Rex says
Same equations the textbooks use — just way less awkward. Pop in your stats and I'll tell you what the number actually means for you.
Try a scenario
Click to load — tweak from there.Inputs
Result
Correction dose
2.6
Insulin stacking risk
No
Recommendation
Give approximately 2.6 units
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How to use this
- 1Enter current blood glucose (mg/dL).
- 2Enter target blood glucose (mg/dL).
- 3Enter correction factor (mg/dl drop per unit) (mg/dL/unit).
- 4Enter hours since last rapid-acting insulin dose (hr).
- 5Read your correction dose on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
A correction dose (also called a sliding-scale or supplemental dose) is the extra rapid-acting insulin given to bring an elevated blood glucose down to a target range, separate from any basal insulin or meal-time carbohydrate coverage. It uses the patient's correction factor (also called insulin sensitivity factor), the estimated glucose drop per unit of rapid-acting insulin, commonly derived from the "1800 rule" (1800 ÷ total daily insulin dose) for rapid-acting analogs. A correction dose should generally not be given within 3-4 hours of the last rapid-acting dose ("insulin stacking") because prior insulin may still be active and lowering glucose, risking hypoglycemia if a full correction is stacked on top. This calculator computes only the correction component — total mealtime dosing also needs a separate carbohydrate ratio calculation, and any insulin regimen should be individualized and adjusted based on glucose logs and clinical response, not applied rigidly from a single formula. This tool is for education and workflow support only — not medical advice. Always verify results with a clinician and use clinical judgment alongside your institution's protocols.
Worked example
Using the values the calculator loads with:
Inputs
- Current blood glucose: 260 mg/dL
- Target blood glucose: 130 mg/dL
- Correction factor (mg/dL drop per unit): 50 mg/dL/unit
- Hours since last rapid-acting insulin dose: 5 hr
Results
- Correction dose: 2.6
- Insulin stacking risk: No
- Recommendation: Give approximately 2.6 units
What each field means
Inputs
- Current blood glucose (mg/dL)
- The current blood glucose used in the calculation, measured in mg/dL. Starts at 260 mg/dL so you have a working example on load. Accepted range: 40–700 mg/dL.
- Target blood glucose (mg/dL)
- The target blood glucose used in the calculation, measured in mg/dL. Starts at 130 mg/dL so you have a working example on load. Accepted range: 70–200 mg/dL.
- Correction factor (mg/dL drop per unit) (mg/dL/unit)
- The correction factor (mg/dl drop per unit) used in the calculation, measured in mg/dL/unit. Starts at 50 mg/dL/unit so you have a working example on load. Accepted range: 5–200 mg/dL/unit.
- Hours since last rapid-acting insulin dose (hr)
- The hours since last rapid-acting insulin dose used in the calculation, measured in hr. Starts at 5 hr so you have a working example on load. Accepted range: 0–24 hr.
Results
- Correction dose
- Returned as a decimal number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Insulin stacking risk
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Recommendation
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How is the correction factor determined?
It's commonly estimated with the '1800 rule' for rapid-acting analog insulin: 1800 ÷ total daily dose of insulin (units) gives the expected mg/dL drop per unit. Many clinicians round or adjust this based on actual patient response, since the rule is a starting estimate, not a guarantee.
What is insulin stacking and why does it matter?
Stacking happens when a correction dose is given before the previous rapid-acting dose has finished working, effectively doubling up the glucose-lowering effect and raising hypoglycemia risk. Rapid-acting insulin analogs typically remain active for 3-5 hours, so most protocols recommend waiting at least that long between correction doses unless specifically directed otherwise.
Does this replace mealtime insulin dosing?
No. This calculates only the correction component for an elevated glucose. If the patient is also eating, a separate carbohydrate-to-insulin ratio calculation is needed for the meal, and the two components (correction + meal coverage) are typically added together into one injection.
Is a single correction factor accurate all day?
Not always — many patients have different insulin sensitivity in the morning versus evening due to the dawn phenomenon and daily activity patterns. Insulin pump users and some multiple-daily-injection regimens use time-of-day-specific correction factors rather than one fixed number.
Accuracy and limitations
- Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.
- Results do not account for medical conditions, medication, or pregnancy.
- Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Insulin Correction Dose Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/insulin-correction-dose
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/insulin-correction-dose" target="_blank" rel="noopener">Insulin Correction Dose Calculator — RevenueLab</a> (2026).</p>
Source: [Insulin Correction Dose Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/insulin-correction-dose) (2026).