days
As written on your prescription label
Enter days supply
Enter last fill date
days
Insurance typically allows refill 2–7 days before depletion
$
For annual cost projection
Earliest Refill Date
—
⚕️ Note: Refill eligibility dates vary by pharmacy, insurance plan, and state laws. Always confirm with your pharmacy. For controlled substances, state PMP (Prescription Monitoring Program) rules apply. This calculator is for general estimation only.
Was this calculator helpful?
When Can I Refill My Prescription?
Most insurance plans allow prescription refills when you have 75%–80% of your current supply used — typically 2–7 days before running out on a 30-day supply. For controlled substances, stricter rules apply: Schedule IV medications (benzodiazepines, sleep aids) may not be refilled until within the final 7 days, and Schedule II medications (Adderall, opioids) cannot be refilled at all — each fill requires a new prescription.
Refill Date Formula
Earliest Refill Date = Last Fill Date + (Days Supply − Early Refill Buffer)
Example: Filled 30-day supply on Jan 1, 2-day buffer:
Earliest refill = Jan 1 + (30 − 2) = January 29
Depletion date = January 31 | Days until depletion from today calculated automatically
Earliest refill = Jan 1 + (30 − 2) = January 29
Depletion date = January 31 | Days until depletion from today calculated automatically
Refill Rules by Medication Type
- Non-controlled medications: Typically refillable at 75%–80% used (2–7 days early on 30-day supply)
- Schedule V (e.g., Robitussin AC): Refillable up to 5 days early; no new Rx needed for up to 5 refills
- Schedule IV (Xanax, Ativan, Ambien, Valium): No refill until within 7 days of depletion; 5 refills allowed within 6 months
- Schedule III (testosterone, anabolic steroids, Suboxone): No refill until within 7–10 days; 5 refills in 6 months
- Schedule II (Adderall, Ritalin, oxycodone, fentanyl): No refills permitted — a new prescription is required for every fill
- 90-day mail order: Usually refillable at day 68–75 of a 90-day supply (based on 75%–83% used)
💡 Save Money with 90-Day Supply: Most insurance plans offer a significant co-pay discount for 90-day mail order fills — often 2× the 30-day co-pay rather than 3×, saving you one co-pay per quarter. Many PBMs (CVS Caremark, Express Scripts, OptumRx) offer free home delivery for maintenance medications ordered through their mail pharmacy.
Popular Calculators
Related Calculators
Frequently Asked Questions
When can I refill a 30-day prescription?
Most insurance plans allow refills of 30-day prescriptions when 75%–80% of the supply is used — typically on day 22–25, which is 5–8 days before depletion. This allows 2–7 days of buffer. Your pharmacy's system calculates this automatically based on your last fill date and days supply. Cash-pay patients (no insurance) can often refill immediately upon depletion or even early, as no insurance restriction applies.
Can I refill my prescription early if I'm going on vacation?
Most insurance plans offer a vacation override exception allowing an early refill if you're traveling and will be away when the refill would normally be due. Call your insurance member line or ask the pharmacist to process a vacation override. Most plans allow 1–2 vacation overrides per year for 30-day supplies. CVS, Walgreens, and other chains typically handle this as a courtesy when you show travel documentation or simply explain your situation.
Why won't insurance let me refill my prescription yet?
Insurance refill-too-soon rejections occur when you try to fill before the plan's allowed refill date. Common causes: you filled early last month and the days supply hasn't elapsed; you received a larger days supply than usual; the previous fill date is wrong in the system. Solutions: wait until the allowed date; pay cash and switch back to insurance later; request a vacation override; or call your insurance to request an exception for documented medical necessity.
How do prescription refills work for controlled substances?
Controlled substance refill rules vary by schedule: Schedule II (stimulants, opioids) — no refills; each dispensing requires a new written or electronic prescription. Schedule III–V — up to 5 refills within 6 months of the original prescription date. After that, a new prescription is needed. States may have additional restrictions — many states limit opioid prescriptions to a 7-day supply for acute pain, regardless of what's prescribed.
What is a days supply on a prescription?
Days supply is the number of days a prescription quantity is expected to last based on the prescribed dosing frequency. It's calculated by the dispensing pharmacist: quantity dispensed ÷ doses per day = days supply. Example: 60 tablets at 2 tablets/day = 30 days supply. The days supply determines when insurance will allow the next refill. Errors in days supply calculation can cause either premature refill rejections or potential overuse coverage.
Is it cheaper to use mail order pharmacy or retail?
For maintenance medications (blood pressure, cholesterol, diabetes, etc.), mail order is almost always cheaper: typical co-pay structure is $10 retail/$20 mail order for 30/90 days — effectively a 33% savings on mail order. Mail order also eliminates pharmacy trips. Disadvantages: 7–10 day delivery time, requires planning ahead, not ideal for acute/short-term medications. Check your insurance plan's formulary and co-pay structure — some plans mandate mail order for maintenance meds after 2–3 retail fills.