Calculate mealtime insulin from a prescribed carbohydrate ratio and correction factor.
The bolus combines a meal component from the carbohydrate ratio and a correction component from the glucose excess. Deducting active insulin prevents stacking, which is a common cause of hypoglycaemia. Ratios and correction factors are individual, change over time and differ by time of day, so they must come from the prescriber rather than from any general rule.
Insulin Dose
Bolus = carbohydrate ÷ carb ratio + (glucose − target) ÷ correction factor − active insulin
This performs arithmetic on figures you supply and does not recommend any drug, dose or route. Medication errors can cause serious harm or death. Always verify every calculation independently, confirm against the prescription and product literature, and follow your institution's double-check procedures. Never self-medicate or alter a prescribed dose. Insulin is a high-risk medicine and dosing errors can be fatal. Use only the ratios and factors prescribed for you by your diabetes team, follow their guidance on hypoglycaemia and illness, and contact them before changing any setting. This tool does not replace your prescribed regimen or your device.
Bolus = carbohydrate ÷ carb ratio + (glucose − target) ÷ correction factor − active insulin The bolus combines a meal component from the carbohydrate ratio and a correction component from the glucose excess. Deducting active insulin prevents stacking, which is a common cause of hypoglycaemia.
Ratios and correction factors are individual, change over time and differ by time of day, so they must come from the prescriber rather than from any general rule.
This calculator takes 6 inputs: Carbohydrate in the meal, Prescribed carbohydrate ratio, Current blood glucose, Prescribed target glucose, Prescribed correction factor, Active insulin on board. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.