Days’ Supply Calculator for Pharmacy Claims (US)

About the Days’ Supply Calculator for Pharmacy Claims (US)

Works out the days’ supply to put on a pharmacy claim from the quantity dispensed and the directions already written on the prescription: tablets and capsules, liquids, insulin pens and vials (with the priming units before each injection and the days a pen or vial may be used once opened), inhalers (actuations per canister, less priming sprays), eye and ear drops (with the drops-per-ml figure your pharmacy uses) and creams or other measured products. Choose how to round, and with a fill date see the last day covered, when the next fill is due and the earliest refill at your plan’s share.

It is arithmetic on the prescriber’s directions, for billing accuracy: it never chooses, checks or changes a dose. Without a pass it shows a free preview — the days’ supply in full, the working and the dates hidden — and copying the full working unlocks with a Pro pass.

Common uses

• A pharmacist or technician entering the days’ supply on an insurance claim.
• Checking a claim rejected as refill too soon against the supply actually dispensed.
• Working out how many insulin pens or inhalers cover a 30- or 90-day fill.

How the days’ supply is worked out

The days’ supply is how long the quantity dispensed lasts at the prescribed daily use. CMS’s Medicare Prescription Drug Benefit Manual, chapter 6 uses it that way: “30 tablets for a 30 day supply (i.e., 1 tablet daily)”, and plans check refills against the supply as determined by the prescribed daily dose.

• Tablets, capsules, liquids, creams: quantity ÷ (amount each time × times a day).
• Insulin: units dispensed (pens or vials × ml × units a ml) ÷ (units a day + priming units × injections a day). When a pen or vial would last longer than the in-use period its labeling gives once opened, each one counts only that many days.
• Inhalers: (actuations a canister − priming sprays) × canisters ÷ (puffs each time × times a day).
• Drops: ml × drops a ml ÷ (drops each time × eyes or ears × times a day).

Refill dates

With a fill date, the supply covers that day and the days after it: a 30-day supply filled on the 1st covers to the 30th and the next fill is due on the 31st. Plans use early-refill edits to stop refills that come too soon (CMS chapter 6, section 30.4), and each plan sets the share of the supply that must be used first — enter your plan’s figure to see the earliest day a refill would pass it. A dose increase or a change of level of care can justify an earlier fill; that is between the pharmacy and the plan.

The figures it needs from you

Priming units, actuations per canister, in-use periods and drops per ml come from the product’s labeling and your pharmacy’s own practice — they differ by product, device and bottle. Enter them every time; the calculator holds no product data.

Limitations

• It does the arithmetic on the directions you enter; it does not check the dose, the quantity limits of a plan or what a plan will pay.
• Tapering doses, alternate-day doses and weekly doses need their own average daily use, or a pharmacist’s judgement.
• It holds no product data: priming, actuations, in-use periods and drops per ml come from the labeling and your pharmacy.

Privacy

Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.