Basal vs Bolus Split Calculator
See what percentage of your total daily insulin is basal (background) vs. bolus (mealtime), and whether your split is in the ideal range.
Educational estimator only - not medical advice.
units/day * long-acting or pump basal
units/day * add all mealtime doses
Enter your basal and bolus units above to see your split analysis.
In a basal-bolus insulin regimen, your total daily insulin (TDD) is split between background (basal) insulin that runs continuously, and mealtime (bolus) insulin taken to cover meals and correct elevated blood glucose:
The widely cited target is a 50/50 split, with an acceptable range of 40-60% basal. This reflects the idea that roughly half your insulin is needed to manage fasting glucose, and half to manage food and corrections.
A high basal percentage (>60-70%) may suggest the basal rate is absorbing some of the work that should be done by bolus doses - which can mask poor mealtime dosing or indicate basal over-dosing.
A low basal percentage (<30-40%) may indicate underdosing of background insulin, leading to high fasting glucose corrected by excessive bolus doses - a less stable pattern. Always discuss your split with your healthcare provider.
Understanding the basal-bolus concept is fundamental to flexible insulin management. Learn how to adjust your split, what different patterns mean, and how to use this information to improve your time in range - in the FOD Trilogy.
Deep Dive: FOD Trilogy - Ch 11This calculator is for educational and informational purposes only. Adjusting your basal or bolus insulin doses is a safety-critical medical decision. Changes to your insulin regimen should only be made under the guidance of your healthcare provider, endocrinologist, or certified diabetes educator. The 40-60% target is a general guideline - your individual needs may differ significantly based on your insulin type, lifestyle, and health status. This tool does not replace clinical assessment.