The Bolus calculation is the calculation of the amount of insulin needed with a meal or to correct elevated blood sugar. It is a central component of intensive insulin therapy (ICT) and insulin pump therapy and enables precise adjustment of insulin to the amount of carbohydrate consumed and the current blood sugar level.
Basic principle of bolus calculation
A bolus usually consists of two parts:
- Meal bolus: Insulin for the carbohydrates consumed
- Correction bolus: Insulin to lower high blood sugar
Practical implementation
The calculation is based on the individual insulin-carbohydrate ratio and the correction factor. Example (with 1 KE = 10 g KH and correction factor 40 mg/dl per IU):
| situation | Calculation | Result |
|---|---|---|
| Meal with 45g carbohydrates | 45g ÷ 10g = 4.5 KE | 4.5 IU |
| Blood sugar 220 mg/dl (target 100 mg/dl) | (220 – 100) ÷ 40 = 3 IU | 3 IU |
| Total bolus | 4.5 IU + 3 IU | 7.5 IU |
Influencing factors
The bolus factors are not static and must be adjusted for:
- Time of day (often higher demand in the morning due to the dawn phenomenon)
- Physical activity (insulin sensitivity increases)
- Infections or stress
- High-fat and high-protein meals (delayed rise)
Further information:
→ Diabetes mellitus – knowledge and overview
→ Why hyporest
→ Carbohydrate unit (KE)
Sources
- German Diabetes Society (DDG). S3 guideline “Insulin therapy”. As of 2025. Available at: www.deutsche-diabetes-gesellschaft.de/leitlinien.
- American Diabetes Association. Standards of Medical Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl 1). Available at: diabetesjournals.org.
- Robert Koch Institute (RKI). Federal health reporting – diabetes mellitus in Germany. Berlin 2024.
- International Diabetes Federation (IDF). IDF Diabetes Atlas. 11th edition. Brussels 2025. Available at: diabetesatlas.org.
Important note:
The information in this encyclopedia article is intended solely for general and non-binding information. They do not replace medical advice, diagnosis or therapy. If you have any health questions or complaints, please always consult a doctor or qualified healthcare professional. The content was created with the greatest possible care, but errors cannot be completely ruled out.
Last updated: February 26, 2026
