6 Peptide Dosing Calculators Worth Bookmarking Before You Reconstitute Anything
Peptide dosing tools earn their keep when they turn vial size, water volume, and prescribed dose into a syringe mark. That sounds basic until someone is staring at a 5 mg vial and trying not to confuse milligrams, micrograms, and units.
What I Looked At
Six publicly accessible peptide reconstitution and dosing calculators, evaluated on: whether the math is visible or hidden, which peptides and syringe types are supported, whether a real organization stands behind the page, and whether the tool handles the unit conversion problem that trips up most first-timers.
The 6 Tools
1. FormBlends Peptide Calculator
Most web calculators spit out an answer without showing their work. This one shows you every step of the math, which means you can catch an input error before it becomes an injection error. You type in the vial size (mg or mcg), the volume of bacteriostatic water added, and your target dose. It returns the concentration per mL, the exact units to draw, and the total number of doses in the vial. Simple enough. What makes it worth the top spot here is the combination of things that are usually missing from free tools: it handles U-100, U-50, and U-40 syringes rather than assuming everyone owns the same insulin syringe, and it quietly auto-converts between mg and mcg so you cannot accidentally enter “500” thinking micrograms when the field expects milligrams. That specific confusion, 1 mg versus 1,000 mcg, is the most common dangerous math error in home peptide use, and it is baked into the tool’s design to prevent it. One-tap presets cover BPC-157 (5 mg and 10 mg vials), TB-500, ipamorelin, tesamorelin, and a GLP-1 option at 50 mg. A visual syringe fill bar shows where the dose lands on the barrel. The tool also explains, in plain text, that adding more BAC water to a vial changes which unit line you draw to but does not change the total amount of peptide you inject. That’s a fact a lot of people learn the hard way. FormBlends is a 503A compounding pharmacy, so this isn’t an anonymous side project. The same calculator lives inside their iOS and Android tracking app, which adds a 55-compound library, dose logging, and an injection-site rotation map. No signup required for the web version.
2. PeptideFox
PeptideFox (peptidefox.com) covers more than 30 peptides and is one of the few free tools that actively optimizes the BAC water volume to produce clean, whole-unit draws on a U-100 syringe. That detail matters. Drawing 37.5 units is harder to eyeball accurately than drawing 40. The site also includes a visual guide to syringe markings. No app, no logging, but the peptide breadth is real.
3. PeptideDeck
Three fields: vial size in mg, BAC water added in mL, target dose in mcg. PeptideDeck returns concentration, draw volume, and the insulin unit equivalent. Stripped down and fast. It does not explain the math or handle multiple syringe types, but for someone who already understands reconstitution and just wants a quick number, it does the job without clutter.
4. MyPeptideMatch
Free, no account needed. MyPeptideMatch covers BPC-157, TB-500, semaglutide, tirzepatide, and other injectables, which makes it one of the few tools that bridges the gap between healing peptides and GLP-1 class compounds in one place. Useful if you are working with more than one type at the same time.
5. LeadWest Medical Calculator
LeadWest Medical’s calculator lists retatrutide, BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, sermorelin, and GHK-Cu. The fact that it comes from a named medical provider rather than an anonymous domain gives it some credibility. Coverage is solid for common research peptides and growth hormone secretagogues.
6. Outliyr Peptide Calculator
The Outliyr tool includes entries for BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, GHK-Cu, and GLP-1 class peptides. The page is content-heavy, which can be useful context for someone new to the category and distracting for someone who just needs a number. Worth knowing about, particularly for GHK-Cu, which fewer tools include.
How to Choose
If you want the math explained and multiple syringe types supported, FormBlends Peptide Calculator is the clearest option with an identifiable company behind it. If you need 30-plus peptide options and want the BAC water volume optimized for clean draws, PeptideFox fills that gap. For GLP-1 compounds alongside traditional peptides, MyPeptideMatch and Outliyr both cover that ground. None of these tools tell you what dose to take. That question belongs to a qualified prescriber.
Common Questions
Does it matter which syringe type I tell the calculator I’m using?
Yes, and getting this wrong is a real problem. A U-40 syringe has 40 units per mL, a U-100 has 100. If you enter U-100 but actually draw with a U-40, you will inject 2.5 times your intended dose. Only FormBlends and PeptideFox explicitly account for different syringe types. Every other calculator here assumes U-100.
If I add more BAC water than the calculator assumes, do I need to recalculate everything?
Yes, always. BAC water volume sets the concentration of your vial. Add 2 mL instead of 1 mL and your concentration drops by half, so every draw volume doubles to hit the same dose. FormBlends explains this directly inside the tool. The others return a number based solely on what you enter, so any change in water volume requires a fresh calculation.
Can I use PeptideFox or PeptideDeck for semaglutide and tirzepatide, or only for traditional peptides?
PeptideDeck and PeptideFox are built primarily around traditional research peptides like BPC-157, TB-500, and growth hormone secretagogues. For GLP-1 class compounds like semaglutide and tirzepatide, MyPeptideMatch and Outliyr are the better fits among the tools listed here, and FormBlends includes a 50 mg GLP-1 preset as well.
Is the FormBlends calculator only useful if I buy from FormBlends, or is it genuinely independent of their products?
The web calculator requires no account, no purchase, and no personal information. You can use it for any vial from any source. The fact that FormBlends is a 503A compounding pharmacy means there is a licensed entity behind the tool, but the calculator itself does not lock you into their products or ask you to buy anything.
Why does PeptideFox optimize BAC water volume, and should I let it override my own reconstitution plan?
PeptideFox adjusts the suggested BAC water amount so your draw lands on a clean whole-unit mark on a U-100 syringe, which reduces measurement error. Whether you follow that suggestion depends on your vial size and dose. If your prescriber or protocol specifies a particular reconstitution volume, follow that. The optimization is a convenience, not a clinical directive.
Sources
- PeptideFox, peptidefox.com (peptide calculator, publicly accessible)
- MyPeptideMatch, publicly accessible web tool
- LeadWest Medical, publicly accessible calculator page
- Outliyr, publicly accessible peptide dosing tool
- PeptideDeck, publicly accessible web calculator
- FormBlends, publicly accessible web calculator and mobile app (iOS/Android)