Type 2 Diabetes Insulin Calculator
Estimate a starting basal (long-acting) insulin dose for type 2 diabetes, with a simple titration plan to reach your fasting glucose target.
How to Use This Calculator
- Enter your body weight in kilograms.
- Choose a starting method — a fixed 10 units/day start, or a weight-based 0.1–0.2 units/kg/day estimate.
- Read the starting basal dose, then follow the titration guidance to adjust toward your fasting glucose target.
This estimates a starting basal dose for discussion with your provider — it does not replace their prescription, target, or titration plan.
How Insulin Is Started in Type 2 Diabetes
Type 2 diabetes is treated with insulin differently from type 1. Most people start with a single basal (long-acting) insulin added to their oral medications — not a full basal-bolus regimen. The starting dose is deliberately conservative and then titrated upward to bring the fasting morning glucose into target.
Example: a 90 kg person at 0.1 u/kg → 9 units/day to start; at 0.2 u/kg → 18 units/day. The fixed "10 units" start is also widely used.
This contrasts with type 1 diabetes, which usually begins at about 0.5 units/kg/day split between basal and mealtime insulin. If basal insulin alone can't control after-meal glucose, mealtime insulin or other agents may be added later — see the basal-bolus calculator.
Titrating to Target
| Fasting glucose pattern | Typical adjustment |
|---|---|
| Consistently above target | Increase by ~2 units every 3 days |
| In target, stable | Hold the dose |
| Below target or any lows | Decrease and review with your provider |
Some regimens titrate by larger steps or weekly; always follow the specific plan your care team gives you.
When Is Insulin Needed in Type 2 Diabetes?
Insulin is usually not the first treatment for type 2 diabetes — metformin, then other tablets and often a GLP-1 receptor agonist, come first. Insulin is added when those are not enough or when glucose is very high.
Common reasons to start basal insulin
- A1c stays above target despite oral medicines and lifestyle changes.
- Very high glucose at diagnosis — for example A1c above 10% (86 mmol/mol) or glucose over ~300 mg/dL, especially with symptoms like thirst, frequent urination or weight loss.
- Ongoing weight loss or symptoms of high glucose that suggest the body is short of insulin.
- Times when tablets aren't suitable, such as serious illness, hospital stays, or pregnancy.
Basal (long-acting) insulin options
Most people start with one long-acting basal insulin: glargine (Lantus, Basaglar, Semglee), detemir (Levemir), ultra-long-acting degludec (Tresiba), or concentrated glargine U-300 (Toujeo). Intermediate-acting NPH is a lower-cost alternative. Your provider chooses based on cost, hypoglycemia risk and dosing convenience.
Frequently Asked Questions
What is the starting insulin dose for type 2 diabetes?
Basal insulin is usually started at 10 units per day, or 0.1–0.2 units per kg per day. A 90 kg person might start around 9–18 units, then titrate up by about 2 units every 3 days to reach a fasting glucose target.
How is type 2 insulin different from type 1?
Type 2 usually begins with basal insulin alone added to oral medicines, at a low starting dose. Type 1 requires full basal-bolus insulin from the start (about 0.5 units/kg/day split between basal and mealtime doses) because the body makes little or no insulin.
How do I titrate my basal insulin?
A common plan is to increase the dose by about 2 units every 3 days while fasting glucose stays above target, holding when in range and reducing if lows occur. Your provider sets your target and the exact titration steps.
Will I need mealtime insulin too?
Not always. Many people do well on basal insulin plus oral medicines. If after-meal glucose stays high once fasting glucose is controlled, your provider may add mealtime (bolus) insulin or other medications.
Does starting insulin mean my diabetes has gotten worse?
Not necessarily, and it isn't a personal failure. Type 2 diabetes tends to progress over time as the pancreas makes less insulin, so many people eventually need it regardless of how well they manage. Insulin is simply the most effective tool to bring glucose back to target and protect against complications.
Can I stop insulin once I start it?
Sometimes. If insulin was started for a temporary reason — very high glucose at diagnosis, illness, surgery or pregnancy — it can often be reduced or stopped later. Significant weight loss and other glucose-lowering medications can also lower or remove the need for insulin. Any change must be made with your provider, never on your own.
Sources
- American Diabetes Association. Standards of Care in Diabetes — 2024. Section 9 (Pharmacologic Approaches to Glycemic Treatment).
- Davies MJ, et al. "Management of hyperglycaemia in type 2 diabetes: ADA/EASD consensus report." Diabetes Care. 2022.
Last reviewed: June 2025