Insulin Dosage Calculator

Calculate your insulin correction dose based on your current blood glucose, target level, and insulin sensitivity factor.

mg/dL
mg/dL
mg/dL per unit

Quick Facts

Common ISF Range
30-100 mg/dL
per unit of insulin
Target Range
80-130 mg/dL
before meals (ADA)
1800 Rule
1800 / TDD = ISF
for rapid-acting insulin
Important
Consult Your Doctor
before making changes

Your Results

Calculated
Correction Dose
0 units
Recommended insulin
BG Difference
0 mg/dL
Current - Target
Expected Drop
0 mg/dL
Per unit of insulin

Key Takeaways

  • The correction dose formula is: (Current BG - Target BG) / ISF
  • Your Insulin Sensitivity Factor (ISF) is unique to you and prescribed by your doctor
  • The 1800 Rule: Divide 1800 by your Total Daily Dose (TDD) to estimate ISF
  • Always round down when calculating insulin doses to avoid hypoglycemia
  • This calculator is for educational purposes - consult your healthcare provider

What Is an Insulin Correction Dose?

An insulin correction dose (also called a correction bolus) is the amount of rapid-acting insulin needed to bring high blood glucose levels back to your target range. This calculation is essential for people with Type 1 diabetes and many with Type 2 diabetes who use insulin.

The correction dose works alongside your basal insulin and mealtime boluses to maintain optimal blood sugar control throughout the day.

The Insulin Correction Formula

Correction Dose = (Current BG - Target BG) / ISF
Current BG = Your current blood glucose reading
Target BG = Your target blood glucose level
ISF = Insulin Sensitivity Factor

Understanding Insulin Sensitivity Factor (ISF)

Your ISF tells you how much 1 unit of rapid-acting insulin will lower your blood glucose. For example, if your ISF is 50, one unit of insulin will lower your blood sugar by approximately 50 mg/dL.

ISF varies between individuals based on factors such as:

  • Body weight and composition
  • Level of physical activity
  • Time of day (many people are more insulin resistant in the morning)
  • Stress levels and illness
  • Hormonal changes

The 1800 Rule for Estimating ISF

If you don't know your ISF, the 1800 Rule provides an estimate for rapid-acting insulin:

ISF = 1800 / Total Daily Dose (TDD)
Example: If your TDD is 36 units, ISF = 1800/36 = 50 mg/dL per unit

Important Medical Disclaimer

This calculator is for educational purposes only. Always consult your healthcare provider or certified diabetes educator before making any changes to your insulin regimen. Individual insulin needs vary greatly, and incorrect dosing can lead to dangerous hypoglycemia or hyperglycemia.

When to Use a Correction Dose

Correction doses are typically used when:

  • Your blood glucose is above your target range before a meal
  • Your blood glucose is high between meals
  • You need to correct for high blood sugar before bedtime

Tips for Safe Correction Dosing

  • Wait before stacking: Allow 3-4 hours between correction doses to prevent insulin stacking
  • Round down: When in doubt, give less insulin rather than more
  • Consider active insulin: Account for insulin already in your system (IOB)
  • Monitor closely: Check blood glucose more frequently after corrections
  • Keep records: Track your corrections and results to optimize your ISF