Total Daily Dose (TDD) Estimator

The Total Daily Dose (TDD) of insulin is the combined amount of basal (background) and bolus (mealtime/correction) insulin required in a 24-hour period. While TDD varies wildly based on insulin resistance, this tool provides a starting clinical estimate based on body weight for patients initiating insulin therapy.

The Math (Manual Calculation)

A common starting formula for an adult with Type 1 Diabetes is 0.55 × Weight in Kilograms = TDD.

For Type 2 Diabetes, where insulin resistance is a factor, multipliers range from 0.8 to 1.2+ units/kg.

In intensive insulin therapy, the TDD is generally split 50/50: half as basal (long-acting) insulin, and half distributed as rapid-acting boluses across meals.

Why It Matters

Knowing your TDD is the prerequisite for calculating almost all other insulin dosing metrics. Without a solid TDD baseline, you cannot accurately calculate your Carb Ratio or Correction Factor using standard clinical rules.

Common Mistakes

• Sticking strictly to the estimate: This is only a starting point. TDD is dynamic; it drops significantly with exercise and rises during illness, stress, or menses.
• Over-basalization: The 50/50 rule is a guideline. If your basal insulin makes up 70% of your TDD, you are likely covering meals with basal insulin, leading to daytime hypoglycemia. Basal insulin should hold your blood sugar steady while fasting.

Frequently Asked Questions (FAQ)

Does weight loss change my TDD?

Yes. Weight loss, especially in Type 2 diabetes, reduces insulin resistance, meaning less insulin will be required to achieve the same glycemic control.