Insulin Sensitive Factor Calculator

The Insulin Sensitivity Factor Calculator estimates your specific ISF based on total daily insulin dose, body weight, and target glucose. This tool helps people with Type 1 and Type 2 diabetes determine exactly how much one unit of insulin lowers blood sugar. Whether you are calculating a correction dose for high glucose, adjusting for unexpected meals, or managing sick days, this calculator provides precise insulin dosing support.

Total amount of insulin you use in a 24-hour period (both basal and bolus)
Your current body weight in kilograms
Your target blood glucose level as recommended by your healthcare provider

How Insulin Sensitivity Factor Is Calculated

Insulin Sensitivity Factor (ISF) measures how many milligrams per deciliter (mg/dL) one unit of insulin will lower your blood glucose level. This calculation typically uses the "1700 Rule" or similar medical formulas to establish a personalized correction factor.

ISF = Rule Number ÷ Total Daily Insulin Dose

Where:

  • Rule Number = 1700, 1800, or 1500
  • Weight-based: ISF = 100 ÷ (Total Daily Insulin Dose ÷ Body Weight)

The calculator determines your total daily insulin usage to gauge your overall sensitivity. Then, it divides a standard rule number by this total to estimate the precise effect of one unit of insulin. This method provides a reliable baseline for managing blood sugar levels effectively.

What Your Insulin Sensitivity Factor Means

Your ISF tells you exactly how many mg/dL your blood sugar will drop with each unit of rapid-acting insulin. A higher number means you are more sensitive to insulin, while a lower number indicates more resistance.

Correcting High Blood Sugar

If your blood sugar is 200 mg/dL and your target is 100 mg/dL with an ISF of 50, you need 2 units to bring it down. To find this, subtract your target from your current glucose and divide by your ISF.

Adjusting for Meals

If you eat more carbohydrates than planned, you can use your ISF to calculate extra insulin. For example, if your ISF covers 10g of carbs per unit, you can add units to cover the excess food intake.

This calculator is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before making changes to your diabetes management plan to ensure your safety.

Monitor your blood sugar 2-3 hours after taking a correction dose to verify your ISF is accurate, and adjust your plan as needed with your doctor's help.

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