Insulin Sensitive Factor Calculator

Calculate your insulin sensitivity factor (ISF) to determine how much 1 unit of insulin will lower your blood glucose level. This is an essential tool for diabetes management.

How to Use This Calculator

Enter your total daily insulin dose in units (includes both basal and bolus insulin)
Enter your current body weight in kilograms
Enter your target blood glucose level as recommended by your healthcare provider
Select a calculation method (1700 Rule is most commonly used)
Click Calculate to see your insulin sensitivity factor

Formula Used

ISF = Rule Number ÷ Total Daily Insulin Dose

Where:

ISF = Insulin Sensitivity Factor (mg/dL per unit of insulin)
Rule Number = 1700, 1800, or 1500 (depending on selected method)
For weight-based method: ISF = 100 ÷ (Total Daily Insulin Dose ÷ Body Weight)

Example Calculation

Real-World Scenario:

A person with type 1 diabetes uses a total of 40 units of insulin per day (25 units basal and 15 units bolus). They want to calculate their insulin sensitivity factor using the 1700 Rule.

Given:

Total Daily Insulin Dose = 40 units
Body Weight = 70 kg
Target Blood Glucose = 120 mg/dL
Method = 1700 Rule

Calculation:

ISF = 1700 ÷ 40 = 42.5 mg/dL per unit of insulin

Result: 1 unit of rapid-acting insulin will lower this person's blood glucose by approximately 42.5 mg/dL

Why This Calculation Matters

Practical Applications

Determining correction doses for high blood glucose
Adjusting insulin for meals with unexpected carb content
Managing sick days when insulin needs change

Key Benefits

More precise blood glucose management
Reduced risk of hypoglycemia from overcorrection
Personalized insulin dosing based on individual needs

Common Mistakes & Tips

Make sure to include ALL insulin used in a 24-hour period, including both basal (long-acting) and bolus (mealtime and correction) insulin. Forgetting to include basal insulin will result in an incorrect ISF calculation.

Your insulin sensitivity can change due to factors like illness, stress, exercise, or hormonal changes. Recalculate your ISF whenever you notice a pattern of over or under-correction of high blood glucose levels.

Frequently Asked Questions

The 1700 Rule is most commonly used and works well for many people. The 1800 Rule results in a slightly higher ISF (less insulin sensitivity), while the 1500 Rule results in a lower ISF (more insulin sensitivity). Your healthcare provider can help determine which rule is best for you.

You should recalculate your ISF whenever your total daily insulin dose changes significantly (more than 10-15%), or if you notice a pattern of over or under-correction of high blood glucose levels. Many people review their ISF every 3-6 months or when their diabetes management plan changes.

Yes, you can use this calculator if you're on an insulin pump. Your total daily insulin dose would be the sum of your basal rate and all bolus doses over 24 hours. Many insulin pumps have built-in calculators that use similar formulas, but this can be useful for verifying your pump settings or making manual adjustments.

References & Disclaimer

Medical Disclaimer

This calculator is for informational purposes only and should not replace professional medical advice. Always consult with your healthcare provider before making changes to your diabetes management plan. The results from this calculator should be used as a starting point for discussion with your healthcare team.

References

American Diabetes Association - Correction Factor - Information on insulin sensitivity factors and correction doses
Walsh J, Roberts R. "Using Insulin: Everything You Need for Success With Insulin" - Comprehensive guide to insulin therapy including ISF calculations
"Practical Guide to Insulin Therapy in Type 1 Diabetes" - Clinical guidelines for insulin management

Accuracy Notice

The insulin sensitivity factor calculated by this tool is an estimate based on standard formulas. Individual insulin sensitivity can vary significantly based on factors not accounted for in this calculator, such as time of day, recent exercise, stress levels, illness, and hormonal changes. Always verify your ISF through blood glucose monitoring and adjust based on your personal response to insulin.

About the Author

Kumaravel Madhavan

Web developer and data researcher creating accurate, easy-to-use calculators across health, finance, education, and construction and more. Works with subject-matter experts to ensure formulas meet trusted standards like WHO, NIH, and ISO.

Connect with LinkedIn

Tags:

health medical-clinical-calculators insulin sensitive factor medical body weight

Related Calculators