28-day prescription refill calculator takes the guesswork out of determining the next date you should go for your prescription refill. It’s easy. It’s accurate. Select original fill date. Click “Calculate Next Refill”.
28 Day Prescription Refill Calculator
About Our Calculator
Tracking refills is a hassle. Multiple medications have different schedules. Our calculator is handy. It simplifies 28-day refill date calculation. It ensures no medication shortage.
How to Use Our 28-Day Refill Calculator
To use the calculator, enter the date you started your current 28-day prescription supply. You can type the date or select it from the calendar. The calculator will then count forward 27 days to determine the date of your final dose for that supply.
To get your next refill start date, add one day to the final dose date. For example, if your last dose is July 5th, your next 28-day cycle starts July 6th.
Each 28-day supply should last exactly 28 days. The final dose date marks the end of that cycle. Get your refill a few days before the final dose to stay on schedule and avoid running out of medication.
How to Calculate a 28-Day Prescription Refill
Calculating your 28-day prescription refill is very easy. All you need to do is first calculate the days supply of the medication and then march it with the date on your calendar.
To calculate the day supply, use the following formula:
Days Supply = Total Quantity Dispensed / (Dosage Per Time × Frequency Per Day)
Where:
- Total Quantity Dispensed is units dispensed (e.g., 60 tablets, 32 capsules, or 100 milliliters).
- Dosage Per Time is the amount per time (e.g., 2 tablets or 10 milliliters).
- Frequency Per Day is times per day (e.g., once daily, twice daily, or three times daily).
Example Calculation
If you were dispensed 56 tablets of a medication to be taken as 1 tablet twice daily on January 1st, your next refill date for the 28-day supply will be calculated as follows:
Days Supply = Total Quantity Dispensed / (Dosage Per Time × Frequency Per Day)
Days Supply = 56 tablets / (1 tablet × 2 times per day)
= 56 tablets / 2 tablets per day
= 28 days
To determine the refill date, simply count 28 days starting from the date you took the first dose of the medication. If you took the first dose on January 1st, then your refill date will be January 28th. This date is also the date that you will take your last dose of the medication.