Last Updated on July 31, 2025
Total Daily Dose (TDD) is the total insulin used in 24 hours, vital for managing diabetes. Also called Total Insulin, 24‑Hour Total, or Daily Insulin Requirement, TDD varies by age, device, and therapy. This article explains TDD and its uses, shows differences across patient profiles (basal vs bolus), highlights recent advances in insulin dosing algorithms and AID systems, and points to clinical trials and ADA standards for reference.
What Is TDD?
Total Daily Dose (TDD) refers to the total amount of insulin taken over 24 hours. It includes:
- Basal insulin – background coverage throughout the day and night
- Bolus insulin – in response to meals or to correct high blood sugar
In pump reports like Tandem’s t:slim X2, it may be labeled Total Insulin, but clinical studies often use TDD, 24‑Hour Total, or Daily Insulin Requirement.
Why It’s Important
- Starting and adjusting insulin: Helps estimate basal/bolus splits and carb ratios (e.g., Insulin to Carb Ratio (ICR or Carb Factor) = 450 ÷ TDD; Correction Factor (Insulin Sensitivity Factor/ISF) = 1800 ÷ TDD).
- Evaluating insulin sensitivity: A lower TDD per kg often means a more sensitive metabolism.
- Tuning Automated Insulin Delivery (AID) systems: Algorithms in hybrid closed‑loop pumps rely heavily on accurate TDD values.
How to Find Your Total Daily Dose (TDD)
Your TDD is the total amount of insulin you use over 24 hours. Here’s how to calculate it:
For Insulin Pump Users
- Go to your pump history screen or download your data using the pump software (e.g., t:connect, CareLink).
- Look for “Total Insulin” or “24-Hour Total”—this includes both basal and bolus insulin.
- To get an average TDD, review data over 7 or 14 days and calculate the daily average.
For People Using Injections (MDI)
- Add up all basal (long-acting) insulin taken in 24 hours (e.g., Lantus, Tresiba).
- Add all bolus (rapid-acting) insulin given before meals or for corrections.
- The total of basal + bolus = your TDD.
- Optional: average several days for a more stable number if your doses vary.
Example: If you take 22 units of basal insulin and 18 units of bolus insulin per day, your TDD is 40 units.
Basal vs. Bolus: How It Varies by Age & Device
| Profile | TDD (U/kg/day) | Basal % | Bolus % | Notes |
|---|---|---|---|---|
| Adult (MDI or Pump) | 0.4–0.6 | 40–50% | 50–60% | Stable routines; balanced split |
| Child (MDI or Pump) | 0.5–1.0 | 30–40% | 60–70% | Growth and activity drive variability |
| AID Adult | 0.35–0.6 | 30–45% | 55–70% | Auto-adjustments reduce TDD needs |
| AID Child | 0.45–0.9 | 25–35% | 65–75% | Hormones and meals need bolus accuracy |
Common Alternative Terms for TDD
- Total Insulin – Tandem t:slim X2 / Control‑IQ
- 24‑Hour Total – CareLink, Tidepool, pump reports
- Daily Insulin Requirement, Total Units per Day, Insulin Total – EMR and clinical documents
- Average Daily Dose (ADD) – Multi-day averages in research
Strategies for Improving Your TDD (from Pumping Insulin, 7th Ed.)
This guidance is adapted from the 7th edition of Pumping Insulin, a trusted and widely used resource among healthcare professionals and people with diabetes for its practical, evidence-based insulin strategies.
A. Are you already at your goal?
- If TIR >70% and GV <30%, your TDD is well-tuned.
- Consider improving further by increasing your TDD 5–10% and updating settings.
B. Are you having frequent lows?
- If you spend >4% time <70 mg/dL, reduce your TDD by 5–10%.
- Adjust basal/bolus balance—lower the one contributing most to the lows.
- Temporarily raise your glucose target and extend DIA to prevent insulin stacking.
| 9.4 For Frequent Lows, Reduce Your TDD | ||||||
|---|---|---|---|---|---|---|
|
Reduce your TDD by 5% or 10% for frequent lows that are mild or more severe, respectively. Find your current average TDD in the left column and go across for a lower TDD from which to get new pump settings in Table 9.7. Multiply your current average TDD by 0.95 for a 5% reduction or by 0.90 for a 10% reduction, as shown in the table below. _____ u/day × 0.95 (or 0.90) = _____ u/day |
||||||
| Current Avg. TDD | 5% Lower TDD | 10% Lower TDD | Current Avg. TDD | 5% Lower TDD | 10% Lower TDD | |
| 20.0 u | 19.0 u | 18.0 u | 55.0 u | 52.4 u | 50.5 u | |
| 25.0 u | 23.8 u | 22.5 u | 60.0 u | 57.1 u | 54.0 u | |
| 30.0 u | 28.5 u | 27.0 u | 65.0 u | 61.9 u | 58.5 u | |
| 35.0 u | 33.3 u | 31.5 u | 70.0 u | 66.7 u | 63.5 u | |
| 40.0 u | 38.1 u | 36.0 u | 80.0 u | 76.2 u | 72.0 u | |
| 45.0 u | 42.9 u | 40.5 u | 90.0 u | 85.7 u | 81.0 u | |
| 50.0 u | 47.6 u | 45.0 u | 100.0 u | 95.0 u | 90.0 u | |
| My new better TDD = ______ units/day. | ||||||
| Keep lowering your TDD every four to seven days until the lows largely disappear. Each time you lower your TDD, use the better TDD to find more appropriate BC settings in Table 9.7. | ||||||
C. Are you at your goal but have excess Glucose Variability?
- If GV >30%, even with good average glucose, focus on stability.
- Bolus early, eat consistent meals, and use settings matched to your TDD.
D. Do you have a high average glucose?
- Calculate your glucose elevation (avg glucose – goal), then multiply your current TDD by a % from Table 9.6.
- Alternatively, use the One-for-Five Rule: Raise TDD by 1% for every 5 mg/dL above goal.
Refine your Correction Factor for a better TDD
CorrF = Correction Factor Scale Number ÷ TDD
To correct for high average glucose, use a lower CorrF-SN (e.g., 1700 instead of 2000) as glucose levels increase. This allows more aggressive correction boluses that match higher insulin needs.
Example: If your Correction Factor Scale Number is 1800 and your TDD is 50 units, then CorrF = 1800 ÷ 50 = 36 mg/dL per unit. This means 1 unit of insulin is expected to lower your glucose by about 36 mg/dL.
Use the Online Tool
Visit our interactive tool to calculate better TDDs, basal rates, CarbFs, and CorrFs based on your current data.
Conclusion
Total Daily Dose (TDD) is a key metric in insulin therapy, influencing carb ratios, correction factors, and algorithm performance. Whether you’re using MDI, pumps, or AID, knowing your TDD—and how it’s labeled—helps fine-tune your insulin plan. Advances in AI, longer-acting insulins, and CGM-integrated systems promise even greater control for those living with diabetes.