NovoLog Days Supply Calculator
This page explains how pharmacists calculate NovoLog days supply using insulin pen units, total daily dose, and priming considerations. Use this insulin days supply calculator to estimate the correct insulin day supply for prescriptions including priming and expiration considerations
How to calculate NovoLog days supply
Step 1: Determine total units dispensed
Multiply the number of insulin pens dispensed by the number of units contained in each pen. This gives the total insulin units available before priming or wastage adjustments.
Step 2: Calculate the total daily dose
NovoLog is often used before meals. Add together all injections given in a full day to determine the patient’s total daily dose.
Step 3: Consider priming doses
Insulin pen priming removes air from the needle before injection. When included in pharmacy workflow calculations, priming reduces usable insulin units.
See the insulin priming doses chart for reference.
Step 4: Divide usable units by total daily dose
Divide the remaining insulin units by the daily dose to estimate the patient’s NovoLog days supply.
Example NovoLog days supply calculation
- Dispensed: 5 pens
- Units per pen: 300 units
- Total units dispensed: 1500 units
- Daily insulin use: 36 units/day
If priming loss is included in your workflow, usable units may be slightly lower and the calculated days supply may decrease.
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Frequently asked questions about NovoLog days supply
How do you calculate days supply for NovoLog?
Multiply the number of pens dispensed by the units in each pen, subtract priming loss if used in your workflow, then divide by the patient’s total daily dose.
Does priming affect NovoLog days supply?
Yes. Priming uses small amounts of insulin before injections to remove air from the pen. Over multiple injections this can reduce usable insulin.
Why can NovoLog days supply be difficult to calculate?
NovoLog is often used before meals or for correction dosing, which can make total daily insulin usage vary from day to day.
Why does expiration after opening matter?
Even if the mathematical days supply is longer, insulin may expire after opening and limit how long the pen can be used.