Tirzepatide cost per mg runs from $7.48 to $49.90 at Eli Lilly's own cash prices for Zepbound and Mounjaro (checked 10/18/2026). The cheapest milligram is the 15 mg strength of Zepbound, if you refill on time. The most expensive is Mounjaro's 2.5 mg pen.
The spread comes from how Lilly sets prices. Zepbound's price rises with the strength, then stops at $449. Mounjaro costs $499 at every strength. Either way, the higher strengths pack more milligrams into a similar price.
This is arithmetic, not advice. Per-mg math tells you what each dollar buys. It isn't a reason to choose a strength.
How do you work out tirzepatide cost per mg?
Divide the price by the total milligrams in the supply. Every Lilly cash price we track buys four weekly doses, which Lilly counts as a month.
So the formula is: price ÷ (strength × 4).
Take the Zepbound 10 mg KwikPen at $449. Four doses of 10 mg make 40 mg. $449 ÷ 40 mg = $11.225, which rounds to $11.23 per mg.
We round to the nearest cent, and a half cent rounds up. Every figure below follows that rule.
Most results aren't that tidy. Mounjaro 7.5 mg costs $499 for 30 mg, which is $16.6333 per mg with the 3s repeating. That rounds down to $16.63.
The 4-dose count comes from Lilly's labels. The Zepbound label (revised 08/2026) says each KwikPen holds four doses, so a 10 mg pen holds 40 mg in 2.4 mL. Single-dose vials and pens hold one dose each, and a month's supply is four.
How much is Zepbound per mg?
Between $7.48 and $29.90, if you refill within 45 days. LillyDirect charges the same for the KwikPen and for vials, so one table covers both.
Zepbound KwikPen or single-dose vials on LillyDirect, refilled within 45 daysOur arithmetic: price divided by the total mg in the supply shown, rounded to the nearest cent. Prices checked 10/18/2026.
Product
mg per 28 days
Price
Per mg
Zepbound 2.5 mg$299 for 10 mg
10 mg
$299
$29.90/mg
Zepbound 5 mg$399 for 20 mg
20 mg
$399
$19.95/mg
Zepbound 7.5 mg$449 for 30 mg
30 mg
$449
$14.97/mg
Zepbound 10 mg$449 for 40 mg
40 mg
$449
$11.23/mg
Zepbound 12.5 mg$449 for 50 mg
50 mg
$449
$8.98/mg
Zepbound 15 mg$449 for 60 mg
60 mg
$449
$7.48/mg
Sources for this table
Source
What it says
Date checked
Link
LillyDirect, Zepbound page (Eli Lilly)
KwikPen and vials: $299 (2.5 mg), $399 (5 mg), $449 (7.5 to 15 mg when refilled within 45 days); regular $499 (7.5 mg) and $699 (10 to 15 mg); month = 28 days and 1 KwikPen or 4 single-dose vials
The per-mg cost falls fast as strength rises. At 2.5 mg, $299 buys 10 mg. At 15 mg, $449 buys 60 mg, six times the medicine for $150 more.
LillyDirect notes that 2.5 mg is a starting dose and is not approved as a maintenance dose. So the priciest milligram in this table belongs to a strength Lilly itself describes as a starting point.
What happens to the per-mg price if you refill late?
It jumps. LillyDirect's $449 price at 7.5 mg and up needs a refill within 45 days. After that, regular prices apply: $499 at 7.5 mg and $699 at 10 mg to 15 mg.
Zepbound when a refill comes more than 45 days after the last one (regular price)Our arithmetic: price divided by the total mg in the supply shown, rounded to the nearest cent. Prices checked 10/18/2026.
Product
mg per 28 days
Price
Per mg
Zepbound, late refill 7.5 mg$499 for 30 mg
30 mg
$499
$16.63/mg
Zepbound, late refill 10 mg$699 for 40 mg
40 mg
$699
$17.48/mg
Zepbound, late refill 12.5 mg$699 for 50 mg
50 mg
$699
$13.98/mg
Zepbound, late refill 15 mg$699 for 60 mg
60 mg
$699
$11.65/mg
Sources for this table
Source
What it says
Date checked
Link
LillyDirect, Zepbound page (Eli Lilly)
KwikPen and vials: $299 (2.5 mg), $399 (5 mg), $449 (7.5 to 15 mg when refilled within 45 days); regular $499 (7.5 mg) and $699 (10 to 15 mg); month = 28 days and 1 KwikPen or 4 single-dose vials
At 10 mg, one late refill takes the cost from $11.23 to $17.48 per mg. At 15 mg, it goes from $7.48 to $11.65.
Over a year, the refill date adds up. Lilly counts a month as 28 days, so a year takes 13 fills. At 10 mg to 15 mg, 13 on-time fills cost $5,837. Thirteen fills at the regular $699 would cost $9,087.
How much is Mounjaro per mg?
Between $8.32 and $49.90. LillyDirect sells Mounjaro single-dose pens for $499 a month at every strength, so only the milligrams change.
Mounjaro single-dose pens on LillyDirectOur arithmetic: price divided by the total mg in the supply shown, rounded to the nearest cent. Prices checked 10/18/2026.
