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Prescription Refill Date Calculator: When Can I Refill My Medication?

Calculate when you can refill a prescription based on fill date, days supply, and insurance policy. Track multiple medications with status alerts.

Add Medication

How to Use This Calculator

  1. 1

    Select your insurance refill policy

    Choose Standard Insurance for most commercial plans (7-day early window), Mail-Order Pharmacy for home delivery prescriptions (14-day early window), or Controlled Substance for Schedule II–V medications (2-day window). This affects when your earliest refill date is calculated.

  2. 2

    Enter your medication name

    Type any name to identify this prescription — generic or brand name, dosage, or any label you'll recognize. For example: 'Metformin 500mg' or 'Blood pressure pill.'

  3. 3

    Set the last fill date and days supply

    Enter the date this prescription was last filled (check the bottle label). Select 30, 60, or 90 days supply, or enter a custom days supply for non-standard prescriptions. The days supply is printed on your prescription bottle label.

  4. 4

    Add medication and track multiple prescriptions

    Click Add Medication to add this prescription to your list. Repeat for each medication you take. The list is sorted by earliest refill date, with color-coded status: green = refill available now, yellow = refill due within 7 days, grey = not yet eligible.

What Each Value Means

Days Supply (days)
The number of days a prescription is expected to last at the prescribed dosage. For a 60-tablet prescription taken twice daily, days supply = 60 ÷ 2 = 30 days. Printed on your prescription bottle. Pharmacies must report days supply accurately to insurance — inaccuracies can cause early refill denials.
Early Fill Window (days before run-out)
The number of days before run-out that your insurance will allow a refill. Standard commercial insurance: 7 days. Mail-order pharmacy: 14 days (to account for shipping time). Medicare Part D: 2 days. Schedule II controlled substances: 0 days (no early fill). Exceeding the early fill window triggers a 'too soon to refill' rejection at the pharmacy.
Run-Out Date (date)
The date your current medication supply is expected to be exhausted: fill date + days supply. This is the latest you should wait to refill. Refilling on the run-out date risks a gap in therapy if the pharmacy is out of stock, has a delay, or your insurance requires prior authorization renewal.

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Frequently Asked Questions

How early can I refill a 30-day prescription?
Most insurance plans allow you to refill a 30-day prescription 7 days early — on day 23 of your 30-day supply. This means if your prescription was filled on May 1, your earliest refill date would be May 24. Mail-order pharmacies typically allow 14 days early to account for shipping time. Medicare Part D allows only 2 days early (day 28).
How do I calculate my prescription refill date?
Your refill date = fill date + days supply − early fill window. For a 30-day supply filled May 1 with standard insurance (7-day early window): May 1 + 30 days = May 31 (run-out date). May 31 − 7 days = May 24 (earliest refill). Your pharmacy can deny a fill if you request it before this date. The calculator on this page computes this automatically for multiple medications at once.
Can I refill a controlled substance prescription early?
Controlled substances have strict refill rules. Schedule II substances (Adderall, oxycodone, Ritalin) cannot be refilled early — they require a new prescription each time and many states prohibit electronic prescribing. Schedule III–V substances (Xanax, Tylenol with codeine, Ambien) may be refilled up to 2 days early, but this is at the pharmacist's discretion and varies by state. Insurance plans may have even stricter rules than state law.
What is 'too soon to refill' at a pharmacy?
'Too soon to refill' means your insurance has denied the claim because your refill request was submitted before your early fill window opened. Your pharmacy's point-of-sale system checks with your pharmacy benefit manager (PBM) in real time. You can pay cash at full price to fill early, or wait until your eligible date. Some plans allow a 'vacation supply override' once per year.
How does mail-order pharmacy refill timing work?
Mail-order pharmacies (CVS Caremark, Express Scripts, OptumRx) allow 14-day early refills because prescriptions are mailed and take 5–10 business days to arrive. For a 90-day supply running out July 14, order by June 30. Most mail-order pharmacies send auto-refill reminders 2–3 weeks before your run-out date. Standard retail pharmacies typically only allow 7-day early fills.
Does my refill date reset if I switch pharmacies?
Your refill eligibility is tracked by your pharmacy benefit manager (PBM), not the individual pharmacy. Most PBMs track fills across all network pharmacies, so switching pharmacies doesn't reset your early fill window. However, if you switch insurance or PBMs, the new plan typically won't have your previous fill history and you may be able to fill immediately. Always check with your new pharmacist.