A FormBlends network publication

True monthly cost calculator

Turn a per-fill price into what you really pay per calendar month, per dose and per milligram. Handles insurance copays with savings-card floors and caps, LillyDirect and NovoCare self-pay tiers, the Medicare GLP-1 Bridge, and compounded vial offers with memberships, consult fees and shipping. Formula and dated assumptions shown.

By FormBlends editorial teamAssumptions checked September 4, 2026Runs in your browser; nothing is sent to a server

Your situation

Pick the strength on your prescription. Nothing is pre-selected.

days

Default 28 days (4 doses). Enter 84 or 90 for a 3-month fill.

$
$/mo

Telehealth membership, visit fee spread per month, pen needles. Leave blank for none.

True monthly cost

Select your prescribed strength and enter the price or copay per fill. Nothing is pre-filled. Results update as you type and stay in your browser.

Dated brand and program prices with sources: price index. For the network cost report see the FormBlends GLP-1 cost report.

Formulashown in full, nothing hidden
Brand fills (insurance, card, self-pay, Medicare Bridge)
  fills per year        = 365.25 / days per fill          (28-day fill: 13.045; 30-day: 12.175)
  fills per month       = fills per year / 12
  card savings per fill = min(max per fill, max(0, copay - floor))
  annual card savings   = min(annual cap, savings per fill x min(fills per year, max fills))
  average per fill      = (copay x fills per year - annual card savings) / fills per year
  monthly               = average per fill x fills per month + other monthly fees
  per dose              = monthly / (doses per fill x fills per month)
  per mg                = monthly / (doses per month x strength in mg)

Compounded vial
  mg per month          = dose x injections per week x 4.3333   (52 weeks / 12)
  vials per month       = mg per month / mg per vial   (rounded up in whole-vial mode)
  orders per month      = vials per month / vials per order   (rounded up in whole-vial mode)
  monthly               = vials x price + orders x shipping + membership + one-time fee / months spread
  per mg, all-in        = monthly / mg per month;   per mg, medication only = price per vial / mg per vial

Days per calendar month = 365.25 / 12 = 30.4375

Whole-vial mode reflects what you actually pay when a pharmacy sells whole vials and the remainder expires. Exact mode is the fair per-mg comparison between offers. Brand pens and vials are always whole fills.

Assumptions, checked September 4, 2026

  • Published self-pay prices offered by the buttons were read from the manufacturer pages listed below on the date above. They are convenience presets, not quotes; the field stays editable and nothing is entered until you click.
  • A calendar month is 365.25 / 12 days. A 28-day brand fill is 13.04 fills a year; a 30-tablet bottle is 12.18 bottles a year.
  • Savings-card arithmetic uses the floor, per-fill cap, annual cap and fill limit you enter. Cards apply only with commercial insurance that covers the product; government beneficiaries are excluded by every manufacturer program listed here. Card terms change on the manufacturer's schedule (most current cards expire December 31, 2026).
  • The Medicare GLP-1 Bridge is a flat $50 per month from July 1, 2026 to December 31, 2027 for Wegovy (pen and pill), Zepbound KwikPen and Foundayo, under CMS clinical criteria. Pen needles are not included.
  • Titration changes the strength, and with it the self-pay tier and the per-mg figure. Run the tool once per step for a month-by-month picture.
  • Compounded semaglutide and tirzepatide are not FDA approved, are priced by the pharmacy or provider rather than by a list price, and are not interchangeable with the brand products. A lower per-mg figure says nothing about quality, sourcing or safety.
  • Waste from priming, draw-up loss and partial vials is modelled only as whole-vial rounding. Insurance deductibles, coinsurance phases and plan-year resets are not modelled; enter the copay you actually pay in the phase you are in.

This calculator is an arithmetic aid for medication a licensed prescriber has already prescribed. It does not recommend a dose. Confirm any result with your prescriber or pharmacist before use.

Read before you use it

Guides for this calculator

Educational, not medical advice. Read the medical disclaimer.