Product
mg per 28 days
Price
Per mg
Mounjaro 2.5 mg$499 for 10 mg
10 mg
$499
$49.90/mg
Mounjaro 5 mg$499 for 20 mg
20 mg
$499
$24.95/mg
Mounjaro 7.5 mg$499 for 30 mg
30 mg
$499
$16.63/mg
Mounjaro 10 mg$499 for 40 mg
40 mg
$499
$12.48/mg
Mounjaro 12.5 mg$499 for 50 mg
50 mg
$499
$9.98/mg
Mounjaro 15 mg$499 for 60 mg
60 mg
$499
$8.32/mg
Sources for this table
Source
What it says
Date checked
Link
LillyDirect, Mounjaro page (Eli Lilly)
Single-dose pen at every strength from 2.5 to 15 mg: self-pay starting at $499/month; purchase terms define a month as four pens
Strength for strength, Mounjaro costs more per mg than Zepbound. At 2.5 mg the gap is $20.00 per mg ($49.90 against $29.90). At 15 mg it's $0.84 ($8.32 against $7.48).
Same drug, different products. Mounjaro is approved for type 2 diabetes, and Zepbound for weight management and some related conditions. You can buy only the one your prescription is for, so this comparison won't change what you can pay. Our Mounjaro cost and Zepbound price pages cover each one's savings card and coverage rules.
What does tirzepatide cost per mg at list price?
Roughly $18 per mg at the top strength, and over $100 at the lowest. Lilly's own price disclosure page blocked our check on 10/18/2026, so we used the government's TrumpRx site. It shows the same "before" or "original" price at every strength.
List prices as shown on TrumpRx.gov, for comparisonOur arithmetic: price divided by the total mg in the supply shown, rounded to the nearest cent. Prices checked 10/18/2026.
Product
mg per 28 days
Price
Per mg
Zepbound vials, 'before' price 2.5 mg$1,087 for 10 mgSame $1,087 at every strength
10 mg
$1,087
$108.70/mg
Zepbound vials, 'before' price 15 mg$1,087 for 60 mg
60 mg
$1,087
$18.12/mg
Mounjaro pens, 'original' price 2.5 mg$1,112.16 for 10 mgSame $1,112.16 at every strength
10 mg
$1,112.16
$111.22/mg
Mounjaro pens, 'original' price 15 mg$1,112.16 for 60 mg
60 mg
$1,112.16
$18.54/mg
Sources for this table
Source
What it says
Date checked
Link
TrumpRx.gov, Zepbound vial page (US government)
Vials $299 to $449 against a 'before' price of $1,087 at every strength
A flat list price means the per-mg list cost swings by a factor of six. That matters if your plan bills you coinsurance, a percentage of the price. A cash buyer on LillyDirect pays far less.
Try your own numbers
Got a price from a pharmacy, a plan or a quote? Type it in. Use the strength printed on the box and the number of doses the supply holds. For a KwikPen, or a box of four vials or single-dose pens, that number is 4.
Per-mg calculator
Type in a price from your pharmacy or a page you trust. The calculator only divides; it doesn't know any prices.
$29.90/mg$299 for 10 mg
It won't tell you whether a price is real, current or legal. Treat the answer the way we treat ours: a way to compare, not a reason to change strength.
What isn't in these per-mg prices?
Supplies, for one. LillyDirect says the KwikPen needs a pen needle purchase and vials need a needle and syringe purchase. It doesn't list their cost, so they're not in our math. The Mounjaro listing doesn't mention a needle purchase.
Taxes and fees are the other gap. Lilly's Mounjaro page says Additional taxes and fees may apply, without saying how much.
Insurance changes the math entirely. With coverage and a savings card, a fill can cost as little as $25 regardless of strength. That's covered on each product's own page.
Can you compare tirzepatide and semaglutide per mg?
Not in a useful way. Tirzepatide and semaglutide are different molecules, sold at very different strengths. A milligram of one doesn't do the same job as a milligram of the other, so their per-mg prices don't line up.
Compare monthly prices instead, and only between products your prescriber has said fit your situation. Our Wegovy price page runs per-mg math within semaglutide pens.
What about compounded tirzepatide per mg?
We don't publish per-mg prices or doses for compounded tirzepatide. FDA declared the tirzepatide injection shortage resolved on 12/19/2024, and its grace periods for compounders ended in March 2025.
FDA says compounded drugs are not FDA-approved and aren't reviewed for safety, effectiveness or quality before they're sold. Our compounded semaglutide cost page walks through the same rules for semaglutide, with dates.
Before you pay
1Use per-mg math to compare prices, not to choose a strength. Your prescriber sets the dose.
2Check the refill date. At 10 mg and up, a late Zepbound refill raises the per-mg cost from $11.23 or less to as much as $17.48.
3Add supplies to your sums. KwikPen and vial prices on LillyDirect don't include needles or syringes.
4Divide by what's actually in the box. A KwikPen holds four doses, and a box of vials or single-dose pens holds four.
5Treat any per-mg price for compounded tirzepatide with caution. FDA ended its shortage grace periods in 2025, and we don't publish compounded dosing.
How we checked
We read every price on Lilly's or the government's own pages on 10/18/2026. The milligram counts come from the FDA-approved labels. We did the division ourselves and show the inputs in every row, so you can check our math. When a price changes, we update the tables, date the correction here and add it to the price change log.
