The mealtime dosage calculator is intended as an aid in figuring mealtime rapid-acting insulin requirements. It should only be used under the supervision and guidance of your health care team.

Choose the version that applies to your units of measure. Please read the “Instructions” for directions on how to use the calculator.

*The first is calculated using mg/dl and the second is calculated using mmol.

Mealtime Dosage Calculator Instructions


Do not use the Mealtime Dosage Calculator without first discussing your exact insulin requirements with the clinician who prescribes your insulin.  All values entered into the calculator should be determined with the guidance of your health care team.

note:  the Mealtime Dosage Calculator will work on most major spreadsheet programs, including Excel.

To Use The Mealtime Insulin Dose Calculator:

1. You will need to enter your insulin dosage formulas into the boxes in the top left. Information can only be entered in the YELLOW boxes.

First, enter the meal/situation that the chart applies to.  For example, “breakfast” or “lunch before exercise” or “all meals”.

Second, enter your target blood glucose (your “ideal value”).  This should be one exact number in mg/dl, such as “100” or “120”.

Third, enter your sensitivity factor.  This is the amount that one unit of insulin lowers your blood glucose.

Fourth, enter your carb:insulin ratio.  This is the grams of carbohydrate “covered” by one unit of insulin.

Fifth, enter an exercise factor (if needed).  An exercise factor of 1.00 means that you will not be exercising and want to take your usual dose.  If you want to lower your doses by 25% in anticipation of exercise, enter “.75”.  If you want to lower your doses by 33%, enter “.67”.  If you want to take half of your usual doses, enter “.50”.

2. The numbers on the large chart will update to reflect your mealtime insulin doses based on the parameters entered above.  Find the grams of carbohydrate in the top row (in orange) and the current blood glucose level (B.G.) in the left column.  Line up the row corresponding to your BG with the column corresponding to your carbs to find your insulin dose.

Note:  any values in red and in parentheses (in the top left corner of the chart) represent negative values.  If your dosage is a negative value, you should not take any insulin. Instead, you should consume more carbohydrates than originally planned in order to return your blood glucose to a safe level.

3. The “Quick Calculator” (near the top center, in the black box) is designed to give you an exact dosage for a specific combination of carbs and blood glucose.  Enter the carbs and current blood glucose in the yellow box, and your precise mealtime dose will appear just below in the blue box.

4. The Unused Insulin (I.O.B., or Insulin On Board) Calculator in the top right area lets you estimate the amount of insulin that is still active in your body from a dosage that was given previously (within the past 3 hours).  Enter the number of rapid-acting insulin units given previously.  Then determine how many hours have passed since this insulin was given.  Below the time (in the purple area) is the approximate number of units that are still working.

It is usually advisable to deduct the Unused Insulin from any dosage that you would normally give according to the dosage calculation chart.

For example, if you need 5.0 units to cover your current blood glucose and carb intake, but you also have 2.0 units of Unused Insulin, you should take 5.0 – 2.0, or 3.0 units.

The Unused insulin calculation applies only to rapid acting insulin (aspart, lispro, glulisine).  It does not apply to Regular or NPH insulin.  Also, the actual duration of insulin action can vary from person to person.  Check with your health care team before applying the unused insulin calculation to your own dosing schedule.

For more information, contact: Integrated Diabetes Services

333 E. Lancaster Ave., Suite 204,
Wynnewood, PA 19096

(877)735-3648 or (610) 642-6055