Frequently asked questions
Common questions about how the calculators work and how the site is run. Each calculator page also answers questions about that calculator.
About the site
What does Peptide Dose Calculator do?
It converts a dose you already have into the volume and the units to draw on a U-100 insulin syringe, and converts units back into a dose. It also works out bacteriostatic water volumes, two-compound blends, shows the FDA label steps for semaglutide and tirzepatide, and estimates daily protein, water and calories. Every result shows the math.
Does the site recommend doses?
No. The calculators only convert numbers you enter. They never fill in a dose, a dilution or a schedule, because those depend on the product, the person and the prescriber. The semaglutide and tirzepatide schedule pages show the steps printed on the FDA labels, not a plan for any one person.
Is it free, and does it sell anything?
Every calculator is free and needs no account. The site sells nothing, has no affiliate links, accepts no sponsorship from peptide sellers and never links to sellers.
Are the compounds named on this site approved?
Some are and some aren't. Semaglutide (Wegovy, Ozempic) and tirzepatide (Zepbound, Mounjaro) are FDA-approved prescription medicines. Retatrutide is investigational and isn't FDA-approved for any use. FDA has identified safety concerns for BPC-157 and thymosin beta-4 fragment. A correct calculation can't verify what's in a vial.
The math
How do I convert mg to units on a U-100 syringe?
First find the concentration: the mg in the vial divided by the mL of total solution. Divide the dose in mg by that concentration to get mL, then multiply by 100 to get units. As arithmetic: 10 mg in 2 mL is 5 mg/mL, so 0.5 mg is 0.1 mL, or 10 units. The peptide calculator does this for you and draws the syringe.
How many units are in 1 mL?
100. On a U-100 insulin syringe, 100 units equal 1 mL, so 1 unit is 0.01 mL. That holds for 0.3 mL, 0.5 mL and 1 mL barrels alike; the barrel size only changes how many units fit.
Why can the same dose be a different number of units?
Units measure volume, not drug, so the answer depends on how concentrated the solution is. 250 mcg from a 10 mg vial with 2 mL of solution is 5 units; from a 10 mg vial with 1 mL it's 2.5 units. Always calculate from your own vial and volume.
Which calculator should I use?
For a powder vial, use the peptide calculator, or the retatrutide or tirzepatide versions with vial sizes for those compounds. For a two-compound vial, use the BPC-157 / TB-500 blend calculator. To find a solution volume for a concentration you've chosen, use the bac water calculator. For a pen, see the pen instructions page.
Privacy and corrections
Is what I enter saved or sent anywhere?
No. Every calculator runs in your browser, and the numbers you enter aren't sent to this site or anyone else. The exception is a link made with Copy result: it carries your numbers so it opens with the same result, and anyone you share it with sees them.
Does the site use cookies or ads?
No. There are no cookies, no ads and no Google Analytics. Visits are counted with Vercel Web Analytics, which sets no cookies and reports only totals. The privacy page has the details.
How are the calculations checked?
Every formula is defined once and shared by all the calculators and tables. Automated tests check each one against hand-worked values and round trips, and every number in the site's tables is recalculated before each release. A mismatch blocks the release. The editorial policy has the rest.
I found a mistake. How do I report it?
Email ezra@peptidedosecalculator.org with the page and the numbers you entered. Calculation errors are fixed first, and a page's updated date changes when its content does.