pract 2008 |
| 1500 Rule (ISF) | ISF = 1500 ÷ TDD (Regular insulin) | Davidson et al., Endocr Pract 2008 |
| Correction dose | (Current BG − Target BG) ÷ ISF | ADA Standards of Care |
| HOMA-IR | (Glucose mg/dL × Insulin µU/mL) ÷ 405 | Matthews et al., Diabetologia 1985 |
| QUICKI | 1 ÷ [log(insulin) + log(glucose)] | Katz et al., JCEM 2000 |
| GMI | 3.31 + 0.02392 × mean glucose (mg/dL) | Bergenstal et al., Diabetes Care 2018 |
| eAG / HbA1c | eAG = 28.7 × A1c − 46.7 | Nathan et al. (ADAG), Diabetes Care 2008 |
| Glucose unit conversion | mg/dL = mmol/L × 18.018 | Molecular weight of glucose (180.16 g/mol) |
| Insulin units ↔ mL | mL = units ÷ concentration (U-40/U-100/U-500) | Manufacturer labeling / ISMP |
| Warsaw method (FPU) | 1 FPU = 100 kcal fat/protein → extended bolus | Pańkowska et al. |
| DKA / drip protocols | 0.05–0.1 u/kg/h IV infusion frameworks | ADA consensus / institutional protocols |
Each calculator page carries its own reference list; this table is the master index.
Build & Review Process
- Source first. A tool is only built if a published formula exists for it. Where multiple rules exist (500 vs 450), the tool states which it uses and when each applies.
- Cross-checked implementation. Formula code lives in one shared library (
calc-core.js) with the citation in a comment above each function, and outputs are spot-checked against hand calculations and published worked examples. - Plausibility guards. Inputs outside physiologic ranges (weight, glucose, TDD, carbs) trigger warnings rather than silent results.
- Safety framing. Every page carries an educational-use disclaimer, an emergencies banner, and explicit "confirm with your care team" steps — dosing tools are deliberately framed as estimate explainers, not dose prescribers.
- Review cadence. Content is reviewed against the current ADA Standards of Medical Care in Diabetes annually, and when major guideline updates publish. Each page shows its "Last reviewed" date.
Who Maintains This Site
insulin-calculator.org is written and maintained by founder Ryan Mitchell, drawing on a background in the healthcare and pharmaceutical industry, with every formula referenced against the clinical sources listed above. See About Us for the full story and Contact to report an error — corrections are prioritised over all other work.
What These Tools Cannot Do
- They cannot individualise a dose. Population formulas are starting frameworks; real doses come from supervised titration.
- They cannot account for insulin on board, illness, activity, alcohol, pregnancy, renal function, or drug interactions unless the specific tool says so.
- They are not FDA-regulated medical devices and must not be used for autonomous dosing decisions.
Master Reference List
- American Diabetes Association. Standards of Medical Care in Diabetes — 2024. Link
- Walsh J, Roberts R. Using Insulin: Everything You Need for Success with Insulin. Torrey Pines Press.
- Davidson PC, Hebblewhite HR, Steed RD, Bode BW. Analysis of guidelines for basal-bolus insulin dosing. Endocr Pract. 2008;14(9):1095-101.
- Matthews DR, et al. Homeostasis model assessment: insulin resistance and β-cell function. Diabetologia. 1985;28(7):412-9.
- Katz A, et al. Quantitative insulin sensitivity check index. J Clin Endocrinol Metab. 2000;85(7):2402-10.
- Bergenstal RM, et al. Glucose Management Indicator (GMI). Diabetes Care. 2018;41(11):2275-80.
- Nathan DM, et al. Translating the A1C assay into estimated average glucose values. Diabetes Care. 2008;31(8):1473-8.
- Pańkowska E, Błazik M. Bolus calculator with nutrition database software. J Diabetes Sci Technol. 2010.
- NIDDK. Insulin Medicines & Treatments. Link
Last reviewed: July 2026