Prescription Refill Calculator

Calculate next refill dates and medication days supply for prescriptions and over-the-counter medications

Prescription Refill Calculations

The date you received/started your current prescription

Number of days the medication should last

Example: 30-Day Prescription

Patient Scenario

Medication: Blood pressure medication

Fill date: January 1, 2024

Quantity: 30 tablets

Directions: Take 1 tablet once daily

Calculation Results

Days supply: 30 tablets ÷ (1 tablet × 1 time/day) = 30 days

Next refill date: January 1 + 30 days = January 31, 2024

Refill reminder: Contact pharmacy around January 28-29

Common Prescription Periods

7 daysShort-term/Acute
14 daysAntibiotics
28 daysBirth control
30 daysMost common
90 daysChronic conditions

Refill Management Tips

Set reminders 3-5 days before refill date

Check insurance coverage before refilling

Keep track of remaining refills on prescription

Use pharmacy apps for automatic refill reminders

Consider 90-day supplies for chronic medications

Never stop medications without consulting your doctor

Understanding Prescription Refills

Days Supply Calculation

Days supply determines how long your medication will last based on the prescribed dosing regimen. This calculation is essential for planning refills and ensuring continuous therapy.

Prescription vs. OTC Medications

  • Prescription (Rx): Requires doctor's authorization, stronger medications
  • Over-the-Counter (OTC): Available without prescription, generally milder
  • Both types can benefit from refill tracking and supply calculations

Calculation Formulas

For Tablets/Capsules:

Days Supply = Total Tablets ÷ (Tablets per Dose × Doses per Day)

For Liquids:

Days Supply = Total Volume ÷ (Dose Volume × Doses per Day)

Dose Volume = Dose (mg) ÷ Concentration (mg/ml)

Important: This calculator is for planning purposes only. Always follow your healthcare provider's instructions and consult your pharmacist for medication-specific questions.