Insulin Dose Calculator by Weight
Estimate your total daily insulin dose using the standard weight-based formula (0.4–0.6 units/kg/day). Educational use only.
⚖️ Dose by Weight Calculator
Estimated Results
Estimated Total Daily Dose (TDD)
(0.4 u/kg)
(0.6 u/kg)
(~50% TDD)
(~50% TDD)
How to Use This Calculator
Enter Weight
Type your weight and choose kg or lbs — values convert automatically when you toggle.
Choose Dose Factor
Select 0.5 u/kg for most adults (ADA midpoint). Use 0.2 u/kg for a conservative Type 2 starting estimate.
See the Range
Results show your specific estimate plus the full 0.4–0.6 u/kg range so you understand the clinical window.
Note Basal/Bolus Split
Roughly half of TDD is basal (long-acting), half is bolus pool (split across meals and correction).
Review the Formula
The exact calculation is shown — take a screenshot or copy it to share with your provider.
Confirm With Your Team
Bring this estimate to your next appointment. Your provider will confirm, adjust, and guide titration.
How the Dose by Weight Formula Works
Weight-based insulin dosing is the standard method for estimating a starting total daily dose (TDD) in adults newly initiating insulin therapy. The approach is grounded in the observation that insulin requirements scale roughly with body mass — larger bodies generally require more insulin to manage glucose homeostasis.
The Weight-Based TDD Formula
ADA-recommended starting range: 0.4–0.6 u/kg/day for most adults. This calculator uses 0.5 u/kg (midpoint) as the default. Worked example: 80 kg × 0.5 = 40 units/day → basal ≈ 20 u, bolus pool ≈ 20 u.
The resulting TDD is typically split approximately 50% basal (long-acting insulin given once or twice daily) and 50% bolus pool (rapid-acting insulin given at meals, divided across 3 meals as ~17% TDD each). Mealtime doses are further refined using the insulin-to-carb ratio, and correction doses use the insulin sensitivity factor — both derivable from TDD using the 500 Rule and 1800 Rule respectively.
Why the Range Is 0.4–0.6 u/kg
The 0.4–0.6 range reflects real-world variability in insulin sensitivity at the population level. A person who is more insulin-sensitive (lean, active, no metabolic syndrome) will often do well at the lower end; someone with higher insulin resistance (obesity, sedentary, Type 2 with significant beta-cell dysfunction) may need the upper end or beyond. The range is a starting window — not a ceiling or a floor. Actual TDD emerges from titration over weeks.
For insulin-naïve Type 2 patients, many guidelines recommend starting more conservatively — 0.2 u/kg/day or a fixed 10 units of basal insulin — to minimise hypoglycemia risk during initial therapy. This is available via the dose factor dropdown above.
Why Use This Tool
Shows the Full Range
Displays the low (0.4) and high (0.6) ADA estimates alongside your selected factor, not just one number.
Formula Transparency
Your exact calculation — weight, factor, TDD — is shown so you can verify or share it.
kg / lbs Toggle
Enter weight in either unit — the calculator converts without losing your entry.
Private — No Data Sent
All calculation runs in your browser. Nothing is transmitted or stored.
Limitations & Safety Notes
- Weight alone does not determine insulin need — activity, diet, and physiology all matter significantly.
- Do not apply adult weight-based formulas to children — pediatric dosing requires specialist supervision.
- Renal impairment reduces insulin clearance; standard formulas may overestimate requirements.
- This estimate does not account for current blood glucose, carbohydrate intake, or time of day.
Sources & References
- American Diabetes Association. Standards of Medical Care in Diabetes — 2024. Section 9. Link
- AACE/ACE. Comprehensive Type 2 Diabetes Management Algorithm 2020. Link
- NIDDK. Insulin Medicines & Treatments. Link
Last reviewed: June 2025
Frequently Asked Questions
How do you calculate insulin dose by weight?
Multiply body weight in kilograms by 0.4–0.6 units/kg/day to estimate total daily dose. Most adults use 0.5 u/kg as the standard midpoint (ADA guidelines). A 70 kg adult: 70 × 0.5 = 35 units/day, split as ~17.5 u basal and ~17.5 u bolus pool. Always confirm with your healthcare provider before acting on any estimate.
What is 0.5 units per kg of insulin?
0.5 u/kg/day is the midpoint of the ADA-recommended starting range (0.4–0.6 u/kg/day) for adults initiating insulin therapy. It balances efficacy against hypoglycemia risk for most adults. A 75 kg person would estimate TDD = 37.5 units/day at this factor. Real TDD is refined through titration guided by actual blood glucose readings over days to weeks.
Is insulin dose the same for all body weights?
No. Weight scales the estimate — a heavier person generally requires more insulin as a starting point — but weight is just one input. Two people of identical weight may need very different actual doses depending on diet, physical activity, insulin sensitivity, other medications, kidney function, and many other factors. Weight-based formulas are starting points, not precise prescriptions.
What is the low vs high dose range?
ADA guidelines suggest 0.4 u/kg/day as the conservative lower bound and 0.6 u/kg/day as the higher starting estimate for most adults. Insulin-naïve Type 2 patients often start at 0.2 u/kg or 10 units fixed basal to minimise hypoglycemia risk. People with significant insulin resistance may eventually require doses well above 0.6 u/kg — sometimes several units per kg per day — adjusted by their care team over time.
Should I round my insulin dose to the nearest unit?
Most syringes and pens deliver insulin in 1-unit or 0.5-unit increments, so rounding is practically necessary. This calculator rounds to the nearest 0.5 unit. Insulin pumps can deliver much smaller increments (0.025–0.1 u). Your provider will give guidance on rounding appropriate for your specific device and regimen.